Residues of DDT, DDE, and DDD in Fish in the Saskatchewan River after using DDT as a Blackfly Larvicide for Twenty Years

Concentrations of organochlorine pesticide residues in the muscle tissues of fish collected from the Saskatchewan River after a 20-year blackfly larviciding program using DDT ranged from less than 0.01–0.05 ppm of DDT, less than 0.01–0.05 ppm DDD (TDE), 0.01–0.06 ppm DDE, and 0.002–0.006 ppm dieldrin. These concentrations are well below the actionable level of 5.0 ppm of DDT residues in edible flesh. Tests with DDT-C14 showed that a single extraction of fish tissues with acetonitrile removed about 93% of metabolically incorporated residues.