TRENDS IN POLLUTANTS IN BLUE MUSSEL MYTILUS-EDULIS AND FLOUNDER PLATICHTHYS-FLESUS FROM 2 DUTCH ESTUARIES, 1985-1990

Temporal trends and length-concentration relationships are presented for data from the Joint Monitoring Programme for microcontaminants in the blue mussel Mytilus edulis and flounder Platichthys flesus from the Ems Dollard and Western Scheldt estuaries in the Netherlands over the period 1985 to 1990. Statistical analyses were carried out in conformity with ICES procedures. The analyses show only a decrease in levels of dieldrin in mussels from the Western Scheldt. Cadmium concentrations in flounders from the Ems Dollard have increased. No linear trend has been detected in either estuary for the other contaminants (PCB, PAH, pp'DDE, lindane, Hg, As, Cu, Cr, Zn, Pb, Ni). The importance of taking the fat weight into account in analysing PCB trend and length relationship is illustrated. Concentrations of PCB, PAH, chromium and nickel in mussels and PCB in livers of flounders decrease with increasing size. Mercury concentrations in flounders increase with length.