Ecological Risk Index Method Research Articles

Heavy metal pollution characteristics and potential ecological risk assessment of soils around three typical antimony mining areas and watersheds in China

China is the largest antimony resource globally. The mining and smelting of antimony will inevitably have a significant impact on the surrounding and downstream farmlands of the mining area, Therefore, it is necessary to understand the pollution characteristics of antimony and evaluate its potential environmental risks. In this paper, three typical antimony mining areas were used as research districts to analyze the contents of heavy metals in soils of the mining areas and watersheds. The single-factor pollution index method, Nemerow comprehensive pollution index method, geo-accumulation index method, and potential ecological risk index method were used to comprehensively evaluate the pollution status and ecological risk of heavy metals in soils around the mining areas. The soil around the Lengshuijiang tin mine was polluted by As, Cd, Zn, and Sb, it was a heavily polluted soil and at a high ecological risk level. The arable soil around the Nandan tea mountain antimony mine was polluted by As, Cd, Cu, Pb, Sb, and Zn, and it was a heavily polluted soil with very high ecological risk level. The soil around the Xunyang antimony mine was mainly polluted by Sb and it was a moderately polluted soil with moderate ecological risk level. The results revealed that the overall soil heavy metal levels in the Lengshuijiang mining area and the Nandan mining area were in a high-risk state, most likely due to the mining and smelting of metal ores and the weathering of mineralised rocks. showing a high-potential ecological risk in these mining areas. We expect to provide a scientific basis for the safe utilization of farmland and pollution control around the antimony mining areas and watersheds in China.

Distribution characteristics and potential ecological risk assessment of heavy metals in soils around Shannan landfill site, Tibet.

At present, sanitary landfill is mainly used for domestic waste treatment in Shannan City, Tibet. However, there are few studies on heavy metals in the soil around the landfill in Shannan city. Therefore, the surrounding soil of Luqionggang landfill in Shannan City, Tibet Autonomous Region, is taken as the research object. In the study, the geo-accumulation index method, Nemerow comprehensive pollution index method and potential ecological risk index method are mainly used to evaluate the pollution and risk of heavy metals in the soil around the landfill site. The main results are as follows: The average pH value of the soil around the landfill site is 9.37, belonging to the strong alkaline range. The average values of heavy metals Hg and Ni in soil exceeded the background content, and the average contents of other heavy metals Cu, Pb, Zn, Cr, As and Cd did not exceed the background content. The average content of these eight heavy metals did not exceed the screening value of the national soil environmental quality standard. In the horizontal direction, the average content of heavy metal elements Cu, Cr, Cd, Hg and Ni is relatively high in the west. The average content of heavy metals As, Zn and Pb in the north, east and south is slightly higher than that in the west. And the farther away from the landfill, the less the soil is affected by heavy metals. The evaluation results of geo-accumulation index show that heavy metal Hg is the most affected. The average value of the comprehensive pollution index is 2.969, which is between 2 and 3, belonging to the moderate pollution level. And the west side of the landfill (downstream area) is greatly affected. The evaluation results of potential ecological hazard pollution index show that the potential risk index of single pollutants of heavy metals Cu, Pb, Zn, Cr, Ni, As and Cd belongs to low ecological hazard level, and the potential risk index of single pollutants of heavy metal Hg belongs to relatively heavy ecological hazard level. On the whole, the total potential risk coefficient belongs to medium pollution hazard degree. According to the correlation analysis, there is no significant correlation between heavy metal elements As and Hg and the other six heavy metal elements. In addition, the pollution source of heavy metal As may be mainly soil forming factors and the pollution source of Hg may be mainly human factors.

