PCB Pollution of the Karstic Environment (Krupa River, Slovenia)
S. Polič, H. Leskovšek , M. Horvat - (29/1,2000)
The PCB (Polychlorinated biphenyls) pollution problems in Krupa River are related to sinking surficial streams that mix with the regional groundwater supply, thus endangering the quality of the groundwater reservoirs. The last state of contamination with PCBs and their fate and exposure in the polluted environment were studied in the period 1995 to 1998 within the Remedial Environmental Programme that began in 1984. The concentrations of PCBs in the environmental compartments (air, water, sediment, and soil) of the Krupa were determined. A simple two-compartment (air/water) fugacity mass balance model was applied to these figures, and yielded a reasonable simulation of long-term trends in concentration. The net flux of PCBs from water to air was determined (0.3 ng/m2s). Research into levels of pollution in the Krupa area showed the situation and trends regarding pollution after ten years of remedial measures, and produced a quantitative assessment of the emission of PCBs from the underground catchment area of the source of the river. Comparisons between PCB concentrations in the polluted water measured from 1986 to 1988 and the concentrations measured in 1995 to 1997 show a decreasing trend (i.e. from a mean of 380 ng/l to a mean of 100 ng/l in the Krupa's water). The emission flux of PCBs from water to air for the entire River Krupa (2.6 km long) was estimated at 200 to500 g/year, i.e. approximately one-tenth of the figure at the time the remedial measure was initiated.