山东南四湖底泥典型重金属的形态分布、稳定度与风险评价

为研究南四湖底泥重金属赋存形态与稳定度的空间差异,利用柱状底泥采样器分别在南阳湖、独山湖、昭阳湖和微山湖采集原位柱状样,在对典型重金属Pb、Cd、Hg、As形态分析的基础上,结合地积累指数法和潜在生态风险指数法,对表层底泥(0-4 cm)重金属污染程度进行评价,并对其稳定性进行分析.结果表明,南四湖的4个湖区采样点位表...     

Distribution and assessment of mercury (Hg) in surface sediments of Futian mangrove forest,China

Environmental Geochemistry and Health - To investigate the distribution of mercury (Hg) in Futian mangrove wetland, surface sediments from land to sea were collected, including Kandelia obovata,...     

Mercury distribution,speciation and potential ecological risk assessment in sediments from Lake Taihu,China

Abstract

Twenty-one surface sediments collected from seven surroundings areas of Lake Taihu in two different years were analyzed for total mercury (THg) concentrations, physicochemical characteristics and speciation using a sequential extraction method to assess spatial distribution, sources, and potential ecological risk. Surface sediments from Lake Taihu contained elevated levels of Hg in two sampling years with THg levels ranging from 77 to 346?ng/g (mean 145?ng/g) in October 2010 and ranging from 122 to 573?ng/g (mean 266?ng/g) in November 2012, respectively. The mean THg concentrations in all studied surface sediments exhibited an increasing trend over time. The oxidizable fraction (F3) and residual fraction (F4) were the predominant Hg species in sediments, while more mobile Hg phases of acid-soluble fraction (F1) and reducible fraction (F2) made up less than 0.5% THg. Significant relationships were found between total organic carbon (TOC) and THg and geochemical speciation indicating an important role for organic matter in affecting distribution, mobility, and bioavailability of Hg in sediments. As evidenced by Hakanson’s potential risk index the total ecological risk of Hg was low in the entire Lake Taihu in 2010 but considered moderate in Zhushan Bay, West Coast, and Meiliang Bay in 2012. These findings provide conservation managers with information needed to more effectively regulate the environment of Lake Taihu.     

南四湖沉积物营养盐释放特性

通过营养盐静态释放模拟试验,研究了南四湖沉积物NH4＋-N、TP和有机质（OM）的释放能力;针对微山湖区（WS）沉积物氮含量较高、释放较强的特点,为明晰WS湖区的氮释放潜力,考察了该湖区16个点位沉积物对NH4＋-N的等温吸附特性.静态释放试验表明,沉积物TP和OM释放能力较弱,对南四湖上覆水水质影响不明显;而WS湖区的NH4＋-N释放能力较强.WS湖区沉积物的NH4＋-N等温吸附试验表明,湖心区沉积物NH4＋-N释放能力最强,吸附/解吸平衡浓度（CEAC）高于1 mg.L-1的区域面积约占微山湖的1/5,该区域沉积物NH4＋-N释放将会对南水北调东线调水水质产生不利影响.     

深圳蛇口渔港沉积物重金属分布及潜在生态风险评价

沉积物重金属污染对水生生态系统具有潜在危害.渔港是海岸带水环境的重要组成部分.对取自深圳蛇口渔港的10个表层沉积物样品中的As、Cd、Cu、Pb和Zn等典型重金属元素进行了分析,探讨了其空间分布;运用地积累指数法(Igeo)和生态危害指数法(RI),评价了表层沉积物中重金属的富集程度和潜在生态风险,初步探讨了其污染来源.结果表明:(1)蛇口渔港海域沉积物重金属Cu的污染十分严重,Zn和Pb污染较严重,其浓度均为港内>港口>港外;(2)渔港内沉积物重金属的富集达重度污染程度,潜在生态危害风险强.其中,又以Cu的富集程度最高,潜在生态危害风险最强;(3)渔港内Cu的污染,可能与电子工业废水的排放,以及渔业特有的防附着生物涂料有关.     

