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    PESTICIDE RESIDUES IN FOOD - 1980


    Sponsored jointly by FAO and WHO






    EVALUATIONS 1980





    Joint meeting of the
    FAO Panel of Experts on Pesticide Residues
    in Food and the Environment
    and the
    WHO Expert Group on Pesticide Residues
    Rome, 6-15 October 1980




    OXAMYL

    IDENTITY

    Chemical names

    N,N-dimethyl-2-methylcarbanoyloxyimino-2-(methylthio)acetamide
    (IUPAC)
    Methyl N',N'-dimethyl-N-[(methylcarbamoyl)oxy-i-thio-
    oxamimidate S-methyl-1-(dimethylcarbamoyl)-N-[(methylcarbamoyl)
    oxy] thioformimidate 2-dimethylamino-1-(methylthio) glyoxal 
    O-methylcarbamoylmonoxime

    Synonyms

    VydateTM, D-1410, DPX 1410, Du Pont 1410

    Structural formula



    Molecular formula:  C7H13N3O3S

    Molecular weight:   219.3

    Description:        slightly sulphurous

    Melting point:      100-102 changing to a different crystalline
    form                which melts at 108-110

    Specific gravity:   0.97 25/4

    Vapour pressure:    2.3  10-4 mm Hg at 25C
                        3.75  10-4 mm Hg at 30C
                        8.4  10-4 mm Hg at 40C
                        7.6  10-3 mm Hg at 70C

    Solubility at 25C    g/100 g Solvent

    Methanol                    144
    DMF                         108
    Acetone                      67
    Ethanol                      33
    Cyclohexanone                29
    Water                        28
    Isopropanol                  11
    Toluene                       1

    Oxamyl is commercially available as a 24% liquid formulation and a
    10% granular formulation.  The liquid formulated material is a
    clear liquid before colour addition.

    No information was available on the manufacturing process, inerts
    or technical impurities.

    DATA CONSIDERED FOR DERIVATION OF ACCEPTABLE DAILY INTAKE

    BIOCHEMICAL ASPECTS

    Absorption, distribution, excretion and biotransformation

    A male Charles River CD rat was given 50 mg/kg non-radiolabelled
    oxamyl in the diet.  Thirty-two days later, the rat received by
    intragastric intubation 2 ml of peanut oil containing 1.0 mg (3.74
    Ci) of [14C]oxamyl.  A second rat was preconditioned for 18 days
    on a diet containing 150 mg unlabelled oxamyl/kg feed.  This animal
    was treated like the first with 1.03 mg (5.6 Ci) of [14C]oxamyl. 
    Both animals were killed after 3 days.

    Most of the radiolabelled doses (68-72%) were eliminated within 72
    hours.  Most of the activity was recovered in the urine (61%, 48%
    in each animal respectively), with a lesser amount in the faeces
    (6% and 23%).  Little, if any, radioactivity appeared in the
    expired air (<0.3%).  Levels of radioactivity were distributed
    throughout the body, but mainly in the hide, carcass, GI-tract and
    blood.  Total recovery was about 91%.

    About 51 and 43% of the original radioactivity in the rat skin,
    hair and blood, respectively were found to be present as 14C which
    had been reincorporated into natural amino acids (protein).  The
    remainder of the radioactivity in tissues has not been identified,
    but it was not found as known metabolites of oxamyl.

    The radioactivity in the urine was present as a very complex
    mixture of compounds.  Conjugates of methyl-N-hydroxy-N',
    N'-dimethyl-1-thiooxamimidate (I), methyl
    N-hydroxy-N'-methyl-1-thiooxamimidate (II), N,N-dimethyloxamic acid
    (III) and N-methyloxamic acid (IV), present in about equal amounts,
    accounted for approximately 79 and 72% of the elimination products
    in urine and faeces, respectively.  No oxamyl or other
    organosoluble metabolites were detected (Harvey and Han, 1978).

    A male Charles River CD rat was given a water supply containing
    1540 mg/l of non-labelled plant metabolite methyl
    N',N-dimethyl-N[(1-glucosyl)oxy]-1-thiooxamimidate (metabolite A).
    Eight days later the rat received by intragastric intubation 4 ml
    of an aqueous solution containing 0.67 mg (3.77 Ci) of 14C
    metabolite A.  About 69% of the total 14C was eliminated in 72
    hours: 64% in the urine and 5% in the faeces.  The major component
    (45%) of the urinary radioactivity was identified as unchanged
    metabolite (30% of the original dose), 19% as conjugates of I and
    II.  Conjugates of III an IV account for a substantial part of the
    remainder.  Extracts of liver, carcass and blood showed no
    radioactivity in the form of I, II or V (< 1%).  Evidence was
    presented that about 65% of the remainder was incorporated in amino
    acids. (Harvey and Han 1978).

    A male Charles River CD rat received 450 mg/kg unlabelled
    N,N-dimethyl-1-cyanoformamide (DMCF), another plant metabolite of
    oxamyl in the diet.  Seven days later the rat was given, by
    intragastric intubation 4 ml of an aqueous solution containing 1.1
    mg (10.7 Ci) of 14C-DMCF.  Excretion and distribution were
    comparable to those after oxamyl or metabolite A treatment.  The
    results showed no DMCF or other organosoluble 14C-material in the
    urine.  However 15% of the total radioactivity of the urine was
    accounted for by conjugates of III and 7% by IV, (Harvey and Han,
    1978).

    The incubation of oxamyl with rat liver microsomes for 2 hours
    resulted in a mixture of six compounds.  In addition to intact
    oxamyl, substantial amounts of I, III and DMCF (V) were found. 
    Smaller amounts of the monomethyl analogue of oxamyl (VI) and II
    were detected, indicating that N-demethylation was occurring at a
    slower rate.  The control incubation (no microsomes) produced only
    the corresponding oximino compound (I) in approximately the same
    amount, suggesting that hydrolysis is not mediated by the liver
    enzyme system, but by chemical hydrolysis.

    Liver microsome incubation of DMCF (V) produced III as the only
    breakdown product.  In the incubation of metabolite A, >9O% of the
    metabolite A was recovered intact.  Likewise, incubation of
    metabolite I resulted in less than 1% degradation.

    In figure 1 the metabolism of oxamyl by rat liver microsomes is
    given (Harvey and Han, 1978; Han and Harvey, undated).

    FIGURE 1

    TOXICOLOGICAL STUDIES

    Special studies on cholinesterase activity

    Rat

     Two groups of 10 male rats were given orally 4.8 mg oxamyl/kg bw. 
    One group received 50 mg/kg atropine sulphate i.p. immediately
    after dosing of oxamyl.  Cholinesterase activity in blood was
    determined 24 hrs before and 5 min., 4 hrs and 24 hrs after dosing. 
    The animals without atropine showed a decrease in cholinesterase
    after 5 min. with a maximum after 4 hrs.  After 24 hrs, the
    activity was normal again. Animals that were treated with atropine
    showed a slight inhibition initially, but the activity was normal
    after 4 hrs.  The experiment was repeated with the same result
    (Schmoyer and Henry, 1970).

    Four groups of 8 ChR-CD rats were fed oxamyl in the diet at dosage
    levels of 0 (control), 50, 100 or 150 mg/kg feed during 29 days.

    Erythrocyte and plasma AChE were measured at day 1, 7, 21, and 28. 
    On the 29th day the rats were sacrificed to measure AChE in the
    brain.

    Eight additional rats were assigned to each group for assay of
    brain AChE 14 days after the start of the experiment.

    With male animals cholinesterase activity of the plasma was only
    marginally decreased in the 150 and 100 mg/kg groups throughout the
    study.  In the females plasma cholinesterase activity was
    dose-related decreased in the 150 and 100 mg/kg groups from day 7
    onwards.  No clear effects were observed on the AChE activity in
    the erythrocytes. At the end of the study cholinesterase activity
    in brain tissue of females was dose-related decreased in the 150
    and 100 mg/kg groups. After 14 days cholinesterase activity in the
    brain was inhibited in the 150 mg/kg group.  In summary, 50 mg/kg
    in the diet was a no-effect level (Barnes and Aftosmis, 1978).

    Special study on delayed neurotoxicity

    Chicken

    The animals were given various oral doses of oxamyl.  The ALD
    (approximate lethal dose) was established at 40 mg/kg bw.  Two
    groups of 5 adult hens received 20 or 40 mg/kg bw respectively
    followed by 0.5 mg/kg atropine i.m.  No mortality occurred.  The
    animals were kept for 28 days.  They showed marked symptoms of
    cholinesterase inhibition but recovery was complete after 12 hours. 
    As a positive control 1200 mg/kg TOCP was used, followed by
    atropine.  Two weeks after dosing the animals showed typical signs
    of delayed neurotoxicity (Ki Poong Lee, 1970).

    Special study on reproduction

    Rat

    The animals of the long-term feeding study were also used for a
    3-generation reproduction study.  Groups of 16 males and 16 females
    on a diet containing 0, 50, 100 or 150 mg/kg were chosen for
    breeding three generations of each two litters.  Throughout the
    study the litter size, viability and lactation indices and body
    weights of weanlings were decreased at 100 and 150 mg/kg.  A
    marginal effect on the body weight of the weanlings was also
    observed at 50 mg/kg.  No effect on fertility and gestation indices
    was detected.  Organ weights of the weanling pups of the F3b
    generation showed a slight increase in relative kidney weight at
    150 mg/kg.  The relative testes weight was increased at 100 and 150
    mg/kg.  No histopathological abnormalities were found that could be
    ascribed to the compound (Sherman et al. 1972).

    Special study on mutagenicity

    Microorganisms

    Oxamyl showed no mutagenic action in a rec-assay using two strains
    of Bacillus subtilis, and reverse mutation tests with and
    without a liver activation system using 5 strains of Salmonella
    thyphimurium TA and E. coli WP2 hcr.  A host-mediated assay
    in mice using S. typhimurium G-46 was also negative (Shirasu
    et al, 1976).

    Special study on teratogenicity

    Rat

    Groups of 26-28 pregnant females received 0, 50, 100, 150 or 300
    mg/kg oxamyl in the diet from day 6-15 of pregnancy.  In the
    mothers, a dose-related decrease in body weight and food
    consumption was found for 100, 150 and 300 mg/kg groups.  There
    were no effects on number of implantation sites, resorptions and
    live foetuses nor on embryonal development.  Oxamyl does not show
    teratogenic or embryotoxic properties (Culik and Sherman, 1971).

    Acute Toxicity
                                                                   

    species  sex    route    LD50 in mg/kg bw     reference
                                                                   

    rat       M     oral       371 (27-51)         Carroll, 1972
    rat       M     oral       1102 (97-185)       Gibson, 1973
    rat       M     oral       5.4 (3.7-7.8)       Fretz, 1969
    rat3      M     oral       16 (22)             Schmoyer, 1969
    rat3      F     oral       11 (7-16)           Schmoyer, 1969
                                                                   

    1 formulation Vydate L (26% ai) in aqueous solution 
    2 Vydate G (10% ai) in corn oil 
    3 fasted overnight

    Dermal studies

    Rabbits

    When oxamyl was applied as a suspension in a hydrophillic ointment
    for 24 hrs, the ALD (approximate lethal dose) was 2250-5000 mg/kg
    bw on the intact skin, but only 90-130 mg/kg on the abraded skin. 
    When oxamyl was applied as a slurry in propylene glycol the ALD was
    130 or 60 mg/kg bw in the intact and abraded skin respectively
    (Colburn, 1970).

    When Vydate L (27% ai) was applied during 24 hrs the LD50 was 740
     150 mg/kg bw on active ingredient basis on the intact akin
    (Morrow, 1973).

    Inhalation studies

    Rats

    The LC50 (1 h) for oxamyl was 0.035 mg/l air when Vydate L (27% ai)
    was used in the test (males only) (Barras 1974).  When the
    experiment was carried out with oxamyl dust the LC50 (1 h) for male
    and female animals was 0.17 and 0.12 mg/l respectively.  The
    concentration in air was calculated after chemical analysis
    (Tayfun, 1969).

    Symptoms of intoxication

    Fasciculations, tremors, salivation, lacrimation, bulging eyes and
    chromodacryorrhoea were found after an acute oral dose of oxamyl. 
    They can be considered as symptoms of cholinesterase inhibition
    (Carroll, 1972).

    A good antidotal effect was obtained when rats orally treated with
    oxamyl received an i.p. injection with atropine sulphate (Sherman,
    1969) 

        Acute toxicity of oxamyl metabolites in rats

                                                                                             
                                                              LD50 in
    metabolite                                sex    route    mg/kg bw         reference
                                                                                             

    methyl N-hydroxy-N,N' dimethyl-            M     oral     11,000 (=ALD)    Fretz, 1968
    -1-thiooxamimidate (INA-2213)

    methyl N-hydroxy-N' methyl-1-              M     oral     6,675 (6370-     Dale, 1973
    thiooxamimidate (IEL-2953)                                 6690)

    N,N-dimethyloxamic acid (IND-2708)         M     oral     3,540            Barbo, 1972

    N,N-dimethyl-1-cyanoformamide              M     oral     450 (=ALD)       Ashley, 1974
    (DMCF) (INN-79)

    methyl N'-methyl-N [(methyl-carbamoyl)     M     oral     60               Schmoyer, 1969
    oxy]-1-thiooxamimidate (IND-14O9)

    glucose conjugate of methyl N'-            M     oral     > 7500           Henry, 1976
    methylhydroxy-N',N'-dimethyl
    -1-thiooxamimidate (ING-3515)
                                                                                             
    
    Short-term studies

    Rat

    Six male rats were given orally 2.4 mg/kg bw oxamyl for 10 days.  No
    mortality occurred.  Oxamyl does not exhibit cumulative oral toxicity
    (Fretz and Sherman, 1968). 

    Rabbit

    Rabbits were treated dermally for 15 days during a period of 4 weeks
    with Vydate L (26% ai) in dimethylformamide.  Groups of each 5 male
    and 5 female animals received 193 mg/kg Vydate L, or 50 mg/kg bw of
    oxamyl during 6 hrs/day on the intact or abraded skin.  Control
    animals received dimethylformamide.  All oxamyl treated animals with
    abraded skin showed marked signs of cholinesterase inhibition.  Only
    slight symptoms were seen on the animals with intact skin.  No
    mortalities occurred.  No changes in body weight, organ weight or
    histopathology were found that could be ascribed to the treatment. 
    All animals showed mild erythema of the treated skin (Dion, 1970).

