Polychlorinated dibenzo- p- dioxins and dibenzofurans in cod ( Gadus morhua) from the Northwest Atlantic

Abstract

There is limited information available on the levels of polychlorinated dibzenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in major fish populations removed from local sources of contamination including populations from the Northwest Atlantic. Muscle, liver and ovaries of 7–9 year old female cod ( Gadus morhua) caught in the Northwest Atlantic, off Labrador, Canada were analyzed for congeners and selected isomers of PCDDs and PCDFs. PCDDs and PCDFs were not detected in either muscle or ovaries (< 0·1 to 0·8 pg/ g, wet weight), while the congener T 4CDF predominated in liver (9·7 ng/g lipid), followed by P 5CDF and O 8CDD (1·6 ng/g lipid), H 6CDD (0·6 ng/g lipid) and T 4CDD (0·2 ng/g lipid). The total concentrations observed in cod from the Northwest Atlantic were lower than those observed in cod from waters around Norway and Finland and are well below levels associated with adverse effects on animal or human health. The area of fish collection in the Labrador Sea is far removed from industrial (effluent) sources of pollution and urban associated plastic garbage incineration. The dioxins and furans in major fish populations in the Northwest Atlantic could be fossil fuel combustion byproducts a significant proportion of which may originate from trawler fleets on the surrounding fishing banks.