Strand, J., Vorkamp, K., Larsen, M.M., Reichenberg, F., Lassen, P., Elmeros, M. & Dietz, R. 2010. Mercury compounds, HCBD and HCCPD in the Danish aquatic environment. A NOVANA screening study. National Environmental Research Institute. 36 pp. - NERI Technical Report no. 794.
This screening study has been designed to provide monitoring data for some of the EU priority substances, of which only limited knowledge exists regarding their occurrence in the Danish aquatic environments. The study concerns the two chlorinated compounds hexachlorobutadiene (HCBD) and hexachlorocyclopentadiene (HCCPD) and the metal mercury (Hg) and its compounds, i.e. primarily methylmercury in relation to the total content of mercury. The study assesses the presence of those compounds, their bioaccumulations and the associated risk for aquatic organisms. This information will contribute to the assessment of whether these substances should be included in future national monitoring programmes of the aquatic environment in relation to obligations under the EU Water Framework Directive, which includes environmental quality standards (EQS) for mercury and HCBD in biota.
Approximately 50 samples of mussels, fish and piscivorous birds and mammals were selected to represent the fauna from various freshwater and marine areas in Denmark.
The study showed that mercury and its compounds were present in aquatic organisms from different trophic levels of the food webs in both freshwater and marine environments. The levels of mercury exceeded in several areas the EU environmental quality standard of 20 ?g/kg wet weight in both mussels and fish, which has been established to protect fish-eating top predators. Methylmercury constituted 10 % - 45 % of total mercury in mussels. However, in the muscle tissue of fish, 80 % - 100 % of total mercury was methylated. Even higher mercury concentrations were found in piscivorous wildlife species like cormorant, otter and harbour seal, indicating a significant biomagnification from dietary exposure. The maximum level for mercury in fishery products useful for human consumption was not exceeded in any of the analysed fish samples, although the mercury levels can pose a risk for fish-eating top predators.
The chlorinated compounds HCBD and HCCPD were not found in concentrations higher than the detection limits in any of the biota samples analyzed. All analytical results indicated levels below the method detection limit of <0.27 µg/kg of wet tissue. However, HCBD has been detected in sediments from Danish coastal waters under the NOVANA monitoring program in 2008 and 2009, albeit at low levels.
Full report in PDF format (2,56 MB)