    Rat

    Groups of 16 male and 16 female animals each received for 90 days 0,
    50, 100 or 500 mg/kg oxamyl in the diet.  After a few days the highest
    dose level was reduced to 150 mg/kg because with 500 mg/kg all animals
    showed strong symptoms of cholinesterase inhibition.  They were given
    control diet for 3 days and the symptoms disappeared or became less
    severe.  Then the animals were given 150 mg/kg.  No clinical signs of
    toxicity were seen in the remainder of the experiment.  The body
    weight gain was lower at 100 and 150 mg/kg and slightly affected in
    the females of the 50 mg/kg group.  The food consumption was lower at
    150 mg/kg only.  Urinalysis showed a higher number of animals with
    blood in urine at 100 and 150 mg/kg and a higher number with protein
    at 150 mg/kg.  Male rats showed lower absolute organ weights for
    heart, kidneys, liver, spleen and thymus at 100 and 150 mg/kg.  In the
    females this effect was found for the liver at 100 and 150 mg/kg and
    the kidneys and lungs at 100 mg/kg.  No effects were found on
    haematology, clinical chemistry and histopathology.  Cholinesterase
    activity was not determined.  The marginal no-effect level is 50 mg/kg
    (Snee et al, 1969).

    At the end of the experiment 6 animals per group per sex were used for
    reproduction performance.  In the F1a and F1b generation the
    fertility index and the number of pups/litter were decreased at 100
    and 150 mg/kg.  The weight of the young at weaning was significantly
    lower at all dose levels (Snee et al, 1969).

    Dog

    Groups of 4 male and 4 female animals each received for 90 days 0, 50,
    100 or 150 mg/kg oxamyl in the diet.  Only marginal effects were found
    with 150 mg/kg.  A slight increased activity was found for alkaline
    phosphatase after 4 and 13 weeks.  In the males the weight of
    adrenals, spleen and testes was somewhat decreased.  The females
    showed a slight increase in thyroid weight and a decrease in adrenal
    weight.  Histopathologically no abnormalities were found that could be
    ascribed to the compound (Holsing, 1969).

    Groups of 4 male and 4 female animals each received for 2 years 0, 50,
    100 or 150 mg/kg oxamyl (95%) in the diet.  After 1 year 1 male and 1
    female animal from the control and 150 mg/kg groups were killed.
    Haematology, clinical chemistry and urinalysis were carried out after
    1, 2, 3, 6, 9, 12, 15, 18, 21 and 24 months.  The haemoglobin content,
    haematocrit and number of erythrocytes in blood at 150 mg/kg were
    found to be lower than the controls on most times of measurement in
    both sexes.

    Higher values for cholesterol and alkaline phosphatase activity were
    found more often at 150 mg/kg in males and females.  On some occasions
    cholesterol was also higher in the other experimental groups.

    No effects on organ weights, cholinesterase or aliesterase activity,
    or histopathology were found that could be ascribed to the compound
    (Sherman, et al, 1972).

    Short term study with DMCF, a metabolite of oxamyl

    Rat

    Groups of 16 male and 16 female animals each received for 90 days 0,
    50, 150 or 450 mg/kg N,N-dimethyl-1-cyanoformamide (DMCF) in the diet.
    Growth inhibition was found at 450 mg/kg in males and females, and the
    food consumption was also lower.  At the highest dose level
    haemoglobin content, haematocrit and number of erythrocytes were
    lower.  At 150 mg/kg a slight effect was found on these parameters in
    the females or males.  In the male animals an increased LDH activity
    was found at 450 mg/kg and in the female animals a decreased activity
    in GPT, GOT, and LDH at the same dose level.  Organ weights were not
    reported in this study.  Histopathologically an increase was found in
    hydronephrosis of the kidneys in the males and minute foci of
    mineralization in the kidneys of females at 450 mg/kg.  The animals of
    the other dose levels were not studied histopathologically.  The
    no-effect level is probably 50 mg/kg (Kaplan, 1976).

    At the end of the experiment 6 animals per group were used for
    reproduction performance.  With 450 mg/kg a decreased weight of the
    young at weaning was observed (Kaplan, 1976).

    Long-term studies

    Rat

    Groups of 36 male and 36 female animals each received for 2 years O,
    50, 100 or 150 mg/kg oxamyl (95%) in the diet (2 control groups were
    used).  After one year of feeding the number of rats of each sex in
    each group was reduced to 30.  With 100 and 150 mg/kg a decreased body
    weight was found with male and female animals that was related to
    dose.  With 50 mg/kg the male animals showed a slightly lower body
    weight, which was apparent after 4 weeks and remained so throughout
    the study.  Food consumption was lower at 150 mg/kg.  Cholinesterase
    activity in blood in the 150 mg/kg group was only decreased in the
    females after 4 days of feeding and in the males after 8 days, and not
    after 1, 6, 12 and 24 months.  Aliesterase activity was not affected
    throughout the study.

    At the end of the experiment relative weights of brain, testes and
    adrenals were increased in the males and brain, heart, lungs, kidneys
    and adrenals in females at 150 mg/kg.  In the females most or these
    organ weights were also increased at 100 mg/kg.   These changes are
    probably connected with the decreased body weight.  No haematological,
    biochemical or histopathological abnormalities were found that could
    be ascribed to the compound (Sherman et al, 1972).


    RESIDUES IN FOOD

    USE PATTERN

    Oxamyl formulations, either as a 24% liquid or 10% granular, are
    recommended or registered for use in numerous countries.  Food uses
    made available to the Meeting by the manufacturer are summarized in
    Table 1.  Proposed uses are not included but are discussed under
    appropriate commodities when residues are discussed.

    According to information provided to the Meeting, uses listed for the
    United States also apply to Argentina, Barbados, Bolivia, Brazil,
    Chile, Colombia, Costa Rica, The Dominican Republic, Ecuador,
    Guatemala, Mexico, Nicaragua, Peru, El Salvador, Trinidad and Tobago,
    Uruguay and Venezuela unless indicated otherwise in Table 1.  Only a
    few national governments provided usage information directly to the
    meeting.

    The liquid formulation is a contact-type, moderately residual
    insecticide when applied as a foliar spray.  When so applied it is
    effective on several species of mites and, by systemic action in many
    plants, on nematodes.  When oxamyl formulations are applied to the
    soil they function as a contact type broad-spectrum nematocide and, by
    systemic action, as a miticide/insecticide.

    Applications may be pre-planting, at planting, or foliar (to
    fruit-bearing or non- fruit-bearing plants).  They may be applied in

    the furrow or broadcast.  Soil incorporation may be mechanical or by
    irrigation.


    RESIDUES RESULTING FROM SUPERVISED TRIALS

    There are numerous combinations of type of formulation, method and
    time of application suitable for a wide range of pest control needs.
    Because of this, the residue level can vary widely, even on the same
    commodity.  A large volume of data on 29 commodities or groups of
    commodities was presented to the meeting; this has been considerably
    condensed into Table 2 (Du Pont, 1980).

    The analytical method used extracts both oxamyl and its oxime
    metabolite (I), converts the oxamyl to the oxime which is quantitised,
    so the residue levels quoted are of oxamyl plus the oxime expressed as
    oxamyl.  Data on residues of the DMCF metabolite are in parentheses.

        TABLE 1.  Recommended uses for oxamyl1

                                                                                                                               

                                  Rate, kg                         No. of       pre-harvest
    Crop           Country        or % ai      Formulation2,3     treatments   interval (wks)   notes
                                                                                                                               

    Apples

    non-bearing    U.S.A.         0.28-2.2        24% Liq.                            52
                                  6.7 - 9                                                       pre-plant, soil incorporation
    bearing                       0.28-2.2                                             2        do not graze treated orchards
    non-bearing    Greece           2-4           10% G                               52        soil
                                    1.2           24% G            multiple           52        foliage

    Bananas        Greece         3 g/plt         10% G               3                         at planting
                                  2-3 g/plt                           2                         on plantations (around plant)
                                  0.01%           24% Liq.                                      foliage
                   Central Amer.  0.9-1.3         24% Liq.           5-8                        foliar
                   Spain          3.8             24% Liq.                                      in irrigation water

    Beans          Greece         3-4             10% G                                2        pre-plant broadcast, glasshouse 
                                                                                                and in open
                                  2-3             10% G                                2        furrow, broadcast glasshouse and
                                                                                                in open
                                  1.2             24% Liq.            2                2        spray, broadcast glasshouse and 
                                                                                                in open

    Beets (roots   Denmark        0.7-1.8         10% G                                         row, at planting
    or tops)                      2.5-5           10% G                                         broadcast, before planting

    Carrots        Greece         3-4             10% G                                2        pre-plant, broadcast
                                  2-3             10% G                                2        furrow
                                  1.2             24% Liq.            2                2        spray
                                  1.2             24% Liq.         multiple           52        foliage

    Celery         Greece         3-4             10% G                                2        preplant broadcast, glasshouse and 
                                                                                                in open
                                  2-3             10% G                                2        furrow, glasshouse and in open
                                  1.2-1.4         24% Liq.            2                2        spray, glasshouse and in open


    TABLE 1.  Continued...

                                                                                                                               
                                  Rate, kg                         No. of       pre-harvest
    Crop           Country        or % ai      Formulation       treatments   interval (wks)   notes
                                                                                                                               

                   USA            0.56-2.2        24% Liq.                             2        untrimmed
                                  4.4             24% Liq.                             2        pre-plant soil incorporated

    Citrus         Greece         2-4             10% G                                52       soil, non-bearing
                                  1.2             24% Liq.         multiple            52       foliage, non-bearing
                   USA            up to 1.1                                            1        do not graze treated orchards
                                  (0.008-0.03%)

    Cherries       Greece         2-4             10% G                                52       soil non-bearing
                                  1.2             24% Liq.         multiple            52       foliage non-bearing

    Cucumbers      Bulgaria       0.024%          24% Liq.         multiple            2        foliage (greenhouse)
                   Czechoslovakia 0.1 g/plt.                          1                2        glasshouse
                   Netherlands    5               10% G                                         glasshouse, shortly before planting

    Cucurbits      Greece         3-4             10% G                                2        pre-plant broadcast,
                                                                                                glasshouse and in open
                                  2-3             10% G                                2        furrow, glasshouse and in open
                                  1.2             24% Liq.            2                2        spray, glasshouse and in open
                   USA            0.56-2.2        24% Liq.            2                         untrimmed

    Eggplant       Greece         3-4             10% G                                2        pre-plant broadcast,
                                                                                                glasshouse and in open
                                  2-3             10% G                                2        furrow, glasshouse and in open
                                  1.2-1.4         24% Liq.            2                2        spray, glasshouse and in open

    Onions         Denmark        0.7-1.8         10% G                                         row, at planting
                                  2.5-5           10% G                                         broadcast, before planting
                   United
                   Kingdom        13-4.9          10% G                                         furrow, at planting

    Peaches        Greece         2-4             10% G                                52       soil, non-bearing
                                  1.2             24% Liq.         multiple            52       foliage, non-bearing

    TABLE 1.  Continued...
                                                                                                                               
                                  Rate, kg                         No. of       pre-harvest
    Crop           Country        or % ai      Formulation         treatments   interval (wks)  notes
                                                                                                                               
    Pears          Greece         2.4             10% G                                52       soil, non-bearing
                                  1.2             24% Liq.         multiple            52       foliage, non-bearing

    Peas           United         2.5             10% G                                         pre-plant
                   Kingdom

    Peppers        Bulgaria       0.024%          24% Liq.         multiple            2        foliage, glasshouse
                   Czechoslovakia 0.1 g/plt       10% G               2                2        glasshouse
                   Greece         3-4             10% G                                2        pre-plant broadcast, glasshouse 
                                                                                                and in open
                                  2-3             10% G                                2        furrow, glasshouse and in open
                                  1.2-1.4         24% Liq.                             2        2spray, glasshouse and in open

    Pipfruit       N. Zealand     0.048-0.06%     24% Liq.            2                1

    Potatoes       Denmark        2.5-5           10% G               1                         broadcast, pre-planting
                   Greece         3-4             10% G                                2        pre-plant, broadcast, glasshouse 
                                                                                                or in open
                                  2-3             10% G                                2        furrow, glasshouse or in open
                                  1.2-1.4         24% Liq.            2                2        spray, glasshouse or in open

                   Libya          4-5.5           10% G                                         pre-plant, soil
                                  1.7             24% Liq.            3 (foliar)       4        soil, pre-plant and foliar
                   Mexico         0.24-0.72       24% Liq.         multiple            1        foliage
                   Netherlands    10% G                                                         before or at planting
                   N. Zealand     5               10% G                                13       pre-plant broadcast
                   United
                   Kingdom        4-5.5           10% G                                         pre-plant, soil

                   U.S.A.         0.28-1.1        24% Liq.                             1        foliar

    Squash         Greece         3-4             10% G                                2        pre-plant broadcast, glasshouse 
                                                                                                or in open
                                  2-3             10% G                                2        furrow, glasshouse or in open
                                  1.2-1.4         24% Liq.             2               2        spray, glasshouse or in open

    TABLE 1.  Continued...

                                                                                                                               
                                  Rate, kg                         No. of       pre-harvest
    Crop           Country        or % ai      Formulation         treatments   interval (wks)  notes
                                                                                                                               

    Strawberries   Denmark        0.48            24% Liq.             3                        after final harvest
                   Greece         2-4             10% G                                         non-bearing
                                  1-2             24% Liq.          multiple                    non-bearing

    Sugarbeets     Greece         0.8-1           10% G                                         at planting
                                  0.18            24% G                                         foliage
                   Netherlands    0.75            10% G                                         at sowing
                   Spain          0.8             10% G                                         in row
                   Syria          2.4-3.6         24% Liq.                             1        at plant
                                  1.8             24% Liq.                             1        foliar
                   United
                   Kingdom        0.6-0.9         10% Liq.                                      in furrow at planting

    Tomatoes       Bulgaria       0.024%          24% Liq.          multiple           2        foliage, glasshouse
                   Czechoslovakia 0.1 g/plt.      10% G                2               2        glasshouse
                   Denmark        4.8             24% Liq.                                      field, preplant
                                  0.05%           24% Liq.                                      field, preplant
                                  0.07%           24% L1q.                                      4 wk. after planting
                   Egypt          1.8             24% Liq.                             4
                   Greece         3-4             10% G                                2        preplant broadcast,
                                                                                                glasshouse or in open
                                  2-3             10% G                                2        furrow, glasshouse
                                                                                                or in open
                                  1.2-1.4         24% Liq.             2               2        spray, glasshouse or in open
                   Netherlands    5               10% G                                         glasshouse, shortly before
                                                                                                planting
                   Jordan         1.8             24% Liq.             2               4        foliar
                   Libya          3               10% G                1               4
                                  1.7             24% Liq.             2               4
                   Mexico         0.06-0.12%      24% Liq.                           1 (day)    foliar
                   Syria          1.8             24% Liq.             2                        foliar (seedlings)
                   United
                   Kingdom        0.1 g/plt       10% G                2               2

    TABLE 1.  Continued...

