Acute lethal and sublethal effects of diltiazem and doxepin for four aquatic environmental bioindicators covering the trophic chain

Abstract

Pharmaceuticals are becoming an environmental and health problem of concern. We present here the results obtained in the ecotoxicological evaluation of two drugs (diltiazem and doxepin) recurrently present in the environment. To carry out this study, four aquatic bioindicators (Vibrio fischeri, Daphnia magna, Selenastrum capricornutum, and Danio rerio) were used and the lethal, sublethal and/or inhibition effects were obtained. Furthermore, in order to complete environmental information, several key physicochemical properties were also measured (solubility, critical aggregation concentration and partition coefficient). High solubility for doxepin seems to be related with its bioavailability and thus, lead to higher toxicity. However, EC50 ecotoxocity values for doxepin and diltiazem are between 100 and 1000 mg/L for all the studied environmental bioindicators, and thus, none of the drugs should be considered as potentially harmful for the environment.