WHO Pesticide Residues Series, No. 1



    The evaluations contained in these monographs were prepared by the
    Joint Meeting of the FAO Working Party of Experts on Pesticide
    Residues and the WHO Expert Committee on Pesticide Residues that met
    in Geneva from 22 to 29 November 1971.1

    World Health Organization



    1 Pesticide Residues in Food: Report of the 1971 Joint Meeting of
    the FAO Working Party of Experts on Pesticide Residues and the WHO
    Expert Committee on Pesticide Residues, Wld Hlth Org. techn. Rep.
    Ser., No. 502; FAO Agricultural Studies, 1972, No. 88.

    These monographs are also issued by the Food and Agriculture
    Organization of the United Nations, Rome, as document AGP-1971/M/9/1.

    FAO and WHO 1972



    Chemical name

    2-chloro-1-(2,4 dichlorophenyl) vinyl diethyl phosphate.


    chlorfenvinfos, "Supona" (R), "Birlane" (R)

    Structural formula


    Chlorfenvinphos exists in two geometric isomeric forms: alpha (=cis)
    isomer and ß (=trans) isomer. In the ß (=trans) isomer the vinyl
    chlorine atom is opposite to the substituted aryl ring.

    The technical material contains not less than 92% of total isomers; a 
    typical sample contains 9.7% w/w cis-and 83.8% trans-isomer. The alpha
    isomer is less insecticidally active than the ß isomer.

    Other information on identity and properties

    (a)  Composition of technical chlorfenvinphos

         Analysis of a typical sample of technical chlorfenvinphos gave
         the following results:

                                  Component                             %w

         Chlorfenvinphos, cis-isomer (alpha isomer)                    9.7
         Chlorfenvinphos, trans-isomer (beta isomer)                  83.8
         1-(2,4-dichlorophenyl)vinyl diethyl phosphate                 1.1
         2,2 dichloro-1-(2,4-dichlorophenyl) vinyl diethyl
         phosphate                                                     3.8
         2-chloro-1(3,4-dichlorophenyl) vinyl diethyl phosphate
         (cis plus trans isomers)                                      0.9
         alpha, 2,6-trichloroacetophenone                              0.6
         alpha, alpha, 2,6-tetrachloroacetophenone                     0.1


    (b)  Physical and chemical properties of technical chlorfenvinphos

         Physical state:          Liquid at 25°C
         Colour:                  Amber
         Odour:                   Mild chemical
         Melting point:           -19 to -23°C
         Boiling point:           167-170°C at 0.5 mm Hg
         Vapour pressure:         1.7×10 mm Hg at 25°C
         Specific gravity:        1.36 at 15.6°/15.6°C
         Refractive index:        n25°C : 1.5272
         Inflammability:          Non-flammable
         Solubility:              Miscible with aceton, xylene, alcohol,
                                  Kerosene, propylene glycol and Korn oil.
                                  Sparingly soluble in water

         Stability:               Stable when stored in glass or
                                  polyethylene-lined steel containers

         Compatibility:           Can be used with most pesticides in
                                  common use

         Hydrolysis rate:         Half-life in water at 38°C is greater
                                  than 400 hours at pH 9.1, and greater
                                  than 700 hours at pH 1.1


    Biochemical aspects

    Absorption, distribution and excretion

    Six male and six female rats given an oral dose of 2 mg/kg
    (3.0 µci/mg) C14-labelled chlorfenvinphos (labelled in the vinyl
    moiety) excreted 51.9-77.4% of the C14 in urine within 24 hours. An
    additional 6.1-25.6% was excreted during the next 24 hours. Faecal
    elimination comprised 11.2% of the C14, and a further 1.4% was
    excreted via the lungs within 96 hours. The total dose was eliminated
    within 96 hours (Hutson et al., 1967).

    Two male and two female dogs were given capsules orally containing 0.3
    mg/kg (8 µCi) of C14-labelled chlorfenvinphos. 86% (82.6-91.4%) and
    4.1% of the administered C14 was eliminated in urine and faeces
    respectively within 24 hours (Hutson et al., 1967).

    Administration of 25-30 mg/kg orally to young rats resulted in
    detection of unchanged chlorfenvinphos in peripheral blood. A dog
    receiving 88 mg/kg orally showed similar concentrations of unchanged
    chlorfenvinphos in peripheral blood at similar time intervals (Hutson
    and Hathway, 1967).

    FIGURE 2

    The estimated half-life of chlorfenvinphos in the body fat of the
    rabbit is about 1 day (Hunter, 1964).

    Following intramuscular injection of C14-labelled chlorfenvinphos
    (647 µCi, 233 mg) into a lactating cow, only 0.2% of the
    radio-activity appeared in the milk, mainly in the first two milkings.
    75% of this C14 was secreted as unchanged chlorfenvinphos (Hunter,

    Oral administration of C14-labelled chlorfenvinphos (35.1 µCi,
    12.5 mg) to an adult man resulted in rapid elimination of the C14 in
    the urine, 72% of the dose being excreted in 4-1/2 hours, and 94%
    within 24 hours (Hutson, 1969).


    In rats, oral administration of 2 mg/kg, C14-labelled
    chlorfenvinphos is followed by complete metabolism of the
    chlorfenvinphos. Urinary metabolites comprise
    2-chloro-1-(21,41,dichlorophenyl) vinyl ethyl hydrogen phosphate
    (32.3% of administered C14,
    [1-(21,41dichlorophenyl) ethyl ß-D-glucopyranosid] uronic acid
    (41.0% of administered C14), 2,4-dichloromandelic acid (7.0% of
    administered C14), 2,4-dichlorophenylethanediol glucuronide (2.6% of
    administered C14), and 2,4-dichlorohippuric acid (4.3% of
    administered C14) (Hutson et al., 1967).

    In dogs receiving 0.26 mg/kg C14-labelled chlorfenvinphos complete
    metabolism also occurred. The urinary metabolites were present in
    different proportions as follows:
    2-chloro-1-(21,41 dichlorophenyl) vinyl ethyl hydrogen phosphate,
    69.6%; [1-(21,41-dichlorophenyl) ethyl ß-D-glucopyranosid]
    uronic acid, 3.6%; 2,4-dichloromandelic acid, 13.4%;
    2,4-dichloro-phenylethanediol glucuronide, 2.7%. The
    2,4-dichlorohippuric acid was not detected (Hutson et al., 1967).

    In the lactating cow following 0.58 mg C14-labelled
    chlorfenvinphos/kg injected intramuscularly, the 0.2% radioactivity
    found in milk contained 75% unchanged chlorfenvinphos; together with
    small amounts of 2,4-dichloroacetophenone, 1-(2,4-dichlorophenyl)
    ethanol, and 2,4-dichloromandelic acid. Urinary metabolites comprised
    1(2,4-dichlorophenyl) ethanol and 1(2,4-dichlorophenyl) ethanediol.
    The glucuronides of these compounds were not detected (Hunter, 1969a).

    In man, five metabolites were identified in the urine following a
    single oral dose of 12.5 mg C14-labelled chlorfenvinphos. These were
    2-chloro-1-(2,4-dichlorophenyl) vinyl ethyl hydrogen phosphate
    (23.8%), 2,4-dichloro-mandelic acid (23.9%),
    [1-(2,4-dichlorophenyl) ethyl ß-D-glucopyranosid] uronic acid,
    2,4-dichlorophenyl-ethanediol glucuronide, and 2,4-dichlorobenzoyl
    glycine (Hutson, 1969).

    Effects on enzymes and other biochemical parameters

    In vitro incubation with dog, rabbit and rat liver slices show the
    conversion rates of chlorfenvinphos to
    2-chloro-1-(21,41-dichlorophenyl) vinyl ethyl hydrogen phosphate
    were 88:24:1 respectively. The enzyme was associated with the
    microsomal fraction of rabbit liver homogenate, and possessed the
    properties of a hydroxylase, the reaction being an oxidative
    0-deethylation (Donninger et al., 1966). In addition, a soluble
    de-0-methylation fraction has been isolated from the supernatant
    fraction, whose activity is lost after dialysis.

    Glutathione appears to act as the methyl acceptor for the soluble
    enzyme. Enzyme activity, in similar amounts was found in mouse, rat,
    and pig livers (Hutson et al., 1967).

    I50 values following incubation with blood of various mammalian
    species were 1.6 × 10-6, 1.4 × 10-5, 3.0 × 10-3, 3.9 × 10-6,
    4.0 × 10-4, 86.3 × 10-4 for "true" cholinesterase and 1.0 ×
    10-14, 6.3 × 10-4, 5.6 × 10-12, 7.0 × 10-5, 1.0 × 10-14 and
    1.0 × 10-14 for "pseudo" cholinesterase for mouse, rat, guinea pig,
    rabbit, dog, and man respectively (Brown, 1964).

