Mercury concentrations in plaice, flounder and dab from Belgian continental shelf waters (1971-1990)

Results obtained during a survey of 20 years on plaice (Pleuronectes platessa) and 15 years on flounder (Platichthys flesus) and dab (Limanda limanda) are reported. With flounder, two periods could be distinguished. In 1975-1981, higher mercury concentrations (0.38 mg/kg on average) with rather large variations were noted. From 1982 on, concentrations fluctuated around the same mean value (0.23 mg/kg). A gradual decrease of mercury levels in plaice was observed during the twenty years' monitoring period. The mean concentration in 1990 (0.06 mg/kg) was only one third of that of 1971 (0.18 mg/kg). In contrast with flounder and plaice, mercury concentrations in dab remained practically at the same level (0.09-0.13 mg/kg)

De evolutie van het kwikgehalte in tong (<i>Solea solea</i> L.) uit de Noordzee en de Ierse Zee

The mercury content of sole from the North Sea and the Irish Sea was followed during a 5 yr period (1973-1977). With the exception for the first 2 yr, no significant difference was found between the 2 areas, nor was there a clear trend in the evolution of the mercury concentrations in time. The average mercury content varied between 0.19 and 0.31 mg/kg (North Sea) and 0.21 and 0.41 mg/kg (Irish Sea)