Assessment of Heavy Metal Pollution Characteristics andEcological Risk in Soils around a Rare Earth Mine in Gannan

In order to explore the pollution of heavy metals in the soils around the mined rare-earth mines, this paper used the geoaccumulation index method, the Nemerow pollution index method, and the potential ecological risk index method during the high water period and the withered water period, respectively, to analyze and assess the pollution characteristics and ecological risks of Mn, Cu, Cr, As, Cd, Ni, Pb, and Zn in the soils of the study area. The results showed that all the eight heavy metals in thesoil of the study area have accumulated to varying degrees, and the accumulation indices were Pb > Mn > Zn > Cd > Cu > Ni > Cr > As in descending order, with Pb and Mn accumulating most seriously. According to the results of the Nemerow pollution index, more than 25% of the sampling points in the soil were lightly contaminated, the Nemerow index of heavy metal Pb was greater than 2, which was moderately contaminated, and Cd was lightly contaminated in the withered water period. The potential ecological risk index showed that the heavy metal Cd was moderately ecologically hazardous, while the other seven heavy metals were all mildly ecologically hazardous. The heavy metals Pb and Mn in the soils of the study area were more seriously polluted, and there was also a certain degree of heavy metal Cd pollution during the withered water period, and the more seriously polluted areas were mainly located around the open pit of the rare-earth mines. Based on Java, the software platform of soil heavy metal pollution characteristics and ecological risk assessment around rare-earth mines is realized. The overall structure of the platform is designed, the background development framework is planned based on SSM, and the database is designed with SQL Server.

Characteristics and Assessment of Soil Heavy Metals Pollution in the Xiaohe River Irrigation Area of the Loess Plateau, China

Heavy metals in soil are a potential threat to ecosystems and human well−being. Understanding the characteristics of soil heavy metal pollution and the prediction of ecological risk are crucial for regional eco−environment and agricultural development, especially for irrigation areas. In this study, the Xiaohe River Irrigation Area in the Loess Plateau was taken as the study area, and the concentration, as well as their accumulation degree and ecological risk and distribution of soil heavy metals, were explored based on the geo−accumulation index (Igeo) and Hakanson potential ecological risk index methods. The results showed that the concentrations of soil heavy metals were all lower than the second grade Environmental Quality Standard for Soils of China. However, the average concentrations of Cu, Hg, Cd, Pb, Zn, Ni and As were higher than the above−mentioned standard. Compared with the soil background values of Shanxi Province, eight heavy metals of all samples presented different accumulation degrees, with the highest accumulation degree in Hg, followed by Cd, and the values were 11.3 and 4.0 times more than the background value, respectively. Spatially, the distribution of soil heavy metals in the Xiaohe River irrigation area was quite different, generating diverse pollution patterns with significant regional differences and complex transportation routes. The content of soil heavy metals in the Xiaohe River irrigation area was highly affected by land use types. The pollution degree varied with the distance to an urban area, declining from the urban area to suburban farmland, and the outer suburban farmland. Among these heavy metals, Hg and Cd were the principal contamination elements, and transportation, service industry and agricultural activities were the main potential contamination sources. The potential ecological risk of soil heavy metal positioned as follows: Hg > Cd > Pb > Zn > Cu > As > Ni > Cr. As indicated by the Hakanson potential ecological risk index strategies, except for the Wangwu examining site, the other six sampling sites experienced extremely strong risks, and as a whole, the entire study region was in a condition of incredibly impressive perils. Consequently, these results suggest that improving soil environmental investigation and assessment, setting up soil heavy metal contamination prevention and control innovation framework and reinforcing contamination source control are effective approaches for soil heavy metal contamination anticipation and control in irrigated areas of the Loess Plateau.

Synthetic Evaluation on the Potential Ecological Risks of Heavy Metal Pollution in Sediments in the Sea near Bohe Port of Maoming

The pollution index method and Hakanson potential ecological risk index method were used to study and analyze the pollution factors (Hg, Cu, Pb, Zn, Cd, As, Cr) in surface sediments of the sea near Bohe Port of Maoming. The results show that the overall contamination level and potential ecological risk of typical pollutants are at the low level in this sea area. The sequence of the pollution degree of heavy metals in surface sediments is As> Cr >Zn> Hg>Cu>Pb>Cd; and the potential ecological risk sequence is Hg>As>Cd>Cu>Pb>Cr >Zn. Hg is the major factor of potential ecological risk in surface sediments of this sea area.

