Organochlorine compounds in mussels cultured in the Ría of Vigo: accumulation and origin.

This paper analyzes the influence of mussel physiological conditions on bioaccumulation of organochlorine pollutants. A direct relationship between reproductive stage, lipid content and accumulation of PCBs, DDTs and HCHs was observed. The organochlorine compounds accumulated by mussels cultured in the Ría of Vigo show levels below the limits set by the European legislation for human consumption, ranging between 12.50-58, 2.21-10.80 and 0.50-2.69 μg kg(-1) dry weight for PCBs, DDTs and HCHs, respectively. Other organochlorine pesticides normally present in estuarine areas, such as hexachlorobenzene (HCB), aldrin, chlordane and nonachlor were not detected. The proportion of PCBs, between 2 and 7 times higher than OCPs, indicates a pollution of predominantly industrial origin in the sampling area. Several molecular indices were used to identify the source of accumulated OCPs by Mytilus, showing recent inputs of technical DDT, mainly in summer-autumn, and continued discharges of lindane. On the other hand, other pesticides containing DDT impurities, such as dicofol, can contribute to DDT pollution in the Ría of Vigo. Multivariate analysis suggests the usefulness of including physiological parameters such as the gonad condition index and lipid content of sentinel organisms in environmental biomonitoring of lipophilic pollutants, as well as in the determination of their origin.