DDT residues in poultry from rice hulls used as poultry litter

Abstract

The uptake of DDT into poultry tissues arising from the use of DDT contaminated rice hulls as poultry litter was assessed in trials conducted at the Poultry Research Station, Seven Hills. Litter treatments and periods of exposure were respectively 25, 50 and 100 mg kg-1 DDT and 22 weeks for laying hens and 50 mg kg-1 DDT and up to nine weeks for broiler chickens. Feed, eggs, body fat and litter were sampled at intervals for DDT residue and analysis. DDT uptake in egg yolk increased with the period and level of treatment, the highest residuesoccurring about two months after the start of the trial. Whole egg residues (0.29-1.45 mg kg-1) in some cases (1 00 mg kg-l treatment) exceeded the 0.5 mg kg-l Codex and 1 mg kg-l Australian recommended maximum residue limits and approached the 1.5 mg kg-1 actionable level of the United States Food and Drug Administration. The body fat residues of layers at 22 weeks (3.34-10.1 mg kg-1) varied with the treatment, the 50 mg kg-1 and the 100 mg kg-1 treatments producing levels approaching or exceeding the 7 mg kg-1 Australian and overseas limits. DDT uptake in the body fat of broilers increased with the period of exposure, highest residues occurring about six weeks after the start of the trial. Residues (19-133 mg kg-1) grossly exceeded the 7 mg kg-l limits