Heavy metals pollution characteristics and risk assessment in sediments and waters: The case of Tianjin, China

Potential health and ecological risks due to heavy metal pollution in surface waters and sediments were evaluated based on a health risk assessment model and a potential ecological risk index method. Combined with the reclamation progress of Tianjin Nangang Industrial Zone, in China, a survey was carried out in the area dealing with heavy metals concentrations in surface waters and sediments, covering from 2008 to 2018. Specifically, concentrations were determined for As, Cd, Hg, Cu, Pb, and Zn. The results show that As、Cd、Hg、Cu 、Pb、Zn average concentrations in surface water were 0.99 μg/L∼1.27 μg/L, 0.13 μg/L∼0.63 μg/L, 0.03 μg/L∼0.13 μg/L, 1.5 μg/L∼4.65 μg/L, 1.25 μg/L∼4.7 μg/L, 13.5 μg/L∼20.99 μg/L and which average concentrations in sediment were 5.12 mg/kg∼12.34 mg/kg, 0.12 mg/kg∼0.18 mg/kg, 0.04 mg/kg ∼0.087 mg/kg, 13.45 mg/kg∼31.92 mg/kg, 13.2 mg/kg ∼21.26 mg/kg, 21.58 mg/kg ∼77.21 mg/kg, respectively. The background values of the Hailuan River basin near the study area were taken as the reference and compared with the national sediment quality standards a tell us the quality of the sediments in Tianjin Nangang coastal area being good. As regards the characteristics of pollution, heavy metals showed a high concentration in 2008 and then decreased significantly, which related to the dredging of large amounts of contaminated surface sediment during port construction. According to the phase equilibrium partition coefficient (Kp) and temporal and spatial distribution characteristics of heavy metals, sediments can be seen as an obvious sink for lead, with this element being mainly affected by exogenous input in coastal seawater. Zn, As, Cd, and Hg contents in surface water were greatly affected by the endogenous release from sediments. The results of the environmental risk assessment showed that the main environmental health risk of Tianjin coastal waters was carcinogenic, and specifically due to As. The potential heavy metals ecological risk assessment results of surface sediments were mild for the affected areas.

Investigating and Compiling a Map of the Severity of Heavy Metal Pollution in the Soil around the Landfill of Sabzevar Municipal Waste with Different Indicators

Introduction: Uncontrolled and improper landfilling of solid waste increases the concentration of heavy metals in the soil. Therefore, this study aimed to investigate soil contamination with heavy metals in the landfill of municipal and hospital waste in Sabzevar city by compiling a map of the severity of heavy metal pollution in the soil. Materials and Methods: Concentrations of heavy metals were analyzed by ICP-OES at distances of 10, 100 m from the burial site and at depths of 10 and 30 cm. To quantitatively evaluate the severity of pollution and the environmental effects of heavy metals in the soils around the Sabzevar landfill, enrichment factor (EF), index of geoaccumulation (Igeo), and investigating carcinogenic and noncarcinogenic hazards of heavy metals were used. Then a general map of soil pollution severity was prepared using the limitation scores (LS) and potential ecological risk index (RI) method. Results: Mean concentrations of As, Zn, Pb, Cr, and Cu in topsoil were 6.01, 41.4, 6.31, 26.77, and 31.45 mg/kg, respectively, as well as Hg and Cd were 60.79, and 61.60 µg/kg, respectively. However, mean concentrations of As, Zn, Pb, Cr, and Cu in the soil at a depth of 30 cm were 5.75, 38.33, 6.25, 22.68, and 31.04 mg/kg, respectively, as well as Hg and Cd were 66.57, and 59.98 µg/kg, respectively. Conclusion: According to the estimates of Igeo and FE indices, only Hg and Cd showed severe contamination. The noncarcinogenic risks of heavy metals were estimated to be less than 1.

