Sources and health risks of PM2.5-bound polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in a North China rural area

Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) are typical persistent organic pollutants (POPs), which have high toxicity, bioaccumulation and long-distance transfer capability. Daily variation, sources of PCBs and OCPs in PM_2.5 are rarely explored in polluted rural area. Here, the sources and health risks of the PCBs and OCPs were evaluated for 48 PM_2.5 samples collected in winter 2017 in Wangdu, a heavy polluted rural area in the North China Plain. The average diurnal and nocturnal concentrations of Σ₁₈PCBs and Σ₁₅OCPs were 1.74-24.37 and 1.77-100.49, 11.67-408.81 and 16.89-865.60 pg/m³, respectively. Hexa-CBs and penta-CBs accounted for higher proportions (29.0% and 33.6%) of clean and polluted samples, respectively. Hexachlorobenzene (HCB) was the dominant contributor to OCPs with an average concentration of 116.17 pg/m³. Hexachlorocyclohexane (ΣHCHs) and dichlorodiphenyltrichloroethane (ΣDDTs) were the other two main classes in OCPs with the average concentrations of 4.33 and 15.89 pg/m³, respectively. β-HCH and p,p’-DDE were the main degradation products of HCHs and DDTs, respectively. The principal component analysis and characteristic ratio method indicated both waste incineration and industrial activities were the main sources of PCBs, contributing 76.8% and 12.7%, respectively. The loadings of OCPs were attributed to their application characteristics and the characteristic ratio method reflected a current or past use of OCPs. Health risk assessment showed that the respiratory exposure quantity of doxin-like PCBs (DL-PCBs) and the lifetime cancer risk from airborne OCPs exposure was negligible, while the other exposure modes may pose a risk to human bodies.     

Organochlorine compounds and polycyclic aromatic hydrocarbons in surface sediment from Baiyangdian Lake, North China： Concentrations, sources profiles and potential risk

Organochlorine pesticides(OCPs),polychlorinated biphenyls(PCBs),and polycyclic aromatic hydrocarbons(PAHs) were determined in nineteen surface sediment samples collected from Baiyangdian Lake and its inflowing river(Fuhe River) in North China.Total concentrations of OCPs,PCBs and PAHs in sediments ranged from 5.4 to 707.6 ng/g,2.3 to 197.8 ng/g,and 101.3 to 6360.5 ng/g,respectively.The levels of contaminants in Fuhe River were significantly higher than those in Baiyandian Lake.For hexachlorocyclohexane(HCHs) and dichlorodiphenytrichloroethanes(DDTs),α-HCH and p,p-DDT were predominant isomers;while for PCBs,PCB 28/31,PCB 40/103,PCB 60,PCB 101,and PCB 118 were predominant congeners.Possible sources derived from historical usage for OCPs and incomplete combustion fuel,wood,and coal and exhaustion of boats or cars for PAHs.Risk assessment of sediment indicated that sediments in Fuhe River were likely to pose potential biological adverse impact.     

Magnetic polyamidoamine dendrimers for magnetic separation and sensitive determination of organochlorine pesticides from water samples by high-performance liquid chromatography

Organochlorine pesticides (OCPs) have received much attention due to their toxicity. Reliable methods to monitor their residues in the environment are needed. Here, magnetic polyamidoamine dendrimers were prepared by co-precipitation, Michael addition, and amidation. The magnetic polyamidoamine dendrimers demonstrated good adsorption ability for OCPs—this feature was utilized to construct a sensitive tool for monitoring OCPs in water samples. The proposed method provided remarkable linearity from 0.1 to 500 μg/L and satisfactory limits of detection from 0.012 to 0.029 μg/L. The spiked recoveries of the four target analytes were 91.8%?103.5% with relative standard deviations less than 4.5%. The magnetic materials had good reusability. The results indicated that the resulting method was an efficient, easy, rapid, economical, and eco-friendly tool for monitoring OCPs in aqueous samples.     

