Bioaccumulation profiles of chemical contaminants in fish from the lower Willamette River, Portland Harbor, Oregon.

Twenty-five PCBs (polychlorinated biphenyls), 15 organochlorine (OC) pesticides, and mercury were determined in fish from the Willamette River in Oregon, including a Portland Harbor superfund site. Fish were collected during the summer of 2000 along a 20-mile stretch of the lower Willamette River. Concentrations of sumPCBs (sum of 25 individually determined PCB congeners) and sumDDTs (sum of p,p'-DDT, p,p'-DDE, and p,p'-DDD) in fish ranged from 14 to 530 and from 18 to 510 ng/g-wet weight, respectively. SumPCBs concentrations at all sites exceeded US EPA fish advisory's screening values. Hexachlorobiphenyl congener 153 was the most abundant of the PCBs detected and p,p'-DDE was the most abundant OC pesticide detected. Low levels of dieldrin were detected in fish at all sites with the highest concentration at the superfund site (4.6 ng/g-wet weight), while other OC pesticides tested were near or below detection limits (approximately 2 ng/g). In general, organic chemical contaminant concentrations were highest in fish from the superfund site and were lower further upriver. Smallmouth bass had the highest levels of OC compounds of three fish species examined. They also had the largest site-to-site variations whereas black crappie had little variation throughout the study area. Mercury levels in fish ranged from 13 to 520 ng/g. Historical fish residue data are limited from the Portland Harbor superfund site, what data is available is over a decade old, generally consisted of only a few fish (< or = 3) and analyses quantified only a few PCB congeners (< 3).

DDT residues in forest floors and soils of western Oregon, September-November 1966.

Between 1945 and 1965, 1.82 million hectares, or about 17 percent of the total commercial forestland in Oregon, were treated with 2.02 million kg DDT. Detectable residues of this insecticide might be present in forest soils, even those which have never received a direct application of insecticide. Forest floor and mineral soil samples were collected along four east-west transects across the Coast and Cascade Ranges. DDT residues were found in all samples, even though all but one site had never received a direct application of insecticide. In the Coast Ranges, mean concentrations of sigma DDT in forest floor samples were 0.049 ppm at the coast and 0.047, 0.064, 0.075, and 0.119 ppm at 16, 32, 48, and 64 km inland, respectively. Mean residue levels in the surface layers of mineral soil were much lower, 0.009 ppm and 0.006 ppm in the 0 to 7.5-cm and 7.5 to 15-cm depths, respectively. Sampling sites along the Cascade Range transects were selected on the basis of elevation except that the eastern site of each transect was located 16 km east of the crest of the Cascades. Residue concentrations in forest floor samples were three to four times higher than in the Coast Ranges, but were still below 0.50 ppm. In general, sigma DDT levels increased with increasing elevation up to 1,372 meters and then decreased quite sharply east of the crest. Variations can be explained on the basis of total rainfall distribution and by transect location relative to agricultural and metropolitan centers.