                                                                                                                               
                                  Rate, kg                         No. of       pre-harvest
    Crop           Country        or % ai      Formulation         treatments   interval (wks)  notes
                                                                                                                               

                   U.S.A.         0.56-1.1        24% Liq.          multiple           1 (day)  (AL, FL, MD, NJ, PA, P.R.,
                                                                                                 SC, VA) foliar
                                                                                       2 (day)  (HI) foliar
                                                                                       3 (day)  (CA) foliar
                                  4.5-9           24% Liq.                             1 (day)  (HI, soil, by
                                                                                                 drip irrigation)
                                                                                                                               

    1 Most listed U.S. uses are special local need registrations, limited to specific geographical areas.
    2 G = granular
    3 Liq. = liquid


    TABLE 2.  Oxamyl residues from supervised trials (DMCF in parentheses)

                                                                                                                                            
                                                Rate, kg                      Interval
                                                ai/ha or                  last application                        No. in
    Crop          Country        Year      No.    % ai      Formulation   to harvest (days)      Range, mg/kg     range
                                                                                                                                            

    Apples        N. Zealand     1980      1   0.03-0.06%      24% EC              1              0.1-0.2           2
                                                                                  2-3             0.03-0.11         2
                                                                                  6-8                N.D.1          2
                                                                                 12-14               N.D.1          2
                  U.S.A.       1972-75    2-6    0.28          24% Liq.           2-3          0.19-0.2 (<0.02)     2
               (10 states)                                                        4-5          0.21-0.36 (<0.02)    2
                                                                                  9-11         0.11-0.21 (<0.02)    3
                                           2     0.67          24% Liq.           11                 0.12           1
                                          1-3    0.76-1.1      24% Liq.           2-3        0.32-0.84 (0.03-0.05)  5
                                                                                  4-5              0.1-0.23         2
                                                                                  6-8        0.09-0.68 (<0.02-0.04) 14
                                                                                 12-14               1.2            1
                                          1-2     1.7-2.2      24% Liq.           2-5              0.31-1.5         3
                                                                                  6-8        0.05-1.4 (<0.02-0.03)  4
                                                                                 12-17       0.14-1.1 (<0.02-0.04)  5
                                                                                 21-30               0.27           1
                                           1         4         24% Liq.           2-3                1.9            1
                                                                                  6-8              1.2-1.4          2
                                                                                 12-14        0.99-1.0 (0.05-0.15)  1

    Banana2       Costa        1975-77    1-8     0.9-2.2      24% Liq.           1-10         <0.02 (0.02)      10 bagged or unbagged,
                  Rica3        (aerial)                                                                          whole fruit or edible peel
                                                                                                                                           

    1  0.05 limit of determination
    2  Cavendish and Giant Cavendish
    3  five farms

    TABLE 2.  Continued...

                                                                                                                                            
                                                Rate, kg                      Interval
                                                ai/ha or                  last application                        No. in
    Crop          Country        Year      No.    % ai      Formulation   to harvest (days)      Range, mg/kg     range
                                                                                                                                            

    Beans          U.S.A.      1975-77
    (succulent, green
    snap, lima)                                                                                       Beans                  Foliage-hay

    preplant                               1      2.2-4.51     10% G               67                <0.02
    foliar        VA                       1      0.28         24% Liq.            2-3             0.1 (<0.04)       1
                                                                                   6-8             0.02 (<0.04)
                  VA, FL, CA              1-8     0.56         24% Liq.             1            0.05-0.84 (<0.04)   2       2.5 (<0.04)
                                                                                   2-3           <0.02-5.3 (<0.04)  10     1-14 (<0.04-0.08)
                                                                                   6-11          <0.02-0.97 (<0.04)  9     0.24-16 (<0.04)
                                                                                   12-14         <0.02-0.65 (0.04)   8     0.26-5.7
                  CA, FL                  5-8     1.1          24% Liq.             1                    1.9         1     6.7 (0.14)
                                                                                   2-3       <0.02-7.7 (<0.04-0.19) 10     3.2-29 (<0.04-0.41)
                                                                                   6-9       <0.02-2.3 (<0.04-0.17)  8     0.59-33 (<0.04-0.36)
                                                                                  11-14      <0.02-1.0 (<0.04-0.09) 10     0.08-15 (0.06-0.20)
                  CA, FL                  5-8     2.2          24% Liq.             1               6.5 (0.35)       1
                                                                                   2-3       0.04-13 (0.04-0.37)     9     77 (0.66)
                                                                                   6-8       0.1-7.3 (<0.04-0.31)    8     0.91-67 (<0.04-0.83)
                                                                                  12-14      0.05-2.0 (<0.04-0.09)   9     0.06-37 (0.06-0.67)
                  CA                       5      4.5                               1               8.9 (0.84)       1
                                                                                   2-3              12  (0.54)       1
                                                                                  12-14            0.28 (<0.04)      1


    Beans                                                                                              Beans                   Straw
    (dry-pinto,   WY           1977        1     0.56          24% Liq.            50              <0.02 (<0.04)           0.04 (<0.04)
    navy, dry)                             1     1.1                               50              <0.02 (<0.04)           0.18 (<0.04)
                                                                                                                               vines
                  CA, MI       1973-78           1.1-2.2       10% G             103-111           <0.02 (<0.04)           <0.02-0.08 (<0.04)
                                                3.4 (preplant)                   111-132           <0.02 (<0.04)
                                                                                                                                           

    1  12 inch band incorporated

    TABLE 2.  Continued...

                                                                                                                                            
                                                Rate, kg                      Interval
                                                ai/ha or                  last application                        No. in
    Crop          Country        Year      No.    % ai      Formulation   to harvest (days)      Range, mg/kg     range
                                                                                                                                            

                                                                                                 Range, mg/kg
    Beets, red    U.S.A.       1973        1     3.4-6.7       G                  84               <0.02   soil
                                           2     1.1           Liq.               48               <0.02   foliar
                                           1     3.4-6.7       G                  84               <0.02   soil
                                           +        +          +                                            +
                                           2       1.1         Liq.                                <0.02   foliar

    Cantaloupe    U.S.A.
                  GA           1971        1     4.5           10% G              80               0.05
                                                 4.5           10% G
                                                  +             +
                                                 1.1           2 Liq.             39               <0.02
                                                                                                                  No. in range

                  CA, FL       1976-78     5-8   1.1 (foliar)  2 L                1                0.04-0.25           4
                                                                                 2-3               0.19-0.26           3
                                                                                 4-5               0.05                1
                                                                                 6-8               0.06-0.16           4

                  FL, IN, CA   1976-78     5-8   1.1 (foliar)  2 L                1            0.1-0.62 (<0.02-0.03)   5
                                                                                 2-3           0.12-0.48 (<0.02-0.04)  4
                                                                                 4-5           0.06-0.19 (<0.02)       2
                                                                                 6-8           0.07-0.59 (<0.02-0.05)  6

                  AZ, CA, IN   1976-78     5-8   2.2 (foliar)  2 L                1            0.23-0.91 (0.05-0.1)    3
                  FL                                                             2-3           0.03-0.66 (0.66)        5
                                                                                 6-8           0.05-0.5 (0.04-0.05)    3

                  IN           1974-78     2-5   4.5-6.7       2 L                1            0.44-0.69 (0.05-0.08)   2
                                                 (foliar)                        2-3           0.12-0.52 (0.04-0.08)   2
                                                                                 6-8                0.3 (<0.02)        2
                                                                                41-51                   0.02           1
                                                                                                                                           

    TABLE 2.  Continued...

                                                                                                                                            
                                                Rate, kg                      Interval
                                                ai/ha or                  last application                        No. in
    Crop          Country        Year      No.    % ai      Formulation   to harvest (days)      Range, mg/kg     range
                                                                                                                                            

                  IN           1978         5     9-13         2 L                1            0.49-1.4 (0.07-0.2)     2
                                                (foliar)                         2-3           0.44-1.4 (0.02-0.09)    2
                                                                                 6-8           0.41-0.87 (0.02-0.8)    2

                  FL           1972         1     2.2          2 L
                                                   +            +
                                                  1.1          2 L              31-40               0.18 (<0.02)

    Carrot        U.S.A.
    preplant      OH, MI       1975        1     3.4-4.1     unspecified       120-135              <0.02

    soil          MI, OH, FL   1970-73     1     3.4-6.7     G. or Liq.        103-185              <0.02   (<0.02)
                  DE

    foliar        DE           1971        5     0.56           Liq.             18                 <0.02  (<0.02)

    soil          OH           1973-74     1     3.4-6.7     G. or Liq.        122-185
      +                                    +        +            +
    foliar                                3-5    0.56-2.2       Liq.        22 or unspecified       <0.02  (<0.02)


    Celery        U.S.A. (FL)  1974        3     0.56           Liq.               4-5                    8.1          1
                                                                                   6-8                    6.6          1
                                                                                  12-14                   0.88         1
                               1974        5     1.1            Liq.                1                     3.6-24       3
                                                                                   4-5              0.99-8.1 (0.81)    3
                                                                                   6-8                  0.66-6.6       6
                                                                                                  1.5-1.7  (trimmed)   2
                                                                                  12-14                 0.12-1.5       4
                                                                                                    0.94 (trimmed)
                                                                                  15-20                 0.36-0.39      2
                                                                                                  0.27-0.33 (trimmed)  2
                                                                                                                                           

    TABLE 2.  Continued...

                                                                                                                                               
                                                Rate, kg                      Interval
                                                ai/ha or                  last application                        No. in
    Crop          Country        Year      No.    % ai      Formulation   to harvest (days)      Range, mg/kg     range
                                                                                                                                               

                               1974       3-5    2.2            Liq.               4-5                     20          1
                                                                                  12-14                 0.86-3.1       3
                                                                                                      2.4  (trimmed)   1
                                                                                  15-20                 1.3-1.4

                                                                                           grapefruit   lemons    oranges    tangelos  tangerines
    Citrus2       U.S.A.       1971-75    1-5  0.59-1.11        Liq.                1      0.14-0.25   0.21-0.29  0.13-0.6
                  AZ,CA,FL,TX          (foliar)                                    2-3     0.03-2.1    0.17-0.25  0.02-1.1

                                                                                   4-5     0.11        0.18       <0.04
                                                                                   6-8     0.03-1.2    0.05-0.17  0.02-0.8
                                                                                   9-11    <0.02                  <0.02
                                                                                   12-14   0.03-0.08              0.06-0.37
                                                                                   15-21                          <0.04-0.3
                                          2-7     1.1      90% sol. powder          84                            0.04
                                                                                    105                           0.14
                                           1    1.4-1.51       Liq.                 2-3     3.6                   0.51
                                                (foliar)                            4-5                           .42
                                                                                    6-8     1.2-2                 0.34
                                                                                   12-17    0.46-0.8              0.06
                                          1-6   2.1-2.2        Liq.                  1      1.3         0.39      0.26-0.36
                                     or    3   2.2+4.5+2.2                          2-3    <0.02-0.67   0.29      <0.02-0.52             <0.02-0.1
                                                (foliar)1                           4-5    <0.02-0.84   0.04      <0.02-0.92  0.06-0.88 
    <0.02-0.57
                                                                                    6-8    <0.02-0.3    0.04      <0.02-3     0.02-0.24  <0.02-0.4
                                                                                    9-14   <0.02                  <0.02-0.87             0.02
                                                                                     21                           <0.02
                                                                                                                                              

    1  presumed on the basis of proposed label
    2  DMCF is <0.06 mg/kg in fruit, peel or pulp except for a 0.54 value at high dosage (4-5 days)

    TABLE 2.  Continued...

                                                                                                                                            
                                                Rate, kg                      Interval
                                                ai/ha or                  last application                        No. in
    Crop          Country        Year      No.    % ai      Formulation   to harvest (days)      Range, mg/kg     range
                                                                                                                                            

                               1971-75     3   2.2+4.5+4.5     Liq.                  1      1.5         0.55      2.-4.8
                                          1-3    4.2-4.5                            2-3     0.08-1.1    0.36      0.22-4.4
                                                (foliar)1                           4-5     0.07-0.64   0.32      0.25-3.6       0.88
                                                                                    6-8     0.05-0.64   0.36      0.13-2       0.24-0.36
                                                                                   12-14    <0.02                 <0.02-0.67
                                                                                     21                           0.03
                                                                                     84                                          0.04

    Corn, field   USA          1970-75     1     0.56-4.5      Liq.               93-198         <0.02  (<0.02)     27  (kernal or stalk)
                  (GA,FL,NC)                    (band or furrow)

    Cottonseed    USA          1969-75     1     0.06-0.28     Liq.               51-75          <0.02
                  (AZ,TX,CA,NC)                  (foliar)1
                                          1-5    0.37-0.56     Liq.               6-8            <0.02-0.09
                                                 (foliar)1                        12-17          <0.02-0.13
                                          1-5     0.75-1.1     Liq.                 1              25                     1
                                                 (foliar)1                         4-5             0.75                   1
                                                                                   6-8           0.02-0.17               19
                                                                                  12-17          <0.02-0.18              19
                                          1-5     1.7-2.2      Liq.                6-8           0.03-0.26               12
                                                 (foliar)1                        12-14          <0.02-0.17               7
                                                                                  15-17          0.02-0.05                2
                                                                                   146             0.02                   2
                                          3-5       4-5        Liq.                6-8           0.25-0.64                4
                                                 (foliar)1                       15-17            0.02                   1

    Cucumber      U.K.         1973        -        5          unspecified        unspecified      0.41-0.68              2
                  U.S.A.
    preplant      VA           1977        1     2.2-4.5       10% G              51-75          0.15-0.47 (<0.02-0.06)   2
                                           1        9          10% G              76-100           <0.02
                                                                                                                                            

    1  presumed on the basis of proposed label

    TABLE 2.  Continued...

                                                                                                                                            
                                                Rate, kg                      Interval
                                                ai/ha or                  last application                        No. in
    Crop          Country        Year      No.    % ai      Formulation   to harvest (days)      Range, mg/kg     range
                                                                                                                                            

    foliar        FL,VA,CA     1973-78    2-7       0.56       2 L                  1              0.15-0.36              5
                                                                                   2-3             0.18-0.38              3
                                                                                   6-8             0.18-0.28              4
                                                                                  12-14            0.07                   1
                                                                                  31-40            0.02 (<0.02)           1
                  FL,CA,VA     1973-78    2-7       1.1        2 L                  1            0.22-0.54 (0.1-0.14)     5
                                                                                   2-3           0.26-0.39 (0.03-0.15)    3
                                                                                   6-8           0.26-0.38 (0.07-0.19)    5
                                                                                  12-14            0.15                   1
                                                                                  31-40            0.03 (0.02)
                  AR,CA,FL,VA  1974-78    1-7       2.2        2 L                  1            0.45-1.1 (0.14-0.19)     4
                                                                                   2-3           0.03-0.7 (0.23-0.24)     4
                                                                                   4-5             <0.02                  1
                                                                                   6-8           0.02-0.78 (0.12-0.25)    5
                                                                                  12-14            0.16 (0.02)            1
                                                                                  41-75          0.05-0.08 (<0.02)        2
                               1972-76    1-7       4.5        2 L                  1            0.87-2.2 (0.17-0.13)     2
                                                                                   6-8           0.84-1.8 (0.25-0.35)     2
                                                                                  12-14          0.32 (0.03)              1
                                                                                  31-40          0.02-0.26 (<0.02-0.07)   2
                                                                                  51-75            <0.02                  1
    glasshouse    Netherlands  19791        1        5         10% G                42           0.16-0.28 (av. 0.21)
                                            1       10         10% G                42           0.08-0.33 (av. 0.27)
                                            2        5         250%g/l              14           0.37-0.52 (av. 0.43)

    Honey dew     USA                      6-9      0.56       2 L                  1              0.2-0.24               3
                  FL           1976-78            (foliar)                         2-3             0.18-0.28              2
                                                                                   6-8             0.19-0.23              3
                  FL           1976-78              1.1        2 L                  1            0.36-0.4 (<0.02-0.03)    3
                                                  (foliar)                         2-3           0.39-0.5 (<0.02-0.03)    2
                                                                                   6-8           0.32-0.44(0.02.-0.03)    3
                                                                                                                                             
    1  CIVO report R 6282 (1979)

    TABLE 2.  Continued...