    Incubation of chlorfenvinphos with mouse liver slices caused an
    increase in anti-"true" cholinesterase activity which reached a peak
    at 30 minutes and was still elevated at 45 minutes. Chlorfenvinphos
    concentration decreased 29.8% in 30 minutes. In rat, anti-"true"
    cholinesterase activity declined sharply throughout the 45 minutes of
    incubation. Chlorfenvinphos concentration decreased 37.8%. In dog,
    there was an initial drop of anti-"true" cholinesterase activity for
    10 minutes, followed by rapid recovery. Percentage decrease of
    chlorfenvinphos was only 10.9% (Brown, 1964).


    Special studies


    Four groups of 30 male and 20 female rats were fed 0, 30, 100 or 300
    ppm in the diet through three generations, the second litters of each
    generation being used as parents for the next generation. Males were
    rotated three times during each breeding sequence of 20 days.
    Autopsies were performed on parent rats, and on F1-3/b weanlings.
    Plasma and erythrocyte cholinesterase levels were measured in F2b
    generation 30-week-old adults (0, 30 and 100 ppm levels) and in F3b
    siblings at 0 and 30 ppm three weeks after weaning. After weaning of
    F3b rats, F2b females fed 30, and 100 ppm diets were cross-mated with
    rats on 0 ppm diet, to produce F3c litters. Body-weight for all parent
    generations was reduced at all dose levels. No offspring on the 300
    ppm diet survived beyond the F1 generation. Fertility was unaffected

    in the Fo generation; reduced at 100 and 300 ppm in the F1/b
    generation; and also reduced at 30 ppm in the F2/b generation.
    Viability and lactation indices were reduced at 100 and 300 ppm in all
    matings; and at 30 ppm in the F1/b and F3/b litters, lactation index
    was reduced. In the F2/b 30 ppm female × control male cross, fertility
    index was still reduced (fertility index 25%). A reverse cross
    (control females × 30 ppm males) resulted in a fertility index of 42%.
    Vaginal smears of 0, and 30 ppm females were normal. Plasma and
    erythrocyte cholinesterase levels were depressed in F2/b adults, at 30
    and 100 ppm, and in F3/b weanlings at 30 ppm (Ambrose et al., 1970).

    Four groups of 10 male and 20 female rats were fed 0, 1, 5, or 15 ppm
    in the diet through three generations, of two litters/generation.
    Parent animals commenced on treated diet at weaning in the Fo animals.
    During mating, two males were exposed to each female over a 14-day
    period. F3/b weanlings were autopsied. The only adverse effects were
    reduction in body-weight of F1/b pups at 1 ppm, and of F1/b adult
    males at 1 and 5 ppm (Eisenlord et al., 1967).


    Groups of adult hens were injected i.p. daily for 10 days (or until
    death) with 0 (5 hens), 100 (6 hens), 150 (3 hens), and 200 (4 hens),
    or 300 (2 hens) mg/kg/dose in 20% ethanol-80% propylene glycol
    solution. Two further groups of three hens received 100, or 200 mg/kg
    together with 1 mg atropine sulphate/kg. The hens were autopsied 20
    days after the last dose. All doses induced symptoms of cholinesterase
    depression, and all groups suffered mortalities. Atropine did not
    protect against the lethal effects. Survivors (5 hens at 100, 2 at
    150, and 1 at 200 mg/kg) showed no behavioural or histopathologic
    signs of neurological damage (Ambrose et al., 1970).

    Potentiation study

    Studies on the acute LD50 of chlorfenvinphos in combination with
    other pesticides show that mild potentiation occurred with Guthion;
    and strong potentiation with Diazinon, Malathion, methyl Parathion,
    and Ronnel. No potentiation occurred with Vapona, Ciodrin, Bidrin,
    Co-Ral, Delnav, Dibron, Dimethoate, Disyston, EPN, Ethion, OMPA,
    Parathion, Phosdrin, Phosphamidon, Sevin, Systox or Trithion (Kehoe,

    Acute oral toxicity of metabolites

    Compound                                     Species       LD50 (mg/kg)     Reference
    2-chloro-1-(21, 41-dichlorophenyl)-vinyl                                    Hutson et
    ethyl hydrogen phosphate                     Rat           >1 000           al., 1967

    Compound                                     Species       LD50 (mg/kg)     Reference
    2,4-dichloromandelic                                                        Hutson et
    acid                                         Rat           >1 000           al., 1967

    2,4-dichlorophenacyl                                                        Hutson et
    chloride                                     Rat           1 450            al., 1967

        Acute toxicity

    Technical compound
    Species         Route         Solvent               LD50 (mg/kg)        Reference
    Mouse           Oral          Arachis oil           133 - 155           Hunter, 1964

    Mouse           Oral          DMSO                  150 - 200           Hutson and Hathway, 1966

    Mouse           Oral          Polyethylene          117                 Pickering, 1965

    Mouse           i.p.          Polyethylene          37                  Hutson and Hathway,
                                  glycol                                    1966

    Rat             Oral          Arachis oil           9.6 - 39.0          Ambrose et al., 1970
                                                                            Gaines, 1969, Virginia
                                                                            Medical College, 1962,
                                                                            Hunter, 1964

    Rat             Oral          DMSO                  10 - 15             Hutson and Hathway, 1966

    Rat             Oral          Polypropylene         10.9 - 13.3         Hunter, 1964

    Rat             Oral          Polyethylene          23.8                Pickering, 1965

    Rat             Oral          Propylene             10.8                Virginia Medical

                                  glycol                                    College, 1962

    Rat             i.v.          Lipomul 1%            6.6                 Ambrose et al., 1970

    Rat             i.p.          Polyethylene          8.5                 Hutson and Hathway, 1966

    Rat             Dermal        Xylene                30-108              Gaines, 1969,
                                                                            Pickering, 1965

    Species         Route         Solvent               LD50 (mg/kg)        Reference
    Guinea-pig      Oral          Undiluted             125 - 250           Hutson and Hathway, 1966
                                                                            Brown 1965

    Guinea-pig      s.c.          Undiluted             500                 Brown, 1965

    Rabbit          oral          Arachis oil           ca 300              Ambrose et al., 1970

    Rabbit          oral          Undiluted             500 - 1 000         Hutson and Hathway, 1966
                                                                            Brown, 1965

    Rabbit          Dermal        Undiluted             412 - 4 700         Ambrose et al., 1970
                                                                            Hunter, 1964
                                                                            Witherup and Schlecht.

    Dog             Oral          Corn oil              >12 000             Ambrose et al., 1970

    Dog             i.v.          Lipomul 1%            50.5                Ambrose et al., 1970

    Chicken         Oral          Polyethylene          36.6                Pickering, 1965

    (1 week)                      glycol/water

    Chicken         i.p.          Polyethylene          23.1                Pickering, 1965

    (1 week)                      glycol/water

    Hen             Oral          Polyethylene          240                 Pickering, 1965

    Hen             Oral          Undiluted             44 - 62.5           Brown,  1965

    Sheep           Abomasal      AR395/water           71.3                Pickering, 1965

    Calves          Abomasal      AR395/water           20                  Pickering, 1965

    Symptoms in all recorded cases were typical of anticholinesterase

    Short-term studies

    Six groups of 10 male and 10 female weanling rats were observed for
    five weeks during which base-line plasma and erythrocyte
    cholinesterase values were determined on five males and five females
    per group. The rats were then fed 0, 3, 10, 30, 100, or 1000 ppm
    chlorfenvinphos in the diet for 12 weeks. Plasma and erythrocyte
    cholinesterase was measured after 1, 2, 4, 6, 8, 10 and 12 weeks. All
    rats in excess of five males and five females/group were sacrificed
    after 12 weeks; the remainder being returned to normal diet for
    further cholinesterase studies after 1 and 4 weeks. These animals were
    autopsied after four weeks' withdrawal. Growth was depressed in both
    sexes at 1000 ppm, a slight reversal of the effect being apparent
    during the withdrawal period. Significant plasma and erythrocyte
    cholinesterase-depression occurred at 30 ppm and above, and sporadic
    depression was observed at 10 ppm. Plasma cholinesterase recovery was
    complete in one week at all levels except females at 1000 ppm where
    recovery was complete after four weeks' withdrawal. Erythrocyte
    cholinesterase activity recovered in four weeks, except in males
    previously fed 100 and 1000 ppm diets. Spleen organ/body-weight ratios
    were decreased in females at 30 and 100 ppm and kidney weights in both
    sexes at 30 ppm in rats sacrificed at 12 weeks only (Ambrose at al.,

    Three groups of 35 male and 35 female rats were fed 0, 1 or 3 ppm in
    the diet for three months. Plasma cholinesterase was marginally
    depressed at 3 ppm (Virginia Med. Coll., 1963).

