污染过程与控制实验室知识库

(1) 中国科学院烟台海岸带研究所中国科学院海岸带环境过程与生态修复重点实验室

Dichlorodiphenyltrichloroethanes (DDTs) are still detected in various environmental matrices,although their usage in agriculture has been banned for about 30 years in China.Intertidal zone,as the intersection area of land and sea,is the final sink for contaminants.To comprehensively understand the deposition features of DDTs in intertidal sediment of Daliao River Estuary,a sediment core was sampled in this study.Combined with the dating data,the distribution,potential risk,source and fate of DDTs were investigated.The results showed that DDTs concentrations ranged from 0.313 ng·g~(-1) to 4.116 ng·g~(-1) (median:2.061 ng·g~(-1)),with p,p'-DDTs being the major components.Interestingly,the peak of DDTs concentrations (3.4364.116 ng·g~(-1)) during 1988 1996 corresponded well with the peak of pesticide production during 19711981,and a 15-year-round time lag was observed between these two peaks.Possible usage of technical DDT was implied after year 2000 for the control and prevention of disease in Liaoning Province.The risk assessment of DDTs revealed that concentrations of DDT and DDE in sediment core rarely (<25%) showed negative effect,while concentrations of DDD and total DDTs in the depth of 044 cm occasionally (25%50%) showed negative effect.The specific ratios of DDTs demonstrated that DDTs in the intertidal sediments were mainly from historical use of technical DDT rather than the use of dicofol.DDE and DDD were the main degradation products of DDT in the deeper layer (62110 cm) and shallower layer (061 cm),respectively.Further analysis revealed that the increased TOC content caused by human activities after year 1971 was the main reason that led the sediment environment changing from aerobic environment to anaerobic environment.What's more,DDTs concentrations in sediment core had strong positive correlations with sediment properties (TN,TP and TOC) (P <0.01),and also had a significant positive correlation with anthropogenic activities (such as GDP,urbanization and total agricultural output value) (P <0.01).Therefore,the results of the concentrations and compositions of DDTs in intertidal sediment core could reflect the direct and indirect influence of human activities on the occurrence and fate of contaminants in intertidal sediment.

滴滴涕(DDTs)在中国农业生产中的使用已被禁止30多年,但仍在多种环境介质中有检出.潮间带作为陆地与海洋交汇区,是污染物在环境中重要的汇.为全面了解近百年来大辽河口潮间带中DDTs的沉积特征,本研究通过在大辽河口潮间带采集柱状沉积物样品,结合定年结果,揭示了近百年来大辽河口潮间带柱状沉积物中DDTs的污染特征,并对其潜在风险、源趋和影响因素进行了分析.结果显示,大辽河口潮间带柱状沉积物中DDTs浓度范围为0.3134.116ng·g~(-1)(中值:2.061ng·g~(-1)),以p,p'-DDTs为主要污染物.1988 1996年为沉积物中DDTs污染高峰期(3.4364.116ng·g~(-1)),与19711981年农药生产高峰期相对应,且存在约15年的延迟.2000年以后,辽宁省可能存在工业DDT的使用,且与疾病防控有关.经风险评估发现,DDT和DDE在0110cm范围内均极少(<25%)对底栖生物产生负效应,而DDD和总DDTs在044cm范围内偶尔(25%50%)对底栖生物产生负效应.DDTs的特征比值分析表明,大辽河口潮间带沉积柱中DDTs主要来源于工业DDT的历史污染而非三氯杀螨醇的使用.DDT降解产物在深层(62110cm)以DDE为主,而在浅层(062cm)以DDD为主.1971年后人为活动导致TOC含量的增加是促使大辽河口潮间带沉积物由好氧环境转变为厌氧环境的重要因素.此外,大辽河口潮间带沉积物中DDTs浓度与沉积物性质(总氮(TN)、总磷(TP)和总有机碳(TOC))具有极显著相关性(P<0.01),且与辽宁省GDP、城市化率和农业总产值等人为活动具有极显著正相关性(P<0.01).综上,由潮间带沉积柱中DDTs的浓度和组成反映出人类活动直接或间接影响了潮间带中污染物的存在和归趋.