                                                                                                                                            
                                                Rate, kg                      Interval
                                                ai/ha or                  last application                        No. in
    Crop          Country        Year      No.    % ai      Formulation   to harvest (days)      Range, mg/kg     range
                                                                                                                                            

                  AZ,CA,FL     1976-78      5-9     2.2        2 L                  1              0.68-0.71 (0.04)       2
                                                  (foliar)                         2-3             <0.02-0.68 (0.05)      3
                                                                                   4-5             <0.02                  1
                                                                                   6-8           <0.02-0.7 (0.06-0.1)     3
                  FL           1976          9      4.5        2 L                  1              1.0  (0.04)            1
                                                  (foliar)                         6-8             0.92  (0.06)           1


    Onions        U.K.         1972          11  0.84-3.4      10% G1          unspecified         <0.04
                  Netherlands  1977          2      0.41       3.3% G            100-150           <0.01                 12

                                                                                              nuts        hulls       hay (dry)
    Peanuts       U.S.A.       1971-76       1   1.7-5 (soil)  10% G             76-100       0.03                      0.07
                 (OK,TX,VA,                                                      101-150      <0.02       <0.02        <0.02-0.38
                  GA,NC)                                                         151-200      <0.02-0.04  <0.02-0.1    <0.02-0.04
                                             1     1-4.5       10% G             12-14        <0.02       <0.02        <0.57
                                             +     (soil)        +               51-75        <0.02-0.03  <0.02        <0.02-0.07
                                            2-3   0.56-1.7     24% Liq.          76-100       <0.02       0.04         0.91
                                             1    1.7-2.8      24% Liq.          76-100       <0.02       <0.02        <0.26-1.0
                                                   (soil)                        100-200      <0.02       <0.02
                                            2-3   0.56-1.7     24% Liq.            6-8        <0.02       0.05         0.06
                                                  (foliar)                        21-30       <0.02       <0.01        0.04
                                                                                  76-100      <0.02

                                                                                               pea         pod
    Peas          U.K.                             1.4-2.8     10% G             unknown     <0.01        <0.01
                                                             (preplant)1
                                                    11.1       10% G             unknown     <0.01        0.15
                                                             (preplant)1
                                                                                                                                             

    1  presumed on the basis of proposed label

    TABLE 2.  Continued...

                                                                                                                                            
                                                Rate, kg                      Interval
                                                ai/ha or                  last application                             No. in
    Crop          Country        Year      No.    % ai      Formulation   to harvest (days)      Range, mg/kg          range
                                                                                                                                            

    Pepper        U.S.A.       1975-78     4-18     0.561      24% Liq.             1             0.04-0.88              6
                (AL,CA,FL)                        (foliar)                         2-3       0.15-0.58 (<0.02-0.04)      5
                                                                                   4-5       0.47-0.7 (0.08)             3
                                                                                   6-8       0.11-0.7 (<0.02-0.003)      7
                                           4-18      1.1       24% Liq.             1        0.23-1.1 (0.03-0.12)        7
                                                   (foliar)                        2-3       0.14-1.0 (0.03-0.06)        6
                                                                                   4-5       0.62-1.5  (0.14)            2
                                                                                   6-8       0.15-1.3  (0.03-0.14)       6
                                            5-6      2.2       24% Liq.             1        1.3-3 (0.04-0.08)           3
                                                   (foliar)                        2-3       0.46-1.9 (0.04-0.46)        2
                                                                                   4-5             1.4                   1
                                                                                   6-8             1.2  (0.07)           1

                                                                                        wholefruit     bran      leaves      hay       DMCF fruit2
    Pineapple     U.S.A.       1975-76      1-6       1.1      24% Liq.          13-14  <0.02-0.46  0.04-0.57  0.26-0.55  0.11-0.46
                  Hawaii                                                         23-27  <0.02-0.43  0.28-1.7   <0.02-0.22 0.14-1.2     (<0.02)
                                                                                 35-42  0.03-0.09              0.06-0.15               (<0.02)
                                                      2.2      24% Liq.          13-14  0.03-1.1    0.10-3.5   0.76-1.5   0.27-1.3
                                                                                 23-27  0.02-0.59   1.1-3.2    0.04-1.4   0.55-1.2     (<0.02-0.04)
                                                                                 35-42  <0.02-0.36             0.02-0.82               (<0.02)
                                                      4.5      24% Liq.          13-14  0.13-2.5    0.22-3.0   1.9-6.8    0.75-2.3
                                                                                 23-27  <0.02-0.91  2.5-5.2    0.02-0.70  1.9-8.5      (<0.02-0.1)
                                                       9       24% Liq.           14    0.14-1.2    0.57-1.7              2.4-7.3
                                                                                  23    0.17-0.46               0.3-1.9                (0.09-0.2)

    Potatoes      S. Africa    1974         4-5       0.24%    24% Liq.          51-75           <0.002-0.033       plant water and/or foliar
                  U.K.         1973         13        5.6      10% G3            unspecified     <0.02-0.03
                                                                                                                                            

    1  with and without 0.56 kg ai/ha in transplant water
    2  DMCF residues in pineapple leaves were generally compared to those in the fruit
    3  presumed on the basis of proposed label

    TABLE 2.  Continued...

                                                                                                                                            
                                                Rate, kg                      Interval
                                                ai/ha or                  last application
    Crop          Country        Year      No.    % ai      Formulation   to harvest (days)      Range, mg/kg
                                                                                                                                            

    (soil)        USA (DE)     1969-71      1       1.1-3.4    10% G             76-150          <0.02              pre-plant, soil incorporated
                  NY, FL, MI   1966-75      1       3.4-6.7    10% G             104-106         <0.02
                  FL           1974-75      1       10.1-13.4  24% Liq.          21-30           <0.02              broadcast, soil incorporated
                  FL           1974         1       3.4-4      24% Liq.          100-150         <0.02

    (foliar)      DE           1969-74      3-6     0.21-0.28  24% Liq.          6-20            <0.02
                  CA, DE       1969-74      3-13    0.43-0.56  24% Liq.          1-5             <0.02
                                                                                 6-8             <0.02-0.10
                                                                                 12-14           <0.02-0.03
                                                                                 18-30           <0.02
                  CA,DE,FL,MI  1972-75      1-5      1-1.1     24% Liq.           1              <0.02
                                                                                 2-3             <0.02-0.03
                                                                                 4-14            <0.02-0.03
                                                                                 18-30           <0.02
                  CA, DE       1969-72      1-5      2.2-3.4   24% Liq.          4-5             <0.02
                                                                                 2-3             0.02-0.05
                                                                                 4-5             <0.02-0.02
                                                                                 6-14            <0.02-0.06         high value from low dosage
                  DE, CA       1969-74      1-5      4.5       24% Liq.          4-5             <0.02
                                                                                 6-8             0.05-0.11
                                                                                 12-14           0.09
    (soil +       MI           1974         1 +      3.4-6.8+  G +               100-150
    foliar)                                 1.7      1.1-2.2   24% Liq.          6-8             <0.02
                  CO           1973-74      1 +      3.4-6.7   G +               100-150
                                            3        1.1       24% Liq.          6-40            <0.02-0.02
                  DE           1971         1        2.2       10% G                             soil incorporated
                                            2      (foliar)    24% Liq.          18              <0.02
                                              (dose unspecified)
                                                                                                                                             

    TABLE 2.  Continued...

                                                                                                                                            
                                                Rate, kg                      Interval
                                                ai/ha or                  last application
    Crop          Country        Year      No.    % ai      Formulation   to harvest (days)      Range, mg/kg
                                                                                                                                            

                                                                                               soil        straw
    Soybeans   U.S.A. (TN,MO   1970-77     1-3     0.56-6.73   10% G            113-185     <0.02-0.051  <0.02-0.052 
    (dry)      VA,AL,FL,NC;
               25 tests)

    Squash,       U.S.A.       1976         5    2.2 (foliar)   2 L               2-3            <0.02
    summer                                                                        4-8            <0.02

    Squash,       U.S.A.       1976         5    2.2 (foliar)   2 L               2-3            <0.02-0.06
    vining                                                                        4-8            <0.02

                                                                                                   tops       roots
    Sugarbeets    U.K.                      14   0.6-0.95      10% G4         unspecified      0.05        0.04
                U.S.A. (GA,NC               1    0.56          Liq.             76-100                     <0.02 transplant water
                LA,VA,NY)                  1+1   0.56+1.1      Liq.             76-100                     <0.02 transplant water+foliage
                                            1    4.5-9         G                76-200                     <0.02 soil
                                            1    4.5           Liq.             100-150                    <0.02 soil
                                            2                  Liq.             51-75                      <0.02 foliar
                                            1+   0.56-9 +      G +              75-100                     <0.02 soil +
                                            2    1.1           Liq.             51-75                      <0.02 foliar

    Sugarcane     S. Africa    Data provided were not useful because of uncertainty of dosage rates.

    Sweet potato  U.S.A. (GA,  1970-74      1    4.5-95        24% Liq.         100-150            <0.02  (<0.02)
                  NC,VA,ML)                      preplant-row and broadcast
                                                                                                                                             

    1  only 1 of 25 results was at 0.05 mg/kg 
    2  only 1 of 7 results was at 0.05 mg/kg
    3  all but one application were at planting or 1 day prior
    4  presumed on the basis of proposed label
    5  under glass

    TABLE 2.  Continued...

                                                                                                                                            
                                                Rate, kg                      Interval
                                                ai/ha or                  last application
    Crop          Country        Year      No.    % ai      Formulation   to harvest (days)      Range, mg/kg
                                                                                                                                            

    Watermelon    U.S.A.       1976-78     5-8   0.56          2L (foliar)       1                 0.05-0.29  (<0.02)
                  (FL,CA)                                                       2-3                0.27
                                                                                6-8                0.03-0.28 (0.02)
                  FL           1976-78     8-9   1.1           2L (foliar)       1                 0.38-0.77  (<0.02)
                                                                                2-3                0.47  (0.02)
                                                                                6-8                0.32-0.56  (0.02)
                  AZ,CA,FL     1976-78     5-9   2.2           2L (foliar)       1                 0.1-1.2
                                                                                2-3                <0.02-0.87  (0.05)
                                                                                4-5                <0.02
                                                                                6-8                0.05-0.78  (<0.02-0.1)

    Tomato        Netherlands1  1979        1     5            10% G             5                 0.02-0.11
                                                            (glasshouse)
                                            1    10            10% G             5                 0.04-0.23
                                                            (glasshouse)
                                            2     5            250 g/l           5                 0.32-0.57

                                                 preplant broadcast
                                                 5.6           10% G           51-150              0.11-0.132
                  U.K.          1974             11.2          10% G                               0.05-0.12
                                                 post plant broadcast
                                                5.6-6.7        10% G            12-14              0.66
                                                                                21-30              0.012
                                                   9           10% G            21-30              0.092
                                                 11.2          10% G            21-30              0.52
                                                 preplant + postplant broadcast
                                                 5.6+5.6       10% G            12-14              0.152  (0.85)
                                                 11 + 5.6      10% G            12-14              0.072
                                                 11 + 11       10% G            12-14              0.78
                                                                                                                                             

    1  CIVO report R 6282 (1979)
    2 under glass

    TABLE 2.  Continued...

                                                                                                                                            
                                                Rate, kg                      Interval
                                                ai/ha or                  last application                        No. in
    Crop          Country        Year      No.    % ai      Formulation   to harvest (days)      Range, mg/kg     range
                                                                                                                                            

                                                 unspecified application method
                                                 2.2-5         10% G1           unspecified        0.06-0.19
                                                 10.1                                              0.07-18.7

                  U.S.A.       1974-75     5-11  0.56          24% Liq.1          1                0.14-0.44            6
                  FL, 10                        (foliar)1                        2-3               0.04-0.31            6
                  locations                                                      4-5               0.08-0.35            6
                                                                                 6-8               0.25                 1
                                           5-12  0.84-1.1      24% Liq.1          1                0.26-1.0  (0.21)    11
                                                (foliar)1                        2-3               0.1-0.71            10
                                                                                 4-5               0.11-0.55           10
                                                                                 6-8               0.34                 1
                                           5-11    2.2         24% Liq.1          1                0.82-1.9             6
                                                 (foliar)1                       2-3               0.15-0.78            7
                                                                                 4-5               0.24-0.49            6
                                                                                 6-8               0.24                 1
                                            5      4.5         24% Liq.1          1                0.57                 1
                                                 (foliar)1                       4-5               0.35                 1
                                                                                 6-8               0.37                 1
                                                                                                                                             

    1  0.05 limit of determination
    

    Apples - Maximum oxamyl residues from approved dosage rates were 1.5
    mg/kg at 2-5 days after application and 1.2 mg/kg at the interval of 2
    weeks recommended for uses on bearing trees although the application
    rate at the latter residues level was less than the maximum permitted.
    Residues of DMCF ranged from 0.02-0.05 mg/kg from approved use.  There
    was no data from uses on non-bearing trees although a one-year
    interval is applied for that use.

    Bananas - Residues of oxamyl or DMCF were <0.02 mg/kg from
    application rates up to 1.7 times maximum recommended dosage in whole
    fruit (bagged or unbagged) or edible pulp.  The data reflect foliar
    applications only.

    No residue data were provided for non-foliar uses on bananas.