    Four groups of two male and two female mongrel dogs were observed for
    five weeks during which time plasma and erythrocyte cholinesterase
    values were determined. The dogs were then fed 1, 10, 100, or 1000 ppm
    for 12 weeks. Cholinesterase determinations were made at 1, 2, 4, and
    10 and 12 weeks, when 1 dog/sex/group was sacrificed. The remaining
    dogs were returned to basic diets for eight weeks prior to sacrifice.
    Cholinesterase activity was determined at 1, 2, 4, and 8 weeks post
    dosing. Plasma cholinesterase was depressed at all dose levels.
    Erythrocyte cholinesterase depression was sporadic. By eight weeks
    post treatment, recovery trends were apparent for plasma
    cholinesterase activity, but not for erythrocyte cholinesterase
    activity (Ambrose et al., 1970).

    Four groups of beagle dogs were fed 0 (5 male and 5 female), 0.5
    (3 male and 3 female), 1.0 (4 male and 2 female) or 3.0 (1 male and 1
    female) ppm in dry diet for 16 weeks. The only effect was a decrease
    of between 14 and 24% in plasma cholinesterase when the 0 and 3 ppm
    levels were compared (Walker, 1965).

    Four groups of two male and two female beagle dogs were fed 0, 30, 200
    or 1000 ppm in the diet for two years, at which time survivors wore

    autopsied. One control dog was sacrificed in a moribund state at 97
    weeks. Plasma cholinesterase activity was depressed during the first
    39 weeks of the study at all dose levels. However, the lack of
    significant depression does not appear to be due to recovery, but to a
    drop in the plasma cholinesterase activity of the controls.
    Erythrocyte cholinesterase activity was significantly depressed at the
    1000 ppm level during the first 12 weeks, and again at 79 weeks
    (Ambrose et al., 1970).

    Long-term studies

    Five groups of 30 male and 30 female weanling rats were fed 0, 10, 30,
    100 or 300 ppm in diet for 104 weeks. At least 4 rats/sex/group were
    sacrificed at 13 weeks. The 300 ppm male survivors were sacrificed at
    95 weeks, and all other survivors at 104 weeks. Bodyweight of females
    on 100 and 300 ppm diets was depressed from 26 weeks to almost the
    termination of the study. Plasma and erythrocyte cholinesterase
    activity was reduced in all groups throughout the study, with the
    exception of male rats at 10 ppm during the second year.
    Organ/body-weights for female rat spleen were depressed at 300 ppm at
    13 weeks only, and male liver-weight ratio was increased at 100 ppm at
    104 weeks. There was no increase in tumour incidence. (Ambrose et al.,

    Observations in man

    Dermal exposure on the forearms of 11 adult males of 5-10 mg/kg of
    chlorfenvinphos for up to four hours, in three formulations (80% and
    24% E.C. and 25% WP + water) resulted in chlorfenvinphos detection in
    whole blood. Only the 24% E.C. caused plasma cholinesterase depression
    (Hunter, 1969).

    In vitro studies on human blood indicate that 50% cholinesterase
    depression require 1.1 × 10-8, or 4.9 × 10-7 concentrations for
    plasma and erythrocyte respectively (cf 1.1 × 10-8, and 1.6 × 10-8
    for paroxon) (Larson, 1964).


    Information is available on the metabolism of chlorfenvinphos in rat,
    dog and man. Over 90% of an administered dose is excreted in these
    species within 24 hours.

    Acute toxicity studies are available in three species and short and
    long-term studies are available in rats and dogs as well as
    multi-generation reproduction studies in rats. There appear to be
    considerable species differences in acute toxicity. In the short-term
    rat study the Meeting assumed that the description "disseminated
    granulomatous inflammatory processes" referred to changes attributable
    to non-specific respiratory diseases to which laboratory rats are
    prone. Some sporadic depression of red blood cell cholinesterase was
    noted in dogs but there was no consistent depression of plasma

    cholinesterase at 1 ppm. The 0.05 mg/kg bodyweight level was
    considered to be of no toxicological effect in both species and an
    acceptable daily intake was established on the basis of these studies.


    Level causing no toxicological effect

    Rat -1 ppm in the diet equivalent to 0.05 mg/kg body-weight per day

    Dog -1 ppm in the diet equivalent to 0.05 mg/kg body-weight per day

    Estimate of acceptable daily intake for man

    0-0.002 mg/kg body-weight per day.



    1.   Clarification of differences in acute toxicity between species.

    2.   Further information on the depression of red blood cell
         cholinesterase levels in dogs.


    Use pattern

    Chlorfenvinphos is a non-systemic organo-phosphorus insecticide which
    is used against soil-borne and foliage insects in both agricultural
    and horticultural crops and against ectoparasitic insects, ticks and
    mites on livestock.

    Pre-harvest applications

    Main uses are for the control of various root flies in root
    vegetables, e.g. carrots, potatoes, radishes, in brassicas and onions;
    for the control of Colorado beetle and other foliage pests on
    potatoes. The material is used as a seed dressing, soil or foliar
    application in cereal crops, e.g. wheat, corn and rice.

    Chlorfenvinphos is widely used in the following countries: Australia,
    France, Federal Republic of Germany, Hungary, Japan, Netherlands,
    United Kingdom and the following tables summarise the recommendations
    in accordance with good agricultural practice on crops and together
    with the more important insect pests concerned.

    Livestock uses

    Chlorfenvinphos is widely used for the control of ectoparasites of
    livestock (e.g. ticks, itch mites, lice, blowfly, screw worm),

    especially on sheep and beef cattle; it is only occasionally used on
    dairy cattle. On meat producing animals it is normally applied more
    than seven days before slaughter; rather shorter intervals are
    observed rarely, the minimum interval is two days before slaughter.
    When used on dairy cattle the material is used directly after the
    morning milking; the interval between application and next milking
    will then be about seven hours. Chlorfenvinphos is used both on cattle
    and sheep against ectoparasites mainly as a dip (0.05% a.i.) but it
    may also be applied as a saturation spray of similar strength.

    Main areas of use, on sheep: Australia, New Zealand, United Kingdom,
    South Africa; on cattle: South Africa, South and Central America,

    In some countries, a.o. France, the material is used as a residual
    spray (0.05%-0.1% a.i.) for the control of flies in dairy barns.

    Post-harvest treatments

    Chlorfenvinphos is not recommended for post-harvest use on
    agricultural commodities.

    Other uses

    Chlorfenvinphos is also used in the sphere of public health and
    municipal control programmes, a.o. against housefly,
    Musca domestica; stablefly, Stomoxys calcitrans; German cockroach,
    Blatella germanica; and mosquito larvae, Culex sp.

    Residues resulting from supervised trials

    Residue data are available from supervised trials carried out in
    different countries on food crops grown under various conditions and
    on livestock, using various rates of application and various
    pre-harvest or pre-slaughter intervals.

    In most cases, normal dosage rates were applied in accordance with
    label recommendations; the data from these trials on crops are
    summarized in Tables I, II and III. However, in some experiments
    higher dosages were also included; the results are summarized in
    Tables IV and V.

    In the more recent trials, samples were analysed for residues of both
    the cis-and trans-isomers of chlorfenvinphos, and where appropriate,
    these values are given in the tables. In all other cases the results
    of the analyses are given as the sum of the cis- and trans-isomers of
    chlorfenvinphos. Since field studies have she" that metabolites of
    chlorfenvinphos at detectable levels occur rarely in food crops,
    livestock and livestock products, no further reference will be made to
    them in this section (see section on Fate of Residues).

    Crop              Main pests          Recommended       Time of          Application
                                          dosage            application      method
    Brassicas         Cabbage root        up to 2 kg        at or near       as a drench,
    i.e. Cabbage      fly:                a.i./ha           planting         root dip or
    Brussels          Chortophila                                            granular soil
    sprouts,          brassicae                                              application in
    Swedes,                                                                  the row
    Turnips and

    Carrots,          Carrot rust         2-4 kg a.i.       before or        as granular or
    parsnips,         fly:                /ha               at sowing        spray appl., in
    celeriac and      Psilla rosae                                           the row or
    celery                                                                   broadcast

    Radishes          Radish fly:         2-4 kg a.i.       before           granular appl.,
                      Chortophila         /ha               sowing           in the row or
                      brassicae and
                      Ch. cilicrura

    Potatoes          Potato              2-4 kg a.i.       before           granular appl.,
                      weevil:             /ha               planting         in the row or
                      Phyrdenus                                              broadcast

    Onions and        Onion fly:          3-5 kg a.i.       before           as granular or
    lettuce           Hylemia             /ha               sowing or        spray appl., in
                      antiqua                               planting         the row or

    Wheat             Wheat bulb fly:     80 g a.i./        at sowing        as seed
                      Leptohylemia        100 kg                             dressing
                      hylemia             seed


    Crop              Main pests          Recommended       Time of          Application
                                          dosage            application      method
    Maize             Frit fly:           1-2 kg a.i.       at or near       as granular or
    (corn)            Oscinella           /ha               sowing           spray appl.
                      Frit                                                   over the seed
                      Rootworms:                                             row

    Peanuts           soil-borne          2-4 kg/ha         prior to         band treatment
                      insects                               pegging          with granulars

