DNA adducts, histopathological abnormalities, and organosomatic indices were used to study contaminant effects on fish along a polycyclic aromatic hydrocarbon (PAH) gradient, leading away from an aluminum smelter on the Swedish Baltic coast. The level of DNA adducts, analysed using the 32P-postlabelling method, was at least 145 times higher in the liver of female perch (Perca fluviatilis) from the innermost site on the gradient, closest to the suspected point source of PAHs, than at a distant reference site. Of the DNA adducts analysed, a relatively small number accounted for a very high proportion of the total level of adducts (30-60% at the innermost site and close to 100% at the outermost site). These particular adducts could also be observed in extrahepatic tissues, such as trunk kidney and head kidney, along the entire gradient. Similar patterns of adducts were also observed in northern pike (Esox lucius). Focal hepatocellular degeneration in perch was about 15 times more extensive at the innermost site than at the next site in the gradient and absent in perch from the two outermost sites. Body size relative to age was also significantly reduced in perch from the three innermost sites compared with the outermost site.
Intestinal polycyclic aromatic hydrocarbon-DNA adducts in a population of beluga whales with high levels of gastrointestinal cancers
