Organochlorine insecticide residues in fish and birds from three river systems on the North Coast region of New South Wales.

Abstract

In a study on the occurrence and management of organochlorine (OC) insecticide residues on the North Coast Region of New South Wales (NSW), the authors recorded the presence of dieldrin, aldrin, heptachlor, and BHC residues in dairy pasture, sugar cane, or banana plantation soils. DDT residues were seldom present in these soils but others have detected relatively low levels of DDT residues in soils on the Cudgen-Duranbah plateau, an important vegetable and tropical fruit production area overlooking the Tweed, one of the major rivers on the North Coast Region. Although OC residues in these agricultural soils were all relatively low, they could be one source of contamination of North Coast river systems. The authors report results of further work done to assess the extent to which fish and birds collected from river systems in the NSW North Coast Region are contaminated with OC residues. Three of the major rivers - Clarence, Richmond, and Tweed - on the North Coast Region were selected for study. Fish were taken between October, 1983 and February, 1984.