Amphibians, turtles, rodents, and birds collected from a tropical conservation area in northwestern Costa Rica where pesticides are not directly applied were analyzed for organochlorine (OC) pesticide contamination. Six of thirty-nine amphibians (three of eight species), three of six turtles (two species), one of eight rodents (one species), and nine of twenty-five insectiverous birds (four species) contained OC compounds ranging from 2.77 ng/g to 277.70 ng/g. The most frequently detected compound (found in thirteen organisms) was p,p'-DDE. Heptachlor, delta-BHC, dieldrin, endosulfan II, and p,p' -DDD were each found in four or more organisms, while eight additional OC compounds were detected in at least one organism. The average body mass of contaminated amphibians was 156.40 g, compared to 56.89 g for uncontaminated amphibians, which suggests that biomagnification of OC compounds may occur in this taxon. The presence of OCs in wildlife from this conservation area indicates that long-distance transport of pesticides through the atmosphere is likely.



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