Distribution of polychlorinated biphenyls in the Housatonic River and adjacent aquifer, Massachusetts

Abstract

Polychlorinated biphenyls (PCBs) are sorbed to the fine-grained stream-bottom sediments along the Housatonic River from Pittsfield, Massachusetts, southward to the Massachusetts-Connecticut boundary. The highest PCB concentrations, up to 140,000 micrograms per kilogram, were found in samples of bottom material from a reach of the river between Pittsfield and Woods Pond Dam in Lee, Massachusetts. Sediments in Woods Pond have been estimated to contain about 11,000 pounds of PCBs. Approximately 490 pounds per year of PCBs have also been estimated to move past the Housatonic River gaging station at Great Barrington. The distribution of hydraulic-heads, water-temperatures, and concentrations of dissolved-oxygen, ammonia, nitrate, iron, and manganese in ground water show that industrial water-supply wells in a sand and gravel aquifer adjacent to a stretch of the river called Woods Pond have been inducing ground-water recharge through the PCB-contaminated bottom sediments of the pond since late 1956. These data indicate that, at one location along the shore of the pond, the upper 40 feet of the aquifer contains water derived from induced infiltration. However, this induced recharge has not moved PCBs from the bottom sediments into a vertical section of the aquifer located 5 feet downgradient from the edge of Woods Pond. Samplesmore » taken at selected intervals in this section showed no PCBs sorbed to the aquifer material or dissolved in the ground water within the detection limits of the chemical analyses. 30 refs., 15 figs.« less