Bioassay procedure to evaluate the acute toxicity of salinity and geothermal pollutants (pesticides) to Gambusia affinis. Final report

Abstract

The salinity tolerance of Gambusia affinis was determined in static bioassays. Gambusia easily tolerated salinity of 47.5 percent in 96 hour static bioassays. Survival at this level was 93.3 percent with the lowest survival being 68 percent at 40 percent salinity. The acute toxicities of endrin, DDT, aldrin, and dieldrin to Gambusia were determined by static and intermittent-flow bioassays. Toxicity was measured as the Mediant lethal Concentration (TL/sub 50/) for 96-hr exposures. TL/sub 50/ values were lower in the intermittent-flow bioassays than in static bioassays. Residue concentrations were also compared in surviving and dead fish from the intermittent-flow bioassays. Residue concentrations in fish that died during tests were higher than those of fish that survived. However, the range of concentrations in dead and living fish overlapped.