    Beans - Although no residue data were available from the single
    country for which recommended usage information was available, data
    encompassing those rates were available from trials in the U.S. where
    similar uses and a 7-day pre-harvest interval have been proposed.
    Residues of oxamyl from pre-plant uses on succulent beans were <0.02
    mg/kg although such data were quite limited.  Maximum residues of
    oxamyl from recommended foliar rates were 1.0, 11 and 15 mg/kg in
    succulent beans, foliage, and hay respectively and 0.09, 0.15 and 0.20
    mg/kg respectively for DMCF, all at a 14-day interval.  At 7 days
    maximum oxamyl residues were 2.3, 33 and 25 mg/kg respectively on
    succulent beans, foliage and hay.  A 14-day pre-harvest interval is
    recommended for beans but not specified for forage-hay.  An 18-day
    pre-graze or pre-forage interval is proposed in the U.S.A.

    Oxamyl residues on dry beans from rates reflecting recommended uses
    were <0.02 mg/kg and were 0.18 and 0.08 mg/kg on straw and vines
    respectively, although most such applications were pre-plant.

    Residue data from foliar uses are needed on dry bean varieties and
    additional residue data from pre-plant uses on succulent beans,
    including additional data on feed items from these uses.  Such data
    should come from other countries as well as from the U.S.A.  The
    potential for residues in meat and milk warrants complete data on feed
    items.

    Celery - Good agricultural practice information (both pre-plant and
    foliar) was available from 2 countries although of these only residue
    data from foliar treatments in the U.S.A. were available. Maximum
    residues at the recommended 2-week pre-harvest interval were 3.1 and
    2.4 mg/kg respectively for untrimmed and trimmed celery.  Residue data
    from other countries would be desirable.

    Citrus - (grapefruit, lemons, oranges, tangelos, tangerines) - Residue
    data on these citrus crops were available from the U.S.A. reflecting
    foliar good agricultural practices.  No data were available from good
    agricultural practices on non-bearing citrus trees.  The maximum
    residue on citrus from recommended usage was 1.2 mg/kg on grapefruit
    from only one application at the recommended 7-day pre-harvest

    interval and this at an application rate 0.7 kg ai/ha, thus less than
    the maximum 1.2 kg ai/ha recommended.  At 1.5 kg ai/ha maximum
    residues, again on grapefruit, were 2 mg/kg at 7 days from only one
    application.  Residues on oranges from application rates 2 times the
    maximum recommended rate were 3 mg/kg.  Residues from multiple
    applications at recommended rates would be expected to be less than 3
    mg/kg.

    No additional residues of oxamyl were released when citrus samples
    were subjected to -glucosidase enzyme treatment.

    Corn field - Good agricultural practice information was not provided
    for corn although a 0.56-2.2 kg ai/ha at planting 24% liquid
    formulation use is proposed in the U.S.A.  Residues from applications
    up to 2 times this rate resulted in oxamyl residues of <0.02 mg/kg in
    the kernels and stalk at 93-198 days after treatment. Only 3 analyses
    were made on stalks.  Additional residue data are needed for forage
    and fodder as well as additional residue data from major corn
    producing areas.

    Cottonseed - Good agricultural practice information was not provided
    for oxamyl uses on cotton although uses at 0.028-1.1 kg/ha foliar
    applications of a 24% liquid formulation and a 21-day PHI interval
    have been proposed in the U.S.A.  Residue data reflecting these uses
    were available with residues up to 0.17 mg/kg near the proposed 21-day
    pre-harvest interval.  Residues would not be expected to exceed 0.2
    mg/kg.  No DCMF residue was detected in cottonseed meal or oil.

    Cucurbits - (cantaloupe, cucumbers, honeydew, summer squash, vining
    squash, watermelons) - The only available registered use information
    for cucurbits were on greenhouse cucumber, in Bulgaria, Czechoslovakia
    and the Netherlands and for cucurbits (greenhouse and in the open) in
    Greece.  No residue data were provided from these countries except the
    Netherlands although residue data on the above cucurbits were
    available from the USA where pre-plant and foliar liquid formulation
    uses with a 1-day pre-harvest interval are proposed, the former at
    2.2-4.5 kg ai/ha and the latter proposed use at 0.56-1.1 kg ai/ha. 
    The proposed foliar treatment rate is therefore comparable to the
    Greek spray uses.  Some data from pre-plant granular trials in the
    U.S.A. were also provided but none for the proposed pre-plant liquid
    formulation uses.

    Maximum residues on cucurbits at the recommended 1.2 kg ai/ha foliar
    rate were 0.77 and 0.48 mg/kg at 1 and 3 days respectively and 0.47
    mg/kg for granular pre-plant treatment at 66 days; for a combined
    pre-plant-foliar application a maximum residue of 1.24 mg/kg was
    observed.  Foliar residues on the various cucurbits were generally
    comparable at comparable intervals and application rates.  Residue
    data from the U.K. were of little value because of lack of knowledge
    of the interval, formulation and method of application.

    Residue data resulting from recommended uses in countries other than
    the U.S.A. (including glasshouse uses) are needed as well as
    additional data from pre-plant uses (including liquid formulations).

    Onions - Only limited data were available.  Maximum residues from
    apparent at-plant applications at less than the maximum recommended
    rates were <0.04 mg/kg at 100-150 days or at intervals unspecified.
    Data from other countries are needed.

    Peanuts - Information on recommended good agricultural practices for
    oxamyl on peanuts was not provided although pre-plant application of a
    10% granular formulation at 3.4-5 kg ai/ha and 24% liquid formulation
    at 3.4-5.6 kg ai/ha are proposed uses in the U.S.A.  No specific
    pre-harvest interval is proposed.  Also proposed is a 1.1 kg ai/ha
    foliar application of the 24% liquid formulation.  Residue data from
    the U.S.A. reflecting these proposed rates were provided.  Maximum
    residues were 0.04 mg/kg in hulls and 1.0 mg/kg in hay.  Combining
    maximum residues from separate soil and foliar uses results in 0.06
    mg/kg for nuts, 0.15 for hulls and 1.6 for hay.  Residues would not be
    expected to exceed 0.1, 0.2 and 2 mg/kg in the nuts, hulls and hay
    respectively.

    Peas - Only very limited data were available and it was on an
    unspecified pea variety.  Maximum residues from recommended granular
    pre-plant application rates were <0.01 mg/kg in pea or pod although
    the interval was not given.  At over 4 times the recommended granular
    rate residues were <0.01 for the pea and 0.15 mg/kg on the pod, again
    the interval was not provided.  Additional data are needed on specific
    peas and with known intervals.

    Bell peppers - No residue data were provided from the three countries
    for which recommended uses were provided.  However, residue data on
    bell peppers provided from field trials in the U.S.A. reflect proposed
    uses of 0.56-1.1 kg ai/ha foliar and 0.56 kg ai/ha transplant water
    treatments.  A one-week pre-harvest interval is proposed as compared
    to the two-week interval recommended.  The foliar treatment was
    reasonably close to the maximum recommended foliar use in Table 1. 
    Maximum residues from the proposed foliar treatment were 1.3 mg/kg at
    7 days (1.7 at recommended rates) after last application or at
    intervals greater than 8 days.  No data were available from the
    proposed transplant water treatment alone.  Maximum residues from the
    proposed transplant water application with a less than maximum foliar
    application was 0.7 mg/kg at 7 days.  Combined residues could
    therefore be expected to be about 2.4 mg/kg at 7 days.  A limit of 3.0
    mg/kg would allow for some variability due to the relatively small
    number of samples.  Residue data from additional countries are
    desirable and should include data from glasshouse uses.

    Pineapples - Good agricultural practice information was not made
    available although a liquid formulation pre-plant use at 4.5-9 kg
    ai/ha and a foliar use at 1.1-4.5 kg ai/ha with a 30-day pre-harvest
    interval are proposed in the U.S.A.  Data reflecting the proposed
    foliar use were available with maximum residues of 0.91 mg/kg in whole

    fruit (27 days), 5.2 in bran (27 days), 1.4 in leaves at 23 days or
    0.82 at 35 days and 8.5 in hay (27 days).  Residues would therefore
    not be expected to exceed 1.0, 6.0, 1 or 10 mg/kg in the whole fruit,
    bran, forage, and hay respectively at the proposed 30-day interval.

    Root and tuber vegetables (beets, carrots, sugar beets and sweet
    potatoes) - Although good agricultural practice information for root
    and tuber crops was available from a number of countries, most of the
    residue data on the above root and tuber crops were from trials in the
    USA where, in addition to USA-recommended uses in Table 1, additional
    uses have been proposed.  Of these proposed uses, broadcast and furrow
    pre-plant liquid formulation application of 4.5-9 and 2.2-4.5 kg ai/ha
    respectively are proposed for carrots and similar pre-plant rates and
    a 7-day pre-harvest interval are proposed for potatoes.  From
    recommended application rates and methods of application, maximum
    residues on root and tuber crops were 0.06 mg/kg at 14 days after last
    application and from proposed uses, 0.1 mg/kg at 7 dove (both on
    potatoes).  The majority of residues from recommended or proposed uses
    were 0.03 mg/kg or less.  Residues for the root and tuber crops for
    which data are provided would not be expected to exceed 0.1 mg/kg from
    recommended and proposed uses.  No data were available from processing
    fractions of root crops.

    Residue data on root and tuber vegetables resulting from recommended
    good agricultural practices from additional countries are desirable.

    Soybeans - Good agricultural practice information was not available. 
    A proposed USA use would allow liquid formation at-plant and pre-plant
    treatments at 2.2-4.5 kg ai/ha and data from 7 states reflecting and
    up to 1.5 times these proposed uses were available for dry beans and
    straw.  Maximum residues were 0.05 mg/kg for the dry seeds and straw
    at 113-185 days after last application although all but one sample
    each for seeds and straw from the 24 tests were <0.02 mg/kg.  The
    maximum 0.05 mg/kg residue in soybean seed was from an application
    rate of one-fourth of the maximum proposed.  On this basis residues
    from the proposed uses would be expected to be less than 0.2 mg/kg.

    No data were available for the oil, meal, hulls, forage or hay,
    although a forage restriction is proposed.  Although no concentration
    data for the oil or meal were available, a 0.33 n-octanol water
    partition coefficient would suggest that concentration of residues may
    not occur.  This would be consistent with fractionation studies on
    cottonseed and peanuts.

    Sugarcane - Good agricultural practice information was not provided
    for oxamyl on sugarcane.  The limited residue data from trials in
    South Africa were not useful because of uncertainties on dosage rates.

    Tomatoes - Good agricultural practice information was available from
    eleven countries, although of these residue data were available only
    from the United Kingdom and the USA.

    The application rates for the U.K. residues data cannot be compared to
    the 0.1 g/plt use described in the label provided.  Maximum residues
    from the trials were 0.85 mg/kg at the U.K. recommended 2-week pre-
    harvest interval.

    In the USA 1-3 day intervals are allowed for foliar uses.  Maximum
    residues from foliar uses recommended in the USA (FL) were 1.0 mg/kg
    at a one-day interval and 1.9 mg/kg at two times the recommended rate.
    No data were available for drip irrigation uses.  The data would
    indicate that residues would not exceed 1.0 mg/kg from U.K. uses and
    USA foliar uses, taking into account their different pre-harvest
    intervals.  However, the relatively small number of samples at a given
    rate would dictate a higher limit.  Additional data from these and
    other countries reflecting good agricultural practices would be
    desirable.


    FATE OF RESIDUES

    Figure 2 lists the names and structures of oxamyl and related
    compounds.


        Figure 2.  Names and structures of oxamyl and related compounds


    COMPOUND         NAME                                    STRUCTURE


                                                                     O     O
    OXAMYL           METHYL N',N'-DIMETHYL-N[METHYL                  "     "
                     CARBAMOYL)OXY]-1-THIOOXAMIMIDATE        (CH3)2N-C-C=NOCNHCH3
                                                                       '
                                                                       SCH3

    (I)              OXIMINO METABOLITE                              O
                     METHYL N-HYDROXY-N',N'-                         "
                     DIMETHYL-1-                             (CH3)2N-C-C=NOH
                     THIOOXAMIMIDATE                                   '
                                                                       SCH3

    (II)             METHYL N-HYDROXY-N'-METHYL-1-                  O
                     THIOOXAMIMIDATE                                "
                                                              CH3NH-C-C=NOH
                                                                      '
                                                                      SCH3

    Figure 2 (continued)

    COMPOUND         NAME                                    STRUCTURE


                                                                      O
    (III)            N'N-DIMETHYLOXAMIC ACID                          "
                                                              (CH3)2N-C-COOH

                                                                    O
    (IV)             N-METHYLOXAMIC ACID                            "
                                                              CH3NH-C-COOH

                                                                      O
    (V)              DMCF                                             "
                     N,N-DIMETNYL-1-CYANOFORMAMIDE            (CH3)2N-C-CN

                                                                    O     O
    (VI)             METHYL N'-METHYL-N-                            "     "
                     [(METHYLCARBAMOYL)OXY]-1-                CH3NH-C-C=NOCNHCH3
                     THIOOXAMIMIDATE                                  '
                                                                      SCH3

                                                                      O O
                                                                      " "
    (VII)            N,N-DIMETHYLOXAMIDE                      (CH3)2N-C-C-NH2

                                                                      O
                                                                      "
    METABOLITE A     GLUCOSE CONJUGATE OF I                   (CH3)2N-C-C=NO-GLUCOSE
                                                                        '
                                                                        SCH3

                                                                     O
                                                                     "
    METABOLITE A'    GLUCLOSE CONJUGATE OF II                  CH3NH-C-C=NO-GLUCOSE
                                                                       '
                                                                       SCH3
    
    

    In animals

    In a ruminant metabolism study two lactating goats were maintained on
    diets containing approximately 10 mg/kg 14C-oxamyl for 10 and 20 days
    respectively (Harvey, 1980a).  60-70% of the radioactivity was
    eliminated in the urine and faeces, about 6% was expired, 2-3% was
    found in milk and an estimated 22% in the entrails and carcass.  The
    radioactive compounds were not identified.  However, there was no
    evidence of oxamyl or oximino compound in milk, blood and tissues
    (<0.01 ppm).

    If calculated as oxamyl, maximum residues would have been 0.4-0.6
    mg/kg in milk, and about 1.4 mg/kg in blood and tissues.  Little was
    found in fat.  Milk residues peaked at about 10-14 days but in blood
    they continued to rise throughout the feeding.  In each case residues
    rapidly decreased after withdrawal of the fortified diet.

    About 5% of the activity in milk was incorporated into natural
    lactose, caesin and lipids.  Two additional components were isolated
    and accounted for an additional 30% of milk residues.

    In a more recent study 14C-labelled oxamyl and selected metabolites
    were studied in vitro by incubation in rumen fluid of a Holstein
    cow (Belasco and Harvey, 1980).  Oxamyl was 41% metabolized within one
    hour and 99% within six hours.  After 24 hours incubation the oximino
    metabolite (I) and DMCF (V) accounted for 80% of the radioactivity (67
    and 13% respectively).  The remaining radioactivity at 24 hours was
    dimethyloxamic acid 5%, dimethyloxamide 10% and 1-2% each of minor
    metabolites previously identified in rat metabolism studies.

