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    PESTICIDE RESIDUES IN FOOD - 1997


    Sponsored jointly by FAO and WHO
    with the support of the International Programme
    on Chemical Safety (IPCS)




    TOXICOLOGICAL AND ENVIRONMENTAL
    EVALUATIONS 1994




    Joint meeting of the
    FAO Panel of Experts on Pesticide Residues
    in Food and the Environment
    and the
    WHO Core Assessment Group 

    Lyon 22 September - 1 October 1997



    The summaries and evaluations contained in this book are, in most
    cases, based on unpublished proprietary data submitted for the purpose
    of the JMPR assessment. A registration authority should not grant a
    registration on the basis of an evaluation unless it has first
    received authorization for such use from the owner who submitted the
    data for JMPR review or has received the data on which the summaries
    are based, either from the owner of the data or from a second party
    that has obtained permission from the owner of the data for this
    purpose.



    MEVINPHOS

    First draft prepared by
    Dr W. Erichson
    Environmental Fate and Effects Division
    US Environmental Protection Agency
    Washington DC, USA

         Identity and physical and chemical properties
         Sources of environmental exposure
         Environmental transport, distribution, and transformation
         Effects on nontarget organisms in the laboratory and the 
         field
         Evaluation of effects on the environment
              Risk assessment
                   Terrestrial organisms
                   Aquatic environment
         References

    1.  Identity and physical and chemical properties

    Mevinphos is produced as a mixture of  E (> 60%) and  Z (< 25%)
    geometrical isomers. It is a pale-yellow liquid with a boiling-point
    of 99-103°C at 0.03 mm Hg (0.004 kPa) and a vapour pressure of 0.003
    mm Hg (0.0004 kPa) at 21°C. Mevinphos is miscible in water, with an
    estimated solubility of 600 000 mg/L. The octanol:water partition
    coefficient (Kow) is 1.1-1.5.

    2.  Sources of environmental exposure

    Mevinphos is a broad-spectrum organophosphate insecticide and
    acaricide with both contact and systemic activity. Its mechanism of
    pesticidal action is direct inhibition of cholinesterase. Mevinphos
    was used to control aphids, mites, grasshoppers, cutworms,
    leafhoppers, caterpillars, and other insects, predominantly on a
    variety of vegetable, fruit, and field crops. All uses of mevinphos
    were voluntarily withdrawn in the United States from 1 December 1995
    owing to concerns about workers' health.

    Mevinphos products have been formulated as emulsifiable concentrates,
    soluble concentrates, ready-to-use liquids, and dusts. Its trade names
    included Phosdrin, Duraphos, Apavinphos, OS-2046, Mevinox, Menite,
    Gesfid, Phosfene, and Compound 2046. The application rates were
    0.15-3.4 kg ai/ha but were typically 0.56-1.12 kg ai/ha per
    application for most crops when distributed with conventional ground
    or aerial equipment. Multiple applications were allowed as needed.

    3.  Environmental transport, distribution, and transformation

    The available data on the environmental fate of mevinphos indicate
    that it dissipates rapidly in the terrestrial environment. In one
    field study in the San Joaquin Valley of California (USA), six

    applications of 0.9 kg ai/ha were made from a tractor-mounted boom
    sprayer at seven-day intervals, for a total application of 5.4 kg
    ai/ha. The residues of the  E and  Z isomers in the top 15 cm of
    soil on the day of application were reported to be < 0.01 mg/g soil;
    the half-lives of the isomers in soil were difficult to determine
    owing to the low concentrations of residues and the rapid degradation
    of mevinphos, but they were less than four days for both isomers
    (Leech & McKane, 1990).

    Biotic degradation appears to be a main route of terrestrial
    dissipation of mevinphos. The aerobic half-lives for the  E and  Z 
    isomers are 1.21 and 3.83 h, respectively, under laboratory conditions
    at 25°C in the dark (Reynolds, 1994, 1995). The major degradation
    pathways appear to be the formation of methylacetoacetate followed by
    rapid binding to soil and mineralization to carbon dioxide. The
    anaerobic half-life of mevinphos (a mixture of  E and  Z isomers) in
    flooded sandy soil after 24 h of aerobic incubation is about 12 days.

