Temporal trends in soft tissue metal levels in the periwinkle Littorina littorea along the Scheldt estuary, The Netherlands

摘要

Because estuaries are usually important areas for industrial and urban development, they are often used as waste fields for domestic and industrial pollutants, including heavy metals which accumulate in estuarine sediments (e.g. Lam et al., 1997; Verslycke et al., 2004). However, metal bioavailability and the extent to which metals accumulate in, and are released from estuarine sediments, does not depend solely on metal input but is also determined by the spatio-temporal variability of the physico-chemical properties of the estuaries (e.g. Paucot and Wollast, 1997; Nolting et al., 1999; Monbet, 2004). Indeed, environmental factors such as salinity, pH, suspended and particulate matter and oxygen concentration are known to affect metal release and metal speciation (i.e. bioavailability) in a complex manner (e.g. Paucot and Wollast, 1997; Nolting et al., 1999; Riba et al., 2003; Pan and Wang, 2004). Metals that have, for instance, been accumulated and trapped for a long period in estuarine sediments might suddenly be released during a so called "chemical time bomb" explosion event, caused by changes in physico-chemical environmental factors (Wright and Mason, 1999).