太湖表层沉积物中多磷酸盐检出的环境意义

在氮限制型富营养化湖泊中,沉积多磷酸盐(Poly-P)可以用来示踪营养盐磷的输入和湖泊的富营养化过程。太湖是一个典型的磷限制型富营养化湖泊,通过对太湖表层沉积物中总有机碳(TOC)、总氮(TN)、总磷(TP)、氢氧化钠可提取磷(NaOH-P)以及Poly-P的提取分析,初步探讨了太湖营养盐磷输入的历史记录,并揭示了该湖Poly-P的主要来源和保存机制。太湖Poly-P的质量浓度较低,变化范围为0.004~0.065mg·g-1。NaOH-P占TP组成的22%,是太湖沉积物总磷的主要组成部分之一。结果显示,在湖泊水体藻类生物量较大和NaOH-P是沉积物TP重要组成部分的磷限制型湖泊中,Poly-P也是沉积物磷汇组成的一个重要部分,同时还是一个可以反映由人为磷输入增大导致湖泊富营养化程度加剧的敏感指标。     

洪湖湿地鹭科鸟类组织中有机氯农药的分布特征及风险评价

利用气相色谱-电子俘获检测器(GC-ECD)测定了洪湖鹭科鸟类(包括白鹭、池鹭)的胸脯肌肉、肝脏组织中的有机氯农药(OCPs)的含量.结果显示,鹭科鸟体内六六六(HCHs)、滴滴涕(DDTs)、六氯代苯、艾氏剂、七氯、环氧七氯等大部分有机氯农药均有检出.白鹭肌肉组织中HCHs和DDTs的含量范围分别为:11.3—89.4 ng.g-1和162—2149 ng.g-1(以脂重计,下同),平均值分别为37.3 ng.g-1和943 ng.g-1;肝脏组织中HCHs和DDTs的含量范围分别为:3.73—30.6 ng.g-1和280—957 ng.g-1,平均值分别为14.6 ng.g-1和566 ng.g-1.池鹭肌肉组织中HCHs和DDTs的含量范围分别为:3.61—25.8 ng.g-1和68.4—261 ng.g-1,平均值分别为11.5 ng.g-1和189 ng.g-1;肝脏组织中HCHs和DDTs的含量范围分别为:6.63—18.9 ng.g-1和147—1305 ng.g-1,平均值分别为13.1 ng.g-1和553 ng.g-1.统计分析显示,HCHs和DDTs在洪湖鹭科鸟组织中的含量差异均不显著(P>0.05).分析结果表明,洪湖湿地系统可作为有机氯污染的潜在源区,而候鸟可成为有机污染物在繁殖地与越冬地之间的传输介质.洪湖地区鹭鸟体内有机氯污染与全球其它地区相比处于较低水平,有机氯农药尚未对本区鸟类产生威胁.     

淮河中下游底泥中PAHs的分布及其生态风险评价

通过使用气相色谱质谱仪(GC/MS)测定淮河中下游底泥中多环芳烃(PAHs)单体的含量,探讨其分布特征及进行污染物生态风险评价。结果表明:淮河中下游底泥中PAHs含量总平均值为293.8ng·g-1,变化范围较大,总体呈中游高下游低的趋势;PAHs的种类和环数分布及菲/蒽、荧蒽/芘比值显示何台渡口至新集乡段底泥中的PAHs主要来源于化石燃料的高温燃烧与裂解,而安淮村至小河头段主要来源于化石燃料的低中温不完全燃烧或天然成岩过程;对照有关底泥的生态风险评价标准,淮河中游平圩和洛河段可能具有生物负效应,而其它地区的潜在生态风险则很小。     