    Both the  E and  Z isomers hydrolyse faster in sterile aqueous
    buffered solutions at pH 9 (2.8-7.5 days) than at pH 5 (50.8-84.6
    days) or pH 7 (29.2-62.7 days) (Misra, 1992). At pH 5 and pH 7, both
    isomers hydrolysed mainly to  O-des-methylmevinphos. At pH 9, both
    isomers produced  O-des-methylmevinphos, acetoacetic acid, and
    acetone, but the  E-isomer also produced  cis-mevinphos acid.

    Photolysis of  E-mevinphos in sterile, buffered (pH 5) aqueous
    solution under artificial sunlight at 25°C occurred within 27.2 days
    (Cohen, 1994a). After 480 h of exposure, the degradates included
     Z-mevinphos,  O-desmethylmevinphos, methyl acetoacetate, and an
    unknown product. Aqueous photolysis of the  Z isomer occurred within
    27.8 days, with degradation to  E-mevinphos,  O-desmethyl-mevinphos,
    and an unknown product (Cohen, 1994b).

    Mevinphos is potentially highly mobile in soil, because of its high
    solubility in water (6 × 105mg/L) and low soil partition coefficient
    (Kads, 0.392-1.92). A study conducted in California (USA), however,
    showed that leaching of the  E and  Z isomers in the field is
    minimal. Residues of both isomers were detected below the soil surface
    (0-15 cm) in only a few instances after application of mevinphos at
    0.9 kg ai/ha weekly for seven weeks. It was concluded that rapid
    degradation of both isomers in the top 15 cm of soil precluded
    leaching to greater depths (Leech & McKane, 1990).

    4.  Effects on nontarget organisms in the laboratory and the field

    The acute oral LD50 value of mevinphis in birds is 1.34-4.6 mg ai/kg
    for sharp-tailed grouse, ring-necked pheasant, and mallard (Table 1).
    When given in the diet, the LC50 was 236 mg ai/kg diet for Japanese
    quail and 246 mg ai/kg diet for ring-necked pheasant; it was less
    toxic to bobwhite quail and mallard ducks. The acute oral LD50 value
    in laboratory rats was 2.2 mg ai/kg.


        Table 1. Toxicity of mevinphos to birds

                                                                                                                            

    Species                           Age                 End-pointa           Toxicity           Reference
                                                                               (mg ai/kg)
                                                                                                                            

    Sharp-tailed grouse               Not specified       LD50                 501.34             Hudson et al. (1984)
    (Tympanuchus phasianellus)
    Ring-necked pheasant              3-4 months          LD50                 1.37               Hudson et al. (1984)
    (Phasianus colchicus)             10 days             LC50                 246                Hill et al. (1975)
    Mallard (Anas platyrhynchos)      5-7 months          LD50                 4.63               Hudson et al. (1984)
                                      10 days             LC50                 1991               Hill et al. (1975)
                                                          Reproduction         < 4 / 4            Beavers et al. (1992a)
                                                          (NOEC/LOEC)
    Japanese quail                    14 days             LC50                 236                Hill et al. (1975)
    (Coturnix coturnix)
    Bobwhite quail                    < 10                LC50                 1000               DeWitt et al. (1963)
    (Colinus virginianus)                                 Reproduction         1.5/7.1            Beavers et al. (1992b)
                                                          (NOEC/LOEC)
                                                                                                                            

    a LD50 = single oral dose; LC50 = 5-day exposure to treated food followed by 3-day exposure to untreated food
    

    The NOEC for reproductive toxicity was 1.5 mg ai/kg for bobwhite quail
    and < 4 mg ai/kg for mallards exposed to mevinphos in the diet for
    20-22 weeks. The number of viable embryos and the eggshell thickness
    of bobwhite quail were significantly reduced at 7.1 mg ai/kg in
    comparison with the control. The body weight of mallard hens was
    significantly affected at 4 mg ai/kg.

