The Pearl River Delta (PRD) is one of the most industrialized regions in the world and has been identified as one of the areas in China that has high environmental concentration of pesticides, such as organochlorine pesticides (OCPs). One of the most commonly used OCPs was dichlorodiphenyltrichlorethane (DDT), also listed as one of the main persistent organic pollutants by the United Nations Environment Program. Although the application of technical DDTs in agriculture has presumably been banned since 1980s, no apparent decline in DDTs concentration has been detected, indicating new inputs of DDTs. This new source could be attributed to the production of dicofol, a pesticide synthesized from technical DDT, and used as an acaricide in agriculture and antifouling agent in paints for ships in southern and eastern China. Because degradation of dicofol is very fast in alkaline conditions and UV light, the present work aimed to evaluate the environmental implications and toxicity of 4,4'-Dichlorobenzophenone (4,4'-DCBP) (its active and main metabolite) in the aquatic ecosystem of the PRD mouth. For this purpose and considering that no toxicological data was available for this metabolite, two well-known animal models were studied. Artemia salina and Daphnia magna were exposed to a range of 4,4'-DCBP concentrations; mortality rate, speed (cm/s) and total displacement (cm) were analysed in order to assess the lethal concentration required to kill 50% of the population (LC50s). With these LC50s, theoretical risk assessments will be performed, considering the 4,4'-DCBP levels quantified in Hong Kong and Macao in a previous study.
Lucia Ivorra Gonzalez, Institute of Science and Environment, University of Saint Joseph, Macao
Karen Tagulao, Institute of Science and Environment, University of Saint Joseph, Macao
Shek Kiu Chan, Institute of Science and Environment, University of Saint Joseph, Macao
Patricia GonÃ§alves Marques Cardoso Teixeira, Interdisciplinary Centre for Marine and Environmental Research, Portugal
Catarina Cruzeiro, Centre for Functional Ecology, Department of Life Sciences, Portugal