Occurrence of persistent organic pollutants in sediments collected near fish farm sites

The sediment under four New Brunswick fish farm net pens was examined for the persistent organic pollutants (POPs): polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), polybrominated diphenyl ethers (PBDEs), pesticides, and polyaromatic hydrocarbons (PAHs). Concentrations of these POPs were compared according to distance from the net pen (0 m, 25 m, 50 m, and 100 m), sediment quality (anoxic, hypoxic, normoxic, and a remediation site), and published levels from locations worldwide. In general, at the anoxic sites POP concentrations were higher than at other sites, and they did not drop in concentration over distance to 100 m. The highest concentrations of the POPs examined here were low relative to polluted sites worldwide.