杭州城区河道底泥重金属污染及潜在生态风险评价

对杭州城区34条河道45个点位河道底泥进行采样,分析了pH及汞、砷、铅、铬、镉、铜、锌、镍等重金属含量,并进行污染及潜在生态风险评价。结果表明,监测点位的底泥为中性偏碱性,重金属含量分布不均,且范围波动很大,部分河道底泥重金属中汞、铅、镉、铬、锌、镍等有不同程度的超标,少数河道镉、铬、锌污染严重;按《农用污泥中污染物控...     

Heavy metal content and distribution in surface sediments of the Seyhan River, Turkey

Chemical fractionation of seven heavy metals (Cd, Cr, Cu, Mn, Ni, Pb and Zn) was studied using a modified three-step sequential procedure to assess their impacts in the sediments of the Seyhan River, Turkey. Samples were collected from six representative stations in two campaigns in October 2009 and June 2010, which correspond to the wet and dry seasons, respectively. The total metal concentrations in the sediments demonstrated different distribution patterns at the various stations. Cadmium was the only metal that was below detection at all stations during both sampling periods. Metal fractionation showed that, except for Mn and Pb, the majority of metals were found in the residual fraction regardless of sampling time, indicating that these metals were strongly bound to the sediments. The potential mobility of the metals (non-residual fractions) is reflected in the following ranking: Pb > Mn > Zn > Cu > Ni > Cr in October 2009 and Mn > Pb > Zn > Cu > Ni > Cr in June 2010. The second highest proportion of metals was bound to organic matter/sulfides, originating primarily from anthropogenic activities. Non-residual metal fractions for all stations were highest in June 2010, which may be linked to higher organic matter concentrations in the sediment samples with 1.40% and 15.1% in October 2009 and June 2010, respectively. Potential sediment toxicity was evaluated using the Risk Assessment Code (RAC). Based on RAC classification, Cd and Cr pose no risk, Cu and Ni pose low risk, Pb and Zn were classified as medium risk metals, while the environmental risk from Mn was high. In addition, based on the sediment quality guidelines (SQG), the Seyhan River can be classified as a river with no, to moderate, toxicological risks, based on total metal concentrations.     

密云水库上游土壤重金属污染调查评价

文章对密云水库周边及上游地区（北京境内）的污染状况作了初步评价。研究结果发现密云水库周边及上游地区重金属污染以Cr和Hg为主，丰亡牛河上游为污染最严重地区，清水河上游、潮河下游放马峪地区、德田沟-崎峰茶地区受Cr元素轻度污染。这些地区土壤重金属污染的主要原因是由于金属矿山不合理堆放的尾砂及废矿石等人为因素所致。     

Fractionation of selected metals in the sediments of Cochin estuary and Periyar River, southwest coast of India

Cochin estuary is one of the highly polluted aquatic systems of the southwest coast of India. The present study focuses on the assessment of heavy metals (Zn, Cd, Pb, and Cu) present in the sediments of Cochin estuary and the adjoining Periyar River. The sediments were analyzed for total metal content and various chemically bound fractions such as exchangeable, carbonate bound, easily reducible, organic, and residual. Total metal content of sediment was found higher than the average values reported from other Indian rivers. The mean concentration of Zn, Cd, Pb, and Cu in the sediments was 1,249.44, 9.5, 221.37, and 166.14???g/g, respectively. The results of sequential extraction showed that the concentration of Cd was high in the first two weakly bound fractions (exchangeable and carbonate bound) than the other metals, which are high in residual and organic bound fractions. Risk-assessment code analysis and environmental indices (enrichment factor and pollution load index) suggest that the sediments are highly polluted with metals, especially Cd.     

Distribution of heavy metals in sediments of Igbede, Ojo and Ojora rivers of Lagos, Nigeria

The distribution of some heavy metals, namely Cd, Pb, Zn, Fe, Cu, Cr and Mn in epipellic sediments of Igbede, Ojo and Ojora rivers of Lagos was studied weekly in the early summer (November) of 2003. The levels of selected trace metals were determined using Atomic Absorption Spectrophotometer (UNICAM 969 AAS SOLAR). Trends in heavy metal burdens in the sediments revealed weekly variations in all the rivers assessed. Statistical analyses also showed different mean levels of trace metals in the aquatic environments, the distribution of which followed the sequence Fe > Zn > Mn > Pb > Cu > Cr > Cd, Fe > Zn > Cu > Mn > Pb > Cr > Cd and Fe > Zn > Mn > Cu > Cr > Pb > Cd in Igbede, Ojo and Ojora rivers respectively. Fe recorded the highest concentration levels (1,582.95 ± 96.57 μ g/g–1,910.34 ± 723.19 μ g/g) in all the sediments investigated while the Cd levels (0.06 ± 0.10 μ g/g–0.47 ± 0.36 μ g/g) were the lowest. Expectedly, trace metal concentrations in fine grain muddy sediments of the Igbede and Ojo coastline were much higher than those of Ojora which consist of coarse and sandy deposits covering the near shore area. Generally, the results obtained fell within tolerable limits stipulated by World Health Organization (WHO).     