    The LD50 values for honeybees were 0.070 mg/bee after contact and
    0.027 mg/bee after oral exposure (Stevenson, 1968). Mevinphos residues
    were not toxic to bees 4 h after an application of 0.9 kg ai/ha
    (Castellon, 1989). Mevinphos applied at standard field rates was toxic
    to predaceous mites, parasitic wasps, and predaceous beetles in
    several studies (Bartlett, 1963, 1964, 1966).

    The toxicity of mevinphos to freshwater organisms is summarized in
    Tables 2 and 3. The 96-h LC50 values for technical-grade mevinphos
    (60%  E isomer and 40% related compounds) in fish are 11.9 mg ai/L
    for rainbow trout and 22.5-87 mg ai/L for bluegill sunfish. The values
    for the formulated product (30.2-34.6% ai) are 81.4 mg ai/L for
    bluegill sunfish, 41.8 mg ai/L for rainbow trout, and 1.46 mg ai/L for
     Daphnia magna. The 48-h EC50 values for the technical-grade
    material are 0.18 mg ai/L for  Daphnia pulex and 0.42 mg ai/L for
     Simocephalus serrulatus. The 96-h EC50 values for invertebrates
    were 2.8-130 mg ai/L for  Gammarus fasciatus at water temperatures of
    15-21°C, 5 mg ai/L for  Pteronarcys californica, 13.5 mg ai/L for
     Palaemonetes kadiakensis, and 61 mg ai/L for  Asellus brevicaudus.

    The toxicity of mevinphos to estuarine and marine organisms is
    summarized in Tables 2 and 3. The 96-h LC50 values for sheepshead
    minnows are 0.81 mg ai/L for total mevinphos and 0.67 mg ai/L for its
     E isomer, and those for mysid shrimp are 1.3 and 1.08 mg ai/L,
    respectively. The 96-h EC50 value for shell deposition in eastern
    oysters is > 1 mg ai/L.

    Longer studies are not appropriate, given the rapid degradation of the
    compound.

    Deaths have been reported among wildlife exposed to mevinphos in
    Scotland, but all of the incidents involved misuse (Hamilton et al.,
    1981). The US Environmental Protection Agency (personal communication)
    has received only one documented incident of acute poisoning of birds
    with mevinphos. In that incident, 120 starlings and blackbirds were
    found dead near treated cole crops in California. The cause of death
    was confirmed to be mevinphos on the basis of a mean concentration of
    1.3 mg/kg residues in the gizzard contents. Although mevinphos
    dissipates rapidly and exposure may be brief, its high acute toxicity
    clearly poses a danger to exposed wildlife.


        Table 2. Toxicity of mevinphos to fish

                                                                                                                                             

    Species                             Mean           Test material      Static/     End-point      Toxicity         Reference
                                        size/age       (% ai)             Flow                       (mg ai/litre)
                                                                                                                                             

    Freshwater species
    Bluegill (Lepomis macrochirus)      0.9-1.3 g      60                 Static      96-h LC50      22.5-87          Mayer & Ellersieck
                                                                                                                      (1986)
                                        0.45 g         34.6               Flow        96-h LC50      81.4             Ward (1992a)
    Rainbow trout                       0.9 g          60                 Static      96-h LC50      11.9             Mayer & Ellersieck
                                                                                                                      (1986)
    (Oncorhynchus mykiss)               0.51 g         34.6               Flow        96-h LC50      41.8             Ward (1992b)
    Largemouth bass                     0.8 g          60                 Static      96-h LC50      115              Mayer & Ellersieck
    (Micropterus salmoides)                                                                                           (1986)

    Estuarine and marine species
    Sheepshead minnow                   Juvenile       100                Flow        48-h LC50      640              Mayer (1986)
    (Cyprinodon variegatus)             0.33g          74.48 E-isomer,    Flow        96-h LC50      670-810          Yurk (1991)
                                                       15.09 Z-isomer
                                                                                                                                             

    Table 3. Toxicity of mevinphos to aquatic invertebrates

                                                                                                                                             

    Species                             Mean           Test material      Static/     End-point      Toxicity         Reference
                                        size/age       (% ai)             Flow        (mg ai/litre)
                                                                                                                                             

