Risk assessment methodologies for exposure of great horned owls (Bubo virginianus) to PCBs on the Kalamazoo River, Michigan.

Dietary exposures of great horned owls (GHO; Bubo virginianus) to polychlorinated biphenyls (PCBs) in the terrestrial food web at the Kalamazoo River, Michigan, USA, were examined. Average potential daily doses (APDD) in GHO diets were 7- to 10-fold and 3-fold greater at the more contaminated location versus a reference location for site-specific exposures quantified as total PCBs and 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQ(WHO-Avian)), respectively. Wetland/aquatic prey contributed significantly to PCB exposure and APDD.

Reproductive success of passerines exposed to polychlorinated biphenyls through the terrestrial food web of the Kalamazoo River.

The eastern bluebird (Sialia sialis) and the house wren (Troglodytes aedon) were identified as ecological receptors of concern due to exposure and potential effects stemming from polychlorinated biphenyl (PCB) contamination in floodplain soils of the Kalamazoo River Superfund Site, Michigan, USA. Measures of population health were compared at a contaminated and a less-contaminated reference location. During this 3-year study, productivity of bluebirds was significantly less at the downstream location than at the reference location.

Differential accumulation of polychlorinated biphenyl congeners in the aquatic food web at the Kalamazoo River Superfund site, Michigan.

A series of field studies were conducted to gain a better understanding of the bioaccumulation and dynamics of polychlorinated biphenyl (PCB) congeners in the aquatic food web of the Kalamazoo River flood plain. Representative species of passerine birds, mammals, fish, aquatic plants, invertebrates, and colocated sediments were collected from areas located within submerged portions of the former Trowbridge impoundment and also from areas located at an upstream reference location. In most matrixes, total concentrations of PCBs were significantly greater in the downstream study area compared to the upstream reference location.

Differential accumulation of polychlorinated biphenyl congeners in the terrestrial food web of the Kalamazoo River Superfund site, Michigan.

A series of field studies was conducted to determine the bioaccumulation of polychlorinated biphenyl (PCB) congeners in the terrestrial food web of the Kalamazoo River flood plain. Samples included colocated soils, native plants likely to be consumed by wildlife, several taxa of terrestrial invertebrates, small mammals, passerine bird eggs, nestlings, and adults, and great horned owl plasma and eggs. Mean concentrations of total PCBs in samples from the former Trowbridge impoundment were 6.

Squamous epithelial lesion of the mandibles and maxillae of wild mink (Mustela vison) naturally exposed to polychlorinated biphenyls.

Approximately 125 km of the Kalamazoo River, located in southwestern Michigan (USA), are designated as a Superfund site, with polychlorinated biphenyls (PCBs) as the contaminant of concern. Mink (Mustela vison) are a naturally occurring predator in this area and also a species of concern because of their known sensitivity to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and structurally similar compounds, such as PCBs. Four of nine mink trapped from the Kalamazoo River area of concern (KRAOC) exhibited histological evidence of a jaw lesion previously identified in ranch mink.

Comparison of risk assessment methodologies for exposure of mink to PCBs on the Kalamazoo River, Michigan.

Risk assessments are generally based on exposures predicted by use of simple models of accumulation from abiotic compartments or the diet. The use of tissue-specific measurements of residue concentrations in wildlife tissues is more accurate and subject to less uncertainty, but these data are often not available. This report compares the results of two different site-specific approaches for assessing the risk of PCBs to mink residing along the Kalamazoo River, MI.