Journal of Hazardous Materials, Vol.313, 159-169, 2016
Influence of temperature on toxicity of single pharmaceuticals and mixtures, in the crustacean A. desmarestii
Lethal and sublethal responses of the shrimp Atyaephyra desmarestii exposed to three pharmaceutical compounds, Diclofenac (DF), Ibuprofen (IB) and Carbamazepine (CBZ), individually and in mixtures, were evaluated under two temperature scenarios. LC50 (96 h) values were obtained individually at 20 degrees and 25 degrees C. At 25 degrees C, mortality in binary and ternary mixtures is higher than at 20 degrees C. The toxicity of the mixtures was predicted on the basis of individual mortality data using two toxicity models: Concentration addition (CA) and Independent action (IA). Our results showed that neither CA nor IA unequivocally predicted the observed toxicity of binary and ternary mixtures. For sublethal toxicity, selected endpoints were: ingestion rate, osmoregulatory capacity and respiration rate. Regarding osmoregulatory capacity, no significant differences were found. The highest ingestion rates were recorded in organisms exposed at 25 degrees C, irrespective of the compound, after 30 and 60 min of exposure. At 20 degrees C, there was a significant decrease in respiration rate (Dunnettis test p < 0.05) under conditions of severe anoxia (1 mg O-2 L-1) in organisms exposed to 13.3 mu g L-1 of DF. At 25 degrees C a significantly lower respiration rate with respect to the control (Dunnettis test p < 0.05) was found in organisms exposed to 13.8 mu g L-1 of CBZ under conditions of moderate hypoxia and well-oxygenated water (3 and 5 mg O-2 L-1, respectively). The respiratory independence of organisms exposed to the higher temperature (25 degrees C) also decreased. This study shows that CBZ and DF individually, even at relatively low concentrations, may produce respiratory deficiencies in the freshwater shrimp, Atyaephyra desmarestii under certain temperature and water oxygenation conditions, thus reducing its ability to function. (C) 2016 Elsevier B.V. All rights reserved.