Ecological risk assessment of pesticide residues in Taihu Lake wetland, China

As a major ecosystem type, wetland provides invaluable ecological services. Environmental pollution, especially pesticides pollution should be paid more attention to keep wetlands healthy. Based on the risk quotient method, coupled with a probabilistic risk assessment model, this paper proposed a methodology suitable for ecological risk assessment of pesticide residues for wetland ecosystems. As an important industrializing and ecologically vulnerable area in China, the Taihu Lake wetland was chosen for the case study. The risks of eight pesticides in Taihu Lake wetland were assessed, as single substances and in mixtures. The assessment indicates that risks of the representative species are not significant. In general, the herbicide is found to be more toxic for algae, whereas insecticides pose more risks to zooplankton, insect and fish. For each pesticide in the wetland, the ecological risk it poses is acceptable. But the combined ecological risk posed by mixture can harm more than 10% of species of the wetland ecosystem, mainly dominated by dichlorvos, dimethoate and malathion contributions. These results imply that pesticide residues have been posing pressures on the ecosystem of the Taihu Lake wetland. It is recommended that proper countermeasures should be implemented to reduce the risks.     

Phosphorus release potential and pollution characteristics of sediment in downstream Nansi Lake, China

The research aimed to evaluate present and potential phosphorous pollution due to high sedimentary phosphorus load and release from sediment, when external phosphorus was reduced in downstream Nansi Lake. Pollution load of the sediment and overlying water was investigated. Kinetics and isotherms of adsorption/release of sedimentary phosphorus were studied to determine equilibrium phosphate concentration (EPC₀) and release potential. Kinetics of phosphorus adsorption on sediment and release from sediment were well described by both the pseudo-first-order rate equation and the pseudo-second-order rate equation, but more appropriate to the pseudo-second-order rate equation with the adsorption/release capacity more close to the measured values, suggesting that the processes were chemically rate controlled and dependent on adsorption capacity. Soluble reactive phosphorus (SRP) sorption isotherms on sediment were best fitted by the modified Langmuir model indicating a monolayer adsorption. By comparing EPC₀ and SRP of water, the status (adsorption, releasing or in equilibrium) of sediment phosphorus could be determined. The sediments at site S1, S3, S4, S5, and S7 where the EPC₀s were greater than the SRPs, had a potential to release phosphorus into the water column. However, those sediments at S9, S10, and S12, where the EPC₀s were approximately equal to the SRPs, were in impermanent equilibrium with overlying water in status of phosphorus, the sediments can be likely to release phosphorus to the water column once the equilibrium was broken. Therefore, sedimentary phosphorus can be a secondary pollution source in downstream Nansi Lake.     

Quantification and fractionation of mercury in soils from the Chatian mercury mining deposit,southwestern China

Contents of total Hg and Hg fraction, organic matter, pH, grain size and chemical composition were measured to investigate the pollution characteristics and binding behavior of Hg in soils collected from the Chatian Hg mining deposit (CMD), southwestern China. The average concentration of Hg concentration in the CMD soils was 155 and 1,315 times higher than that in control soils and Chinese soils, respectively, suggesting that the CMD soils were heavily contaminated by the element. The finding was confirmed by Müller geoaccumulation index assessment with 75% very seriously polluted, 6.25% highly to very highly polluted and 18.75% moderately to highly polluted. Hg sources in the region were natural and anthropogenic: in addition to the pedogenic process and original geochemical situation, human mining–refining activities have also seriously impacted the redistribution of Hg in soils, especially in paddy soils. Based on the BCR protocol, soil Hg was divided into exchangeable (EXC), amorphous Fe–Mn oxides (AFe–MnOX), organic-crystalline iron oxides (OM-CFe) and residual (RES) fraction. The average percentage of the four fractions in the CMD followed the trend: RES (85.77%) > OM-CFe (12.44%) > AFe–MnOX (0.93%) ≥ EXC (0.86%), suggesting that the majority proportion of soil Hg in the study area remained of residual form inside the soil mineral matrix. However, their concentrations and percentages significantly varied among different locations and land use types. Soil physico-chemical parameters were key factors affecting the presence of Hg fraction. Generally, Hg fraction concentrations were positively correlated with the sand contents and soil pH values, which was presumably due to the basic anthropogenic input of Hg-containing materials and their similarity to sand in physical characteristics. However, organic matter caused adsorption–fixation and reduction–volatilization to coexist, which had opposite effects on Hg concentrations in soil, consequently exhibiting its dual nature.     

