Persistent organic pollutants in soil near the Changwengluozha glacier of the Central Tibetan Plateau, China: Their sorption to clays and implication

Twenty-seven soil samples were collected at ca. 5000 m from the Changwengluozha glacier. In addition to soil components, the concentration of 23 organochlorine pesticides (OCPs) and 16 polycyclic aromatic hydrocarbons (PAHs) were analyzed. Clay minerals were found to play a key role in the accumulation of OCPs/PAHs in soil. The sorption ratio of chemical to clay was ordered in the OCPs and PAHs to the vapor pressure in a negatively correlated fashion. Because of the negative relationship between vapor pressure and the soil-air partition coefficients (KSA), it was understood that the higher sorption ratio responded to a higher KSA, which indicated the fate of the contaminants in soil. The soil near the Changwengluozha glacier functioned as a “sink” for OCPs in the decreasing order of 2,4′-DDT, 4,4′-DDD, HCB, δ-HCH, and α-HCH and for PAHs in an decreasing order of Pyr, Flu, Fl, Ace, and Acy.