Imposed by urbanization on soil heavy metal content of lake wetland and evaluation of ecological risks in East Dongting Lake

The properties of heavy metals in soil hold key to effectively protecting the urban ecosystem and predicting the environmental risks. In this study, we selected the wetland of East Dongting Lake as the study area, and measured the contents of their physicochemical properties. We adopted the methods of multivariate statistical analysis and inverse distance weighted (IDW) interpolation, so as to reveal the sources and distribution characteristics of heavy metal content in soil in the study area. By adopting the potential ecological risk index (PERI) method, we assessed the PERI values of heavy metals. The research findings indicate that: (1) As shown by the analysis of correlation matrix, the elements of As, Hg and Zn are positively correlated with SOC (P < 0.01). (2) As shown by the rotation factor load matrix, Factor 1 (F1) accounts for 18.03% of the total variance, which includes As, Fe, Mn, Zn and soil organic carbon. Factor 2 (F2) mainly includes nitrate ammonia, Pb and soil particles, and the factor load all exceeds 0.50. (3) There is a significantly higher level of contents of the elements of Cd, Zn, Pb and Hg in the agricultural land than other types of land use (P < 0.05). (4) Judging from the potential ecological risk coefficient of single heavy metal Eir, Cd features the highest risk coefficient with the mean value of 292, whereas the sampling points that have their E.56ir ≥ 320 account for 36.51% of the total, indicating strong ecological risks. The average value of the comprehensive PERI in heavy metals amounts to 555.03, representing a strong degree of ecological risks.

Soil Properties, Heavy Metal Accumulation, and Ecological Risk in Vegetable Greenhouses of Different Planting Years

The vegetable greenhouse soils in Yanglou Town, Ruzhou City, Henan Province were taken as the research object in the present study to explore the difference in soil physical and chemical properties and the total and fraction of heavy metals of different planting years. The potential ecological risks of heavy metals in greenhouse soils with different planting years were assessed by using single and comprehensive potential ecological risk index methods. The results showed that the soil pH of vegetable greenhouses increased, and fertility factors such as organic matter, available phosphorus, and alkali-hydrolyzable nitrogen accumulated to a certain extent compared to the control group, whereas catalase showed a decreasing trend. Correlation analysis showed that the planting years were significant positively correlated with pH (P<0.05) and organic matter (P<0.01) and significant negatively correlated with catalase (P<0.01). The amount of heavy metals in the vegetable greenhouse soils increased with the increase in planting years, among which Cu, Zn, and Cd increased most obviously, with maximum increases of 129.14%, 204.17%, and 161.11%, respectively. The proportion of acid-soluble and reducible heavy metals in the vegetable greenhouse soils also increased gradually with the planting years, and the proportion of residual heavy metals decreased correspondingly, which resulted in the heavy metals transforming into fractions easily absorbed by plants. The results of the single potential ecological risk index showed that Cd in vegetable greenhouse soils had a strong ecological risk with the increase in planting years, whereas Cu, Pb, Zn, and Ni were in the mild risk category. The comprehensive potential ecological risk index showed that the heavy metals in the vegetable greenhouse soils of different planting years have reached a strong or very strong ecological risk.

Spatial Characteristics and Potential Ecological Risk Factors of Heavy Metals in Cultivated Land in the Transition Zone of a Mountain Plain