    Metabolite A, a major plant metabolite, was almost totally metabolized
    by rumen fluid.  This contrasts to rat metabolism where this compound
    is largely unchanged in vitro by liver microsomes and only slowly
    metabolized in vivo (Harvey and Han, 1978a).  About 70% of
    metabolite A was metabolized to DMCF by rumen fluid and the remainder
    to unidentified components.  The DMCF was found to metabolize to
    N,N-dimethyloxamide, N,N-dimethyloxamic acid and N-methyloxamic acid.
    Only the dimethyloxamide was not previously identified during rat
    metabolism studies.

    In a livestock-feeding study oxamyl was fed to Guernsey dairy cows at
    2, 10 or 20 mg/kg in the diet for 30 days (DuPont, 1973).  Recoveries
    of added oxamyl were 70% or greater in whole milk, milk fat, or milk
    aqueous fractions at 0.02-0.2 mg/kg fortification levels and over 80%
    at 0.04-0.40 mg/kg levels in meat.  No residues of oxamyl were
    detected (<0.02 mg/kg) in any sample of milk or milk fractions,
    liver, kidney, lean muscle or subcutaneous fat at any of the feeding
    levels.

    When these same samples were analysed for DMCF, no residues were found
    at any feeding level in milk or tissues (<0.02 mg/kg for milk, <0.04
    mg/kg for meat and fat).  Recoveries were 67-82% for 0.02-0.05 mg/kg
    fortification levels in milk and 46-100% at 0.04-0.2 mg/kg

    fortification levels in meat and fat (Du Pont, 1976).

    In a poultry-feeding study, adult laying hens were fed diets
    containing 0, 1 or 5 mg/kg oxamyl for a four-week period (Zahnow,
    1978).  Samples of eggs and tissues were collected and analyzed for
    oxamyl and DMCF.  Oxamyl residues were <0.02 mg/kg in eggs, liver,
    muscle and fat and <0.05 mg/kg in skin (due to limited sample
    availability).  Residues of DMCF were reported as <0.01 mg/kg in
    eggs, liver, muscle, fat and skin.

    Oxamyl recoveries from eggs averaged 76% at the 0.02 mg/kg
    fortification level and at this same level, except for an apparent
    error in skin data, averaged 85-97% in meat, tissues, skin and fat.
    Recoveries of DMCF were relatively low, averaging 58 and 50% at 0.01
    and 0.02 mg/kg fortification levels, respectively, in eggs and 54-63%
    in meat, fat and skin tissues at a 0.02 mg/kg fortification level.

    In plants

    Plant metabolism of oxamyl was studied in tobacco, alfalfa, peanuts,
    potatoes, oranges and tomatoes (Harvey, Han and Reiser, 1978).

    In one experiment two tobacco plants were each treated on the leaves
    with 10 mg 14C-oxamyl and grown in a growth chamber for 7 and 15 days
    respectively.  95% of the radioactive material was recovered at 15
    days; about 50% was surface residues, 37% extractable leaf internal
    residues and 0.1% or less in the roots.  About 4-5% were volatile
    components.  The surface residue was 95% oxamyl and 3% the oximino
    compound (I).  Of the leaf internal extractable residues, 56% was
    oxamyl, 5% oximino compound (I) and 39% was in the polar fraction, 93%
    of which was metabolite A and 7% N,N-dimethyloxamic acid.  The
    seven-day plants were not as extensively analyzed, but to the extent
    they were, residues were similar to the 15-day residues with the
    proportion of individual residues reflecting the shorter metabolism
    period.

    Alfalfa received three 0.5 lb. ai/acre 14C-oxamyl spray field
    treatments at two-week intervals and was harvested 2.5 weeks after
    last treatment.  Extractable residues were 75% of applied.  Of this,
    >90% was metabolite A with only about 0.8% each for oxamyl and the
    oximino compound (I).

    Peanuts received two foliar field treatments of 14C-oxamyl at 2 lb.
    ai/acre.  Samples of young plants were taken at four weeks after the
    first treatment, immediately before the second treatment, and
    additional samples at harvest.  There were therefore three fractions
    analyzed - young plants, mature hay and mature nuts.  In the young
    plant 99% of the radioactivity was determined to be a 2:1 ratio of two
    metabolites, A and A' (see figure 2).  No oxamyl or oximino compound
    (I) was detected.

    In mature hay -glucosidase treatment of a very polar fraction
    containing 99% of extractable residues released metabolites A and A',
    giving evidence of an initial polysaccharide type compound, i.e.
    metabolites A and A' with additional hexose units (see Figure 3). 
    Also about 1% of the residue was the oximino compound (I) and <0.5%
    oxamyl.  When unextractable residues (about 40% in mature hay or nuts)
    were treated with a mixture of cellulose enzymes, about 60% was
    released yielding a fraction characteristic of metabolites A and A'. 
    This suggests that the initial unextractable residue was a cellulose
    of starch-like structure.

    No oxamyl or oximino compound could be detected in the nuts.  Of
    extractable residues about 21% was incorporated into peanut oil
    lipids, about 18% into the polysaccharide-type structure found in
    mature hay, about 15% was in lipids or as glucose conjugates and about
    37% was unextractable.  Of the unextractables about 60% was in the
    form of the cellulose-starch type structures discussed above.

    Potatoes received five foliar field treatments of 14C-oxamyl at 0.5
    to 1.0 lb ai/acre giving an oxamyl residue equivalent of 7 mg/kg in
    the tuber.  Peels contained <1% of the total residue.  Free oxamyl or
    oximino compound accounted for <3% of the residue, although mild acid
    hydrolysis yielded 39% of the radioactivity in the form of oximino
    compounds I and II.

    Hydrolysis with -glucosidase yielded metabolites A and A', suggesting
    the initial presence of the polysaccharide conjugates discussed under
    mature peanut hay.  At least 35% of the 14C was determined to be
    incorporated into the glucose of the tuber starch.

    Apples were brush-treated in an orchard at 1.0 lb ai/100 gal and 6
    weeks later at harvest yielded 0.8-2.0 mg/kg residues, evenly
    distributed through the fruit.  About 98% of the residue was
    extracted, 77% being organosoluble.  Of the organosolubles 16% was
    oxamyl, 42% oximino compound I, and 17% DMCF.  The remaining 23% of
    total fruit residue appeared to be in the form of polysaccharide-type
    structures.

    Oranges were harvested for analysis six weeks after brush application
    of 14C-oxamyl to immature oranges at 1.2 lb. ai/100 gal.  Residues
    were 2.5 mg/kg on a whole fruit basis expressed as oxamyl.  Rind
    contained 82% of the residue and the juice 18%.  On a whole fruit
    basis, residues were 9% oxamyl, 6% oximino compound, 20% DMCF, 35%
    metabolite A, 22% metabolite A' and 8% unidentified polar metabolites.

    Small green tomato fruits were evenly spotted by pipet with 0.37 mg
    14C-oxamyl each and the mature fruit harvested two weeks later for
    analysis.  Residues were 59% oxamyl, 13% oximino compound, 5%
    metabolite A, 4% DMCF and 19% polar metabolites and natural products.

    The studies on tobacco, peanuts, and potatoes demonstrate the systemic
    nature of foliarly applied oxamyl, which readily translocates to the
    roots, legumes and tubers respectively.

    Figure 3 summarises a major metabolic pathway for oxamyl in plant
    tissues.  The methylcarbomoyl group is hydrolysed to form the oximino
    compound, followed by conjugate formation of the oximino compound with
    glucose to form metabolite A, which may undergo demethylation to form
    metabolite A'.  Metabolite A predominates in short-term studies (2-6
    weeks) with metabolite A' identified in moderate-length studies (1-2
    months).  At harvest little uncomplexed metabolite A or A' is found
    but 14C is incorporated into polysaccharide, cellulose or starch-like
    structures suggesting the addition of hexose units to metabolites A or
    A'.

    In addition to the metabolic route shown in Figure 2, oxamyl may also
    be completely broken down in plants and incorporated into natural
    plant lipids or into the glucose of starch.  The metabolite DMCF is
    frequently found as a plant residue and so is the oximino compound in
    some fruits.  No residues of the S-oxide or S,S,-dioxide of oxamyl or
    its oxime were observed during these investigations.

    FIGURE 3

    In soil and water

    Numerous studies have been conducted on oxamyl soil metabolism,
    decomposition, dissipation, adsorption, mobility effect on soil
    microorganisms and on dissipation and decomposition in water.  In one
    compilation of studies the decomposition of oxamyl in soil and water
    was investigated with various soils under aerobic and anaerobic
    conditions and in distilled or river water at various pHs, with
    artificial UV light or sunlight, and in the dark.  Also included were
    experiments on soil leaching and mobility in various soils (Harvey and
    Han, 1978b).

    Oxamyl stability was found to be highly pH dependent, hydrolysing to
    the oximino compound I only under mildly basic conditions.  In
    pH-adjusted distilled water 3% and 9% hydrolysis was observed after 24
    and 48 hours respectively at a pH of 6.9 and 30% within 6 hours at a
    pH of 9.1.  At a pH of 4.7 it was completely stable at least through a
    4-day period.

    In another of these studies 14C-oxamyl was rapidly degraded by soil
    under aerobic conditions in a glass metabolism apparatus.  The soil
    was treated at a rate of 4 lb. oxamyl/acre.  After 42 days under
    aerobic conditions 51% of the 14C had been liberated as 14CO2, 4%
    remained as oxamyl, <1% compound I and 37% as unextractable or
    unidentified polar tractions, much of which was found to be
    incorporated into soil organic fractions.  Under anaerobic conditions
    analogous residues at 42 days were 3, 8, 41, and 48% for CO2, oxamyl,
    compound I and unextracted or unidentified residues respectively.

    A half-life of 11-15 days was found under aerobic conditions in the
    laboratory when soil was treated at a rate of 6 mg/kg.  Under
    anaerobic conditions the half-life was about six days.  In another
    study the half-life of oxamyl in a loamy sand was 14 days.

    A study to the effect of soil moisture at 15C indicated half-lives of
    13-14 days in clay loam or loamy sand and 34-39 days in peaty or humic
    loamy sand (Smelt et al, 1979).  As soil moisture decreased to the
    wilting point there was a gradual decrease in conversion and this
    decreased further at below-wilt moisture levels with clay loam.  In
    humic loamy soil the conversion rate increased sharply at very low
    soil moisture content.

    In a soil-TLC experiment oxamyl appeared to be moderately to highly
    mobile with Rf values of 0.53-1.0 in four soils (Harvey and Han,
    1978b).  By one system, compounds with Rf values of 0.35-0.64 are
    rated as moderately mobile and those with Rf values of 0.96-1.00 as
    highly mobile.  This finding was consistent with laboratory adsorption
    studies on three soils which indicated no adsorption under conditions
    of the test.  This is also consistent with another laboratory soil
    adsorption-leaching study in which oxamyl was found to be highly
    mobile with 61-100% eluted through a 45 cm  5 cm diameter column of
    aged and fresh soil with 20 inches of water (Chrazanowski, undated).
    Of unleached residues >70% remained in the top five cm.

    This high mobility observed in laboratory studies was not confirmed by
    field studies.  In another of the collection of studies by Harvey and
    Han (1978b), volatility losses of 14C from three soil types (to a 15
    inch depth) treated at 6 lb. ai 14C-oxamyl/acre were 80-93% of
    original treatment at three-five months.  Only traces of oxamyl or
    compound I (<0.05%) was detected at three-five months in a soil
    extract although significant amounts were found at one week and one
    month.  Unextracted residues accounted for 14% of the original
    treatment at three-five months.  The leachate from a fine sand had the
    highest residues of the three soil types with 14C residues up to 6.8%
    of original treatment.  Of this 6.8% about 1% was oxamyl, 11%
    unidentified polar materials and 88% compound I.  Analysis again
    indicated 14C incorporation into soil organic fractions.

    In another of these studies oxamyl field soil leaching-disappearance
    studies revealed residues of 3.2 mg/kg (calculated as oxamyl) in the
    top four inches at zero days when treated at 5.7 lb ai/acre.  Residues
    decreased to 0.13 mg/kg in the top four inches at 30 days with a
    half-life of about one week.  Residues at the four-eight inch depth
    peaked at 0.15 mg/kg at nine days; at the 8-12 inch depth at 0.15
    mg/kg in the 9-23 day period; at the 12-18 inch depth at 0.11 mg/kg in
    a 9-23 day period; and at 0.06 mg/kg at 23 days at the 18-24 inch
    depth.  Residues were negligible (<0.04 mg/kg) through a 60-day
    interval at the 24-30 inch depth.

    Therefore, under practical conditions the field leaching and
    dissipation experiments do not support laboratory tests, which
    indicate that oxamyl is highly mobile.  They indicate some mobility
    and rapid dissipation, presumably mostly as CO2, with a half-life in
    soil of six to eight days with only trace residues leaching below
    15-18 inches within a 2-3 month period.  The rapid dissipation
    apparently minimizes leaching under field conditions.

    In a crop rotation study, cabbage, red beets and sorghum seeds were
    grown in the greenhouse in soils treated 30 and 120 days earlier with
    14C-oxamyl at 8 lb ai/acre (Harvey, undated).  At 30 days 19% of the
    original oxamyl remained in the soil.  Crops planted therein had at
    maturity residues of 0.6-4 mg/kg (calculated as oxamyl) or 0.01 to
    0.12 mg/kg of oxamyl plus its hydrolysis product.  At 120 days <1% of
    the original oxamyl remained.  Mature crops from the 120-day soil
    contained <0.2 mg/kg residue (calculated as oxamyl), of which <0.02
    mg/kg was oxamyl plus its oximino metabolite.  No DMCF was detected.

    The experiment would suggest that low levels of oxamyl plus its
    oximino metabolite could occur in these commodities if they are
    planted within 30 days of high soil applications of oxamyl.  Similar
    experiments in the field on other commodities reflecting maximum use
    rates would be desirable, including use of both liquid and granular
    commercial formulations.

    Two studies were conducted on the possible effects of oxamyl on soil
    microorganisms.  In one controlled laboratory study 5.0 mg/kg oxamyl
    in silt loam soil increased the time for 50% nitrification by 5 days

    although total nitrification after 3 weeks was the same as in the
    control (Han, undated).  No significant effect was observed at a 0.5
    mg/kg oxamyl level.

    In the other laboratory study the effect on the population and
    respiration of microorganisms was studied in soils treated at 10 mg/kg
    oxamyl (Peeples, undated).  No reduction was observed in the
    populations of either fungi or bacteria at one, two, four and eight
    weeks when compared to controls.  Respiration of soil microorganisms
    in these oxamyl treated soils was determined by measurement of CO2
    evolution.  Oxamyl had no effect on CO2 evolution.

