三亚湾沉积柱有机氯农药的垂直分布特征

采用GC-ECD内标法测定了三亚沉积柱状样中有机氯农药的含量,并以210Pb同位素法对柱样定年,探讨了柱样中有机氯农药的垂直分布特征及可能来源.结果表明:沉积物中HCHs和DDTs的含量分别为0.04～1.46和0.01～0.59ng.g-1(以干重计,下同);自20世纪60年代开始大量使用OCPs后,沉积柱中OCPs在1965年、1971年和1975年分别出现了3个峰值;在我国禁止生产和使用OCPs后,柱样中OCPs含量自1986年后略有降低;自1990年起,OCPs含量明显增加,变化幅度较大,其含量变化与三亚发展建设有关.研究区域调查显示,近年来有林丹的输入,HCHs在沉积柱样表层富集较明显;在该偏氧化的沉积环境中,(DDD+DDE)/DDTs的值逐渐变小,且大部分均小于0.5,说明可能有新的DDTs输入.

Vertical distribution characteristics of organochlorine pesticides in a sediment core from Sanya Bay

A sedimentary core from Sanya, Hainan Province was collected to explore the residues, and reactions of organochlorine pesticides (OCPs) in China over time. Pesticides were quantified by gas chromatography with electrochemical detection (GC\|ECD) with the internal standard procedure and the core was dated by 210Pb methods. The concentration range for HCHs and DDTs were 0.04~1.46 and 0.01~0.59 ng·g-1 respectively. Three peaks around the years 1965, 1971 and 1975 were found after OCPs began to be used in quantities in China in the 1960s. Sedimentary OCP concentrations decreased slightly after 1986 since the production of technical HCHs and DDTs was banned in 1983 in China. Since the 1990s, OCP concentrations showed an increasing trend with large fluctuations, which is closely related to the pattern of development in Sanya. There is some evidence of new input of lindan in recent years and enrichment of HCHs on surface sediment. The ratios of (DDD+DDE)/DDTs were lower than 0.5 in most samples and decrease from the deeper layers to the surface sediments, indicating that new input of DDTs is possible in the studied region.