    Crop          Main pests        Recommended        Type of           Recommended
                                    dosage             application       interval
                                                                         and harvest
                                                                         in days
    Potatoes      Colorado          0.125-0.25 kg      foliar spray      7-21
                  beetle:           a.i./ha
                  Leptinotarsa      repeated if
                  decemlineata      necessary at
                                    2-3 week

                  Potato tuber      0.2-0.4 kg         foliar spray      21
                  moth:             a.i./ha

    Tomatoes,     Phtorimaea        0.25-1 kg          foliar spray      14
    Aubergines    spp.              a.i./ha

    Carrots,      Plutella          0.25-1 kg          foliar spray      30
    Cauliflower,  maculipennis,     a.i./ha
    Radish,       Pieris spp.
    Swedes,       Aphis spp.        0.5-2 kg
    Onions                          a.i./ha            dust

    Rice          Stem borers       0.25-0.5 kg        foliar spray      30*
                  Chilo spp.        a.i./ha
                  Tryporyza spp.    1 kg a.i./ha       granular          30*
                                                       to paddy water
    * Normally applications for borer control are made only in the early development
    of the crop, and only occasionally up until 30 days before harvest.
    The following conventions have been employed in presenting the data:

    1.   All application rates refer to active ingredient.

    2.   lbs/acre has been regarded as being essentially equivalent to

    3.   Mean values have been calculated on the basis that samples
         without detectable residues contained residues at half the limit
         of detection.

    Crops                Range of dosage     Pre-harvest      No. of          No. of       alpha and beta
                         rates in            interval         trial sites     results      chlorfenvinphos
                         kg a.i./ha*         (weeks)                                       in ppm
    Brussels sprouts     2.5-5               17               1               4            < 0.05
    Broccoli             2.5-5               11-17            1               4            < 0.04
    Cabbage              2.5-5               11-20            5               9            < 0.005-0.03
    Cauliflower          1-2.5               7-17             3               4            0.02-0.10
    Swedes               2.5                 14-18            1               2            < 0.05
    Turnips              1.0-4.0             10-16            3               4            < 0.02-0.04
    Potatoes             2.0-4.0             16-27            3               5            < 0.01-0.08**
    Carrots              2.0-4.0             14-48            7               17           < 0.01-0.35
    Celery               1.0-2.0             13-19            2               4            0.03-0.2
    Radish               2.0-4.0             4-9              3               6            < 0.02-0.05
    Wheat grain          3.8                 43               1               2            < 0.02
    Maize grain          1.5-4.0             10-16            3               4            < 0.04-0.05
    Peanuts (shelled)    2.0-4.0             11-31            8               11           < 0.05
    Mushrooms            50-170 ppm          4                1               3            < 0.01
    * Except where stated otherwise.

    ** One result only.

    Crops                Range of dosage     No. of           Pre-harvest     No. of          No. of      Sum of alpha and beta
                         rates in            applications     interval        trial sites     results     chlorfenvinphos
                         kg a.i./ha                           (weeks)                                     in ppm
    Cauliflower          1.0                 3                7               1               1           < 0.05
    Swedes               2.5                 1                14-18           1               2           < 0.05
    Carrots              0.5-2.0             1-6              2-7             2               4           < 0.02-0.18
    Radish               2.0                 1                2.5             1               1           < 0.02
    Potatoes             0.15-0.6            1-8              0.5-16          5               10          < 0.01-0.02
    Sweet potatoes       0.67                3                10              1               2           < 0.02
    Tomatoes             0.25-1              1-6              1-11            4               16          < 0.01-0.06
    Aubergines           0.25                1-3              5-11            3               12          < 0.01
    Onions               1.0                 1                4               1               1           < 0.02
    Maize grain          1.0-1.2             2                6-14            1               2           < 0.01
    Rice (polished)      0.36-0.40           1-4              5-12            8               14          < 0.02-0.04
    Cotton seed          0.25-2.0            1-7              5-13            3               9           <0.02-<0.05

    Crop                 Type                Range of dosage     Pre-harvest     No. of          No. of      Chlorfenvinphos residues
                         application         rated               interval        trial sites     results     sum of alpha and beta isomers
                                                                 (weeks)                                     in ppm range
    Cauliflower          root dip            0.05-0.10%          13              1               4           10.05
    Celery               root drench         17-18 mg/plant      11-16           2               2           0.2-0.49
    Radish               root drench         2.4 kg/ha           26              1               2           < 0.02
    Wheat grain          seed dressing       80-100 kg seed      37-43           2               5           < 0.02

    Crop                 Range of dosage     Pre-harvest      No. of          No. of      Chlorfenvinphos residues
                         rates in            interval         trial sites     results     in ppm
                         kg a.i./ha          (weeks)                                      range
    Cabbage              8                   16               1               1           0.01
    Carrots              5-8                 17-30            4               9           <0.01-0.12
    Onions               6                   22-26            3               3           < 0.01
    Potatoes             90                  26               1               1           0.27
    Radish               8                   8-9              1               3           <0.02-0.05
    Cauliflower          4-5                 11-20            2               3           <0.005-0.02

    Crop                 Range of dosage     Pre-harvest      No. of          No. of      Chlorfenvinphos residues
                         rates in            interval         trial sites     results     in ppm
                         kg a.i./ha          (weeks)                                      range
    Rice polished        0.6-3.0             2.5-12           10              50          <0.02-0.20

    4.   The following abbreviation has been used: a.i. - active

    Residues resulting from supervised trials - livestock


    Cheviot ewes, four years old and recently shorn, were dipped in 0.05
    and 0.1% chlorfenvinphos (i.e. once and twice the recommended dosage).
    A third group was sprayed with 0.2% chlorfenvinphos emulsion.

    From each group two animals were slaughtered 3, 7, 14 and 21 days
    after treatment. Residues of chlorfenvinphos were determined in
    omental, perirenal and pericardial fat. On no occasion chlorfenvinphos
    residues in the fat exceeded 0.10 ppm. After observing a seven-day
    pre-slaughter interval residues in the fat of animals dipped in 0.05
    and 0.1% chlorfenvinphos varied between (0.003 and 0.093 ppm (one
    animal). Chlorfenvinphos was only found in the fat and not in other
    organs or non-fatly tissues such as liver, spleen, adrenals, kidney,
    heart, lung, uterus, ovaries, brain, subcutaneous tissues and muscle
    (Robinson et al., 1966).

    Eight Dorset Dawn lambs (4 shorn and 4 unshorn), 3-4 months old, were
    dipped in chlorfenvinphos 0.05% (recommended dosage). Residues of
    chlorfenvinphos were determined in omental, perirenal, pericardial and
    subcutaneous fat, from animals slaughtered three and seven days after
    treatment. The upper limit was 0.02 ppm (Shell Res., 1965).


    Beef cattle were sprayed with 32P-labelled chlorfenvinphos in 0.05,
    0.25 and 0.5%. Residues were detected in tissues other than fat only
    when animals were sprayed at 5x and 10x the recommended rate of
    application of 0.05% (Ivey et al., 1966).

    In a more detailed study (Ivey et al., 1966) cattle were sprayed with
    0.1% chlorfenvinphos emulsion (= 2x the now recommended dosage) either
    12 times at weekly intervals or six times at intervals of two weeks.
    Residues were determined with a GLC method (Claborn et al., 1965) in
    omental fat of animals slaughtered seven days resp. 14 days after a
    weekly or two-weekly treatment. In the first series the
    chlorfenvinphos residues ranged between 0.009 and 0.245 ppm (one
    animal). In most of the samples the residues were <0.16 ppm. In the
    second series, where animals were slaughtered 14 days after a
    two-weekly treatment the residues in the fat varied between <0.005
    and 0.18 ppm. In fat from animals slaughtered two weeks after the last
    weekly or two-weekly sprays no residues of chlorfenvinphos could be
    determined (limit of determination <0.003 ppm).

    Decreasing the interval between last application and slaughter tended
    to increase the residue levels. In an experiment on nine young beef
    steers treated up to 13 times at weekly intervals with the recommended
    dosage and currently used application methods (spray concentration
    varying between 0.03 and 0.05%) the mean residue in omental fat of
    animals slaughtered two days after last application was 0.07 ppm with
    an upper figure in one sample of 0.11 ppm; with a pre-slaughter
    interval of seven days the mean level was 0.012 ppm (upper limit
    0.026) in subcutaneous fat and 0.006 (upper limit 0.01) in omental fat
    (Shell Res., 1968).

    For higher bath or spray concentrations residues were higher, roughly
    in proportion of the dosage used, where other factors were comparable,
    although higher concentrations are normally not used or recommended.

    There is no evidence of accumulation of chlorfenvinphos residues in
    the fat of treated animals in cases where a number of consecutive
    weekly treatments were applied (Ivey et al., 1966).