Perfluoroalkyl substances and organochlorine pesticides in sediments from Huaihe watershed in China

Twelve perfluoroalkyl substances （PFASs） and nine organochlorine pesticides （OCPs） were quantified in surface sediments from the Huaihe River, China, along which there are intensive industrial and agricultural activities. Concentrations of PFASs ranged from 0.06 to 0.46 ng/g dry weight （dw）, and concentrations of OCPs ranged from 1.48 to 32.65 ng/g dw. Compared with other areas in China, concentrations of PFASs were lesser than the national mean value, while concentrations of OCPs were moderate. Concentrations of perfluorooctanoic acid （PFOA） and perfluorooctane sulfonate （PFOS） ranged from n.d. （not detected） to 0.03 and n.d. to 0.10 ng/g dw, respectively. Among the three groups of OCPs, mean concentrations of hexachlorocyclohexane and its isomers （HCHs）, dichlorodiphenyltrichloroethane and its metabolites （DDTs） and hexachlorobenzene （HCB） were 5.62 ± 4.35, 2.43 ± 3.12 and 1.55 ± 4.17 ng/g dw, respectively. Concentrations of HCHs and DDTs decreased from upstream to downstream along the mainstream of the Huaihe River. When compared to sediment quality guidelines （SQGs）, concentrations of HCHs, DDTs and HCB would pose adverse biological effects. In general, contamination by PFASs in the upstream of the Huaihe River was more severe than that in the downstream, which was mainly caused by interception from dams, locks and industrial emissions. And OCPs from tributaries, especially the Yinghe River and Wohe River, were higher than those from Huaihe mainstream, and primarily came from historical inputs.     

Comparison of using polyurethane foam passive samplers and tree bark samples from Western China to determine atmospheric organochlorine pesticide

Polyurethane foam(PUF)passive samplers were deployed and tree bark samples were collected at 15 sites across western China in 2013,and the organochlorine pesticide(OCP)concentrations in the samples were determined.Dichlorodiphenyltrichloroethane and its degradation products(collectively called DDTs),hexachlorocyclohexanes(HCHs),and hexachlorobenzene(HCB)were the dominant OCPs in the PUF samples and tree bark samples.The mean DDTs,HCHs and HCB concentrations were 33,22 and 18 ng/sample in the PUF samples,and 428,74,and 43 ng/(g lipid weight(lw))in the tree bark,respectively.The OCP concentrations in the air,calculated using PUF–air and tree-bark–air partitioning models,were of the same order of magnitude.Both sample types showed that relatively fresh inputs of DDT and HCHs to the environment have occurred in western China.Meanwhile,PUF passive samplers were compared with the use of tree bark samples as passive samplers.The OCP compositions in the PUF and tree bark samples were different.Only the relatively stable OCPs(such as HCB,β-HCH and p,p′-dichlorodiphenyldichloro-ethylene(DDE))were consistent in the PUF and tree bark samples.     

Distribution of persistent organochlorine pesticides in tissue/organ of silver carp (Hypophthalmichthys molitrix) from Guanting Reservoir, China

The concentration of organochlorine pesticides（OCPs） in tissues and organs of silver carp（Hypophthalmichthys mofitrix） from Guanting Reservoir were investigated to evaluate the pollution potential and distribution of OCPs. A total of 16 OCPs were measured and the concentrations were in the range of 1.61-69.01 ng/g wet weight（ww） for total OCPs, 0.16- 0.75 ng/g ww for HCB. 0.75 -26.80 ng/g ww for SHCH（sum of α-,β-, γ- and δ-HCH） and 0.68-35.94 ng/g ww for SDDT（ sum of p, p＇-DDE, p, p＇-DDD, o, p＇-DDT and p, p＇- DDT）. The mean concentrations of total OCPs, HCB, ∑HCH, and ∑DDT were 18.04, 0.96, 7.14 and 9.28 ng/g ww, respectively. Among the organochlorine pesticides, β-HCH and p, p＇-DDE were the most dominant compounds in tissue and organ with the average concentrations of 4.42 and 8.14 ng/g, respectively. The results obtained in this study show that the levels of 16 OCP residues found in silver carps are low and pose no threat to human health and wildlife fed upon them on the basis of existing related quality guidelines. However, recent input of lindane and DDT might still exist in the area investigated and further investigation should be carried on.     

