Abstract:With gas chromatography-electron capture detector (GC-ECD), this paper analyzed 13 kinds of organochlorinae pesticides (OCP) in surface sediments collected from 22 sites of Song-Liao water system. The results showed that the total concentration of OCP varied from 3.06 to 23.24 ng·g-1 in Daliao River system and from 4.26 to 18.45 ng·g-1 in Songhuajiang River system. The most dominant OCP pollutant in the sediments in Song-Liao Watershed was HCH, but there existed different pollution tendency in the two subsystems. In Songhuajiang River, there were also relatively high concentrations of DDT. High concentration γ-HCH was observed among the isomers of HCH in the whole watershed, which exceeded the initial affecting concentration and could potentially do toxic effect on the water creatures.