Trace Metal and Chlorinated Hydrocarbon Concentrations in Shellfish and Fin-Fish from Irish Waters - 1996

Abstract

In accordance with the monitoring requirements of the 1979 Council Directive 79/923/EC on the quality of shellfish waters, water and shellfish samples were collected from 22 major shellfish growing areas and analysed for physicochemical parameters, trace metal levels and chlorinated hydrocarbon concentrations. Fin-fish were also collected from five Irish fishing ports and analysed for total mercury content in compliance with the European Commission's Decision of 19 May 1993 on mercury in fisheries products. Selected samples of fin-fish were also analysed for trace metal and chlorinated hydrocarbon concentration. As there are no generally accepted European standards for the concentration of these contaminants in shellfish or fin-fish, the levels were compared with the available standards and guidance values compiled by the Oslo and Paris Commission (OSPAR) countries for human consumption. As in previous years, the water quality from shellfish growing areas was good and conformed to the guidelines and requirements of the Directive. Petroleum hydrocarbons were not observed in any of the shellfish waters or as deposits on the shellfish. Chlorinated hydrocarbon levels were very low, evidence of the clean, unpolluted nature of Irish shellfish and shellfish producing waters. Trace metal levels were consistently low with the exception of lead in mussel tissue from Wexford Harbour, which was elevated, and cadmium in oyster tissue, which was slightly elevated in some samples but did not exceed the Dutch human consumption tolerance value of 1.0mg/kg. The concentration of mercury in fin-fish selected from catches at Irish fishing ports ranged from 0.02 to 0.27µg/g wet weight. These levels were well within the maximum limits set down in the EC Decision for mercury in fisheries products. Chlorinated hydrocarbon and trace metal levels were also very low in fish tissue. This survey confirms previous studies that show Irish fishery products are effectively free from trace metal and chlorinated hydrocarbon contamination.