ABSTRACT:
White suckers (Catostomus commersoni) were collected for tissue residue analyses between 2003 and 2006 from the West Branch of the Sheepscot River, Ducktrap River, Cove Brook, Narraguagus River, Pleasant River, Machias River, East Machias River, and Dennys River. Ninety whole-body white suckers from 27 locations in the eight rivers were separated into 47 samples (22 composites and 25 individuals) and analyzed for organochlorine compounds and trace elements in a screening-level contaminant survey. Of 22 organochlorine compounds included in the analytical scan only two were detected with any regularity - Total PCBs and p,p'-DDE. Total polychlorinated biphenyl (PCB) was detected in all sucker samples from the Dennys River (mean 0.041 ﾵg/g), two fish from the Pleasant River (0.007 ﾵg/g, 0.018 ﾵg/g), and four composite samples from the East Machias River (mean 0.005 ﾵg/g). Total PCBs in suckers from the DPS rivers were similar to levels reported in regional and national biomonitoring programs. Although Total PCB was detected in 25 samples, and suckers from the Dennys River had six-fold higher Total PCB concentrations than fish from two other DPS rivers, Total PCB concentrations in DPS river white suckers did not exceed suggested biological effect levels. DDE, a metabolite of the insecticide DDT, was found in 12 of 28 samples (median 0.003 ﾵg/g) from the DPS rivers at levels three to fifteen times lower than levels reported in regional and national biomonitoring programs, and two orders of magnitude below a suggested DDT tissue threshold-effect level of 0.60 ﾵg/g.