Rivierkreeften in beeld : verkenning naar verontreinigingen in rivierkreeften uit het beheergebied van Hoogheemraadschap Delfland

This report investigates the levels of heavy metals, dioxins, PCBs and PFAS in the freshwater crayfish Procambarus clarkii of four locations of Hoogheemraadschap Delfland. The results show that concentrations of pollutants in the white meat of the tail are all below tolerable intake levels. Unfortunately, such levels have not been derived for the brown meat from the head and instead we use the available levels for the white meat for comparison. For certain locations, exceedences of tolarable intake levels for lead and dioxin- like PCBs have been observed in tissues from the crayfish heads. Although tolerable intake levels for PFAS are not yet established, these compounds were found to accumulate mostly in the head tissues of the freshwater crayfish. Nevertheless, their levels fall within the range observed for crustaceans orginating from the Dutch Westerscheld área and consequently the advise on their consumption from the Dutch National Institute for Health and the Environment might be applicable here.