SOILS AT BRIDGES AND ROADWAYS AS POSSIBLE SOURCES OF POLYCHLORINATED BIPHENYLS (PCBS) TO LAKE ANNA WATERS AND SEDIMENTS

Recent studies indicate that polychlorinated biphenyls (PCBs) have been bioaccumulating in fish tissue in Lake Anna, located in central Virginia. In a 2006 Virginia Department of Environmental Quality (DEQ) study, PCB concentrations in fish tissues ranged as high as 5376.8 ng/g in gizzard shad located in Terry's Arm of Lake Anna. This value is well above the 54 ng/g health advisory levels for fish consumption issued by the Virginia Department of Health. DEQ and University of Mary Washington researchers identified elevated levels of PCBs in sediment samples ranging from 1.08 ng/g to 40.9 ng/g. PCB “hot spots” in this sediment study were located near where bridges crossed arms of the lake. In an effort to identify the source(s) of PCBs to Lake Anna, PCB concentrations in soil samples taken along roads and bridges were quantified using EPA Method 8080A. Total PCB concentrations were determined as the sum of seven PCB isomers for which calibration standards were readily available. Soil samples taken in ditches adjacent to roadways were found to have PCB concentrations of these seven isomers of 5.0 ng/g to 6.7 ng/g. At two bridges, soil concentrations of the seven PCB isomers range from 1.5 ng/g to 11.8 ng/g, while at another bridge concentrations of the seven isomers were as high as 988 ng/g in a composite sample and 3875 ng/g in a discrete sample taken above flood levels, indicating that soils near these bridges are possible sources of PCBs to the lake.