PCBs in a dated sediment core of a high altitude Lake in the Chilean Altiplano: The Chungara Lake

This paper documents the occurrence of Polychlorinated biphenyls (PCBs) in a dated sediment core from the highland Chungará Lake in northern Chile. The lake is located at 4520 m.a.s.l., one of the highest lakes in the world and a humanity heritage site (UNESCO). The samples were analyzed for PCBs, ²¹⁰Pb, Organic Carbon and Grain-Size. The ²¹⁰Pb profile allowed the dating of the first 10 cm of sediments, accounted for the last ∼100 years, the deposition rate being about 0.29±0.03 cm/year. Highest concentrations of PCBs (2 ng/g d.w) were found in the upper 5 cm of the core (i.e., last 40 years) with a trend being observed of increasing concentrations towards the uppermost section of the core, with higher fluxes of PCBs deposition during the 1987-1990 period reaching 1,360 ng/m ²/year. The observed fluxes are comparable to those found in the lake sediments from the temperate northern hemisphere.