Aromatic DNA-carcinogen adducts in beluga whales from the Canadian Arctic and Gulf of St Lawrence

Aromatic DNA adduct levels in liver tissues of beluga whales ( Delphinapterus leucas) from two sites in the Canadian Arctic and from the St Lawrence estuary (N.W. Atlantic Ocean) were determined using the highly sensitive 32P-postlabelling technique. Detectable levels of aromatic DNA adducts (16–158 nmole adducts/mole total nucleotides) were found in all animals tested. It is of interest that the average level of adducts in animals from the St Lawrence estuary, which contains relatively high levels of contaminants including polycyclic aromatic hydrocarbons, was comparable to those found in animals from the two remote locations. These observations are of major significance in view of the controversy on the role of polycyclic aromatic hydrocarbons in producing cancer in beluga whales in the Gulf of St Lawrence. (The point made is that PAH may not be the primary reason and other causes should be addressed.) Also given that the study was carried out on animals taken from regions known to be relatively clean and highly contaminated, the results are of major importance for the scientific and regulatory communities with interests in the use of biochemical monitoring techniques. Also, the presence of adducts in whales from the Canadian Arctic suggests the existence of non pollution-related mechanisms for genetic damage.