DDT environmental persistence from its use in a vector control program: A case study

DDT contamination was investigated in soil, sediment, and chicken eggs from an endemic leishmaniasis area located in Rio de Janeiro City, Brazil. The last DDT application in this area was in 1990, for sand-fly vector control. Sampling campaigns were conducted in 1997 and 1999. DDT was extracted by u se of a modified soxhlet apparatus and analysis was performed by gas chroma tography with electron capture detector. The results show that, in 1997, so il samples contained up to 351 pg.kg(-1) d.w. of Sigma DDT near the insecti cide-sprayed sites. In 1999, the soil concentration decreased to 112 mug.kg (-1) d.w. of Sigma DDT. Sediments from small creeks also showed low concent rations (up to 32.9 mug.kg(-1) d.w. of Sigma DDT). Chicken eggs had, on ave rage, 1.98 mg.kg(-1) Sigma DDT (twice FAO's maximum residue limit), compris ing 82% of p,p'-DDE. Taking into account the egg results, DDT bioaccumulati on is a question of concern. Considering just the egg consumption, it was e stimated that DDT intake in the study area is 0.38x10(-4) mg.kg(-1) body we ight.day(-1) whereas the reference maximum dose (US EPA) is 5x10(-4) mg.kg( -1) body weight.day(-1). This approach can be used to estimate DDT exposure in other places where DDT contamination may be of concern, especially in p laces where locally produced animals and eggs are a significant portion of the diet. (C) 2001 Academic Press.