Scope for growth and contaminant levels in North Sea mussels Mytilus edulis

Abstract

ABSTRACT. Mussels Mytilus edulis, collected from 26 coastal sites from the Shetland Islands to the Thames estuary and 8 offshore light vessels, were used to monitor changes in environmental quality along the North Sea coastline of the UK (July 1990 and August 1991). The combined measurements of the stress response, scope for growth (SFG), and chemical contaminants in the tissues of mussels were able to detect, quantify and identify some of the major toxicants causing the observed pollution effects. SFG declined from north to south, reflecting both the major inflow of clean water from the North Atlantic via the north of Scotland, and the overall increase in environmental contamination with increasing urbanisation and industrialisation towards the south. There were coastal regions (e.g. Humber-Wash area and the Thames estuary) as well as specific sites (e.g. Ythan, Montrose, Blyth, Teesmouth, Whitby) which showed markedly reduced SFG. Using experimentally derived tissue concentration-response relationships it was shown that at over half the sites the reduced SFG could be entirely explained by the recorded concentrations of contaminants in the tissues. At the majority of sites, a large contribution towards the observed decline in SFG was caused by toxic (mainly polyaromatic) hydrocarbons, largely reflecting urbanisation and shipping activity. In addition, reductions in SFG appear to be partially explained by the accumulation of significant amounts of 'polar organic compounds' and tributyltin. At no sites were metals accumulated to concentrations that could cause a significant reduction in SFG. At those sites with a large 'unexplained component' to the very low SFG values, there was a significant correlation between this 'residual unexplained toxicity' and concentrations of organochlorines In the mussels. More research on the toxicity of these organochlorine compounds to mussels is needed.

Identification and phylogenetic comparison of p53 in two distinct mussel species (Mytilus)

“…is widely used by Mussel Watch Programs (O'Connor et al, 1995), for monitoring pulp and paper mill effluents (Salazar et al, 1997;St-Jean et al, 2003) and more recently, in municipal effluents effects monitoring (St-Jean et al, in press). The sessile nature of this species facilitates the establishment of cause and effect relationships in time and space (Widdows et al, 1995) and minimizes the possible confounding factor associated with the use of migratory species and those using larger areas for foraging.…”

Assessment of low-level metal contamination using the Mediterranean mussel gills as the indicator tissue

“…In our study, gills were selected as the indicator tissue for metal contamination assessment because they are an important route for metal uptake since they are directly exposed to the external medium as a respiratory organ (Widdows et al 1995). In addition, the gill mass generally shows the smallest seasonal variability compared to other mussel tissues (Martinčić et al 1987;Regoli 1998;Dragun et al 2004).…”

“…In addition, the gill mass generally shows the smallest seasonal variability compared to other mussel tissues (Martinčić et al 1987;Regoli 1998;Dragun et al 2004). Mussels, as filter-feeders, have high filtration rates (Mytilus edulis: 52-196 L g -1 d -1 , Widdows et al 1995) and daily process large volumes of water. Hence, the uptake of metals from the dissolved phase significantly contributes to their accumulation in the gill tissue.…”

Biomonitoring organotin pollution with gastropods and mussels

“…Porte et al 2002), in no case has research provided tools as valuable as imposex for TBT. For instance, tissue residue chemistry data have been adequately construed in terms of some physiological measurement of stress in mussels (Widdows et al 1995), yet the potential of this procedure has not resulted in its common application in vigilance schemes. Possible reasons for this are also applicable to most other candidate techniques, namely the lack of both sensitivity and specificity of the biological response.…”

“…Thus, the toxicological interpretation of present mussel data according to the tissue residue approach would lead to the conclusion that, while TBT exceeds the threshold of effects on respiratory uncoupling (0.2 µg TBT g -1 DW or, approximately, 80 ppb Sn DW) in every population, only 1 surpasses that of severely inhibited scope for growth (4 µg TBT g -1 DW or 1600 ppb Sn DW). In addition, if in the future laboratory experiments were to show such detrimental effects in local mussels, many other individual pollutants (or pollutant families if QSARs were employed, see Widdows et al 1995) would have to be invoked in order to assign responsibilities for the observations. Finally, it is not known how quickly ambient TBT levels are expected to drop, in the OSPAR area and elsewhere, following the IMO total prohibition.…”