Heavy metal contamination in sediment and biomonitors from sites around the Isle of Man

Abstract

The Isle of Man has a long history of mining (Lamplugh, 1903; Garrod et al., 1972) leading to localized heavy metal pollution from abandoned mines. These provide a convenient system for a variety of studies in which closely adjacent contaminated and uncontaminated catchments and estuaries can be compared. This study was a precursor to a detailed examination of tolerance to metal exposure in Littorina saxatilis from contaminated and uncontaminated areas. It was necessary first to characterize the various sites, which also enabled comparisons with previous studies (Southgate et al., 1983) to show if contamination has reduced with time since the closure of the mines (last worked in the 1930s). Both sediments and bioindicators or biomonitors (Mytilus edulis and Fucus serratus) were analysed (see Luoma, 1983; Bryan, G.W., Langston, W.J., Hummerstone, L.G. and Burt, G.R., 1985. A guide to the assessment of heavy metal contamination in estuaries using biological indicators. Occasional Publication of the Marine Biological Association of the United Kingdom 4, p. 91.Bryan et al., 1985; Bryan and Langston, 1992; Phillips and Rainbow, 1993 for discussions of this approach) as they provide distinct measures of time-integrated levels of contamination and bioavailability. The study emphasised estuaries and included a broad coverage of the whole island (cf. Gibb et al., 1996). Five sites were characterized for heavy metals: four estuaries (Castletown, Laxey, Peel and Ramsey) and a coastal site at the Castletown Bay end of Langness near Derbyhaven (see Fig. 1). Laxey and Peel Estuaries drain historical mining regions in the Isle of Man (see Southgate et al., 1983) and the other three were considered relatively uncontaminated control sites.