Characteristics of heavy metals and Pb isotopic signatures in sediment cores collected from typical urban shallow lakes in Nanjing, China

To investigate the contamination levels and sources for heavy metals that have occurred during the development of cities, sediment cores collected from typical urban shallow lakes (Xuanwu Lake and Mochou Lake) in Nanjing, China were analyzed for Cu, Pb, Zn, Cd, Cr, Ni, and for Pb stable isotopic ratios. No significant differences were found in the concentrations of Cu, Ni and Cd among sediment layers from Xuanwu or in the levels of Cr and Ni among sediment layers from Mochou. However, there were significant differences among the layers in the concentrations of Cr, Zn and Pb in Xuanwu and Cu, Zn, Cd and Pb in Mochou. Based on geoaccumulation indexes and enrichment factors, Cd was the primary pollutant at all depths in the sediment cores. The ratios of (206)Pb/(207)Pb and (208)Pb/(206)Pb differ significantly among sediment layers in Xuanwu. No significant differences were found on the ratios of (208)Pb/(206)Pb in Mochou, but the ratios of (206)Pb/(207)Pb differ significantly among some of the sediment layers in Mochou. The range of (208)Pb/(206)Pb and (206)Pb/(207)Pb ratios was found to be 2.098-2.106 and 1.170-1.176, respectively, for sediment cores from Mochou Lake and 2.091-2.104 and 1.168-1.183, respectively, for cores from Xuanwu Lake. The differences in heavy metal concentrations and the Pb isotopic ratios with depth for the cores from Xuanwu and Mochou confirmed that the contamination sources changed during the formation of the different sediment layers. Furthermore, the ratios of (206)Pb/(207)Pb demonstrated that gasoline and vehicular Pb were not the primary sources of Pb contamination at different depths in the sediment cores in Xuanwu Lake and Mochou Lake.     

柴窝堡湖表层底泥重金属污染评价

研究了乌鲁木齐市柴窝堡湖表层底泥的重金属含量,并采用Hakanson潜在生态危害指数法对底泥中的重金属潜在生态风险进行评价。结果表明:底泥中Cu、Zn、Pb、Cd含量均超出乌鲁木齐市土壤背景值。除湖心区外,Cd在5个监测区域中的潜在生态危害均为中等;其它重金属在5个采样点的潜在生态危害均为轻微。各重金属间的相关性分析表明,Zn与Cu,Pb与Cd、Cu呈显著正相关,说明这4种元素污染源可能相同。柴窝堡湖表层底泥受到Cu、Zn、Pb、Cd污染,需采取相应措施防止重金属由底泥进入水相。     

Characteristic levels of heavy metals in sediments and dredged sediments of a municipal creek in the Niger delta, Nigeria

Characteristic levels of metal ions in post dredged sediment and dredged sediments materials of a municipal creek in the Niger Delta show that significant concentrations of heavy metals are found to be accumulated more on the surface (0–15cm depth) of the dredged material as compared to the sub surface (15–30cm) and post dredged sediments. The distribution patterns were in the following order Fe > Mn > Zn > Cu > Pb > Ni > Cd and Fe > Mn > Zn > Pb > Cu > Ni > Cd for the post dredged sediment and dredged sediment materials respectively. The levels of the various metals were far below the EPA screening levels for open water disposal, consequently total levels of heavy metal found in these sediments pose no problem by open-water or upland disposal     

Distribution and movement of sludge-derived trace metals in selected Nigerian soils

