RESIDUAL CHARACTERISTICS OF DDTS AND HCHS IN WATER BODIES OF CHINA: A REVIEW

摘要

In the past decades, a large volume of persistent organochlorinated pesticides, especially, DDTs and HCHs were produced and used in China, moreover, the over-dose and illegal use aggravated the serious environment pollution. In this study, the residual levels and distribution characteristics of DDTs and HCHs in environmental water bodies all over the China were investigated, and the regional variation, vertical distribution, and temporal changes were analyzed as well. It was found that, after prohibiting the agricultural use of DDTs and HCHs in China in 1980s, their residual levels decreased gradually in water although new pollution occurred occasionally. As for vertical distribution in water, the residues in surfacial layer were higher than that in bottom layer, and the residues in middle layer were the lowest. Among the different regions in China, high residues appeared in Minjiang River, Daya bay, Tonghui River, where both of DDTs and HCHs were more than 100ng/L, however, the low residual level appeared in Yangtze River, Yongding River, where both of DDTs and HCHs were less than 10ng/L, and the middle residual appeared in Pearl River, Jiulongjiang River etc. The higher residues in lakes than in rivers, and the new pollution input should be paid more attentions.