Mercury and PCBs in Massachusetts River Otters.

John F. Organ; Curtice R. Griffin

Mercury and PCBs in Massachusetts River Otters.

2004

John F. Organ | Curtice R. Griffin

Mercury and polychlorinated biphenyl (PCB) residues in livers of trapper harvested river otters (Lontra canadensis) from Massachusetts were evaluated. We collected 210 river otters during 1986 and 1987 and composited them into 103 samples based on location. Comparisons among 20 watersheds were made using 96 samples. Mercury residues were detected in all samples and ranged from 0.45 to 4.82 ppm wet weight with an arithmetic mean of 1.93 ppm. PCB residues were detected in all but 2 samples and ranged from none-detected to 22.00 ppm with a geometric mean of 1.03 ppm wet weight. Differences were detected among watersheds for mercury (P = 0.007) and PCBs (P = 0.03). Juvenile otters had lower mercury (P = 0.007) and PCB (P = 0.02) residues than older otters. River otters can provide an indication of general watershed background mercury and PCB contamination levels for prioritizing more intensive monitoring efforts. River otter populations in Massachusetts do not appear to be limited by either mercury or PCB contamination. Population monitoring should evaluate potential additive or synergistic effects of mercury in combination with PCBs in certain watersheds.

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