    Freshwater species
    Water flea (Daphnia magna)          < 24 h         30.2 E-isomer      Flow        96-h EC50      1.5              Lintott (1992)
    Water flea (Daphnia pulex)          1st instar     60                 Static      48-h EC50      0.18             Mayer & Ellersieck
                                                                                                                      (1986)
    Simocephalus serrulatus             1st instar     60                 Static      48-h EC50      0.42-0.49        Mayer & Ellersieck
                                                                                                                      (1986)
    Gammarus fasciatus                  Immature       60                 Static      96-h EC50      2.8-130          Mayer & Ellersieck
                                                                                                                      (1986)
    Pteronarcys californica             1st year       60                 Static      96-h EC50      5                Mayer & Ellersieck
                                                                                                                      (1986)
    Palaemonetes kadiakensis            Immature       60                 Static      96-h EC50      13.5             Mayer & Ellersieck
                                                                                                                      (1986)
    Asellus brevicaudus                 Early instar   60                 Static      96-h EC50      61               Mayer & Ellersieck
                                                                                                                      (1986)
    Estuarine and marine specie
    Mysid shrimp                        < 24 h         74.48 E-isomer,    Flow        96-h LC50      1.03             Vaishnav et al.
    (Mysidopsis bahia)                                 15.09 Z-isomer                                                 (1991)
    Eastern oyster                      Juvenile       100                Flow        EC50 (shell    > 1000           Mayer (1986)
    (Crassostrea virginica)                                                           deposition)
    Brown shrimp (Penaeus aztecus)      Juvenile       100                Flow        48-h EC50      150              Mayer (1986)
                                                                                                                                             
    

    Residues resulting from application of 0.9 kg ai/ha were not toxic to
    bees 4 h after application (Castellon, 1989), but mevinphos applied at
    standard field rates was highly toxic to predaceous mites, parasitic
    wasps, and predaceous beetles in several studies (Bartlett, 1963,
    1964, 1966).

    The US Environmental Protection Agency Office of Pesticides Program
    uses the 'generic expected environmental concentration' to estimate
    the aquatic PEC values for use in preliminary risk assessments. Acute
    risk is assessed on the basis of peak PEC values from single and/or
    multiple applications. Chronic risk is assessed from 21-day average
    PECs for invertebrates and 56-day average PECs for fish; however, as
    chronic toxicity is not applicable to mevinphos, the chronic risk to
    aquatic organisms was not assessed.

    In this calculation, the soil:water partition coefficient, the
    degradation half-lives, and information given on the label are used to
    estimate runoff from a 10-ha field into a 1-ha, 2-m deep pond. It
    accounts for reductions in dissolved pesticide concentrations due to
    adsorption to soil or sediment, soil incorporation, degradation in
    soil before washoff into the pond, and degradation of the pesticide
    within the pond. The model also accounts for direct deposition of
    spray drift into the pond (1% of the application rate assumed for
    ground application and 5% for aerial spray applications), the number
    of applications, and the interval between applications. The model
    assumes that runoff from a single, large rainstorm is sufficient to
    remove 10% of the pesticide two days after the final application. The
    environmental fate values used in the model are soil KOC = 1,
    solubility = 6 × 105mg/L, aerobic soil metabolism half-life = 1 day,
    hydrolytic half-life = 16 days, and water photolytic half-life = 27
    days.

    The PEC values for single aerial and ground sprays at application
    rates of 1.12 kg ai/ha and 0.56 kg ai/ha are presented in Table 4. The
    peak PEC is 16 mg ai/L for a single aerial application. The TER
    values, ranging from < 0.01 to 0.08, indicate that mevinphos applied 

    Table 4. Predicted environmental concentrations (PECs) after 
    single aerial and ground spray applications of mevinphos
                                                                 

    Application ratea      Method of              Peak PEC
    (kg ai/ha)             application            (µg ai/litre)
                                                                 
    1.12                   Aerial spray           16
                           Ground spray           14
    0.56                   Aerial spray           8
                           Ground spray           7
                                                                 

    a Based on the product label for Phosdrin 4 EC (US Environmental 
      Protection Agency registration no. 5481-412, accepted 16/5/94)

    at a typical rate of 1.12 kg ai/ha presents 'very large' acute risks
    to freshwater, estuarine, and marine invertebrates (Table 5). The
    acute risk to freshwater fish is classified as 'large' on the basis of
    the TER value of 0.74, but that to estuarine and marine fish is low
    (TER = 50.6). Although no incidents of fish kills due to mevinphos
    have been reported, overspray of fresh water should be avoided.