    In storage and processing

    No information was provided on residues in stored commodities.  Data
    were provided on the effect of processing or simulated processing
    residues in several commodities:

    Apple - When apples with 1.2 mg/kg aged residues were processed in the
    laboratory to juice and wet and dry pomace (11OC, 17 hours) residues
    were reduced to 0.5, 0.85 mg/kg and none, respectively.

    Citrus - No concentration of residues was found in press juice, wet
    pulp, or dried pulp when field-treated oranges and grapefruit with
    terminal residues of 0.51 and 0.62 mg/kg respectively were analyzed.
    Residues of 0.37 and 0.30 mg/kg in the wet pulp of oranges and
    grapefruit respectively were essentially destroyed during the drying
    process (<0.05 mg/kg remaining).

    Cottonseed - In a fractionation study in which cottonseed was
    fortified with oxamyl at 0.2 and 0.5 mg/kg, residues did not
    concentrate in the meal or oil.  Residues recovered in the meal were
    5-8% of those on the undelinted seed; no residues were recovered in
    the oil.  No conversion to DMCF was detected.  Fortifications with
    metabolite A, the oximino compound I and DMCF also resulted in major
    losses of these compounds during fractionation.  The details of this
    study were not provided to the meeting.

    Peanuts - In a laboratory-simulated commercial oil extraction with
    refluxing hexane, maximum residues in oil and meal were 10 and 28%,
    respectively, of those in peanuts fortified at 0.2 and 2.0 mg/kg.

    Pineapple - A simulated commercial processing study demonstrated that
    residues in bran may be 0.4-6 times that in the whole fruit.  This is
    supported by actual residue data in Table 2.  A similar concentration
    occurs with the metabolite DMCF.

    Soybeans - Although no concentration data were available for soybean
    oil or meal, a 0.33 n-octanol water-partition coefficient would
    suggest that concentration may not occur.  This would be consistent
    with fractionation studies in cottonseed and peanuts.

    Tomatoes - When tomatoes with field-incurred or fortified residues of
    1-10 mg/kg oxamyl were ground and concentrated by cooking to a puree
    of one half the original weight, residues in the puree in mg/kg were
    one half or less of those in tomatoes.  Analytical recoveries were
    61-110%.

    Photodecomposition

    Hydrolysis of oxamyl to the oximino compound (I) was accelerated by UV
    light in both distilled water and river water, more rapidly in the
    latter (Harvey and Han, 1978b).  In river water treated with
    artificial UV light, residues after seven days were 22% oxamyl, 39%
    oximino compound (I) and 3% polar fractions.  In the dark, control
    residues were 84, 16, 0 and 0% respectively for the same compounds at
    ten days.

    Oxamyl degradation was enhanced still further when sunlight was used.
    Oxamyl decreased from 100% at zero day to zero after about 1.5 days.
    Oximino compound (I) decreased from a maximum of about 95% of the
    total radioactivity at 1.5 days to about 68% and 50% at seven and 21
    days, respectively, while its geometric isomer was increasing from
    about 4% at 1.5 days to 32 and 42%, respectively, at seven and 21
    days.  The oximino compound (I) and its geometric isomer declined
    after about 21 days, while the polar fraction increased from about 3%
    of the activity at 14 days to 20% at 42 days.

    At 42 days 14% of the total radioactivity was N,N-dimethyloxamic acid
    and two unidentified polar compounds, which accounted for 3% of the
    total.  A 17% loss of radioactivity during the six-week study was
    attributed to the loss of CO2.  No S-oxidation products of oxamyl or
    its oximino compound were observed.


    RESIDUES IN COMMERCE OR AT CONSUMPTION

    No information was provided to the meeting on evidence of residues in
    food in commerce or at consumption.


    METHODS OF ANALYSIS

    Methods are available for the analysis of oxamyl alone, oxamyl plus
    its oxime, and for its DMCF metabolise.

    A method for the analysis of oxamyl alone uses column chromatography
    to separate oxamyl from its oxime (Bromilow, 1976).  Oxamyl is
    extracted by blending with acetone dichloromethane (1:1) except for
    potatoes, in which case only dichloromethane is used.  After
    concentration the extract is chromatographed on a Florosil column with
    acetone as the eluting solvent.  The eluant is concentrated to a small
    volume for gas chromatographic analysis.

    An aliquot of sample and methanolic trimethylphenylammonium hydroxide
    is injected into the gas chromatograph for on-column derivatization to
    the methoxime derivative.  The gas chromatographic column is 0.5%
    carbowax 20 M + 5% SE-30 and detection is by a flame photometric
    detector equipped with a 394 nm filter.  At 0.02-0.04 mg/kg
    fortification levels average recoveries ranged between 87-91% on
    barley, peas, and potatoes and 69% on tomatoes.  Controls were
    generally <0.01 mg/kg although a high of 0.15 mg/kg apparent residue
    has been observed on pea pods.  Recoveries average 87-96% on soils.

    The low tomato recoveries were attributed to incomplete extraction of
    residues from extract concentrate.  On the basis of discussions, which
    will follow, it is probable that part of this loss was due to the acid
    catalyzed degradation of oxamyl by the highly acidic tomatoes.

    In another procedure oxamyl residues are determined as the oximino
    metabolite and expressed as oxamyl by using a 1.35 conversion factor
    (Holt and Pease, 1976).  The method also measures any free oxamyl
    oxime and this was confirmed with recoveries of 65 and 57% when
    tobacco was fortified with the oxime at 0.2-0.4 mg/kg.

    Oxamyl (and its oxime) are extracted from plant and animal tissues and
    soil by blending with ethyl acetate.  After concentration and
    partitioning with hexane the aqueous extract is made alkaline (pH 12)
    with 1 N NaOH and partitioned with chloroform, which is discarded. 
    The aqueous extract is heated to convert oxamyl to its oxime and again
    partitioned with chloroform.  The aqueous phase is partitioned with
    ethyl acetate - methanol (9:1) and concentrated for analysis with a
    flame photometric detector equipped with a 394 nm filter.  The
    chromatographic column is 10% SP-1200/1% H3PO4 on Chromosorb W AW.

    This method has been successfully used on over 25 agricultural
    commodities as well as on milk, animal tissues, soil, urine and
    faeces.  Average recoveries generally range from 75-100%.  A
    sensitivity of about 0.02 mg/kg is generally attainable for most
    commodities, although apparent residues of 0.04-0.05 mg/kg may occur
    at times in beans, citrus, peanut hay and onions and up to 0.26 mg/kg
    on bean foliage.

    Successful method trials using the Holt-Pease method were conducted in
    laboratories of the Environmental Protection Agency in the United
    States.  Recoveries were 77-82% at oxamyl-fortification levels of 3
    and 6 mg/kg in celery and 0.2-0.4 mg/kg in cottonseed.

    Somewhat low recoveries have been observed during analysis of highly
    acidic commodities, such as citrus, tomatoes, and peaches.  This can
    be minimized by making concentrations under alkaline conditions.

    A method is also available for the determination of the DMCF
    metabolite of oxamyl (Holt, 1976).  In this method the sample is
    extracted by blending with ethyl acetate and a potassium dihydrogen
    phosphate - NaOH buffer.  After concentration to an aqueous phase the

    sample is partitioned with hexane (which is discarded) and
    re-extracted into ethyl acetate, which is concentrated for analysis.

    Analysis is on a 5% Carbowax 20 M gas chromatographic column and
    detection with a nitrogen - phosphorous detector.  Recoveries on
    citrus, celery, strawberries and tomatoes averaged 66-100% and 60% on
    potatoes when the commodities were fortified at 0.04-2.0 mg/kg DMCF.
    Average recoveries were 74-100% on tomato paste, cottonseed oil,
    cottonseed meal and tobacco fortified at 0.2-2.5, 0.2-1.0, 0.1-0.50
    and 0.05-0.5 mg/kg respectively.  The sensitivity is generally
    considered to be 0.04 mg/kg.

    The buffer was incorporated into the procedure to minimize conversion
    of oxamyl or its oxime to DMCF when highly acidic commodities were
    analyzed.  This conversion was 5-15% without the buffer and, as
    discussed earlier, was observed by Holt and Pease (1976), reduced
    recoveries during the development and use of their oxamyl method.  The
    authors also note that under some conditions some thermal degradation
    of oxamyl or its oxime to DMCF may occur in gas chromatographic
    injection ports with temperatures in excess of 100-110C.


    NATIONAL TOLERANCES REPORTED TO MEETING

                                                                 
    Commodities                Tolerances (mg/kg)
                       USA    Netherlands    Fed. Rep. of
                                             Germany
                                                                 
    apples              2
    bananas             0.1 (reflecting 0.02 mg/kg in pulp)
    celery              3
    citrus              3
    cottonseed          0.2
    cucumbers                     1
    pineapple (whole)   1
    pineapple forage   10
    potatoes            0.1       0.05
    sugarbeet (roots)                         0.05 (provisional)
    tomatoes            2         1
                                                                 

    EVALUATION

    COMMENTS AND APPRAISAL

    Oxamyl is a systemic insecticide, miticide and nematicide registered
    or approved for use in numerous countries.  It is available as a
    liquid or granular formulation and is systemic whether applied
    foliarly or to the soil.  Foliar applications result in nematocidal
    action in the roots and likewise soil applications result in
    insecticide and miticidal action in the foliage.  It is also effective
    as a direct contact insecticide, miticide, and nematicide.

    Recommended use information for over 30 countries was provided to the
    meeting by the manufacturer.  Only a few countries officially provided
    this information directly to the meeting.

    Oxamyl is degraded in animals by two major pathways, hydrolysis to the
    oximino compound and enzymic conversion to N,N-dimethyloxamic acid.

    Metabolism studies with 14C-oxamyl in two rats showed that only 70%
    of the dose was eliminated in the urine and faeces in 72 hours.
    Substantial amounts (22% of the dose) were incorporated into the body
    tissues, especially the skin and hair, partly by conversion of
    14C-metabolites into natural amino acids.  The meeting expressed
    concern over the high tissue residues and the lack of identification
    of much (50%) of this material.

    Oxamyl has a high acute toxicity displaying the typical effects of
    carbamate insecticides: rapid onset of cholinesterase inhibition
    followed by rapid complete recovery.  There was no evidence of delayed
    neurotoxicity.  The acute toxicity of most of the metabolites is lower
    than oxamyl.  Oxamyl is not mutagenic or teratogenic.

    In a 3-generation rat reproduction study, 50 mg/kg of oxamyl in the
    feed slightly decreased the body weight of the weanlings.

    The dog is somewhat less sensitive than the rat.  In a 90-day and
    2-year feeding study a no-effect level of 100 mg/kg was observed.  In
    the long-term study with rats growth inhibition was found at 100 and
    150 mg/kg.  A slight effect was also observed in the males at 50
    mg/kg.  Owing to the lack of a clear no-effect level in the rat and
    lack of identification of 50% of the tissue residues, only a temporary
    ADI, based on the 2-year study in dogs, was allocated.

    Residue data were provided on 29 commodities or groups of commodities.
    Residues on individual crops were highly variable, reflecting the many
    combinations of uses and pest control needs.  Because of the many
    variables it was necessary to significantly condense detailed
    information on residues in table 2.  However, the detailed data were
    examined by the meeting.

    In some cases no residue data were available from countries for which
    recommended or approved use information was available but from a
    country with proposed uses.  In other cases no recommended or approved
    use information was available, although residue data were provided
    from a country with a proposed use.  Estimate of residues were made on
    the basis of available data.  The basis for those estimates are
    discussed.

    In plants a major metabolic route is the conversion of oxamyl to its
    oxime, which conjugates with glucose to form metabolite A.  This in
    turn may add additional hexose units to build progressively into
    polysaccharide and starch and cellulose, like structures.  With time,
    demethylation of metabolite A can occur to form metabolite A' which

    way also add additional hexose units.  In some plants complete
    breakdown of oxamyl occurs with incorporation into natural plant
    molecules such as glucose and lipids.  The metabolite DMCF is a
    residue in some plants and the oxime is found in some fruits.  No
    residues were observed for the S-oxide or S-dioxide of oxamyl. 
    Surface residues may be up to 50% of the total and most of this is
    oxamyl in some plants.

    In an in vitro rumen fluid metabolism study oxamyl was rapidly and
    almost totally metabolized.  The oximino and DMCF metabolites
    accounted for 80% of the radioactivity after 24-hour incubation. 
    These and remaining metabolites were similar to those identified in
    the rat metabolism studies.

    The major metabolite of plant metabolism, the glucose conjugate of the
    oxime, was almost completely metabolized in rumen fluid, mostly to
    DMCF.  This contrasts to the rat metabolism where this metabolite was
    resistant to metabolism.  When DMCF was metabolized in the rumen fluid
    the same metabolic products identified in the rat were found plus
    dimethyloxamide.

    In livestock feeding studies at up to 20 mg/kg in the diet of cattle
    and up to 5 mg/kg in the diet of poultry, no residues (<0.02 mg/kg)
    were found in animal tissues, milk, fat or eggs.  No feeding studies
    (or metabolism studies) were provided, for non-ruminant livestock
    other than poultry.  The available data suggest that there is no
    likelihood of residues in meat, fat, milk, poultry or eggs from
    approved uses on certain crops.  However, additional residue data from
    recommended uses on other important crops used for animal foodstuffs,
    e.g. sugarbeet leaves, are needed.

    Oxamyl is stable in acidic to neutral water but rapidly hydrolyses
    under alkaline conditions.  Ultraviolet light catalyzes the
    degradation to the oxime or its geometric isomer and eventually to
    polar compounds.

    Laboratory studies indicate that oxamyl should be highly mobile in
    soils, but field decomposition and leaching studies do not support
    this.  This is apparently because the relatively rapid degradation
    does not allow sufficient time for significant mobility.  On the basis
    of laboratory metabolism studies a major route of dissipation appears
    to be the evolution of CO2, although soil pH is a factor in some
    soils.  Significant residues seldom leached below an 18 inch depth
    under the study conditions.  The half-life of oxamyl in soil was
    highly variable, ranging from 6 -39 days, depending on variables such
    as location, soil type and moisture content.

    In crop rotation studies there was evidence that low levels of
    residues could occur in follow-up crops where oxamyl has been used in
    the soil.  These studies were 14C-oxamyl greenhouse studies.  Crop
    rotation studies under field condition and reflecting recommended
    usage would be desirable.

    No evidence of a permanent effect on soil microorganisms by the use of
    oxamyl was observed.

    No data were available on the effect of storage on oxamyl residues or
    on residues in food in commerce or at consumption.  Studies were
    available on the effect of processing on several commodities.  No
    concentration of residues was noted except in the case of pineapple
    bran where a 6-fold concentration occurred.