Air-soil exchange of organochlorine pesticides in a sealed chamber

So far little is known about air-soil exchange under any sealed circumstances (e.g., in plastic and glass sheds), which however has huge implications for the soil-air-plant pathways of persistent organic pollutants including organochlorine pesticides (OCPs). A newly designed passive air sampler was tested in a sealed chamber for measuring the vertical concentration profiles of gaseous phase OCPs (hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs)). Air was sampled at 5, 15, and 30 cm above ground level every 10th day during a 60-day period by deploying polyurethane foam cylinders housed in acrylonitrile butadiene styrene-covered cartridges. Concentrations and compositions of OCPs along the vertical sections indicated a clear relationship with proximity to the mixture of HCHs and DDTs which escapes from the soils. In addition, significant positive correlations were found between air temperatures and concentrations of HCHs and DDTs. These results indicated revolatilization and re-deposition being at or close to dynamic pseudo-equilibrium with the overlying air. The sampler used for addressing air-soil exchange of persistent organic pollutants in any sealed conditions is discussed.     

Sources, distribution, and risk assessment of organochlorine pesticides in Nairobi City, Kenya

The distribution and sources of organochlorine pesticides (OCPs) in air and surface waters were monitored in Nairobi City using triolein-filled semipermeable membrane devices (SPMDs). The SPMDs were extracted by dialysis using n-hexane, followed by cleanup by adsorption chromatography on silica gel cartridges. Sample analysis was done by GC-ECD and confirmed by GC–MS. Separation of means was achieved by analysis of variance, followed by pair-wise comparison using the t-test (p≤ 0.05). The total OCPs ranged between 0.018 – 1.277 ng/m³ in the air and <LOD – 1391.000 ng/m³ in surface waters. Based on the results, the means of Industrial Area, Dandora and Kibera were not significantly different (p≤ 0.05), but were higher (p≤ 0.05) than those of City square and Ngong’ Forest. The results revealed non-significant (p≤ 0.05) contribution of long-range transport to OCP pollution in Nairobi City. This indicated possible presence of point sources of environmental OCPs in the city. The water-air fugacity ratios indicated that volatilization and deposition played an important role in the spatial distribution of OCPs in Nairobi City. This indicated that contaminated surface waters could be major sources of human exposure to OCPs, through volatilization. The incremental lifetime cancer risks (ILCR) determined from inhalation of atmospheric OCPs were 2.3745  ×  10^?13 – 1.6845  ×  10^?11 (adult) and 5.5404  ×  10^?13 – 3.9306  ×  10^?11 (child) in the order: Dandora > Kibera > Industrial Area > City Square > Ngong’ Forest. However, these were lower than the USEPA acceptable risks, 10^?6 – 10^?4. This study concluded that atmospheric OCPs did not pose significant cancer risks to the residents.     

Air–soil exchange of organochlorine pesticides in a sealed chamber

So far little is known about air–soil exchange under any sealed circumstances(e.g., in plastic and glass sheds), which however has huge implications for the soil–air–plant pathways of persistent organic pollutants including organochlorine pesticides(OCPs). A newly designed passive air sampler was tested in a sealed chamber for measuring the vertical concentration profiles of gaseous phase OCPs(hexachlorocyclohexanes(HCHs) and dichlorodiphenyltrichloroethanes(DDTs)). Air was sampled at 5, 15, and 30 cm above ground level every 10 th day during a 60-day period by deploying polyurethane foam cylinders housed in acrylonitrile butadiene styrene-covered cartridges. Concentrations and compositions of OCPs along the vertical sections indicated a clear relationship with proximity to the mixture of HCHs and DDTs which escapes from the soils. In addition, significant positive correlations were found between air temperatures and concentrations of HCHs and DDTs. These results indicated revolatilization and re-deposition being at or close to dynamic pseudo-equilibrium with the overlying air. The sampler used for addressing air–soil exchange of persistent organic pollutants in any sealed conditions is discussed.     