Environmental contamination and risk assessment of mercury from a historic mercury mine located in southwestern China

A field survey of mercury pollution in environmental media and human hair samples obtained from residents living in the area surrounding the Chatian mercury mine (CMM) of southwestern China was conducted to evaluate the health risks of mercury to local residents. The results showed that mine waste, and tailings in particular, contained high levels of mercury and that the maximum mercury concentration was 88.50 μg g^?1. Elevated mercury levels were also found in local surface water, paddy soil, and paddy grain, which may cause severe health problems. The mercury concentration of hair samples from the inhabitants of the CMM exceeded 1.0 μg g^?1, which is the limit recommended by the US EPA. Mercury concentrations in paddy soil were positively correlated with mercury concentrations in paddy roots, stalks, and paddy grains, which suggested that paddy soil was the major source of mercury in paddy plant tissue. The average daily dose (ADD) of mercury for local adults and preschool children via oral exposure reached 0.241 and 0.624 μg kg^?1 body weight per day, respectively, which is approaching or exceeds the provisional tolerable daily intake. Among the three oral exposure routes, the greatest contributor to the ADD of mercury was the ingestion of rice grain. Open-stacked mine tailings have resulted in heavy mercury contamination in the surrounding soil, and the depth of appreciable soil mercury concentrations exceeded 100 cm.     

山东南四湖摇蚊幼虫群落结构及其对富营养化过程的指示

2010年7月至2011年4月对南四湖摇蚊幼虫群落结构进行了季度调查.共采集到12种摇蚊幼虫,平均密度和生物量分别为(861±701)ind/m2和(6.39±5.12)g/m2.优势种红裸须摇蚊(Propsilocerusi akamusi)和羽摇蚊(Chironomusplumosus)的密度以及生物量分别占总密度和总生物量的97.1%和99.1%,但红裸须摇蚊的密度和生物量显著高于羽摇蚊,分别是羽摇蚊的18.5倍和10.7倍.从水平分布看,红裸须摇蚊在上级湖的密度明显高于下级湖,羽摇蚊则呈全湖性分布,但密度较低.与历史资料相比,南四湖摇蚊幼虫群落发生了显著变化,摇蚊幼虫的平均密度由20世纪80年代初期的88 ind/m2增加到目前的861 ind/m2,优势种由20世纪80年代的羽摇蚊演变为当前的红裸须摇蚊,并且红裸须摇蚊的密度显著升高,这表明南四湖的富营养化趋势加剧.     

Spatial health risk assessment and hierarchical risk management for mercury in soils from a typical contaminated site,China

Due to rapid urbanization and the implementation of ecological civilization construction in China, many industrial factories have been closed or relocated. Therefore, numbers of contaminated sites were generated with contaminated soils which may pose a risk to receptors living nearby. This study presented a spatial health risk assessment and hierarchical risk management policy making for mercury (Hg) in soils from a typical contaminated site in the Hunan Province, central China. Compared with the second class value (0.3 mg/kg) of the Chinese Environmental Quality Standard for Soils, the mean concentrations of Hg in the three soil depths exceeded the second class value. The non-carcinogenic risk of Hg probably posed adverse health effects in 41, 30 and 36 % of the surface soil, the moderate soil and subsoil, respectively, under a sensitive land scenario. The non-carcinogenic risk temporarily posed no adverse health effects in most areas under an insensitive land scenario except for the area around sampling site S29. Spatially, the central, southwest and northeast parts of the contaminated land under a sensitive land scenario should be regarded as the priority regions. For non-carcinogenic effects, the exposure pathways that resulted in the higher levels of exposure risk were ingestion and inhalation of vapors, followed by dermal contact and inhalation of particles. A risk-based integrated risk management policy including the hierarchical risk control values for different soil depths and the calculated remediation earthwork was proposed with consideration of the cost-benefit effect for the related decision-makers.     

