Acute and chronic ecotoxicological effects of four pharmaceuticals drugs on cladoceran Daphnia magna

Abstract

The occurrence of pharmaceuticals in the aquatic environment has received increasing attention in recent years, as concerns have risen about their environmental persistence, biological activity and different effects toward nontarget organisms. Considering the magnitude of concentrations (ng L⁻¹ to mg L⁻¹) and their often-specific modes of action, the assessment of physiological responses of exposed aquatic biota may provide significant information regarding the potential ecological consequences of exposure to these contaminants. The present study intended to assess the acute and chronic effects of four pharmaceuticals: acetaminophen, chlorpromazine, diclofenac sodium and propranolol in the cladoceran species Daphnia magna. Parameters such as immobility, total of offspring and rate of population increase were analyzed. Results of acute exposures showed a considerable variability of toxicity among pharmaceuticals, with the following ranking of toxicity: diclofenac (EC_50 =123.3 mg L⁻¹) < propranolol (EC_50 =5.531 mg L⁻¹) < acetaminophen (EC_50 =2.831 mg L⁻¹) < chlorpromazine (EC_50 =1.805 mg L⁻¹). The chronic toxicity data showed the exertion of reproductive adverse effects. The compounds chlorpromazine and propranolol caused a significant decrease in fecundity, and the rate of population increase parameter suffered a significant decrease from 0.33 mg L⁻¹ to 0.128 mg L⁻¹ onwards, respectively. The levels of exposure to which our test organism was acutely and chronically exposed were above those already reported in the wild. Nevertheless, the extensive production, prescription and release of pharmaceuticals drugs will continue to grow in the future, and consequently their loadings to the environment can result in potential long-term ecological risks to aquatic biota.

Keywords:

• Acetaminophen
• aquatic biota
• chlorpromazine
• diclofenac sodium
• ecotoxicity
• propranolol
• non-target organisms

Declaration of interest

The authors acknowledge the Brazilian Research Council (CNPq) for the financial support provided for this research project (No. 245436/2012-0). This work was supported by European Funds through COMPETE and by National Funds through the Portuguese Science Foundation (FCT) within project PEst-C/MAR/LA0017/2013.