Elevational Gradients of Organochlorine Pesticides and Polychlorinated Biphenyls in Topsoils from Changbai Mountain

Topsoils from an uncontaminated area of Changbai Mountain of Jilin province were generally less polluted by the organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), but it is more so than in other areas. The total concentrations of OCPs and PCBs in the topsoils showed a clear increasing trend with altitude, which can be interpreted as an Alpine condensation trap effect. Topsoil in the scenic spot of Changbai Mountain was slightly polluted by HCHs and DDTs (with each average value as of 12.4 ng/g and 12.3 ng/g respectively). The lower altitude area near Changbai Mountain had slightly higher concentrations of OCPs and PCBs, which indicated that agricultural activity gradually increased. The concentrations of HCHs and DDTs have not exceeded the national soil and environmental quality standards level I, but DDTs in some individual locations may cause a certain potential ecological risks to birds and soil organisms. The possibility is that lindane and dicofol are used in some sampling points. The concentrations of PCBs in topsoil samples from Changbai Mountain and its vicinity were 7.3-31.9 ng/g, with an average value of 17.2 ng/g. PCB contaminated areas are mainly concentrated in places with an altitude of between 1450 m and 1800 m. 7 kinds of PCBs can be ranged by concentrations as follows: PCB 28＞PCB 52＞PCB 180＞PCB 138＞PCB 101＞PCB 153＞PCB 118.