Comparative uptake of a pyrethroid and organophosphate insecticide by selected aquatic insects

Abstract

Numerous reports have shown that aquatic insects are highly sensitive to insecticide poisoning based on the extremely low concentrations (often less than 1 ppb) that produce toxic effects (Coats et al 1989). This is especially true of pyrethroid insecticides where acute toxicity to both aquatic invertebrates and fish has restricted their applications in areas adjacent to aquatic environments. A number of studies have evaluated the effects of pyrethroids on stream invertebrates in laboratory (Muirhead-Thomson 1977; Mulla et al. 1980; Anderson 1982; 1989; Friesen et al. 1983; Coats et al. 1989; Sibley and Kaushik 1991), and field (Kreutzweiser and Kingsbury 1987; Kreutzweiser and Sibley 1991) experiments. Results of these studies indicate that aquatic insects are highly sensitive to pyrethroid insecticides. However, most of these accounts concern acute toxicity tests where the insects have been exposed to insecticides diluted in water and measurements of toxicity are expressed as lethal concentrations. Actual doses of insecticides are unknown, and comparisons with other organisms are therefore difficult to make.