Contamination of Milk from Different Routes of Animal Exposure to DDT

Abstract

The level of DDT [2,2-bis (p-chlorophenyl)-1,1,1 -trichloroethane] and its metabolites was determined in milk of cows treated at the same dosage both for 1 day and for 6 consecutive days in the following manner: intratracheal infusion of p,p''-DDT; alimentary exposure of a corn oil solution of p,p''-DDT in a capsule; an aged residue of technical grade DDT on alfalfa hay which had been pelleted; and an intravenous infusion of p,p''-DDT. It was found that respiratory exposure of cows to DDT produces a lower (rather than higher) level of DDT and its metabolic products in the milk than alimentary exposures. Administration of DDT in the form of aged residues on alfalfa results in a higher residue level than when DDT is administered in solution in oil. Different routes of exposure to DDT result in different ratios of DDT, DDE [2,2-bis (p-chlorophenyl)-l,l-dichloroethane] in the milk. The predominant product resulting from intratracheal and intravenous (I.V.) exposure, which bypass the rumen, is DDT, but some DDE and DDD are produced from the longer-term I.V. exposure. Alimentary exposure by means of DDT in oil solution produces predominantly DDT and DDD in the milk. Alimentary exposure of DDT as an aged residue produces DDT, DDE, and DDD.