The purpose of this study was to explore the spatial distribution characteristics and potential ecological risk factors of heavy metal pollution in cultivated soil in the transitional zone of a typical mountain plain. In this study, a county in Sichuan Province, which has the typical transitional topography of the Chengdu Plain-Longmen Mountain transition zone, was taken as the study area. Geostatistics and potential ecological risk index methods were used to analyze the spatial distribution of Cd, Cr, Cu, Pb, and Zn from cultivated land in the study area, and a potential ecological risk assessment was carried out. This was combined with geographical detector analysis to further explore the main influencing factors leading to the spatial difference in potential ecological risk. The results showed that:① The average values of ω(Cd), ω(Cr), ω(Cu), ω(Pb), and ω(Zn) of cultivated land in the study area were 0.39, 123.00, 31.28, 51.04, and 119.66 mg·kg-1, respectively, which were more than 2.60, 1.59, 1.19, 2.00, and 1.54 times the soil background value in the study area. ② The high value areas of Cd and Cr in cultivated land in the study area were mainly distributed in the west of the mountain area, the south of the transition zone, and the west of the plain area; the high value areas of Cu and Zn were mainly distributed in the west of the mountain area; the high value areas of Pb were mainly distributed in the south of the transition zone and the west of the plain area; and the low values of the five heavy metals were mainly distributed in the north of the transition zone. ③ The soil of cultivated land in the study area was dominated by slight potential ecological risk, and the average value of potential ecological risk index of heavy metals was Cd(32.58) > Pb(3.12) > Cu(2.82) > Cr(1.58) > Zn(0.98). Cd was the main factor causing the potential ecological risk of cultivated land in the study area. ④ There were significant differences in the key influencing factors of soil potential ecological risk of cultivated land in different topographic regions of the study area. The distance from the river and the soil type were the key factors affecting the mountain area; the multiple cropping index and the distance from the industry and mine were the key factors affecting the transition zone, and the soil pH value and the amount of chemical fertilizer were the key factors affecting the plain area.

Heavy metal pollution analysis and ecological risk assessment of shallow sediments in the coastal area of Lake Taihu

近年来太湖底泥重金属污染越来越受到各方关注.为了解太湖沿岸区底泥重金属污染状况，基于2018年太湖全湖污染底泥勘察项目中重金属监测数据，对梅梁湖、竺山湖、西部沿岸区、南部沿岸区、东太湖、贡湖6个太湖沿岸湖区浅层（0~30 cm深度区间）底泥中Hg、Cd、As、Pb、Cu、Zn、Cr、Ni 8种重金属元素含量进行分析，运用潜在生态风险指数法及空间插值分析方法对底泥重金属污染生态风险进行评价，并对底泥重金属来源进行初步分析.结果表明，太湖沿岸区浅层底泥中重金属分布具有明显的空间异质性，竺山湖、西部沿岸区、贡湖、梅梁湖等湖区重金属含量较高，南部沿岸区、东太湖重金属含量相对较低；各个湖区的Cd、Pb、Cu、Zn、Ni含量，竺山湖的Hg、As、Cr含量，贡湖的As、Cr含量，南部沿岸区的As含量以及梅梁湖的Cr含量均高于背景值；0~30 cm不同深度区间内底泥重金属含量越往表层相对越高.潜在生态风险指数法评价结果表明，0~30 cm深度区间内底泥重金属严重污染区域（重金属综合潜在生态风险指数RI≥300的区域）主要分布在西部沿岸区中部（茭渎港至乌溪港近岸侧）、竺山湖北部、贡湖北部（望虞河入河口附近），面积分别为104.54、10.80、6.89 km²，合计约122.23 km²；Cd和Hg是主要的重金属生态风险贡献因子、且毒性较强，西部沿岸区、贡湖主要表现为Cd污染，竺山湖主要表现为Cd、Hg复合污染，且西部沿岸区的Cd污染最为严重.