Analytical determination and biochemical effects of waterborne diclofenac exposure to the common bully ( Gobiomorphus cotidianus)
Degree GrantorUniversity of Canterbury
Degree NameMaster of Science
Diclofenac, a non-steroidal anti-inflammatory drug used as a human pharmaceutical and a veterinary medicine has been identified as a priority emerging organic compound. Diclofenac has been detected within waterways globally at low ng-μg/L concentrations. While diclofenac has been shown to be toxic to aquatic organisms, there is currently a lack of data on the toxicity of diclofenac to endemic New Zealand fish species. A current limitation of ecotoxicity studies is the cost and workload associated with determining exposure concentrations. Cheap and robust alternative extraction methods need to be developed. This study developed a method of passive sampling using nylon filters to extract diclofenac from water samples. Extraction recoveries of diclofenac were concentration dependent and there was no effect of pH on recovery. Average recoveries for diclofenac for 0.05 and 500 μg/L were 103% and 58% respectively. The toxicity of diclofenac on the common bully was investigated in a concentration-dependent and a salinity dependent manner. Exposure concentrations for diclofenac were 0, 0.1, and 1000 μg/L and the salinities tested were 0, 6, and 20‰. The biochemical endpoints used for determination of toxicity were ethoxyresorufin-O-deethylase, glutathione-S-transferase and protein carbonylation. Overall, there was no effect of diclofenac observed on the common bully.