Factors influencing the accumulation of organochlorine pesticides in the surface soil across the Central Tibetan Plateau, China

Abstract

Forty-four soil samples were collected across the Central Tibetan Plateau (CTP) at elevations of between 3711 and 5352 m. The scatter diagram shows that the soil concentrations of organochlorine pesticides (OCPs) were associated with the altitude of sampling site, soil clay minerals, soil organic carbon (SOC) and the fine particle fractions of soil. Pearson correction analysis and principle component analysis were used to deduce the relationship between the OCP concentrations and these factors logically. It was determined that the altitude and clays functioned as the primary factors influencing OCP accumulation, and SOC was weakly related to OCPs. The fitting equation closely matches the observations in the field while only taking the altitude and clay minerals into account. Our study found that clay minerals dominated the sorption of OCPs in soil, whereas the altitude contributed to temperature-driven condensation for the accumulation of OCPs at high altitudinal CTP.