    5.  Evaluation of effects on the environment

    Mevinphos is a broad-spectrum organophosphate insecticide and
    acaricide with both contact and systemic activity. It is a mixture of
     E (> 60%) and  Z (< 25%) geometrical isomers. Its pesticidal
    action is due to direct inhibition of cholinesterase activity. It is
    used (except in the United States) to control aphids, mites,
    grasshoppers, cutworms, leafhoppers, caterpillars, and other insects
    on a variety of vegetable, fruit, and field crops. The available
    formulations include emulsifiable concentrates, soluble concentrates,
    ready-to-use liquids, and dusts.

    Mevinphos dissipates rapidly in the terrestrial environment. The
    half-lives of both isomers in soil are less than four days. Biotic
    degradation is the major means of terrestrial dissipation. The main
    degradation pathway appears to be the formation of methylacetoacetate,
    followed by rapid binding to soil, and mineralization to carbon
    dioxide. Under laboratory conditions at 25°C in the dark, the aerobic
    half-lives of the  E and  Z isomers are 1.21 and 3.83 h,
    respectively. The half-lives for hydrolysis of the isomers in sterile
    aqueous buffered solution are related to the pH: pH 9, 2.8-7.5 days;
    pH 5, 50.8-84.6 days.  O-Desmethylmevinphos is the major product.

    The photolysis half-life in aqueous solution was about 27 days for
    both isomersœ Mevinphos is potentially very mobile in soils because of
    its high solubility in water (6 × 105 mg/L) and low soil partition
    coefficients (Kads, 0.392-1.92), but rapid degradation of both isomers
    in the top 15 cm of soil prevents further leaching.

    Mevinphos is toxic to birds, with acute oral LD50 values ranging from
    1.34-4.6 mg ai/kg bw for sharp-tailed grouse, ring-necked pheasants,
    and mallards The dietary LC50 values were 236 mg/kg diet for Japanese
    quail and 246 mg/kg diet for ring-necked pheasants. In bobwhite quail
    and mallards exposed to mevinphos in the diet for 20-22 weeks, the
    NOEC values for reproductive toxicity were 1.5 ppm ai and < 4 ppm ai,
    respectivelyœ The number of viable embryos and the eggshell thickness
    of bobwhite quail were significantly reduced at 7.1 ppm ai and the
    body weights of mallard hens were significantly affected at 4 ppm ai.
    The oral LD50 value for laboratory rats was 2.2 mg ai/kg bw.

    Mevinphos is toxic to a number of insect species. In the laboratory,
    the LD50 values for honeybees were 0.070 µg/bee for contact and 0.027
    µg/bee for oral exposure. Mevinphos applied at standard field rates
    was toxic to predaceous mites, parasitic wasps, and predaceous
    beetles.


        Table 5. Risks to aquatic organisms after single exposures

                                                                                                                  

    Risk category                         Toxicity value   PECa             Toxicity:exposure    Risk
                                          (µg ai/litre)    (µg ai/litre)    ratio (TER)          classification
                                                                                                                  

    Freshwater fish                       11.9             16               0.74                 Large
    Freshwater invertebrates              0.18             16               0.01                 Very large
    Estuarine and marine fish             810              16               50.6                 Low
    Estuarine and marine invertebrates    1.3              16               0.08                 Very large
                                                                                                                  

    a Calculated from the 'generic expected environmental concentration' model of the US Environmental 
      Protection Agency; acute exposure is based on peak PEC values for a single aerial application of 
      1.12 kg ai/ha

