Tissue Residue Guideline for Sigma DDT for Protection of Aquatic Birds in China

DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) is a chlorinated hydrocarbon insecticide that has been used worldwide. While the use of DDT has been phased out in many countries, it is still produced in some parts of the world for use to control vectors of malaria. DDE (1,1,-dichloro-2,2-bis(p-chlorophenyl)ethylene) and DDD (1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) are primary metabolites of DDT and have similar chemical and physical properties. DDT and its metabolites (DDE and DDD) are collectively referred to as Sigma DDT. The lipophilic nature and persistence of the Sigma DDT result in biomagnification in wildlife that feed at higher trophic levels in the food chain. Wildlife in aquatic ecosystems depend on aquatic biota as their primary source of food, which provide the main route of exposure to Sigma DDT. Studies about effects of Sigma DDT on birds were reviewed. The tissue residue guidelines for DDT (TRGs) for protection of birds in China were derived using species sensitivity distribution (SSD) and toxicity percentile rank method (TPRM) based on the available toxicity data. Risks of Sigma DDT to birds were assessed by comparing the TRGs and Sigma DDT concentrations in fishes from China. The tissue residue guideline for protection of birds in China is recommended to be 12.0ng Sigma DDT/g food.