Disturbance of light-absorbing aerosols on the albedo in a winter snowpack of Central Tibet

A field observation on the albedo of the snowpack in Central Tibet was conducted in the Nam Co region in the winter of 2011. Snow properties, including grain size and density, were measured in the field, and surface-layer snow samples (down to 5 cm) were collected. The average concentrations of black carbon and dust were 72 ppbm (close to that in the glaciers of Mt. Nyainqentanglha) and 120 ppmm, respectively. Inverse trends were found to exist between the albedo of the snowpack and light-absorbing aerosols (LAAs) as well as grain size growth. Modeling showed that black carbon, dust, and grain growth in the winter snowpack can reduce the broadband albedo by 11%, 28%, and 61%, respectively.     

洪湖湿地水鸟肝脏中有机氯农药的分布

对我国中部地区洪湖湿地6种水鸟肝脏中20种有机氯农药进行了测量.发现DDTs是最主要的OCPs,约占总OCPs的38.3%~93.0%,其平均含量范围为2.74~121.72ng/g 湿重.HCHs和DDTs的富集形态说明洪湖湿地这些有机氯农药主要来源于历史残留.不同水鸟肝脏中∑OCPs含量差异显著(P<0.01),表现为白鹭和池鹭体内OCPs含量(37.91~137.22ng/g 湿重)要远高于其他水鸟(5.00~21.49ng/g 湿重),这种差异的产生主要与其饮食习性有关.大多数水鸟HCHs性别间基本无差异;但白鹭、池鹭雄性水鸟中总OCPs平均含量(白鹭: 136.90ng/g 湿重; 池鹭: 52.41ng/g 湿重)高于雌性水鸟(白鹭: 126.60ng/g 湿重; 池鹭: 49.78ng/g 湿重).与已有研究相比,洪湖湿地水鸟体内OCPs含量处于较低水平.风险评价结果表明研究区水鸟肝脏中OCPs含量不会对该地区水鸟种群产生不利效应.     

利用SPMD技术监测珠江三角洲大气有机氯农药

利用半渗透膜装置(SPMD)对珠江三角洲地区大气有机氯农药(OCPs)进行了分季度为期1年的监测分析。结果显示,该地区大气OCPs主要为DDTs,HCHs,氯丹和甲氧基氯,DDTs的含量约占总量的62%～88%。珠江三角洲地区大气有机氯农药时空分布差异明显,OCPs含量夏季高于冬季;各地区大气有机氯农药的年均含量为3 8～27 5ng d,香港和珠海较低(平均为5 0ng d),广州(GZ01)最高,年均值达27 5ng d。大气中m(DDT) m(DDD+DDE)均大于1,表明近期该地区大气中仍有新的DDT输入,对α-HCH和α-氯丹的手性特征进行了分析,它们的旋光异构体比值(年均值)(ER(+-))分别为0 75和0 69。夏季大气与土壤中α-HCH的ER(+-)相当,而冬季大气ER(+-)要低于土壤,表明夏季大气α-HCH基本来自于土壤中α-HCH的挥发,而冬季大气α-HCH可能来自土壤挥发与外来源迁移的组合。      

沉积物中多环芳烃和有机氯农药赋存状态

对珠江广州河段高污染沉积物进行粒度分级,对不同粒径的样品重液分离,收集轻组分(有机质)和重组分(主要为无机矿物及无定型有机质).用显微镜对沉积物中不同粒径轻重组分的吸附剂进行鉴定,测定其中的多环芳烃(PAHs)和有机氯农药(OCPs).结果表明,沉积物样品中有机质占总重量9.1%,富集了81.5%的多环芳烃,77.2%的有机氯农药;无机矿物和无定型有机质占90.9%,富集了18.5%的多环芳烃,22.8%的有机氯农药;轻组分中的有机吸附剂对PAHs和OCPs的富集能力比重组分无机矿物和无定型有机质高1～2个数量级.     

