Monitoring of polycyclic aromatic hydrocarbons and toxic metals in blue mussels and oysters for human consumption from Danish waters (2005–2019)

Bivalve molluscs have for many years been used as indicator organisms for environmental pollution with various chemical substances. However, limited information is available on the levels of chemical contaminants in mussels and oysters intended for human consumption. Polycyclic aromatic hydrocarbons (PAHs) and toxic metals, such as cadmium (Cd), mercury (Hg) and lead (Pb) have been analysed in edible bivalve samples and the present study provides the results from samples collected in Danish waters from 2005 to 2019. Principal Component Analysis (PCA) and Pattern Recognition Neural Network (PRNN) analysis were applied to data to identify any differences according to organism, locality, and contaminant levels. Differences were confirmed for Pb concentrations being generally higher in mussels than oysters. Based on toxic metals results, the PCA and PRNN analyses made it possible to categorise samples as a mussel or an oyster, as well as make decisions on the origin of a specific sample. All concentrations in mussels and oysters were below the current European Union maximum levels for the contaminants.