Use of metal-rich sewage sludge as soil fertilizer may result in trace- metal contamination of soils. This study was conducted to evaluate the effects of long-term sludge application on trace-metal (Zn, Cu, Pb, and Ni) distribution and potential bioavailability in Nigerian soils under a tropical wet-dry climate. Total metal analyses, sequential chemical fractionation, and DTPA extractions were carried out on samples of control and sludge-amended pedons in Nigeria (a Rhodic Kandiustult and two Rhodic Kandiustalfs from Nigeria, respectively). The sewage sludge applied to the soils contained higher levels of Zn and Cu than Pb and Ni. The control pedon contained low levels of all four metals. Soil enrichment factors (EF) were calculated for each metal in the sludge-amended pedons. Compared with the control soil, the sludge-amended pedons showed elevated levels of Zn and Cu, reflecting the trace-metal composition of the sewage sludge. Zinc and Cu in the sludge-amended soils were strongly enriched at all depths in the profile, indicating that they had moved below the zone of sludge application. The sequential extraction and DTPA analyses indicated that the sludge-amended soils contained more readily extractable and bioavailable metal ions than the unamended soil.     

Geochemical properties and pollution assessment of heavy metals in the sediments of Daechung Lake,Korea

In order to examine the forms, sources, and pollution of heavy metals—arsenic (As), aluminum (Al), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), lead (Pb), and zinc (Zn)—in Daechung Lake, Korea, sediment samples were collected in November 2014. Daechung Lake was constructed to supply water for human consumption, agricultural use, and industrial use as well as to generate electric power. The lake is stratified in the summer and surrounded mostly by agricultural and mining areas. Our results indicate that the heavy metals (except As and Cd) displayed similar concentrations at all of the sampling stations. As and Cd were high in locations where fine sediments had built up. Based on the enrichment factor of the metals, the sediments collected from all of the sampling stations were highly polluted by As and Cd. Therefore, deposition of heavy metals in Daechung Lake is possibly controlled by grain size and anthropogenic activity, such as drainage from abandoned mines, agricultural activities, and/or the release of wastewater. The most dominant forms for all of the metals were oxide and silicate forms. This suggests that the sediments of Daechung Lake are not highly sulfidic. However, the sediment samples were collected after the collapse of seasonal stratification. Therefore, future studies should include elucidation of major sources for As and Cd and the collection of sediments during months of stratification.     

Use of constructed wetland for the removal of heavy metals from industrial wastewater

This study was conducted to investigate the effectiveness of a continuous free surface flow wetland for removal of heavy metals from industrial wastewater, in Gadoon Amazai Industrial Estate (GAIE), Swabi, Pakistan. Industrial wastewater samples were collected from the in-let, out-let and all cells of the constructed wetland (CW) and analyzed for heavy metals such as lead (Pb), cadmium (Cd), iron (Fe), nickel (Ni), chromium (Cr) and copper (Cu) using standard methods. Similarly, samples of aquatic macrophytes and sediments were also analyzed for selected heavy metals. Results indicate that the removal efficiencies of the CW for Pb, Cd, Fe, Ni, Cr, and Cu were 50%, 91.9%, 74.1%, 40.9%, 89%, and 48.3%, respectively. Furthermore, the performance of the CW was efficient enough to remove the heavy metals, particularly Cd, Fe, and Cu, from the industrial wastewater fed to it. However, it is suggested that the metal removal efficiency of the CW can be further enhanced by using proper management of vegetation and area expansion of the present CW.     

Total Contents and Sequential Extraction of Heavy Metals in Soils Irrigated with Wastewater,Akaki, Ethiopia

The Akaki River, laden with untreated wastes from domestic, industrial, and commercial sources, serves as a source of water for irrigating vegetable farms. The purpose of this study is to identify the impact of waste-water irrigation on the level of heavy metals and to predict their potential mobility and bioavailability. Zn and V had the highest, whereas Hg the lowest, concentrations observed in the soils. The average contents of As, Co, Cr, Cu, Ni, Zn, V, and Hg of both soils; and Pb and Se from Fluvisol surpassed the mean + 2 SD of the corresponding levels reported for their uncontaminated counterparts. Apparently, irrigation with waste water for the last few decades has contributed to the observed higher concentrations of the above elements in the study soils (Vertisol and Fluvisol) when compared to uncontaminated Vertisol and Fluvisol. On the other hand, Vertisol accommodated comparatively higher average levels of Cr, Cu, Ni, Zn, etc V, and Cd, whereas high contents of Pb and Se were observed in Fluvisol. Alternatively, comparable levels of Co and Hg were found in either soil. Except for Ni, Cr, and Cd in contaminated Vertisol, heavy metals in the soils were not significantly affected by the depth (0–20 and 30–50 cm). When the same element from the two soils was compared, the levels of Cr, Cu, Ni, Pb, Se, Zn, V, Cd at 0–20 cm; and Cr, Ni, Cu, Cd, and Zn at 30–50 cm were significantly different. Organic carbon (in both soils), CEC (Fluvisol), and clay (Vertisol) exhibited significant positive correspondences with the total heavy metal levels. Conversely, Se and Hg contents revealed perceptible associations with carbonate and pH. The exchangeable fraction was dominated by Hg and Cd, whereas the carbonate fraction was abounded with Cd, Pb, and Co. conversely, V and Pb displayed strong affinity to reducible fraction, where as Cr, Cu, Zn, and Ni dominated the oxidizable fraction. Cr, Hg, Se, and Zn (in both soils) showed preference to the residual fraction. Generally, a considerable proportion of the total levels of many of the heavy metals resided in non residual fractions. The enhanced lability is generally expected to follow the order: Cd > Co > Pb > Cu > Ni > Se > V and Pb > Cd > Co > Cu > Ni > Zn in Vertisol and Fluvisol, respectively. For the similar wastewater application, the soil variables influence the status and the distribution of the associated heavy metals among the different soil fractions in the study soils. Among heavy metals that presented relatively elevated levels and with potential mobility, Co, Cu, Ni (either soil), V (Vertisol), Pb, and Zn (Fluvisol) could pose health threat through their introduction into the food chain in the wastewater irrigated soils.     