苏州、无锡和南通城市地表灰尘中的有机氯农药

2009年7月在江苏省南部城市苏州,无锡和南通采集了58个城市地表灰尘样品, 使用加速溶剂萃取、气相色谱质谱法测定了样品中的22种有机氯农药(OCPs).结果表明,样品中有19种OCPs被检出,总OCPs含量为76.6mg/kg.六氯苯(HCB)、总滴滴涕(DDTs)和氯丹是样品中检测出的主要OCPs,检出率分别为100%、100%和82.8%,含量分别为26.8mg/kg(0.432~348mg/kg)、39.6mg/kg(1.95~559mg/kg)和6.17mg/kg(ND~145mg/kg).城市地表灰尘样品与中国城市大气样品中检测出OCPs的种类基本一致,而各化合物之间的比例不同.与郊区农田土比较,地表灰尘中检测出的OCPs种类多且含量高.样品中(DDD+DDE)/DDTs的比值显示地表灰尘中的DDT大部分已经降解.城市地表灰尘中的HCB含量较高,工业污染来源可能性较大,工业污染源释放的HCB已经通过大气传输影响到了城区.城市地表灰尘中的反式-氯丹与顺式-氯丹的比值平均为1.94,表明城市中仍有新近使用氯丹的现象.     

聚合硫酸铁混凝消除水中有机氯的研究

采用聚合硫酸铁(PFS)絮凝剂对水中有机氯农药(OCPs)进行强化混凝处理,并运用响应曲面法(RSM)优化分析了影响OCPs去除率的混凝条件,如pH值、原水浊度、混凝剂投加量和OCPs的初始浓度诸因素.结果表明,各影响因素交互作用显著,最佳混凝条件组合为:pH=5.0、原水浊度=150NTU、PFS投加量为12mg/L、OCPs初始浓度为200ng/L,在此条件下,PFS絮凝剂可有效去除水中OCPs,经模型验证实验得到最佳条件下去除率α-HCH为82.23%、β-HCH为71.15%、γ-HCH为77.28%、δ-HCH为86.27%、 p,p’-DDE为93.78%,与RSM预测值基本相同.结合絮体分形维数和Zeta电位对混凝效果的机理进行了探讨,表明各因素均达到了最佳水平.     

深圳市冬、夏两季大气中有机氯农药的研究

利用大流量主动采样器,选择深圳市13个有代表性采样点,于2009年12月~2010年1月和2010年6月,分2个采样时期对深圳市大气中有机氯农药(OCPs)进行监测.结果显示,深圳市冬、夏大气中,13个点位总有机氯农药浓度变化范围分别为742~3522 pg/m3(平均值1769pg/m3)和507~2197pg/m3(平均值1163pg/m3).冬季大气中有机氯农药主要是DDTs、林丹、七氯、氯丹、六氯苯,占有机氯农药总量的87%;夏季大气中有机氯农药主要为DDTs、氯丹、林丹,三者总量占有机氯农药的89%.研究表明,深圳市大气中存在“新”DDT的输入,认为工业DDT是其主要来源,而γ-HCH以及氯丹的高检出与林丹和用于杀灭白蚁的氯丹的继续使用有关.     

小海湾水体有机氯农药的浓度水平和特征

以海南省万宁市小海湾为研究区,按照美国EPA8080A方法,使用仪器GC-ECD对小海湾海水和汇入其中地表水中样品的OCPs含量进行分析,样品中18种有机氯农药均出,以HCHs和DDTs为主,它们的和占到OCPs含量的60%。外海HCH含量0.26ng/L,DDTs含量0.53ng/L,OCPs含量1.34ng/L。海水中HCHs含量范围:2.39～4.59ng/L,平均值是3.31ng/L;DDTs含量范围:0.27～6.34ng/L,平均值是3.42ng/L;OCPs含量范3.63～17.01ng/L,平均值是11.15ng/L。地表水中HCHs含量范围:0.95～3.46ng/L,总含量是9.70ng/L;DDTs含量:0.96～2.86ng/L,总含量是9.70ng/L;OCPs含量范围3.71～17.16ng/L,总含量是59.13ng/L后山村河以及桥头村河的OCPs含量高出其它河流很多,周围是农田、居民点。由数据及小海湾的地理状况,得出海水中OCPs来源于地表径流,小海湾是OCPs巨大的储存库,OCPs主要汇集在沉积物中。     