重金属源分析结果表明，太湖沿岸区浅层底泥中Zn、Cu、Cr、Ni、Hg、Pb、As具有相似的来源，可能主要来自于工业污染，Cd可能主要来自于农业污染.研究结果可为太湖底泥重金属污染防治提供一定参考和基础数据支撑.;Lake Taihu is the third-largest lake in China, which is located at the junction of Shanghai City, Jiangsu Province and Zhejiang Province. Lake Taihu and Taihu Basin play a crucial role in the implementation of the national strategy of the integrated development of the Yangtze River Delta region. To characterize the pollution characteristics of heavy metals in shallow sediments in the coastal area of Lake Taihu, the monitoring test data for heavy metals of 230 sediment samples at 0-10 cm depth, 159 sediment samples at 10-20 cm depth, and 115 sediment samples at 20-30 cm depth were collected which were from the investigation project of polluted sediments in Lake Taihu in the year of 2018. The contents of eight heavy metal elements (Hg, Cd, As, Pb, Cu, Zn, Cr and Ni) in the samples which in Meiliang Bay, Zhushan Bay, Western Coastal Area of Lake Taihu, Southern Coastal Area of Lake Taihu, East Lake Taihu and Gonghu Bay were analyzed. The potential ecological risk index method and spatial interpolation analysis method were applied to evaluate the ecological risk of heavy metal pollution in sediments, and the sources of heavy metals in sediments were preliminarily analyzed. The results showed that the distribution of heavy metals in shallow sediments had evident spatial heterogeneity. The heavy metals' contents in Zhushan Bay, Western Coastal Area of Lake Taihu, Gonghu Bay and Meiliang Bay were higher than those in the Southern Coastal Area of Lake Taihu and Eastern Lake Taihu. The contents of Cd, Pb, Cu, Zn and Ni in each lake area, the contents of Hg, As and Cr in Zhushan Bay, the contents of As and Cr in Gonghu Bay, the content of As in the Southern Coastal Area of Lake Taihu, the content of Cr in Meiliang Bay were higher than the background value. The heavy metals contents in sediments in different depths of 0-30 cm had a rise from its bottom to its surface. The potential ecological risk assessment results presented that the seriously polluted area of heavy metals in sediments at 0-30 cm depth which heavy metals ecological risk index RI ≥ 300 were mainly distributed in the central part of the Western Coastal Area of Lake Taihu (the nearshore side from Jiaodu River to Wuxi River), the northern part of Zhushan Bay, the northern part of Gonghu Bay. The distribution area was 104.54 km², 10.80 m² and 6.89 m² respectively, with a total area of 122.23 km². Cd and Hg were the main heavy metal ecological risk contributors with strong toxicity. The Western Coastal Area of Lake Taihu and Gonghu Bay were mainly polluted by Cd, Zhushan Bay was mainly polluted by Cd and Hg. The Cd pollution in the Western Coastal Area of Lake Taihu was the most serious. The heavy metals source analysis results demonstrated that the Zn, Cu, Cr, Ni, Hg, Pb and As in shallow sediments in the coastal area of Lake Taihu have similar sources, which may mainly come from industrial pollution. Moreover, the Cd may come from agricultural pollution. The research results can provide references and basic data supports for the prevention and control of heavy metal pollution in the sediments of Lake Taihu.

