Acute and chronic toxicity of tributyltin and linear alkylbenzene sulfonate to the marine copepod Acartia tonsa

Abstract

The acute toxicities of linear alkylbenzene sulfonate (LAS) and tributyltin (TBT) to the marine copepod Acartia tonsa were tested in 48-h tests at two salinities, 18 and 28‰. For LAS 48-h median lethal concentration (LC50) values were 2.1 and 8.8 mg/L, respectively. For TBT the 48-h LC50 values were 0.47 and 0.24 μg/L, respectively. The given effect concentrations are based on nominal concentrations. In an 8-d test, effects of LAS on larval survival and development effects (effective concentration, 10%) were found at 0.2 to 0.3 mg/L. This effect concentration is higher than environmental concentrations, but at the same level as the concentration that can be expected in effluent from well-operated activated sludge treatment plants. Environmental effects of LAS on sensitive organisms such as A. tonsa would only be expected close to the outlet of effective treatment plants, or if the treatment of the sewage effluent was inefficient. Tributyltin inhibited the developmental rate of larvae at 1 ng TBT/L, whereas the survival of larvae was affected at 15 to 20 ng TBT/L. Acartia tonsa is thus extremely sensitive to TBT. Environmental concentrations of TBT of 20 to 100 ng/L have been found near marinas. Effects on organisms as sensitive as A. tonsa are thus to be expected in the vicinities of marinas. The test method using larval survival and development is easy to perform and nonlaborious compared to, for example, a reproduction test with Daphnia magna. The acute test method as well as the egg-embryo test method may he suitable for standardization.