无锡某地区土壤中有机氯农药污染状况调查

调查分析了无锡市某地区土壤有机氯农药污染状况。数据表明,该地区土壤有机氯农药主要残留组分为p,p＇-DDE和p,p’-DDT,其浓度处于较低水平,对生态环境和人类健康无显著危害。     

典型农业生产功能区土壤中六六六、滴滴涕类农药残留及其异构体分布

测定了不同典型农业生产功能区土壤中有机氯农药(OCPs)残留,六六六(HCHs)、滴滴涕(DDTs)各同分异构体均有不同程度检出。结果表明,DDTs含量占有机氯农药含量的56%~95%,是污染的主要贡献污染物。HCHs中γ-HCH占45%~79%,DDTs中DDE>40%。其畜禽养殖基地和污水灌溉区污染指数(DDTs)分别为1.6(重污染)和0.6(中污染),其余均小于0.5(轻污染)。     

兰州西固区土壤中有机氯农药污染特征及风险评价

采集兰州西固区土壤样品,采用GC/μECD方法检测样品中有机氯农药(OCPs)污染残留,并分析调查区土壤中OCPs污染特征、来源及潜在生态风险。结果表明,8种OCPs异构体在兰州西固区土壤中的检出率均为100%,总质量比范围在18.34μg/kg~125.34μg/kg之间,平均值为54.84μg/kg;土壤中BCHs和DDTs残留质量比分别为0.742μg/kg~29.3μg/kg和10.9μg/kg~98.6μg/kg。OCPs残留以p,p'-DDT和β-BCH为主。不同采样点土壤样品中OCPs的残留量从高到低依次为路边样绿化带样树根土样菜地样。对DDTs与BCHs异构体残留组分分析发现,调查区土壤中残留的BCHs主要源于历史应用,而DDTs源于近期污染。     

北京工业废水和城市污水中有机氯农药残留分析

建立了基于HLB固相萃取柱和气相色谱-电子捕获(GC-ECD)测定水体中有机氯农药的方法,并对方法的回收率、灵敏度进行了评价,同时分析了北京市七类典型污染点源50个采样点位有机氯农药的浓度,检测到的有机氯农药包括γ-六六六、β-六六六、4,4’-滴滴涕、α-六六六、δ-六六六、硫丹Ⅰ、4,4’-滴滴伊、艾氏剂和异狄氏剂,它们的检出率分别为90%、60%、50%、46%、26%、8%、6%、2%和2%。主要有机氯农药污染残留为γ-六六六、β-六六六和4,4’-滴滴涕。检出有机氯农药浓度范围是0.20~76.40ng/L。方法对有机氯农药的回收率达到60.93%~141.50%,方法检测限为0.27~2.90ng/L。     

乌江流域中上游水体中有机氯农药残留现状调查

采集了乌江流域中上游30个采样点的60个水样品,用液-液萃取对样品进行前处理,然后用GC-ECD测定有机氯农药含量,分析有机氯农药残留现状。结果表明,有机氯农药在样品中都有不同程度的检出,其中六六六、滴滴涕类物质的检出率分别为90.7%、46.9%,质量浓度为4.03~42.89 ng/L,同我国其它区域相比,乌江流域中上游水体中的有机氯含量处于中等水平,低于相应的标准限值。故就有机氯农药这类污染物在水中的含量来说,乌江流域中上游的水体是相对安全的。但由于这类污染物是持久性的,因此它们在水环境中的存在和影响也是不容忽视的。     

惠州农业土壤、灌溉水和农产品中有机氯农药的残留

用气相色谱法(GC-ECD)对惠州市51个农业土壤样品、12个灌溉水样品和21个农产品样品中的HCHs和DDTs残留量进行了测定.HCHs平均含量分别为土壤1.66μg/kg、灌溉水5.86ng/L、农产品24.74μg/kg;DDTs平均含量分别为土壤4.98μg/kg、灌溉水2.06ng/L、农产品41.72μg/kg,土壤中有机氯农药通过多种方式进入到水体及农产品中.从HCHs和DDTs异构体组成可以看出,环境中绝大多数农药残留是由于历史上使用造成的,个别地区可能还有新的污染输入.同其它地区相比,惠州农业土壤和灌溉水中的有机氯农药残留水平较低,但农产品尤其是蔬菜中DDTs富集程度较高.     

