Polychlorinated biphenyls in polysulfide sealants—Occurrence and emission from a landfill station

Approximately 80 000 kg polysulfide sealant containing 10 000–18 000 kg polychlorinated biphenyls (PCB) was deposited at a Swedish municipal landfill station during 1965–1973. Investigations during 1994 showed that soil layers underneath the landfill had concentration of PCB not alarmingly high. The concentration of PCB congeners in ground water samples was elevated 4–750 times compared to a reference sample. Based on samples of ground water, leachate water, and flux chambers measuring evaporation of PCB from the landfill surface, the emission of PCB was estimated to be 1 g ΣPCB/yr. This very low rate was attributed to the high sorptive capacity of the sealant. Compared to a reference site, the evaporation flux was elevated for the most volatile congeners, but factors 20–1400 lower than from another landfill which was contaminated with PCB in paper-pulp fibres. From a municipal 2-ha landfill containing 10–18 tonnes of ΣPCB bound in polysulfide sealants, only 1 g per year escape to the surroundings.