淮河（安徽段）沉积柱中有机氯农药的垂直分布特征

Vertical Distribution Characteristics of Organochlorine Pesticides in a Sediment Core from Huaihe River, Anhui

本文利用GC-MS内标法和210Pb同位素定年法对淮河流域(安徽段)沉积柱中22种有机氯农药(OCPs)的含量进行定性和定量分析,并探讨沉积柱中OCPs的分布特征及生态风险。结果表明:沉积柱的沉积年代跨度50年(1956—2015年),平均沉积速率为0.45cm·a^-1;沉积柱样品中共检出18种OCPs,总OCPs浓度范围为0.01~7.18ng·g^-1,平均浓度为4.53ng·g^-1,平均检出率为51.60%。几种主要OCPs的平均浓度由大到小为滴滴涕类(1.67ng·g^-1)、六六六类(0.81ng·g^-1)、硫丹类(0.69ng·g^-1)、氯丹类(0.45ng·g^-1)、六氯苯(0.39ng·g^-1)。狄氏剂、异狄氏剂、艾氏剂均未检出,OCPs残留的浓度变化与不同的历史使用情况及自身理化性质有关。近几年OCPs在沉积柱的含量呈明显下降趋势;生物风险评估表明,淮河(安徽段)沉积柱中有机氯农药的生态风险较低。

In this study,we measured the concentrations of 22 organochlorine pesticides (OCPs) in the sediment core from the Huaihe River in Anhui Section,by gas chromatography mass spectrometry (GC-MS) and dating by 210Pb.We also discuss the distribution characteristics and ecological risk of organochlorine pesticides in the environment.The results show that the sedimentary age of the core Spans 50 years (1956-2015),and the average deposition rate is 0.45 cm·a^-1.The total concentration of 18 kinds of OCPs in the sediment core were in the range of 0.01~7.18 ng·g^-1 with average concentration of 4.53 ng·g^-1. The average detection rate was up to 51.60 %.The main categories of OCPs were in the following order:DDTs (1.67 ng·g^-1), HCHs (0.81 ng·g^-1),Endosulfans (0.69 ng·g^-1),Chlordanes (0.45 ng·g^-1),HCB (0.39 ng·g^-1).Drins were all lower than detection limits.The temporal trends of OCPs were influenced by their different historical usages,different properties or different degradation conditions in the environment.In recent years,the content of OCPs in sediment core has shown a significant downward trend biological risk assessment result shows that OCPs have lower ecological risks.