湖南省农田土壤中HCH和DDT残留状况研究

2009年6月采集了湖南省农田土壤中的160个样品,采用ASE萃取技术,用GC-MS方法测定了样品中的六六六(HCH)、滴滴涕(DDT)。结果表明:HCH和DDT的检出率为100%,说明湖南省农田土壤中有机氯农药残留现象普遍存在。HCH和DDT的平均含量分别为8.03和36.26μg/kg,范围分别在0.20～17.89μg/kg和5.05～45.96μg/kg。与国内不同区域的同类研究相比,湖南省农田土壤的有机氯残留水平处于中等水平。在不同类型土壤中,有机氯残留状况有所差异,HCH在水稻土中残留量最高,而DDT在棉花田最高。     

我国农田农药流失现状及减控策略

农业面源污染已经成为全球水污染的主要来源,其中具有生物毒性的农药污染物对人体健康和生态环境安全构成了严重威胁。分析了我国农田农药流失现状,指出流失的主要农药品种与用药历史和特点密切相关,水体中检出的有机氯农药主要源于早期农药残留,检出的有机磷农药和长残效除草剂部分种类目前仍在使用。提出从影响农药流失的各个环节入手,制定严密的减控策略。植物缓冲带是拦截农药流失的常用措施,可以实现对农业面源污染的可持续治理。建议实行生态功能区划,严格限制高毒农药的施用,减少化学农药施用量,规范农药喷洒器械和施药技术,从源头上控制农药流失,从而降低农业非点源污染带来的危险。     

官厅水库沉积物表层中的有机氯农药分布特征及风险评价

采用气相色谱法对北京市官厅水库沉积物表层中持久性有机氯农药(OCPs)的残留状况进行了调查,并对有机氯农药污染水平和生态风险作出评价。结果表明:沉积物中有机氯农药总含量为8.48 ng/g～24.40 ng/g,其中HCHs和DDTs的含量较高,分别为1.11 ng/g～7.73 ng/g和2.97 ng/g～10.52 ng/g,其组分特征为来自环境的残留。与沉积物风险评估低值(ERL)和风险评估中值(ERM)对比评价沉积物中有机污染物的风险程度,官厅水库沉积物表层中的有机氯农药存在一定的生态风险。     

洞庭湖流域土壤中有机氯杀虫剂的残留规律研究

2004年5月采集了洞庭湖流域45个土壤样品,用AES萃取技术,使用GC/MS方法测定了样品中的六氯笨、滴滴涕(DDTs)、氯丹、艾氏剂、狄氏剂、异狄氏剂、七氟和灭蚁灵.结果表明,六氯苯、滴滴涕的检出率为100%,氯丹和灭蚁灵的检出率很低,艾氏剂、狄氏剂、异狄氏剂和七氯未检出.总有机氯杀虫剂残留量平均值216.24μg/k,其中滴滴涕214.7μg/kg,占总OCPs的99.3%,且有些土壤样品中w(DDT)/w(DDE DDD)值较大,说明DDTs曾作为湘江流域的主要杀虫剂在洞庭湖流域土壤中广泛施用过,并且近期内仍然有输入.六氯苯的残留量虽然较低,但其施用范围广泛.总OCPs在棉田中的残留量很高,在茶场土壤中最低,表明棉田土壤曾因为各种原因施用过大量的有机氯杀虫剂,茶场土壤中有机氯农药的残存量处于安全范围.     

Distribution and bioaccumulation of organochlorine pesticides (OCPs) in food web of Nansi Lake,China

The concentration of 12 organochlorine pesticides (OCPs) were measured in water, sediment, aquatic plant, and animal (shrimp and fish) of Nansi Lake by gas chromatography equipped with an electron capture detector. The total OCPs concentrations were 65.31–100.31 ng L^?1 in water, 2.9–6.91 ng g^?1 dry weight (dw) in sediments, 1.29–6.42 ng g^?1 dw in aquatic plants and 7.57–17.22 ng g^?1 dw in animals. The OCPs composition profiles showed that heptachlor compounds was also the predominant OCPs contaminants in addition to hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) in Nansi Lake. According to the source of HCHs and DDTs in sediment samples, there was no new input and the HCHs pollution mainly came from the use of Lindane in Nansi Lake. Bioaccumulation of OCPs in aquatic biota indicated that DDTs and heptachlor compounds had a strong accumulation, followed by HCHs and drins. The accumulation abilities of fish for OCPs were higher than those of plants and shrimps. The OCPs biota-sediment accumulation factor values of Channa argus was the highest in fish samples, followed by Carassius auratus, and Cyprinus caspio. Risk assessment of sediment showed that heptachlor epoxide had a higher occurrence possibility of adverse ecological effects to benthic species. Based on the calculation of acceptable daily intake and hazard ratio, HCHs in fish and shrimps from Nansi Lake had a lifetime cancer risk of greater than one per million. The risk assessment of water, sediment, and fish indicated the water environment of Nansi Lake is at a safe level at present.     

