Response of the estuarine amphipod Gammarus daiberi to chlorinated power plant effluent

Abstract

The amphipod Gammarus daiberi was subjected to plume drifts and laboratory exposures to chlorinated power plant cooling water effluent. Behavioral reactions to unchlorinated and chlorinated effluent were examined in an avoidance trough. During plant chlorination, the amphipods survived 1-h exposures to full-strength cooling water effluent ( ΔT = 7.3–9.3 ° C, 0.05 m l −1 total chlorine). Test groups of G. daiberi drifted through the discharge plume during chlorination displayed no increased immediate or latent mortalities. One-hour static bioassays revealed an initial TL 50 value of 1.85 mg l −1 total chlorine, which decayed to 0.2–0.5 mg l −1 during the exposure period. At ambient temperatures of 26.4–26.6 °C, the amphipods avoided unchlorinated effluent at ΔT' s > 3.3 ° C. At lower ambient temperatures (15.3–15.7 °C), no avoidance was observed at a 7.1 °C ΔT. Chlorinated discharge water was avoided by G. daiberi at both ambient temperatures.