CARBARYL      JMPR 1975

    Explanation

         At the Eighth Session of the Codex Committee on Pesticide
    Residues some countries expressed the view that a limit of 100 mg/kg
    for carbaryl residues in animal foodstuffs was unduly high. A request
    was made for a limit for carbaryl in milk and milk products and advice
    was sought whether the limit in meat was sufficiently high to take
    into account residues in animal feedstuffs.

    APPRAISAL

         Carbaryl was fully evaluated by the Joint Meeting in 1965, 1966,
    1967, 1968, 1969, 1970 and 1973. (FAO/WHO 1965b, 1967b, 1968b, 1970b,
    1971b, 1974b).

         Extensive information on the fate of carbaryl residues in
    domestic animals has been provided in the monographs of the 1966, 1968
    and 1973 Meetings. From these monographs it is obvious that many
    separate investigations have verified that when carbaryl is included
    in the ration of cows only about 0.2% of the amount of carbaryl
    ingested is excreted in milk as carbaryl and metabolites. At least
    seven separate metabolites have been identified in milk, most of them
    water-soluble. Carbaryl itself represents only about 5% of the total
    residue following continuous feeding at levels of 100 mg/kg in the
    ration (equivalent to about 1.5 mg/kg bodyweight). Since it is very
    unlikely that any dairy animal would ever consume as much as 100 mg of
    unchanged carbaryl per kg of the entire ration every day, actual milk
    residues would be negligibly small.

         Since no method of analysis available is suitable for determining
    all of the water-soluble metabolites that could occur in milk the only
    alternative is to determine the amount of parent carbaryl,
    notwithstanding that it constitutes one of the minor components. It is
    considered that the other metabolites are lower in toxicity than the
    parent compound. It is recommended that the maximum residue limit be
    set at or about the limit of determination.

         Radio-tracer studies have shown that when cows are fed the
    equivalent of 100 mg/kg of carbaryl in their ration, residues of all
    fragments do not exceed 1 mg/kg in kidney, 0.4 mg/kg in liver and 0.1
    mg/kg in the muscle. Only about 3-17% of these residues is parent
    carbaryl.

         On the basis of other studies it appears that only 13-30% of the
    meat residues are in a form that can be measured by present analytical
    methods. The maximum residue limit was therefore recommended to be 0.2
    mg/kg. In 1968 the Joint Meeting (FAO/WHO 1969) recommended a
    temporary maximum residue limit of 1 mg/kg in meat of cattle, goats
    and sheep based not only on feeding studies, but also on residue
    studies following dipping in carbaryl suspensions for the control of
    cattle ticks. These studies had revealed that a significant residue of
    carbaryl remained in fat and other tissues after dipping. The residues
    from feeding were much less. The use of carbaryl as a cattle dip has
    declined following the development of carbaryl-resistant strains of
    ticks and the Joint Meeting in 1973 decided that the higher maximum
    residue limit was not necessary.

    RECOMMENDATIONS

         The maximum residue limit for carbaryl residues in meat of
    cattle, sheep and goats (0.2 mg/kg) is confirmed as adequate to
    regulate the residues arising from the feeding of forage or other
    feedstuffs containing, in their green state, up to 100 mg of carbaryl
    per kg of feed.

         The following maximum residue limit is recommended for milk and
    milk products:

                   milk and milk products             0.1 mg/kg*
                 
    * At or about limit of determination.
    

    See Also:
       Toxicological Abbreviations
       Carbaryl (EHC 153, 1994)
       Carbaryl (HSG 78, 1993)
       Carbaryl (ICSC)
       Carbaryl (PIM 147)
       Carbaryl (FAO Meeting Report PL/1965/10/1)
       Carbaryl (FAO/PL:CP/15)
       Carbaryl (FAO/PL:1967/M/11/1)
       Carbaryl (FAO/PL:1968/M/9/1)
       Carbaryl (FAO/PL:1969/M/17/1)
       Carbaryl (AGP:1970/M/12/1)
       Carbaryl (WHO Pesticide Residues Series 3)
       Carbaryl (Pesticide residues in food: 1976 evaluations)
       Carbaryl (Pesticide residues in food: 1977 evaluations)
       Carbaryl (Pesticide residues in food: 1979 evaluations)
       Carbaryl (Pesticide residues in food: 1984 evaluations)
       Carbaryl (Pesticide residues in food: 1996 evaluations Part II Toxicological)
       Carbaryl (JMPR Evaluations 2001 Part II Toxicological)
       Carbaryl (IARC Summary & Evaluation, Volume 12, 1976)