舟山青浜岛水体及海产品中有机氯农药的分布和富集特征

在舟山青浜岛采集了14个生物样品及对应点位的3个海水样品,利用气相色谱(GC-ECD)测定六六六(HCHs)和滴滴涕(DDTs)的浓度,分析不同点位水体及水产品中有机氯农药的分布与富集特征.结果表明,舟山青浜岛HCHs和DDTs检出率高达100%.海产品中HCHs含量范围0.09~11.51 ng·g-1,平均值为2.02 ng·g-1,DDTs含量范围0.02~56.15 ng·g-1,平均值为12.36 ng·g-1;海水样品中HCHs含量范围0.07~0.20 ng·L-1,平均值为0.13 ng·L-1,DDTs含量范围0.23~0.41ng·L-1,平均值为0.34 ng·L-1.整体而言,研究区样品中DDTs残留高于HCHs残留.与国内外其他研究区域相比,青浜岛水生物中有机氯农药残留处于较低水平.对照相应标准可以看出,所有样品均未超过国家相应标准(食品安全国家标准GB2763-2012、海水水质标准GB 3097-1997).通过比值法来源分析得知,青浜岛海域HCHs和DDTs主要为外源输入.OCPs的空间分布特征分析显示,海洋上升流及其锋面的变化是影响OCPs分布的主要因素.水体中OCPs分布与青浜岛的特殊地形有关,且人类活动对当地环境的影响是水体OCPs的贡献方式之一.健康风险评价表明,该区域居民通过食用海产品OCPs平均日摄入量远低于FAO/WHO限定的每日可摄入量(ADI),说明该地区居民食用海产品对人体健康影响较小.     

海河河口表层沉积物中PCBs和OCPs的源解析

采集海河河口表层沉积物样品,测定了其中12种多氯联苯(PCBs)和20种有机氯农药(OCPs)的浓度,运用主成分分析-多元线性回归法(PCA-MLR)解析该区域沉积物中PCBs和OCPs的来源,并定量计算了各污染源的贡献量.结果表明,海河沉积物中PCBs的特征源为非故意产生和大气输送2类,基于多元线性回归法的贡献率分别为55%和45%,对PCBs总量的贡献量均值为6.94,9.42ng/g;OCPs的特征源为历史残留和新的输入2类,贡献率分别为13%和87%,对OCPs总量的贡献量均值为21.18,171.97ng/g.海河河口沉积物中POPs的源贡献与该区域的工业生产有关,改善工业结构和妥善处理历史遗留的生产废物是控制海河河口沉积物中POPs的有效途径.     

改性凹凸棒土及粉末活性炭助凝聚硅硫酸铝消除微污染水中有机氯

以硅酸钠和硫酸铝为原料制备了聚硅硫酸铝絮凝剂(PASS),采用强化混凝的处理方法,对微污染水中有机氯(OCPs)的消除进行了研究.同时,考察了混凝剂投加量、pH值、原水浊度、粉末活性炭和改性凹凸棒土助凝剂等因素对OCPs消除效果的影响.结果表明:PASS投加量为5 mg·L-1时,OCPs的去除率可以达到57%~87%,浊度去除率可以达到99.1%,其效果好于聚合氯化铝(PAC);PASS混凝处理OCPs的最佳pH值范围是6~7;OCPs的去除与浊度的去除具有显著相关性,原水浊度的大小会影响OCPs的去除,低浊条件下OCPs和浊度的去除率明显低于中浊和高浊条件;粉末活性炭和改性凹凸棒土作为助凝剂与PASS复配均可显著提高OCPs的去除率,分别达到78%~100%和72%~95%.相较而言,凹凸棒土储量丰富,廉价易得,因此,以改性凹凸棒土替代粉末活性炭更有优势.