    In addition to meat animals, chlorfenvinphos is also recommended for
    the treatment of dairy cattle. Experiments have been carried out in
    which milking cows were treated according to the recommended dosage
    and to excessive dosages (5-7 times the recommended rate of 0.05%
    chlorfenvinphos) and milk analysed at intervals after treatment.
    Residues were highest when the treatment was given shortly before

    Milk sampled five hours after one application of 9 gram a.i./cow (5-7
    times the recommended rate) contained 0.105 ppm chlorfenvinphos (on
    whole milk), whereas a bulk sample of morning and evening milk of next
    day milking contained 0.013 ppm. Three, resp. five days after the
    treatment, residues of chlorfenvinphos in the bulked milk were 0.002
    and 0.00005 ppm/whole milk (Claborn, 1965a).

    When applied as a spray mist after each morning milking according to
    the recommended dosages, the minimum residues found were 0.001
    ppm/whole milk (range <0.005-0.001) (Claborn et al., 1965b).

    Roberts et al. (1961) compared with 32P chlorfenvinphos the residues
    in milk after using two different methods of application. 5 g
    chlorfenvinphos per cow was either brushed in with an aqueous spray
    (400 ml) or sprayed with 60 ml xylone solution, containing 5 g
    lanoline as sticker after the morning milking. Residues were measured
    as total extracted radio-activity in the morning milk of nine
    following days.

    In an intensive spray regime cattle were treated weekly. The interval
    between application and first milking was resp. 1-1/2, 4 and 7 hours.
    From the samples analysed average residues figures for the milk
    production of a week period were included. For the interval of 4 resp.
    1-1/2 hour the average residue in the milk of a week was about 0.01
    ppm. The corresponding figure for a seven-hours interval was about
    0.005 ppm. After treatments with a double dosage the levels were

    approximately proportionally higher. The residues were highest in milk
    from the first milking after treatment, but fell rapidly thereafter.
    With the recommended levels the figures for the first milking for the
    two shortest intervals were 0.056 and 0.053 respectively, and for the
    seven-hour interval 0.02 ppm. It is this first figure which dominates
    the means for the whole week, since at the next milking (next morning)
    levels had fallen by about 5-7 times and by the third day were barely
    distinguishable from the controls (Shell Res., 1969a).

    Time after         Chlorfenvinphos residues* total
    application    radio-activity basis: morning milk only
                        400 ml                 60 ml
                     Aqueous spray         Xylene spray
    8 hours              0.037                 0.02
    1 day                0.019                 0.009
    2 days               0.017                 0.005
    3 days               0.010                 0.003
    5 days               0.003                 0.002
    7 days               0.001                0.0008
    9 days               0.001                0.0008
    * Adjusted for 4% butterfat.

    Residues of chlorfenvinphos which could arise in milk when cows are
    fed with feed containing chlorfenvinphos, were studied at the North
    Carolina University (1965). Dairy cattle were fed 1, 10 or 50 ppm of
    chlorfenvinphos in their total diet for a period of two weeks. The
    residues of chlorfenvinphos and of 2,2', 4'-trichloroacetophenone in
    the milk of cows fed at the 1 and 10 ppm levels, were so close to the
    background levels, that little significance could be attached to the
    levels measured. Only with chlorfenvinphos levels of 50 ppm in the
    total feed, milk residues were detectable; at this level residues of
    chlorfenvinphos in whole milk were about 0.02 ppm.

    Residues of 2,2', 4'-trichloroacetophenone were also reported in milk
    from animals fed at this high level. In one case they reached 0.05 ppm
    in the whole milk. Thus, the occasional residues of chlorfenvinphos
    (max. 0.14 ppm) detected in samples of maize stover and silage, would
    not produce significant levels of chlorfenvinphos in milk taken from
    cows, which had been fed with a diet containing maize stover or
    silage, from maize treated according to the recommendations (Shell
    Chem., 1963-64, Reports on residues in maize).

    Fate of residues

    General comments

    Although radio-labelled studies suggest that
    1-(2,4-dichlorophenyl)-ethan-1-ol and its sugar conjugate, together
    with much smaller amounts of desethyl-chlorfenvinphos might occur in
    treated crops, field studies have shown that their occurrence at
    detectable levels is rare. Likewise in milk from treated cows only
    extremely low levels of these products have been detected.

    In soils

    The breakdown pathways of chlorfenvinphos were studied in the
    laboratory in glass jars containing clay, loam, sand and peat soil
    treated with a relatively high dosage level, 15 ppm 14C
    chlorfenvinphos (corresponding with more than 15 kg a.i./ha (Beynon et
    al., 1967).

    After four months' storage at 22°C the following radio-labelled
    compounds were detected in the moist soils: unchanged chlorfenvinphos,
    1.0-4.7 ppm; 1-(2,4-dichlorophenyl) ethan-1-ol, 0.06-1.0 ppm;
    2,4-dichloroacetophenone, 0.1-0.5 ppm; desethyl chlorfenvinphos,
    0.1-0.2 ppm; salts or conjugates of desethyl chlorfenvinphos, 0.05-0.6
    ppm. No other breakdown products were detected. From these studies the
    breakdown path shown in Fig. 1 was proposed.

    The results of analyses of various field soils (Beynon et al., 1966)
    treated with chlorfenvinphos at dosage rates of 4 and 8 lb a.m./acre
    (recommended rate and double rate) showed that the initial half-life
    of chlorfenvinphos in soils varied from 2 to 12 weeks in mineral soils
    depending on soil type, formulation and dosage level. In one peat soil
    a half-life of 16-23 weeks was reported. These half-lives would
    probably have all been much shorter but for exceptionally dry
    conditions which occurred during the season when these experiments
    were carried out (1964).

    Further experiments (Beynon et al, 1968b) indicated that after
    application of about the recommended dosage (4-6 lb a.m./acre)
    residues of 1-(2,4-dichlorophenyl)-ethan-1-ol and
    2,4-dichloroacetophenone did not exceed 0.2 ppm by the end of the
    season. There was no evidence for the conversion of the trans-isomer
    of chlorfenvinphos.

    In plants

    Chlorfenvinphos may be applied either directly to soil for soil pest
    control, or to the aerial parts of plants for foliage pest control.
    Studies have been carried out to study the breakdown of
    chlorfenvinphos in crops grown in treated soil (Beynon et al., 1967)
    and in crops sprayed directly (Beynon et al., 1968).

    FIGURE 3;V071pr13.BMP

    In cabbage grown in the greenhouse in soil treated at a rate
    corresponding to 3-4 kg a.i./ha of 14C-chlorfenvinphos, no residues
    of chlorfenvinphos, nor of its breakdown products could be detected in
    the edible parts of the plant (hearts and outer leaves). Onions and
    carrots in the same experiment, however, contained unchanged
    chlorfenvinphos as the principal residue (0.07-0.12 ppm), and small
    amounts of a compound which was probably a salt or conjugate of
    desethyl chlorfenvinphos. The amounts were too small for positive

    After application of 14C-chlorfenvinphos to the foliage of potatoes,
    cabbage and maize in a glasshouse, half of the parent compound
    disappeared from the foliage within 2-3 days. The major breakdown
    product was 1-(2,4-dichlorophenyl)-ethan-1-ol, as in soils. Whereas
    this remains in the free state in soils, it occurs mainly as a sugar
    conjugate in crops. Traces of the desethyl chlorfenvinphos were
    detected, but generally at only 1% of the corresponding residue of the
    conjugated ethan-1-ol. Residues of the breakdown products tended to
    reach levels above those of the remaining chlorfenvinphos, five days
    after foliar application to maize, 12 days after application to
    cabbage, and 30 days after application to potatoes. Nevertheless the
    half-life of the total residue (parent and breakdown products), in so
    far as this concept can be applied to all products together, was not
    more than 5-7 days. Residues were detectable only in treated foliage;
    there was no evidence of translocation of any radio-activity from
    treated leaves to untreated parts of the plant.

    After the radio-labelled studies, analytical methods were developed
    for unlabelled desethyl chlorfenvinphos, the ethan-1-ol and its sugar
    conjugate and field experiments conducted with unlabelled
    chlorfenvinphos. A summary of the results is given underneath (Beynon,
    Davies et al., 1966; Beynon et al., 1968; Shell Res., 1967, residues
    in carrots etc.).