Speciation Characteristics and Ecological Risk Assessment of Heavy Metals in Municipal Sludge of Huainan, China.

In order to fully understand the morphological characteristics and pollution status of heavy metals in the dewatered sludge of Huainan Municipal sewage treatment plant, the physical and chemical properties were analyzed, and the content and occurrence forms of heavy metals (As, Cu, Zn, Pb, Cd, Cr, and Ni) in the sludge were studied using the geological accumulation method (Igeo), risk assessment coding method (RAC), and potential ecological risk index method to evaluate the ecological risk. The results showed that the municipal sludge in Huainan was rich in nutrients, with good prospects for agricultural utilization. There were differences in the morphological distributions of different heavy metals. The Igeo values for Ni, As, Cr, and Pb were below 0. The results of RAC indicated that the risk level of Cr in sludge was a low risk, and those of other heavy metals were moderate risks. The potential ecological risk of Cd had the highest potential ecological risk, and the other six metals were of low ecological risk. This conclusion can provide basic data and a theoretical reference for the comprehensive utilization of sludge in sewage treatment plants.

Concentration, Spatial Distribution and Potential Ecological Risk of Heavy Metals in Stream Sediments of the Misiones Province, Argentina

One hundred and twenty-eight stream sediment samples were collected in the Misiones province of Argentina by the low-density geochemical mapping project of the China Geological Survey. The analyzed data were used to study the concentration, spatial distribution, local pollution level and potential ecological risk of eight heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) by factor analysis, geoaccumulation index (Igeo), enrichment factor (EF) and the Hakanson’s potential ecological risk index (Eir and RI) methods. Results showed that the background values (median) of those elements were 2.97 ppm, 0.13 ppm, 212.60 ppm, 322.53 ppm, 0.013 ppm, 64.42 ppm, 12.58 ppm, and 198.85 ppm, respectively. Except for Hg, the contents of other elements were higher than the abundance of continental crust. The spatial distribution of Cu and Zn in stream sediments were consistent, while that of other elements were different. The factor analysis results implied that Cd, Cr, Cu, Ni and Zn were mainly affected by geological background and inherited the characteristics of regional parent rocks. Furthermore, Pb was not only controlled by natural conditions but also related to human activities, while As and Hg represented the anthropogenic sources, and their concentrations were affected by human activities. The results of Igeo and EF told us that Cu was heavily polluted in stream sediments; Pb and Zn were largely mildly polluted; As, Cr, Cd, Ni and Hg were mostly nonpolluted. The ecological risks were ordered as As &gt; Cu &gt; Cd &gt; Pb &gt; Hg &gt; Cr &gt; Ni &gt; Zn. In general, the potential ecological risk of heavy metals in the Misiones province was low, but As and Cu also have a high ecological risk at some sampling points, which should be considered.

Distribution Characteristics and Ecological Risk Assessment of Soil Heavy Metals in Typical Watersheds of the Qinghai-Tibet Plateau

The Qinghai-Tibet Plateau is an extremely vulnerable area that is sensitive to human activities. In recent years, more and more human disturbances have been detected in this area. This study analyzed the spatial distribution and ecological risks of 7 heavy metals (Cr, Ni, Cu, Zn, As, Cd, and Pb) in two regions, namely the Bailong River and Yellow River and their two tributaries (BY region) in Gannan and the Yarlung Zangbo River and its two tributaries (YZ region) in Tibet. In terms of spatial distribution, concentrations of the seven heavy metals were higher in the east and lower in the west of the BY region. The average concentrations all exceeded the background value of the Qinghai-Tibet Plateau, especially for Cd (4.50 times) and As (2.83 times). High Pb concentrations were mainly found in water, urban and rural residential land, and industrial and construction land. In the YZ region, heavy metal concentrations were lower along the river, while high-altitude areas exhibited higher heavy metal concentrations. The average concentrations of Ni, Zn, As, and Cd exceeded the background values of the Qinghai-Tibet Plateau, especially that of Cd (3.13 times), which mostly exhibited high values in water coverage areas. The geo-accumulation index method and the potential ecological risk index method show that the degree of As and Cd pollution was relatively high in the BY region in Gannan, with the greatest potential ecological risk occurring in the water coverage area. In the YZ region in Tibet, the degree of Cd pollution was high, with the highest potential ecological risk also occurring in the water coverage area. This study provides significant guidance for the environmental protection, sustainable development, and utilization of soil under different types of land use in the Qinghai-Tibet Plateau.

Assessment of cadmium concentration, bioavailability, and toxicity in sediments from Saguling reservoir, West Java Province

This study aims to assess the concentration, bioavailability, and toxicity of cadmium in sediments. Surface sediment samples were taken from 12 sampling locations during the rainy and dry seasons from 2015-2017. Cadmium concentrations were analyzed using ICP-OES. Potential ecological risk index (PERI) methods assess the quality of lake sediments concerning heavy metal contamination. Risk Assessment Code (RAC) is a method used to assess the bioavailability of metals in aquatic sediments. The concentration of cadmium in the sediments during the rainy and dry seasons is high compared to the standards. The average concentration in rainy season 14.82 ± 1.48 mg.kg-1 and dry season 11.12 ± 2.16 mg.kg-1. Based on the assessment of sediment quality is categorized as extremely polluted during the rainy and dry seasons. The sediment quality has been contaminated with cadmium with the serious ecological risk category in two seasons. This means that Cadmium pollution has had a serious impact on the reservoir ecosystem. The bioavailability of cadmium in the dry season is higher than in the rainy season. This suggests that in the dry season, cadmium is more bioavailable and more able to enter the food chain. The toxicity of cadmium is higher in the dry season.

