The effect of pharmaceutical compounds on the larval development of the estuarine shrimp Palaemon longirostris

Abstract

The most frequently detected pharmaceuticals compounds (PhCs) in coastal waters comprise the anti-inflammatory and analgesic diclofenac sodium (DS), the lipid regulator clofibric acid (CA) and the fungicide clotrimazole (CLZ). These compounds are on the priority lists of the UK Environment Agency and the Oslo and Paris Commission (OSPAR). We studied mixture effects of CA and DS, and individual effects of CLZ on growth, development and body mass of larval stages of the estuarine shrimp Palaemon longirostris. Drug residues found in the aquatic environment usually occur as mixtures. Thus, an accurate prediction of the mixture toxicity of DS and CA could be indispensable for environmental risk assessment. In previous studies on marine larvae of P. serratus identified toxic effects of CLZ on larval survival and larval growth, and these effects depended on osmotic and food stress. Not all species should respond to environmental change in the same form; thus, we must also consider the inter-specific life histories to test the potential toxicity effects of CLZ in the estuarine shrimp P. longirostris. The larvae were exposed to environmental relevant concentrations (DS: 36-70, CA: 9.6-40 and CLZ: 0.07-0.14 μg L−1) and concentrations that are higher than those measured in nature in order to explore thresholds that lead to sublethal effect (DS: 700 ; CA: 400 μg and CLZ: 4 μg L−1). Larvae were reared at two temperatures (18°C and 24°C) and two salinities (20 and 32 PSU). At environmental concentrations, these PhCs had no effect on larval survival and development of P. longirostris.The effects of these PhCs on larvae appeared at high doses. At both experimental temperatures, CA increased duration of development in P. longirostris larvae. Toxicity of the mixture DS and CA, increased duration of development at the lowest experimental temperature and reduced number of stages and growth rate. These effects were similar to CLZ effects, but in this case the number of stages had a significative reduction. DS, at high doses and warmer waters, decreased growth rate and larval body mass. In particular, CLZ, CA and the mixture of CA and DS increased intermoult duration required to reach the first juvenile stage.