Organochlorine pesticides in the dust fall around Lake Chaohu, the fifth largest lake in China

The residual levels of organochlorine pesticides (OCPs) in the dust fall around Lake Chaohu were measured using gas chromatography mass spectrometry from April 2010 to March 2011. The fluxes, components, temporal–spatial variations, and sources of OCPs were also analyzed. Twenty-one types of OCPs were detected in the dust fall samples around Lake Chaohu, with a total concentration of 51.54?±?36.31 ng/g and a total flux of 10.01?±?13.69 ng/(m² day). Aldrin (35.3 %), endosulfan (39.1 %), dichlorodiphenyltrichloroethanes (DDTs) (49.8 %), and isodrin (37.1 %) were the major OCPs in the spring, summer, autumn, and winter, respectively. Both the residual level and the flux were higher in the spring than in other seasons and higher at the outer lake sampling sites than inner lake sampling site. The potential source of the hexachlorcyclohexanes in the dust fall may be recent lindane usage. The DDTs mainly came from historical dicofol usage, and a significant input of DDT was found during April and June. The presence of endosulfan may be due to the present use of technical endosulfan. The aldrin in the dust might be due to its occasional usage, and isodrin may be a result of long-distance transport from other countries.     

Distribution,sources, and ecological risk assessment of SVOCs in surface sediments from Guan River Estuary,China

The contamination of semi-volatile organic compounds (SVOCs) in the surface sediments of the Guan River Estuary, China was fully investigated. Total concentrations of 56 species of SVOCs ranged from 132 to 274 ng/g with an average of 186 ng/g (dry weight). Polycyclic aromatic hydrocarbon (PAH) concentrations were positively correlated with clay content and negatively correlated with sediment grain size. Source identification indicated that PAHs originated mainly from pyrolytic sources. However, intense ship traffic in the estuary may provide sources of petrogenic PAHs. Organochlorine pesticides (OCPs) mainly originated from direct input of dichlorodiphenyltrichloroethanes (DDTs) during some industrial processes. The SVOC concentrations were also compared with International Sediments Quality Guidelines and Sediments Quality Criteria, and the results indicated that negative biological impacts may originate from high concentrations of FLO, p,p′-DDE, and total DDTs.     

Distribution and sources of organochlorine pesticides in sediments of the Xiangjiang River, south-central China

The Xiangjiang River (XR), the second largest tributary of the Yangtze River, is mainly located in Hunan province in south-central China. Nineteen surface sediment samples (the top 3-cm layer) collected from XR were analyzed to determine the concentrations, distribution, sources, and ecological risk of organochlorine pesticides (OCPs). The concentrations of OCPs were 3.0–29.8 ng/g (dry weight) with a mean of 12.6?±?7.7 ng/g. The widely detected compounds included HCHs, DDTs, HCB, and dieldrin. Overall, the dominant OCPs in the sediments were mainly composed of residual and degradation products, e.g., β-HCH with a mean of 42.2 % in HCHs and p,p′-DDE with a mean of 43.5 % in DDTs, implying that OCPs in the sediments had suffered from long-term aging without fresh inputs in XR. However, there was a high proportion of p,p′-DDT to DDTs in three sites, suggesting that there was use of technical DDT from their surrounding areas at present. The ratios of α-HCH/γ-HCH and p,p′-DDD?+?p,p′-DDE/DDTs increase from the upper reaches to the lower reaches of XR, suggesting sediments enriched with α-HCH and metabolites DDD and DDE during sediment transport process and could be attributed to the transformation of γ-HCH to α-HCH and DDT to DDE or DDD. The assessment of the ecological risk indicates that the OCPs in the sediments of XR have a moderate adverse biological effect on organisms.     