    b Value for toxicity divided by the PEC
    

    Mevinphos is toxic to fish. The 96-h LC50 values for technical-grade
    mevinphos (60%  E isomer and 40% related compounds) were 11.9 µg ai/L
    for rainbow trout and 22.5-87 µg ai/L for bluegill sunfish. The 96-h
    LC50 values for the formulated product (30.2-34.6% ai) were 81.4 µg
    ai/L for bluegill sunfish, 41.8 µg ai/L for rainbow trout, and 1.46 µg
    ai/L for  Daphnia magna. The 48-h LC50 values for the technical-
    grade material were 0.18 µg ai/L for  Daphnia pulex and 0.42 µg ai/L
    for  Simocephalus serrulatus. The 96-h LC50 values for other
    invertebrates include 2.8-130 µg ai/L for  Gammarus fasciatus in
    water temperatures of 15-21°C, 5 µg ai/L for  Pteronarcys 
     californica, 13.5 µg ai/L, for  Palaemonetes kadiakensis, and 61 µg
    ai/L for  Asellus brevicaudus.

    For estuarine and marine organisms, the 96-h LC50 values were 0.81 mg
    ai/L for total mevinphos and 0.67 mg ai/L for its  E isomer in
    sheepshead minnows, and 1.3 and 1.08 µg ai/L in mysid shrimp,
    respectively. The 96-h EC50 for shell deposition in eastern oysters
    was > 1 mg ai/L. Longer studies are not appropriate in view of the
    rapid degradation of the compound.

    Risk assessment

     (a)  Terrestrial organisms

    Terrestrial organisms may be exposed to mevinphos by consuming
    contaminated foods and/or by dermal contact with contaminated soil and
    vegetation. The risk posed by foliar sprays is assessed by comparing
    the dietary LC50 values with the predicted environmental
    concentrations (PECs) of mevinphos on potential avian food items
    (grass, insects, and seeds). The PEC values are based on the Kenaga
    nomogram (Hoerger & Kenaga, 1992) as modified by Fletcher et al.
    (1994). The maximum PECs immediately after a single, direct
    application of mevinphos at 1.12 kg ai/ha are 240 mg ai/kg for short
    grasses, 135 mg ai/kg for small insects, and 15 mg ai/kg for seeds.
    For birds, the toxicity:exposure ratios (TERs), based on comparisons
    of the PECs with the lowest LC50 value seen in dietary tests for
    acute risk, are given in Table 6.

    This analysis indicates that mevinphos applied at a typical rate of
    1.12 kg ai/ha presents 'very large' to 'present' acute risks to
    herbivorous (TER = 1.0) and insectivorous (TER = 1.7) birds, wheres
    that to granivores is expected to be 'low' (TER = 15.7)œ Deaths due to
    exposure to mevinphos have been reported, but most of the incidents
    involved misuse. Although mevinphos dissipates rapidly and exposure
    may be brief, its high acute toxicity clearly poses a danger to
    exposed wildlifeœ

    Table 6. Toxicity:exposure ratios (TERs) for birds

                                                                          

    Toxicitya          PECb                  TERc    Risk classification
                                                                          

    LC50 = 236         240 (short grass)     1.0     Very large
    (Japanese quail)   135 (small insects)   1.7     Present
                       15 (seeds)            15.7    Low
                                                                          

    a For the most sensitive species tested
    b Maximum PECs after a single application of 1.12 kg ai/ha
    c Value for toxicity divided by value for exposure (i.e. PEC)


    The hazard ratios for honeybees exposed after application at a rate of
    1120g ai/ha, based on the LD50 values, were 16 000 for contact and 37
    333 for oral exposure, indicating a high risk. Mevinphos should not be
    applied or allowed to drift onto blooming crops or weeds while bees
    are visiting the treated area. Mevinphos applied at standard field
    rates was highly toxic to predaceous mites, parasitic wasps, and
    predaceous beetles in several studies.

     (b)  Aquatic organisms

    Aquatic organisms may be exposed to mevinphos from surface water
    runoff and soil erosion and/or drift from treated sites into water
    bodies.

    The risk posed by mevinphos is assessed on the basis of the 'generic
    expected environmental concentration'. Acute risk is assessed from
    peak PECs after single and/or multiple applications. Because chronic
    toxicity is not relevant for mevinphos, the chronic risk to aquatic
    organisms was not assessed.