太湖北部湾多氯联苯分布特征及生态风险评价

采用GC-ECD联用检测技术分析了太湖北部贡湖大贡山(1号点)、小贡山(2号点)与梅梁湖马山(3号点)、拖山(4号点)不同季节10种PCB同系物(PCB28、52、101、112、118、138、153、155、180、198)的含量.其中含量最高的为三氯联苯PCB28与四氯联苯PCB52,占总量的50%～69%,其次分别为五氯联苯与六氯联苯,而PCB180与PCB198基本未检出.不同监测点表现出了季节变化,受"引江济太"调长江水人太湖的影响,贡湖中1号点与2号点监测点夏季PCB总量高于其它季节,而梅梁湖受周围生产及竺山湖大桥入污影响,3号点监测点不同季节PCBs总量变化不显著,4号点监测点春季高于冬季,夏季受高温影响,PCBs总量出现最小值.采用生态风险值与毒性当量法对沉积物中PCBs进行了风险评价.太湖北部湾底泥中PCBs总量较低,未对生态构成严重威胁,但由于这类物质的生态累积效应,其潜在危害仍不容忽视.     

Geochemical speciation and risk assessment of metals in the river sediments from Dan River Drainage,China

This study investigates the partitioning of metals in surface sediments from the Dan River drainage basin, the source of drinking water for the South to North Water Transfer Project, China, to determine their bioavailability and associated levels of risk. Sediment samples were collected from 99 sites along the Dan River, and the concentration of each element fraction was determined using sequential extraction and inductively coupled plasma-mass spectrometry. The residual fraction was the major phase for most metals sampled. Among the non-residual fractions, greater proportions of Zn, Mn and Cd were transported in in the available phase, whereas Ba, Sb, Pb and As were mainly found in the reducible phase. The oxidisable phase was important for the transport of Ni, Co, Cr and Cu in sediments. This analysis of sediments from the Dan River basin indicates a very high risk of pollution from Cd, Co, Mn, Sb and Zn. Combined with the sediments with extremely high concentrations, the Dan, Laoguan and Yinhua rivers, which have been affected by ore-mining activities, pose a very high risk to the surrounding areas and should be the subject of future studies.     

乌梁素海沉积物中营养盐分布特征与固碳能力

通过2008—2011年连续现场采样和室内实验分析,研究了乌梁素海沉积物营养盐的分布特征以及固碳功能.结果发现,乌梁素海沉积物中氮与有机碳水平分布具有相同规律,总磷水平分布差异较大,揭示了沉积环境和水动力条件对磷在沉积物中的累积具有一定影响,也在一定程度上反映了磷来源的多样性.在垂直方向上,总氮、有机碳、硝态氮规律明显,随深度增加有递减的趋势,而总磷和氨氮垂直分布差异性显著,表明其与环境因素和早期演化和成岩作用有关.乌梁素海沉积物中C:N:P=20.2:4.5:1,小于Redfield比(C:N:P=106:16:1).沉积物中总氮与有机碳有明显的正相关性,而总磷与有机碳无相关性.乌梁素海沉积物有机碳沉积速率为169.55 g·m-2·a-1,有机碳密度为5.70 kg·m-2.30 cm深度沉积物中,碳储量为134.39×104t,存在很大的固碳潜力,这对于调节气候变化和维护湖泊区域生态平衡具有重要潜能.