Characteristic levels of heavy metals in soil profiles of automobile mechanic waste dumps in Nigeria

The characteristic levels of heavy metals (Cd, Cr, Cu, Pb, Ni and Zn) of soil profiles of automobile mechanic waste dumps were studied. The concentration of heavy metals decreased with the depth of the profile and lateral distance from the dumpsites. The levels found in this study exceeded background concentrations and limits for agricultural and residential purposes. The distribution pattern of heavy metals in the soil profiles were in the following order Pb > Zn > Cu > Cd > Ni > Cr. The mechanic waste dumps represent potential sources of heavy metal pollution to environment. The elevated levels of heavy metals in these soil profiles constitute a serious threat to both surface and groundwater.     

Phytoremediation of heavy metals by <Emphasis Type="Italic">Eichhornia crassipes</Emphasis>

Eichhornia crassipes was tested for its ability to bioconcentrate 8 toxic metals (Ag, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) commonly found in wastewater from industries. Young plants of equal size were grown hydroponically and amended with 0, 0.1, 0.3, 0.5, 1.0, 3.0, and 5.0 mM of each heavy metal individually for 21 days. The test plant had the lowest and the highest tolerance indices for Hg and Zn, respectively. A significant (P ≤ .05) reduction in biomass production was observed in metal treated plants compared with the control. All strace elements accumulated to higher concentrations in roots than in shoots. Trace element concentrations in tissues and the bioconcentration factors (BCF) were proportional to the initial concentration of individual metal in the growth medium and the duration of exposure. From a phytoremediation perspective, E. crassipes is a promising plant species for remediation of natural water bodies and/or wastewater polluted with low levels of Zn, Cr, Cu, Cd, Pb, Ag and Ni.     

Metal and oxalate contamination in a suburban watershed in the greater Toronto area: the benefits of combining acid leach and selective extraction procedures

Environmentally available concentrations of Fe, Mn, Zn, Cu, Pb, Cr and Ni in soils and sediments from a small suburban catchment, obtained using an acid leach procedure, are compared to the Ontario Ministry of the Environment lowest effect level (LEL) and severe effect levels (SEL) and to Provincial sediment quality guidelines (PSQG's). These data are then compared to the bioavailability, potential bioavailability and non-bioavailability of the same metals, plus oxalate concentration, identified using a selective extraction procedure. This combination of techniques enhanced analytical interpretation with respect to metal mobility and potential metal contamination. Selective extraction highlighted the presence of oxalate as a potential contaminant, especially in poorly drained valley floor deposits (33,633 mg kg(-1) and 26,284 mg kg(-1)) and lakeshore sediments (27,095 mg kg(-1) and 13,729 mg kg(-1)). These levels are considerably in excess of those previously documented in a similar study from Rio de Janeiro, where contamination of urban sediment by sewage is a recognised environmental problem, and could possibly be used both as an indicator of similar contamination and the identification of those areas that warrant further investigation.     

