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

Abstract

Twenty-seven soil samples were collected at ca. 5000m 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.