    In milk

    To study the partition of chlorfenvinphos breakdown products in milk a
    small Friesian cow weighing about 400 kg was injected intramuscularly
    with 233 mg of 14C-chlorfenvinphos shortly after milking at 10 a.m.
    (Shell, 1969). Milk samples were taken at 4 p.m. on the same day and
    on subsequent days from milkings at 10 a.m. and 4 p.m. until the fifth


    Crop         Country          Type of         Crop part      Residues of         Residues of
                                  application                    chlorfenvinphos     ethan-1-ol (ppm)
                                                                 (ppm) (total of
                                                                 cis- plus           Free        Conjugated
    Carrots      Holland          Soil            -              3.8                 < 0.05
                 France           Soil            -              0.08                < 0.05      < 0.05

    Potatoes     U.K.             Foliar          Tubers         < 0.02              < 0.10
                 Brazil           Soil            Whole          0.08                0.05        < 0.05
                 Brazil           Soil            Peeled         0.03                < 0.05      < 0.05

    Onions       Germany          Soil            -              < 0.02              < 0.05

    Leeks        Germany          Soil            -              < 0.01              < 0.05

    Radishes     Germany          Soil            -              0.05                < 0.05

    Celery       U.K.             Soil            -              0.02                < 0.05

    Tomatoes     S. Africa        Foliar          -              0.06                < 0.05      < 0.05

    Maize        France           Foliar          -              < 0.01              < 0.10

    Rice         Thailand         Foliar          Polished       < 0.02              < 0.05      < 0.05
                 Thailand         Foliar          Straw          0.65                < 0.05      < 0.05
                 Thailand         Foliar          Polished       < 0.02              < 0.05      < 0.05
                 Thailand         Foliar          Unpolished     0.03                < 0.05      < 0.05
                 Thailand         Foliar          Bran           < 0.02              < 0.05      < 0.05
                 Thailand         Foliar          Straw          2.7                 < 0.05      < 0.05
                 Philippines      Foliar          Unpolished     0.02                < 0.08      < 0.08
                 Philippines      Foliar          Straw          0.07                0.16        < 0.08

    Using the first milk sample taken after the injection (sample with
    highest radio-activity) the fat fraction was separated from protein
    and whey, and total radio-activity in the milk was distributed as


         Fraction       Percentage total radio-activity in milk

         Fat                            83.1
         Protein                         4.1
         Whey                           12.8

    To identify the breakdown products, fat from the first milk samples
    after the injection was extracted; aliquots of the extract were added
    to 20 mg of the reference compounds 1-9 (q.v.) and the mixture
    streaked onto a T.L.C. plate and developed. The amounts of
    radio-activity associated with each reference compound (expressed as
    ppm of each compound) are shown below.


    Metabolite                  Metabolite                      ppm expressed on
      number                                                    whole milk basis
         1          Chlorfenvinphos                                  0.0485

         2          2,4-dichlorophenacyl chloride                    0.0008

         3          2,4-dichloroacetophenone                         0.0023

         4          1-(2,4-dichlorophenyl) ethanol                   0.0014

         5          1-(2,4-dichlorophenyl) ethandiol              none detected

         6          2,4-dichloromandelic acid                        0.0011

         7          2,4-dichlorobenzoic acid                         <0.0014

         8          1-(2,4-dichlorophenyl) 2-chloro-ethanol          0.0004

         9          des-ethyl chlorfenvinphos                        0.0007
    Compounds responsible for less than 2% of the total radioactivity in
    the extract were difficult to identify with certainty, since such
    levels of radio-activity were close to the background activity level.

    Although the levels were not strictly related to levels arising from
    use of the recommended application, the data serve to show that
    breakdown products occur at much lower levels than chlorfenvinphos
    itself; the highest level being that of the 2,4-dichloroacetophenone
    which occurred at only one-twentieth that of the level of the parent

    Some examination of the radio-activity in the whey was also made.
    Twenty per cent. was extracted at neutral pH and was probably
    unchanged chlorfenvinphos. A further 23% was extracted at pH 2 and
    considered likely to be due to either metabolites 6 or 9.

    The second milk sample, taken the morning after the administration
    contained 0.011 total activity (calculated as ppm chlorfenvinphos);
    the unchanged chlorfenvinphos gave rise to 60% of the total
    radio-activity, thus the metabolites together corresponded with 0.004
    ppm chlorfenvinphos equivalent.

    In meat

    Studies by Robinson et al. (1966), Shell (1965) and Ivey et al. (1966)
    have demonstrated the absence of the most likely metabolite of
    chlorfenvinphos, i.c. 2,2', 4'-trichloroacetophenone, in the body fat
    and organs of sheep and cattle. In these trials, chlorfenvinphos had
    been applied to the cattle and sheep as dip or spray, at dosage rates
    up to twice the recommended level. The limits of determination of the
    analytical methods were 0.001-0.01 ppm.

    Effect of storage and processing

    The process of washing, peeling (either mechanical or chemical) and
    blanching during industrial canning procedures reduced residues of
    chlorfenvinphos from 0.20 to 0.25 ppm in fresh carrots to below the
    limit of determination (c.q. 0.01 ppm). The peeling of the carrots was
    the most effective step in removing any residues of chlorfenvinphos
    (Biston et al., 1969).

    Analyses of peeled and unpeeled potatoes have also demonstrated that
    residues of chlorfenvinphos are mainly concentrated in the peel;
    peeling removes 60-75% of the chlorfenvinphos present (Shell Res.,
    1968, 1970).

    The effect of boiling in a vegetable mash on residues of
    chlorfenvinphos is shown in the Report of the Government Chemist 1967.
    Forty-six per cent. of chlorfenvinphos was hydrolized during boiling
    for 30 min in a potato mash, while 74% was hydrolized in a cabbage
    mash in the same time. No new compounds which could be detected by
    G.L.C. were found.

    In rice, treated according to the recommended rate, residue levels of
    chlorfenvinphos decreased from 0.19-0.20 to 0.04-0.05 after boiling
    and 0.06-0.07 after frying (Shell Chemie, 1971).

    Methods of residue analysis

    Residues of chlorfenvinphos can be determined by a non-specific enzyme
    inhibition cholinesterase method, or by a specific gas-liquid
    chromatographic procedure. The non-specific method should, in general,
    only be used where it can be shown that no pesticide other than
    chlorfenvinphos has been applied to the crop.

    Enzymatic inhibition

    Although enzyme inhibition cholinesterase methods are nonspecific, it
    has been found that the results obtained with this technique are in
    good agreement with those obtained with the specific gas-liquid
    chromatographic method, and it can therefore be inferred that none of
    the degradation products are cholinesterase inhibitors. An enzyme
    inhibition technique for determination residues of chlorfenvinphos is
    described by Beynon et al. (1966). The limit of determination is 0.02

    Gas chromatographic methods

    A gas chromatic method of analysis for chlorfenvinphos is the method
    of choice based on accuracy, specificity, sensitivity and speed. The
    following scheme for analysis has proved successful in analysing soil
    and crops (Beynon et al., 1966). Crop samples are extracted by
    maceration with 30% v acetone in petroleum spirit, while soil samples
    are extracted by end-over-end tumbling with 20% acetone in petroleum
    spirit. The extracts are analysed by gas-liquid chromatography using
    an electron capture detector. If natural products extracted from the
    crops and soils interfere with the analysis, the extract should be
    subjected to clean-up by column chromatography. With this technique
    the cis- and trans-isomers of chlorfenvinphos can be separated, and
    measured separately, if required. Using this procedure, mean
    recoveries are 95% from soils at the 0.20-1.0 ppm level, and 100% from
    crops at the 0.05-0.10 ppm level. The limit of determination of
    chlorfenvinphos with this method is 0.02 ppm. Chlorfenvinphos is
    thermally stable under the G.L.C. conditions used in this method
    (column temperature of 188°C or below), and no decomposition has been

    Gas-liquid chromatographic methods have successfully been employed in
    detecting residues of the metabolites of chlorfenvinphos in crops and
    soils: 2,4-dichloroacetophenone, limit of determination 0.01 ppm;
    2,4-dichlorophenacyl chloride, 0.01 ppm; free
    1-(2,4-dichlorophenyl)ethan-1-ol, 0.10 ppm; and conjugated
    1-(2,4-dichlorophenyl)ethan-1-ol, 0.10 ppm (Beynon at al., 1968). The
    determination of chlorfenvinphos by flame photometric gas
    chromatography with virtually no clean-up can be accomplished by the
    general procedure described by Beroza and Bowman (1968).

    A gas-liquid chromatographic method has been used for the
    determination of chlorfenvinphos residues in animal tissues and milk
    (Claborn and Ivey, 1965), which depends on the conversion of
    chlorfenvinphos to 2,2', 4'-trichloroacetophenone and the subsequent
    determination of the ketone by G.L.C. The amounts detectable with this
    method are 0.005 ppm of chlorfenvinphos and 0.003 ppm of
    trichloroacetophenone in tissues and 0.0001 and 0.0006 respectively in

    A different G.L.C. residue method was used by Robinson for the
    determination of chlorfenvinphos in milk. The limit of detection in
    whole milk with this method is 0.0003 ppm.

    Note: It should be recognized that in practical use the levels of
    detection mentioned to some extent depend on the samples, and
    variation up or down inevitably occurs.

    National tolerances

    The following table lists some of the national tolerances for
    chlorfenvinphos (expressed as the sum of cis- and trans-isomer)
    established at this time.

