Occurrence of organochlorine pesticides in surface soils from college school yards of Xi'an, China.

In this study, surface soil samples from 14 representative college school yards in Xi'an, the capital city of Shaanxi province, China, were collected and analyzed for 21 organochlorine pesticides (OCPs). The total concentrations were in the ranges of 0.2-67.0 ng/g. HCHs and DDTs were the most dominant compounds among the 21 OCPs, and their concentrations ranged from 0.1-8.5 to 0.1-56.3 ng/g, respectively. Source identification analysis indicated that the residues of HCHs and DDTs were mostly due to historical use of these chemicals or from other source regions. The quality of all the Xi'an college school yard soils except sample XAUAT was classified as low pollution by OCPs according to the National Environmental Quality Standards for Soils of China (GB15618-1995).