Metal contamination in sediments of the western Bohai Bay and adjacent estuaries, China

Twelve sediment cores were collected in July 2007 in open waters of western Bohai Bay, the Port of Tianjin, and the adjacent estuaries of the Haihe and Yongding Rivers. While overall concentrations of trace metals at incremental depths in these cores met the Marine Sediment Quality (GB18668-2002) criteria of China, the magnitude of both metal enrichment factors (EF) and geoaccumulation indices (I(geo)) suggested that pollution with Ag, Cd, Cr, Cu and Zn was occurring in the estuaries and Port. Risk analysis also suggested that Ag and Ni concentrations were sufficiently elevated as to cause adverse biological effects in the study area. Although metal concentrations in western Bohai Bay were of less concern, a positive relationship between EF values and excess (210)Pb activity for several metals suggested that their concentrations were increasing over time.     

Fate of biosolids trace metals in a dryland wheat agroecosystem

Biosolids land application for beneficial reuse applies varying amounts of trace metals to soils. Measuring plant-available or total soil metals is typically performed to ensure environmental protection, but these techniques do not quantify which soil phases play important roles in terms of metal release or attenuation. This study assessed the distribution of Cd, Cr, Cu, Mo, Ni, Pb, and Zn associated with soluble/exchangeable, specifically adsorbed/carbonate-bound, amorphous Mn hydroxyoxide-bound, amorphous Fe hydroxyoxide-bound, organically complexed, and residual inorganic phases. Biosolids were applied every 2 yr from 1982 to 2002 (except in 1998) at rates of 0, 6.7, 13.4, 26.8, and 40.3 dry Mg biosolids ha(-)(1) to 3.6- by 17.1-m plots. In 2003, 0- to 20-cm and 20- to 60-cm soil depths were collected and subjected to 4 mol L(-1) HNO(3) digestion and sequential extraction. Trace metals were concentrated in the 0- to 20-cm depth, with no significant observable downward movement using 4 mol L(-1) HNO(3) or sequential extraction. The sequential extraction showed nearly all measurable Cd present in relatively mobile forms and Cr, Cu, Mo, Ni, Pb, and Zn present in more resistant phases. Biosolids application did not affect Cd or Cr fractionation but did increase relatively immobile Cu, Mo, and Zn phases and relatively mobile Cu, Ni, and Pb pools. The mobile phases have not contributed to significant downward metal movement. Long-term, repeated biosolids applications at rates considered several times greater than agronomic levels should not significantly contribute to downward metal transport and ground water contamination for soils under similar climatic conditions, agronomic practices, and histories.     

菌渣施肥对土壤—作物体系重金属污染及迁移特征评价

为研究抗生素制药菌渣施肥对土壤—作物体系中重金属的污染及迁移特征的影响,选取新疆伊宁县某试验田作为研究对象,运用单因子污染指数和内梅罗综合污染指数评价抗生素施加后农田土壤重金属污染状况,采用富集系数(BCF)来表示重金属在土壤—作物体系间的迁移性能.研究表明:大豆和玉米在苗期、开花期和成熟期所有地块的重金属含量均达到标...     

基于GIS的耕地土壤重金属污染与农业功能定位研究——以山东省聊城市为例

按8km×8km的网格将聊城市耕地分为137个采样点，调查砷、镉、铬、铜、汞、镍、铅、锌等重金属的污染状况。采用国家土壤环境质量标准、农产品安全质量标准和绿色食品产地环境条件作为评价标准，采用单因子指数和综合指数为评价方法进行污染评价。研究表明，聊城市土壤污染强度依次为铜〉镍〉锌〉砷〉铬〉镉〉铅〉汞，但均未超标。以GIS为操作平台显示聊城市重金属空间分布状况，并对区域耕地进行了功能的定位。聊城市西南部土壤质量最优，适宜种植绿色食品；无公害蔬菜和安全粮食种植区在各县市均有不同程度的分布。     

河南农田土壤重金属污染状况及其评价

在河南境内取自农田土壤102例表层样品，分析了其中的Cr、Zn、Cu、Pb、Ni、As等8种重金属元素的含量。结果表明：河南农田土壤中除Cr偶有超出我国《土壤环境质量标准》（GB15618—1995）二级标准的土样外，其他项目均不超标，重金属污染由高到低排序为Cr〉Zn〉Ni〉Cd〉Hg〉Cu〉Pb〉As。重金属元素在河南各土壤利用类型中分布规律不明显，按4种主要土壤利用类型考查来看，重金属污染程度大小排序为：果园地〉水田〉菜地〉其他粮田；河南农田土壤综合污染指数总平均为0．981，土壤总体为尚清洁，重金属污染处于警戒水平；河南农田土壤中Cr含量较高的土壤主要是粗骨土与石质土，其天然本底值较高。