    The environmental fate values used in the assessment of mevinphos are
    soil KOC = 1, solubility = 6 × 105 mg/L, aerobic soil degradation
    half-life = 1 day, hydrolytic half-life = 16 days, and water
    photolytic half-life = 27 days. The PEC values after single aerial and
    ground spray applications of mevinphos at rates of 1.12 and 0.56 kg
    ai/ha are shown in Table 4.

    The TERs for mevinphos in aquatic invertebrates are 0.01-0.08 (Table
    5), indicating that mevinphos applied at a typical field application
    rate of 1.12 kg ai/ha presents 'very large' acute risks to freshwater,
    estuarine, and marine invertebrates. The acute risk to freshwater fish
    is classified as 'large' on the basis of the TER of 0.74, but that to
    estuarine and marine fish is low (TER = 50.6). Although no incidents
    of fish kills due to mevinphos have been reported, overspray of
    freshwaters should be avoided.

    References

    Bartlett, B.R. (1963) The contact toxicity of some pesticide residues
    to hymenopterous parasites and coccinellid predators.   J. Econ. 
     Entomol., 56, 694-698.

    Bartlett, B.R. (1964) The toxicity of some pesticide residues to adult
     Amblyseius hibisci, with a compilation of the effects of pesticides
    upon phytoseiid mites.  J. Econ. Entomol., 57, 559-562.

    Bartlett, B.R. (1966) Toxicity and acceptance of some pesticides fed
    to parasitic hymenoptera and predatory coccinellids.  J. Econ. 
     Entomol., 59, 1142-1149.

    Beavers, J.B., Ross, T., Smith, G.J., Lynn, S.P. & Jaber, M.J. (1992a)
    Mevinphos: A one-generation reproduction study with the mallard 
     (Anas platyrhynchos). Unpublished study from Wildlife International
    Ltd, Easton, Maryland, USA. Submitted to US Environmental Protection
    Agency by Amvac Chemical Corp., Los Angeles, California, USA.

    Beavers, J.B., Ross, T., Smith, G.J., Lynn, S.P. & Jaber, M.J. (1992b)
    Mevinphos: A one-generation reproduction study with the bobwhite
     (Colinus virginianus). Conducted by Wildlife International Ltd.,
    Easton, Maryland, USA. Submitted to US Environmental Protection Agency
    by Amvac Chemical Corp., Los Angeles, California, USA.

    Castellon, A. (1989) Residual toxicity of mevinphos to honey bees
     (Apis mellifera). Unpublished study from Pan-Agricultural
    Laboratories, Inc., Madera, California, USA. Submitted to US
    Environmental Protection Agency by Amvac Chemical Corp., Los Angeles,
    California, USA.

    Cohen, S.P. (1994a) Photodegradation of alpha-mevinphos in an aqueous
    pH 5 buffered solution under artificial sunlight. Unpublished study
    from Pittsburgh Environmental Research Laboratory, Inc., Pittsburgh,
    Pennsylvania, USA. Submitted to US Environmental Protection Agency by
    Amvac Chemical Corp., Los Angeles, California, USA.

    Cohen, S.P. (1994b) Photodegradation of beta-mevinphos in an aqueous
    pH 5 buffered solution under artificial sunlight. Unpublished study
    from Pittsburg Environmental Research Laboratory, Pittsburg,
    Pennsylvania, USA. Submitted to US Environmental Protection Agency by
    Amvac Chemical Corp., Los Angeles, California, USA.

    DeWitt, J.B., Stickel, W.H. & Springer, P.F. (1963)  Wildlife 
     studies, Patuxent Wildlife Research Center, 1961-1962 (US Fish and
    Wildlife Service Circular 167), Washington DC, US Fish and Wildlife
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    See Also:
       Toxicological Abbreviations
       Mevinphos (FAO Meeting Report PL/1965/10/1)
       Mevinphos (WHO Pesticide Residues Series 2)
       Mevinphos (Pesticide residues in food: 1996 evaluations Part II Toxicological)