    Country                         Crop                     Tolerance, ppm
    Belgium          Fruits, vegetables (excl. potatoes)           0.1
                     Carrots and other root vegetables             0.4

    Germany          Potatoes, turnips, maize, celery,
                     cabbage, onion, radish,
                     horseradish, cucumbers                        0.1
                     Carrots                                       0.4

    Italy            Cabbage, carrots, potatoes                    0.5

    Netherlands      Fruit, vegetables (excl. carrots)             0.1
                     Potatoes                                     0.05
                     Carrots                                       0.4

    Switzerland      Cabbage                                      0.03

    Yugoslavia       All crops                                 No residue

    Chlorfenvinphos is a non-systemic organo-phosphorus insecticide which
    is used on a considerable scale in many countries on a relatively wide
    range of crops and on livestock animals.

    Main uses are as soil, seed or plant root treatment against soil borne
    insects, especially root-flies and foliar treatments against foliage
    pests such as Lepidopterous larvae, beetles, etc. It is used on
    livestock, especially on sheep and beef cattle, mainly as a dip or a
    spray against ectoparasites i.e. ticks, mites, lice, blowfly and screw
    worm; it is only occasionally used on dairy cattle.

    Technical chlorfenvinphos contains no less than 92% of alpha and
    ß isomer (typical sample 9.7% alpha isomer and 83.8% ß isomer). The
    impurities in the technical material are known ; the main component is
    2,2-dichloro-1-(2,4-dichlorophenyl) vinyl diethyl phosphate (about

    Chlorfenvinphos is used in different formulations, emulsifiable
    liquid, wettable powder, dust and granular. The rates of uses range
    from 1 to 5 kg a.i. when applied to soil or roots and 0.125-1 kg
    a.i./ha applied as foliar application. On sheep, beef cattle and
    occasionally on dairy cattle, chlorfenvinphos is used as a dip (circa
    0.05% a.i.) or as a spray of the same strength.

    The residue data available were obtained from many different countries
    and regions with different climatical conditions and, with a few
    exceptions, they are representative for likely conditions of good
    agricultural practice and veterinarian practice. Information is
    available on the fate of chlorfenvinphos residues in soil, in plants
    and in products of animal origin.

    The residues which may occur in food either from plant or animal
    origin, after observing the recommended directions of use and the
    recommended pre-harvest and pre-slaughter intervals, consist largely
    of chlorfenvinphos itself. Breakdown products, which could be
    identified in radio-labelled studies and confirmed with other relevant
    methods of analysis occur in very low levels under normal limits of

    Little information is available on chlorfenvinphos residues in foods
    in commerce.

    A number of methods for residue analysis based on gas-chromatographic
    procedures are available which enable specific determination of the
    parent chemical and main metabolites. Recommendations are given for
    the most appropriate extraction procedures in food products of animal
    and plant origin.

    The limit of determination in soil and plant material is respectively
    0.01 ppm for chlorfenvinphos, and the metabolites 2.4
    dichloroacetophenone, and 2.4 dichlorophenacyl chloride; 0.1 ppm for
    free and the conjugated 1-(2.4 - dichlorophenyl) ethan-1-ol.

    A gas-liquid chromatographic method is available for the determination
    of chlorfenvinphos residues in animal tissues and in milk and milk
    products depending on the conversion of chlorfenvinphos to 2, 2',
    4'-trichloroacetophenone and the subsequent determination of the

    ketone by G.L.C. Limits of detection are 0.005 0.005 ppm of
    chlorfenvinphos and 0.003 ppm of trichloroacetophenone in animal
    tissues and 0.0001 ppm and 0.0006 ppm in milk and milk products

    Gas chromatic procedures as mentioned are available for the
    determination of residues of alpha and ß chlorfenvinphos, which can be
    adapted for regulatory purposes as required.


    The following tolerances, given as the sum of alpha and ß
    chlorfenvinphos are recommended.

    Since the residues in animals, in tissues other than fat, were
    detected only with animals which were sprayed at 5 to 10 times the
    recommended rate, the tolerances are recommended only on a fat basis.

    In milk, most of the residue (at least 83%) occurs in the butter fat
    and therefore the tolerances are expressed on a fat basis. The
    tolerance figures for milk and milk products are also given on the
    assumption that blending will take place before milk enters in
    commercial channels.

    Food commodity                        Recommendation           Basis of
                                          for tolerance            recommendation
                                          (sum of alpha and beta)  (pre-harvest
                                          chlorfenvinphos          interval
                                          in ppm                   weeks)
    Brassicas (except cauliflower)
    i.e. Brussels sprouts, cabbage,
    broccoli, swedes, turnips             0.05                     swedes 14     x

    Cauliflower                           0.1                      4-7           x

    Carrots, celery                       0.4                      2-7           x

    Potatoes, sweet potatoes              0.05                     1-4           x

    Radish (incl. horseradish)            0.1                      2-5           x

    Tomatoes                              0.1                      1-4           x

    Aubergines                            0.05                     5-10          x

    Onions, leeks                         0.05                     4             x

    Cereals i.e. maize grain,
    rice (raw and polished),                          maize,                     x
    wheat grain                           0.05        rice         5-12    (wheat)

    Food commodity                        Recommendation           Basis of
                                          for tolerance            recommendation
                                          (sum of alpha and beta)  (pre-harvest
                                          chlorfenvinphos          interval
                                          in ppm                   weeks)

    Peanut (shelled)                      0.05                                   x

    Mushroom                              0.05                                   x

    Cotton seed                           0.05                     5-13

    Meat on fat basis                     0.2                      0.5-1*

    Milk and milk products,
    on a fat basis                        0.2                      **

    * Period between application and slaughter.

    ** Weekly sprays on cattle, 4-7 hours between application
    and first milking.

    x Entries marked x refer to applications to the soil or plant
    root prior to, or at, planting or sowing.

    Abbot, D. C. et al. (1970) Pesticide residues in the total diet in
    England and Wales, 1966-1967. III Organophosphorous pesticide residues
    in the total diet, Pestic. Sci., 1 (1) 10-13

    Ambrose, A. M., Larson, P. S., Borzelleca, J. F. and Hennigar, G. R.,
    jr. (1970) Toxicologic studies on
    Diethyl-1-(2,4-dichlorophenyl)O2Ochlorovinyl phosphate. Toxicol. Appl.
    Pharmacol., 17, 323-336

    Beroza, M. and Bowman, M. C. (1968) Gas chromatography of Pesticide
    residues containing phosphorus or sulfur with the Flame Photometric
    Detector. Env. Sci. and Tech., 2, 450-457

    Beynon, K. I., Davies, L. and Elgar, L. (1966) Analysis of crops and
    soils for residues of diethyl: 1-(2,4 dichlorophenyl)-2-chlorovinyl
    phosphate. 1. Development of Method. J. Sci. Fd. Agric., 17, 162-166.
    2. Results, 17, 167-

    Beynon, K. I. and Wright, A. N. (1967) The breakdown of
    14C - chlorfenvinphos in soils and in crops grown in the soils. J.
    Sci. Fd. Agric., 10, 143-150

    Beynon, K. I. and Wright, A. N. (1968a) Breakdown of
    14C - chlorfenvinphos insecticide in crops. J. Sci. Fd. Agric.,
    19, 146-153

    Beynon, K. I. et al. (1968b) Analysis of crops and soils for residues
    of chlorfenvinphos insecticide and its breakdown products. J. Sci. Fd.
    Agric., 19, 302-307

    Beynon, K. I. et al. (1971) Persistence of chlorfenvinphos in natural
    waters. Pestic. Sci., 2 (1) 5-7

    Biston, R., Zenon-Roland, L. and Martens, P. H. (1970) Actions des
    traitements de conserverie sur la degradation des insecticides et des
    fungicides dans les légumes. Cahier No. 1 Centre de Recherches de
    Phytopharmacie Gembloux Belgique, 15-24

    Bro-Rusmusson, F. et al. (1970) Comparison of the disappearance of
    eight organophosphorous insecticides from soil in laboratory and
    outdoor experiments, Pestic. Sci., 1 (5) 179-182

    Brown, V. K. H. (1964) The "in vitro" effects of some halophenyl vinyl
    phosphates on blood acetyl cholinesterases from different mammalian
    species. Tunstall Lab. report submitted by Shell Chemical Co.

    Brown, V. K. H. (1965) Some further data on the acute and subacute
    toxicities of the insecticide SD 7859. Tunstall Lab. report submitted
    by Shell Chemical Co.

    CIBA-Geigy. Unpublished reports on residues of "Sapecron"
    (=chlorfenvinphos) in carrots (1966, 1971), onions (1966, 1967),
    potatoes (1968, 1969), radishes (1966, 1967)

    Claborn, H. V. and Ivey, M. C. (1965a) Determination of
    2-chloro-1-(2,4 dichlorophenyl) vinyl diethyl phosphate and 2, 21,
    41 - trichloroacetophenone in animal tissues and milk. J. Agr. and
    Fd. Chem., 13, 354-356

    Claborn, H. V. et al. (1965b) Comparison of residues in milk resulting
    from two types of spray applications of DDT, Shell compound 4072 and
    Ronnel. J. Econ. Ent., 58, 922-923

    Donninger, C., Hutson, D. H. and Pickering, B. A. (1966) Oxydative
    cleavage of phosphoric acid triesters to diesters. Proc. Biochem.
    Soc., 102, 26-27

    Edwards, M. J. et al. (1971) Movement of chlorfenvinphos in soil.
    Pestic. Sci., 2, (1) 1-4

    Eisenlord, G., Loquvam, G. S. and Nemenzo, J. (1966) Unpublished
    report of Hine Laboratories Inc. submitted by Shell Chemical Co.