    Two methods of analysis are available.  In one, oxamyl is separated
    from its oxime and derivatized on a gas chromatographic column to its
    methoxime.  In the second, oxamyl and its oxime are extracted together
    and the oxamyl hydrolysed to its oxime for the gas chromatographic
    determination of total oxamyl plus free oxime residue as the oxime.
    Although both methods appear to be adequate, the latter would appear
    to be the method of choice for enforcement because it has apparently
    been much more extensively used and tested.  Most of the residue data
    provided to the meeting were developed with this procedure.  A
    disadvantage would be that it also measures the free oxime, which may
    not be of major toxicological concern.  The oxime is not, however, a
    major residue in many plants, although it can be in some fruits.

    The meeting examined residue data from supervised trials reflecting
    established or proposed good agricultural practice on a number of
    crops and commodities.  From these data the meeting was able to
    estimate the maximum residue levels that were likely to occur when
    oxamyl wee used in practice and when reported intervals between last
    application and harvest were observed,

    Level causing no toxicological effect 

    Dog: 100 mg/kg in the diet, equivalent to 2.5 mg/kg bw/day. 

    Estimate of temporary acceptable daily intake for man 

    0-0.01 mg/kg bw/day.


    RECOMMENDATIONS OF RESIDUES LIMITS

    The meeting concludes that the maximum residue levels listed below are
    suitable for establishing maximum residue limits.  The levels refer to
    the sum of oxamyl plus its oxime calculated as oxamyl.  Some figures
    are temporary (T), because either there is no recommended use or the
    data were inadequate to estimate a maximum residue level.


                                                                           
                      Estimated Maximum    Pre-harvest
                      Residue levels       Interval (days)
    Commodity              (mg/kg)
                                                                           

    apples                 2                    14
    banana                 0.051
    beans, kidney          3 (T)                7
    beans, kidney (dry)    0.051 (T)            50
    beans, lima            3 (T)                7
    celery                 3                    14
    citrus                 3                    7
    maize                  0.051 (T)            (at planting use)
    cottonseed             0.2                  21
    cucumber               2                    1
    melon                  2                    1
    summer squash          2                    1
    watermelons            2                    1
    peanuts                0.1 (T)
    peanut fodder          2  (T)
    peppers, bell          3                    7
    pineapple              1 (T)                30

    root and tuber vegetables:

    beets                  0.1                  14
    carrots                0.1                  14
    potatoes               0.1                  7
    sugar-beets            0.1                  7
    sweet potatoes         0.1 (T)              (apply within one week of
                                                 planting)
    soybeans (dry)         0.051 (T)            (pre-planting)
    tomatoes               2                    1
                                                                           

    1 at or about the limit of determination.


    FURTHER WORK OR INFORMATION

    Required (by 1983)

    1. Identification of animal tissue residues.
    2. Clarification of the no-effect level in the rat especially in
    relation to the marginal effect of 50 mg/kg on the body weight in
    several studies.
    3. Further data on beans, maize and soybeans for reconsideration of
    the temporary recommendations.
    4. Additional data on materials used for animal feedstuffs, e.g.
    sugarbeet leaves, maize fodder and bean fodder.
    5. Approved use information on those items for which only proposed
    uses were available.

    6. Further data are required on beans, maize and soybeans for
    reconsideration of the temporary recommendations.
    7. Additional data on materials used for animal feedstuffs, e.g.
    sugarbeet leaves, maize fodder and bean fodder.
    8. Approved use information on those items for which only proposed
    uses were available.

    Desirable

    1. Residue data from short-term feeding studies on pigs.
    2. Toxicological observations in man.
    3. Additional residue data from trials reflecting GAP in additional
    countries; in particular residue data on onions, peas, and sugarcane
    for which there are existing use patterns.
    4. Information on residues in foods in commerce and at consumption.
    5. Information on the effect on oxamyl residues of cooking, processing
    or storage of raw agricultural commodities.
    6, Crop rotation studies on additional commodities and under field
    conditions with applications of commercial formulations (both granular
    and liquid) according to maximum recommendations.


    REFERENCES

    Ashley, W.E. Acute oral test. Unpublished report, dd. 29-8-1974, from
    the Haskell Laboratory, report no. 585-74, submitted to WHO by Du Pont
    de Nemours and Company.

    Barbo, E.C. Oral LD50 test. Unpublished report, dd. 9-10-1972, from
    the Haskell Laboratory, report no. 399-72, submitted to WHO by Du Pont
    de Nemours and Company.

    Barnes, J.R. and Aftosmis, J.G. Cholinesterase tests with oxamyl.
    (1978) Unpublished report from Haskell Laboratory. Report no. 270-78,
    submitted to WHO by Du Pont de Nemours and Company.

    Barras, C.E. Acute inhalation toxicity. Unpublished report, 19-2-1974,
    from the Haskell Laboratory, report no. 30-74, submitted to WHO by Du
    Pont de Nemours and Company.

    Belasco, I.J. and Harvey, J. Jr. In vitro Rumen Metabolism of
    14C-Label Oxamyl and Selected Metabolites of Oxamyl. J. Agric. Food
    Chem., Vol. 28(4), 689

    Bromilow, R.H. Determination of Residues of Oxamyl in Crops and Soils
    by Gas-Liquid Chromatography. Analyst, Vol. 101, 982.

    Chrazanowski, R.L. Soil Absorption Studies With Vydate(R) Oxamyl
    Insecticide/Nematicide. Unpublished study provided to FAO as Vol. 1,
    Section I, May 30, 1980, Exhibit 2 by the Biochemicals Department,
    Experimental Station, E.I. Du Pont de Nemours and Co., Inc.,
    Wilmington, Delaware, 19898.

    Carroll, K.S. Oral LD50 test. Unpublished report, dd. 23-8-1972, from
    the Haskell Laboratory, report no 327-72, submitted to WHO by Du Pont
    de Nemours and Company.

    Civo. Gas Chromatographic Analysis of Residues of Oxamyl Residues in
    Cucumbers and Tomatoes, Report no. R 6282, Ir., PDA, Olthof (1979)
    Central Institute for Nutrition and Research, the Netherlands.

    Colburn, C.W. Acute skin absorption toxicity tests on rabbits.
    Unpublished report, dd. 30-12-1970, from the Haskell Laboratory,
    report no. 282-70, submitted to WHO by Du Pont de Nemours and Company.

    Culik, R. and Sherman, H. Teratogenic study in rats with
    S-methyl-l-dimethylcarbamoyl-N [(methylcarbamoyl)oxy] thioformimidate
    (IND-1410). Unpublished report, dd. 8-1-1971, from the Haskell
    Laboratory, report no. 5-71, submitted to WHO by Du Pont de Nemours
    and Company.

    Dale, N.C. Oral LD50 test. Unpublished report, dd. 30-3-1973, from
    the Haskell Laboratory, report no. 126-73, submitted to WHO by Du Pont
    de Nemours and Company.

    Dion, L.K. Fifteen-exposure dermal study with IND-1410 liquid
    S-methyl-l-dimethyl-carbamoyl-H-[(methylcarbamoyl)oxy]
    thioformimidate. Unpublished report, dd. 4-6-1970, from the Haskell
    Laboratory, report no. 235-70, submitted to WHO by Du Pont de Nemours
    and Company. 

    Du Pont. Oxamyl Livestock Feeding Studies, Milk and Meat. This
    unpublished study, dated January 1973, was provided to FAO as Vol. I,
    section 3, May 30, 1980, exhibit 17, by the Biochemicals Department of
    Du Pont.

    Du Pont. Livestock Feeding study. This unpublished study, dated
    4-19-76 was provided to FAO, Vol. I, Section 3, May 30, 1980, Exhibit
    18, by the Biochemicals Department of Du Pont.

    Du Pont. Residue data were provided to FAO as U.S. data - Vol. I,
    Section 4, Exhibits 21-28, May 30, 1980 by the Biochemicals Department
    of Du Pont.

    Fretz, S.B. Ten-dose subacute oral test. Unpublished report, dd.
    25-6-1968, from the Haskell Laboratory, report no. 150-68, submitted
    to WHO by Du Pont de Nemours and Company.

    Fretz S.B. Acute oral test. Unpublished report, dd. 27-12-1968, from
    the Haskell Laboratory, report no. 300-68, submitted to WHO by Du Pont
    de Nemours and Company.

    Fretz S.B. Oral LD50 test. Unpublished report, dd. 31-7-1969, from
    the Haskell Laboratory, report 214-69, submitted to WHO by Du Pont de
    Nemours and Company.

    Gibson, J.R. Oral LD50 test. Unpublished report, dd. 21-5-73, from
    the Haskell Laboratory, report no. 236-73, submitted to WHO by Du Pont
    de Nemours and Company.

    Han, J. C-Y. and Harvey, J. In vitro rat liver microsomal
    metabolism of oxamyl and selected metabolites of oxamyl. (undated)
    Unpublished report from Du Pont de Nemours and Company, submitted to
    WHO.

    Han, J. C-Y. Evaluation of Possible Effects of DPX-1410 on Nitrifying
    Bacteria In Two Different Soils. This unpublished undated study was
    made available to FAO as Vol. I, Section 1, May 30, 1980, Exhibit 5,
    by the Biochemicals Department of Du Pont.

    Harvey J. and Han, J. C-Y. Metabolism of oxamyl and selected
    metabolites in the rat. J. Agric. Food Chem. 26, 902-910.

    Harvey, J. Jr. and Han, J. C-Y. Decomposition of Oxamyl In Soil and
    Water. J. Agric. Food Chem, Vol. 26(3), 537.

    Harvey, J. Jr., Han J. C-Y. and Reiser, R.W. Metabolism of Oxamyl In
    Plants. J. Agric. Food Chem., Vol. 26(3), 529.

    Harvey, J. Jr. Metabolism of 14C-Oxamyl in the Lactating Goat. This
    unpublished undated study was made available to FAO as Vol. I, Section
    2, May 30, 1980, Exhibit 9, by the Biochemicals Department of Du Pont.

    Harvey, J. Jr. Crop Rotation Study with 14C-Oxamyl in the Greenhouse.
    This unpublished undated study was made available as Vol. I, Section
    1, May 30, 1980, Exhibit 3 by the Biochemicals Department of Du Pont.

    Henry J.E. Acute oral test (mouse). Unpublished report, dd. 2-6-1976,
    from the Haskell Laboratory, report no. 387-76, submitted to WHO by Du
    Pont de Nemours and Company.

    Holsing, G.C. 13-Week oral administration - dogs, insecticide 1410,
    final report. Unpublished report, dd. 10-10-1969, from the Hazleton
    Laboratories, Inc., submitted to WHO by Du Pont de Nemours and
    Company.

    Holt, R.F. Residue Procedure for the Determination of Oxamyl
    Metabolite N,N-Dimethyl-l-cyanoformamide (DMCF). This unpublished
    method, dated 5-3-76 was made available to FAO as Vol. I, Section 3,
    May 30, 1980, Exhibit 16, by the Biochemicals Department of du Pont.

    Holt, R.F. and Pease, H.L. Determination of Oxamyl Residues Using
    Flame Photometric Gas Chromatography, J. Agric. Food Chem., Vol.
    24(2), 263.

    Kaplan, A.M. Ninety-day feeding study in rats with
    1-cyano-N,N-dimethylformamide (INN-79), metabolite of Vydate.
    Unpublished report, dd. 26-8-1976, from the Haskell Laboratory, report
    no. 630-76, submitted to WHO by Du Pont do Nemours and Company.

    Ki Poong Lee. Oral ald and delayed paralysis test (white leghorn
    chickens). Unpublished report, dd. 4-6-1970, from the Haskell
    Laboratory, report no. 234-70, submitted to WHO by Du Pont de Nemours
    and Company.

    Morrow, R.W. Skin absorption acute toxicity test in rabbits - LD50. 
    Unpublished report, dd. 27-2-1973, from the Haskell Laboratory, report
    no. 94-73, submitted to WHO by Du Pont de Nemours and Company.

    Peeples J.L. Effect of Oxamyl on Soil Microorganisms. This unpublished
    undated study was made available to FAO as Vol. 1, Section 1, May 30,
    1980, Exhibit 6, by the Biochemicals Department of du Pont.

    Schmoyer, L.A, Oral LD50 test. Unpublished report, dd. 9-12-1969,
    from the Haskell Laboratory, report no. 375-69, submitted to WHO by Du
    Pont de Nemours and Company.

    Schmoyer, L.A. Acute oral test Unpublished report, dd. 29-12-69, from
    the Haskell Laboratory, report no. 411-69, submitted to WHO by Du Pont
    de Nemours and Company.

    Schmoyer, L.A. and Henry, N.W. Ind-1410 and cholinesterase activity.
    Unpublished report, dd. 14-1-1970, from the Haskell Laboratory, report
    No. 18-70, submitted to WHO by Du Pont de Nemours and Company.

    Sherman, H. Antidote study, Unpublished report, dd. 14-10-1969, from
    the Haskell Laboratory, report no. 322-69, submitted to WHO by Du Pont
    de Nemours and Company.

    Sherman, H., Barnes, J.R. and Aftosmis, J.O. Long-term feeding study
    in rats and dogs with 
    l-(dimethylcarbamoyl)-N-(methylcarbamoyloxy)-thioformimidic acid,
    methyl ester (IBD-1410): final report. Unpublished report, d.d.
    22-2-1972, from the Haskell Laboratory, report No. 37-72, submitted to
    WHO by Du Pont de Nemours and Company.

    Shirasu, Y., Moritani, M. and Watanabe, R. Oxamyl mutagenicity study
    using bacteria. Unpublished report, dd. 4-6-1976, from the Institute
    of Environmental Toxicology, submitted to WHO by Du Pont de Nemours
    and Company.

    Smelt, J.H., Dekker, A. and Leistra, M. Effect of Soil Moisture
    Condition on the Conversion Rate of Oxamyl. Neth. J. Agric. Sc. 27,
    191-198.

    Snee, D.A., Sherman, H., Barnes, J.R. and Stula, E.F. Ninety-day
    feeding study in rats with
    1-(dimethylcarbamoyl)-N-(methylcarbamoyloxy)-thioformimidic acid,
    methyl ester (IND-1410). Unpublished report, dd. 6-10-1969, from the
    Haskell Laboratory, report no. 308-69, submitted to WHO by Du Pont de
    Nemours and Company.

    Tayfun, F.O. One-hour inhalation toxicity. Unpublished report, dd.
    22-9-1969, from the Haskell Laboratory, report no. 281-69, submitted
    to WHO by Du Pont de Nemours and Company.

    Zahnow, E.W. Oxamyl - Chicken and Egg Feeding Study. This unpublished
    study, dated 12-4-78, was made available to FAO as Section 3, May 30,
    1980, Exhibit 19 by the Biochemicals Department of du Pont.

    


    See Also:
       Toxicological Abbreviations
       Oxamyl (JMPR Evaluations 2002 Part II Toxicological)
       Oxamyl (Pesticide residues in food: 1983 evaluations)
       Oxamyl (Pesticide residues in food: 1984 evaluations)
       Oxamyl (Pesticide residues in food: 1985 evaluations Part II Toxicology)