The distribution of organochlorine pesticides (OCPs) in surface sediments of Bohai Sea Bay,China

The residues of organochlorine pesticides (OCPs) in 19 surface sediments of Bohai Sea Bay were determined in this study. Total OCP concentration in surface sediment ranged from 9.01 to 18.04 ng/g dry weight, with a mean concentration of 12.50 ng/g. These findings are in the mid-range of pesticide concentrations compared to those reported in other regions worldwide. DDTs and HCHs were the predominant species. The α-HCH/β-HCH ratios and the predominant γ-HCH indicate that the technical HCH contamination was due mainly to historical usage, although there appeared to be a fresh input of lindane. The results from \(\left( {\mbox{DDD}\,\mbox{+}\,\mbox{DDE}} \right)\mbox{/}\sum {\mbox{DDTs}} \) and DDD/DDE calculations suggest that the usage of DDT in agricultural activities was not terminated, and the historical/fresh inputs of DDT in these areas could be more easily degraded into DDD under an anoxic condition. PCA implies that the recent usage of DDT could serve as important fresh input sources for OCPs.     

Health risk assessment of organochlorine pesticides with emphasis on DDTs and HCHs in abandoned agricultural soils

The aim of this study was to evaluate the consequence of changing land use from agriculture land to other use purposes with respect to OCPs non-cancer and cancer risk on human health, based on concentrations of DDTs and HCHs in soils collected from 55 locations representing 12 different land use types. There were no non-cancer risks of DDTs and γ-HCHs on adults and children, and there were very low cancer risks of DDD, o,p'-DDE, DDT, α-HCH, β-HCH, γ-HCH based on their total concentrations in all samples. Nonetheless, there were significant correlations of DDT to its metabolites (DDE and DDD) (r = 0.506 and r = 0.648) and DDE to DDD (r = 0.438) both at p < 0.01. OCP levels should be routinely monitored in different environmental media and food in order to verify whether there is fresh input. Their potential risks on human health should also be assessed.     

Organochlorine pesticides in the surface water and sediments from the Peacock River Drainage Basin in Xinjiang, China: a study of an arid zone in Central Asia

Fourteen surface water and nine surface sediment samples were collected from the Peacock River and analyzed for organochlorine pesticides (OCPs) by gas chromatograph?Celectron capture detector (GC-ECD). All the analyzed organochlorine pesticides, except o,p ^??-DDT, were detected in sediments from the Peacock River; but in the water samples, only ??-HCH, HCB, p,p ^??-DDD, and p,p ^??-DDT were detected at some sites. The ranges for total OCPs in the water and sediments were from N.D. to 195 ng l^???1 and from 1.36 to 24.60 ng g^???1, respectively. The only existing HCH isomer in the water, ??-HCH, suggested that the contamination by HCHs could be attributed to erosion of the weathered agricultural soils containing HCHs compounds. Composition analyses showed that no technical HCH, technical DDT, technical chlordanes, endosulfans, and HCB had been recently used in this region. However, there was new input of ??-HCH (lindane) into the Peacock River. The most probable source was water flowing from Bosten Lake and/or agricultural tailing water that was returned directly into the Peacock River. DDT compounds in the sediments may be derived mainly from DDT-treated aged and weathered agricultural soils, the degradation condition was aerobic and the main product was DDE. HCB in the sediment might be due to the input from Bosten Lake and the lake may act as an atmospheric deposition zone. There was no significant correlation between the concentrations of OCPs (including ??HCH, ??DDT, chlordanes, endosulfans, HCB and total OCPs) and the content of fine particles (<63 ??m). The concentrations of OCPs were affected by salinity.     

Atmospheric depositional fluxes and sources apportionment of organochlorine pesticides in the Pearl River Delta region, South China

Organochlorine pesticides (OCPs) have variously been phased out in agricultural activities, but they are still widely detected in air, water, and soil systems due to their recalcitrant nature in the environment. The purposes of this study were to assess potential OCP pollution via dry and wet deposition over the fast developing Pearl River Delta area with 41,700 km², where the main effort has been focused on emerging pollutants such as petroleum hydrocarbons and PM2.5. We quantified both the dry and wet deposition fluxes of 19 OCPs including dichlorodiphenyltrichloroethanes (DDTs), endosulfans (Endos), and hexachlorocyclohexanes (HCHs). The results showed that each year about 67.4, 42.0, 15.0, and 8.07 kg of total OCPs, DDTs, Endos, and HCHs were returned to the ground, among which 11.7, 10.4, 0.84, and 0.16 kg were in the dry deposition forms. The large spatial variations in OCP deposition fluxes indicated that OCP pollution in the air is mainly influenced on local scales because evaporation from local soil is likely the major source of the phased out OCPs. Source analysis indicated that DDTs may be still in use as antifouling agent and/or dicofol, but Endos and HCHs were mainly derived from the residual of historical usage. The study suggests that the historical OCP pollutants are persistent at high levels in this area and should not be overlooked, while we tackle emerging pollutants.