    Gaines, T. B. (1969) Acute toxicity of pesticides. Toxicol. Appl.
    Pharmacol., 14, 515-534

    Hunter, C. G. (1964) Preliminary studies on the toxicology of the
    chlorinated-oryl-vinyl phosphate insecticide, SD 7859. Shell Technical

    Hunter, C. G. (1967) The acute toxicities and skin irritant properties
    of four intermediates used in the production of chlorfenvinphos.
    Unpublished report of Tunstall Labs. submitted by Shell Chemical Co.

    Hunter, C. G. (1969a) Excretion of metabolites of chlorfenvinphos in
    the milk of a cow treated with the insecticide. Unpublished report of
    Tunstall Labs. submitted by Shell Chemical Co.

    Hunter, C. G. (1969b) Dermal toxicity of Chlorfenvinphos. Ind. Med.,
    38, 49-51

    Hutson, D. H. (1969) The metabolism of 14C - chlorfenvinphos in man.
    Unpublished report of Tunstall Labs. submitted by Shell Chemical Co.

    Hutson, D. H., Akentonwa, D. A. A. and Hathway, D. E. (1967) The
    metabolism of 2-chloro-1-(21,41-dichlorophenyl) vinyl diethyl
    phosphate (chlorfenvinphos) in the dog and rat. Biochem. J., 102,

    Hutson, D. H. and Hathway, D. E. (1966) Toxic effects of
    chlorfenvinphos in dogs and rats. Biochem. Pharmacol., 16, 949-962

    Hutson, D. H. and Hathway, D. E. (1967) Toxic effects of
    chlorfenvinphos in dogs and rats. Biochem. Pharmacol., 16, 949-962

    Hutson, D. H. Pickering, B. A. and Donninger, C. (1967) Phosphoric
    acid triester: Glutathione alkyl transferase. Proc. Biochem. Soc.,
    106, 20

    Ivey, M. C. et al. (1966) Residues of Shell compound 4072 in the body
    tissues of sprayed cattle. J. Econ. Entom., 59, 379-382

    Kehoe, R. A. (1963) The immediate toxicity of various binary
    combinations of diethyl-1-(2,4-dichlorophenyl-2-chlorovinyl phosphate
    with other organo-phosphorus insecticides. Unpublished report of
    Ketting Labs., submitted by Shell Chemical Co.

    Larson, P. S. (1964) Unpublished report of the Medical College of
    Virginia, submitted by Shell Chemical Co.

    McEwen, F. L. et al. (1970) New insecticides for control of the
    cabbage maggot on root crucifers in Ontario. Unpublished rep. Dept. of
    Zool. Univ. of Guelph Ontario and Prov. Pesticides Residue Testing
    Laboratory, Ontario

    North Carolina State Univ. Raleigh U.S.A. (1965) Final report on the
    exploratory feeding of Shell compound 4072 to cows and the analysis of
    the resulting residues in milk

    Pickering, W. R. (1965) The acute toxicity of chlorfenvinphos to sheep
    and cattle when applied dermally. Vet. Rec., 77, 1140-1144

    Renvall, S. and Akerblom, M. (1971) Determination of organophosphorous
    pesticide residues in fruits and vegetables on the Swedish market.
    Residue reviews, 34 1-26

    Renvall, S. et al. (1970) Residues of organophosphorous pesticides in
    fruits and vegetables on the Swedish market. Rep. Statens
    Växtskyddsanstalt, Sweden

    Report of the Government Chemist. (1967) The effect of cooking on
    organo-phosphorous pesticide residues

    Robinson, J., Bush, B. and Malone, J. C. (1966) Residues of "Supona"
    in sheep. J. Sci. Fd. Agric., 17, 309-312

    Roberts, R. H. et al. (1961) Residues in the milk of dairy cows
    sprayed with p32 labelled general chemical 4072. J. Econ. Ent.,
    54, 1053-1054

    Shell Chemical Cy, New York. Unpublished reports on residues of
    chlorfenvinphos in: broccoli (1965 rep. RES 65-13); Brussels sprouts
    (1965 rep. RES 65-13); cabbage (1964, rep. RES 63-73, 1965, rep. RES
    65-13, 1966 rep. PRL, 65-46); cauliflower (1964 rep. RES 63-73);
    cotton seed (1964 rep. RES 63-156); maize (1963 rep. RES 62-43,

    62-43B, 1964 rep. RES 63-51, 63-58B, 63-63, 63-120, 63-144, 64-10,
    64-13); peanuts (1963 rep. RES 62-114); turnips (1964 rep. RES 63-83)

    Shell Chimie. (1970) Unpublished rep. Etude des résidus dans la
    matière grasse du lait provenant de vaches herbegées dans des étables
    traitées avec Sapona CE 20, rep. FREA 0007.70

    Shell Chimie. (1971) Effect of cooking on "Birlane" residues in rice.
    Unpubl. rep. BEGR 0031/71

    Shell Research Ltd. (1964-1971) Unpublished reports on residues of
    chlorfenvinphos in crops: aubergines (1969 rep. WKGR 0131/69); carrots
    (1967, tech. service note no. 53/67, 81/67, 97/67, 1969 rep. WKGR no.
    0104/69, 0153/69, 1970 rep. BEGR 0007/70); cauliflower (1964 rep.
    Tech. Memorandum 196/64); celery (1967 tech. serv. note 5/17, 1968,
    rep. WKTR 0049.68); cotton seed (1971 rep. WKGR 0013.71); mushrooms
    (1967 tech. serv. note 84/67); onions (1966 tech. serv. note 66/66,
    1970 rep. BEGR 0006/70, 1971 rep. WKGR 0004.71); potatoes (1968, rep.
    WKTR 0064.68, 1969 rep. WKTR no. 0015,69 and 0053.69, 1970 rep. BEGR
    0048/70, 1971 rep. WKGR 0017.71); radishes (1966 tech. serv. note
    180/661, 1969 rep. WKGR 0134/69); rice (1970 rep. WKGR no. 0059.70 and
    0092.70, rep. BEGR no. 0046/70, 0047/70, 0061/70, 0065/70, 0068/70);
    swedes (1964 tech. Memorandum 196/64); sweet potatoes (1970, rep. WKGR
    0123.70); tomatoes (1970, rep. WKGR 0192.70); wheat (1965 tech.
    Memorandum 171/65, 1970 rep. BEGR 0005/70)

    Shell Research Ltd. (1965) "Supona" residues in autopsy samples of
    lamb fat. Unpublished rep. Techn. Memorandum 124/65

    Shell Research Ltd. (1968) Chlorfenvinphos residues in cattle after
    repeated saturation spraying with "Supona". Unpubl. rep. TLTR 0020.68

    Shell Research Ltd. (1969a) The residues of chlorfenvinphos and
    2,4-dichloroacetophenone in milk of cows after spraying with
    chlorfenvinphos. Unpubl. rep. TLGR 0052.69

    Shell Research Ltd. (1969b) Excretion of metabolites of
    chlorfenvinphos (Supona) in the milk of a cow treated with the
    insecticide. Unpubl. rep. TLTR 0009.69

    Suet, D. L. (1971) Persistence and degradation of chlorfenvinphos,
    diazinon; fonofos and phorate in soils and their uptake by carrots.
    Pestic. Sci., 2 (3), 115-112

    Virginia Medical College. (1962) Unpublished report submitted by Shell
    Chemical Co.

    Virginia Medical College. (1963) Toxicologic study of the effect of
    adding 0.1 or 3 ppm GC-4072 to the diet of albino rats. Unpublished
    report submitted by Shell Chemical Co.

    Walker, A. I. T. (1965) The sub-acute oral toxicity of the halophenyl
    vinyl phosphate insecticide chlorfenvinphos (Supona, Berlane) to dogs.
    Unpublished report of Tunstall Labs. submitted by Shell Chemical Co.

    Witherup and Schlecht. (1963) The immediate toxicity of compound 4072
    with reference to its qualifications as a class B poison. Unpublished
    report of Kettering Laboratory submitted by Shell Chemical Co.

    Wit, S. L. Residues van chloorfenvinfos in aardappelen. Unpublished
    rep. Nat. Inst. of Public Health (The Netherlands) No. 62/71 TOX-ROB

    See Also:
       Toxicological Abbreviations
       Chlorfenvinphos (ICSC)
       Chlorfenvinphos (Pesticide residues in food: 1984 evaluations)
       Chlorfenvinphos (Pesticide residues in food: 1994 evaluations Part II Toxicology)