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2C - Biomarkers (TUP/81) Changes in Daphnia magna metabolism during sublethal exposure to Propanil. Villarroel, M.J.1, Ferrando, M.D.1, Andreu, E.1, 1 University of Valencia. Biology Sciences Faculty., Valencia, Spain, Spain ABSTRACT- For many years daphnid reproduction test have been used in aquatic toxicology for the establishment of water quality and aquatic safety assessment. However, in the past decade amount of research have demonstrated that chronic effects of chemicals on survival and reproduction of Daphnia magna were preceded by biochemical changes. Reductions in rate of growth of an organism appear to be responses to chronic toxicant exposure. However, it has been suggested that biochemical changes should occur before reduction in growth is observed. Cladocerans, especially Daphnia sp, are among the most favourable test animals in aquatic toxicology. The herbicide propanil is commonly used on rice fields of the Valencia Community (Spain) and is often implicated in aquatic environment pollution. Daphnia magna were exposed to propanil at sublethal concentrations of 0.07, 0.10, 0.21 and 0.55 mg/L during five days in order to investigate its effect on daphnid metabolism. Total lipid and protein levels were determined after 24, 48, 72, 96 and 120 hr of pesticide exposure using the method of Bligh and Dyer for lipids and the method of Lowry to measure proteins, respectively. The results showed that both daphnid lipids and proteins content decreased as propanil concentration increased specially after 96-120 hr exposure. Results are discussed in relation with data of others studies on the growth of D. magna under propanil stress. Key words: lipids, metabolism, proteins, Daphnia magna |