Are free-living nematodes effective environmental quality indicators? Insights from Bohai Bay, China

Free-living marine nematodes are sensitive biological indicators of environmental quality in marine sediments. This study investigated nematode communities in coastal waters in Bohai Bay, China. Nematode community taxonomic structure, colonizer–persister classes, maturity index (MI), index of trophic diversity (ITD), Shannon–Wiener diversity index (H′), together with the Hakanson’s Ecological Risk Index, were applied to assess the environmental quality of the investigated stations. The taxonomic structure, MI, ITD, and H′ varied among the study stations. In addition to the stochastic causes, variability in environmental variables together with metal concentrations explained, to a certain extent, the observed variations in nematode features. The differentiation in nematode species’ composition was attributed to changes in water depth, temperature, salinity, dissolved oxygen concentration, sediment medium diameter, organic matter, chlorophyll-a and pheophytin-a concentrations, and concentrations of manganese (Mn) and cobalt (Co). Mn was the most influential metal in explaining nematode diversity. MI appeared to be affected more by metals than by other environmental variables. According to the nematode features, the environmental quality ranged from bad to good at the majority of stations, although the rankings varied among different indices. Taxonomic structure, life strategy traits, ITD, and H′ were all effective in highlighting the areas subjected to severe metal contamination in the bay, and could provide more comprehensive assessments when used in combination. These indices suggested a more severe pollution status than the results obtained from the Hakanson’s Ecological Risk Index method, and may be more sensitive to ecological quality deterioration. However, their effectiveness requires further testing over larger spatial ranges and with more data.

Contamination Status and Potential Risk of Metals in Marine Sediments of Shalateen Coast, the Red Sea

ABSTRACT Metal contamination of the aquatic environment is a serious concern, insofar as public health and environmental protection are considered. Owing to their persistent and toxic characteristics, spatial analyses of metal concentrations in sediment with comparisons with natural backgrounds are essential. This study aimed to determine the metal concentrations of Cd, Cr, Co, Cu, Ni, Pb, and Zn and to appraise their probable ecological risk in sediments from the Shalateen coastal area. A total of 18 sediment samples were taken from different locations from the Shalateen coastal area. All sediment samples were kept in plastic bags at −20°C until analysis. The samples were digested using a wet oxidation method. The digested samples were determined for Cd, Cr, Co, Cu, Ni, Pb and Zn using Flame Atomic Absorption Spectrophotometry. Physicochemical characteristics (calcium carbonate content, grain size, organic matter, and pH) were conducted using standard procedures. Diverse procedures, guidelines, and indices have been employed and manipulated to assess risk. The results revealed that the mean value of metal contents in the study area followed the order Zn > Cr > Ni > Cu > Pb > Co > Cd. Most of the studied metals in the sediment did not exceed limits that are regarded harmful for aquatic life. Both pollution load and potential ecological risk index methods displayed that the integrated ecological risk of the investigated metals was quite low. A clear correlation linking the concentrations of metals and anthropogenic sources was not observed. This work designates that even with continuing development of the Shalateen coastal area, the metal contamination status remains relatively low.

Pollution Source Analysis of Heavy Metal and Ecological Risk Assessment in Urban Fringe

With the rapid development of modern urbanization, the unreasonable industrial structure has impacted urban environment, which greatly restricts the use of land resources safely. Especially in some cities with rapid urbanization, on the one hand, urban development requires a large amount of lands; on the other hand, the urban environment exceeds its bearing capacity, and human settlements environment have been negatively affected. Taking the typical urban fringe of Xi’an as the research area, this study detected Cd, Cr, Cu, Ni, Pb and Zn combined with GIS, RS and GPS technologies. Totally 26 sample points were collected. The pollution index method (single pollution index, Nemerow comprehensive pollution index method), geo-accumulation index method and potential ecological risk index method were used to evaluate the results, and the pollution sources were analysed. According to the analysis results, Cd, Pb and Zn existed obviously ecological risks. The Pb pollution of each sample point was quite different. Sample points 1-13 were located in the east of the research area, mainly distributed on both sides of the traffic road. Pb pollution was relatively serious. The average value of Igeo (Pb) reached 4.20, which belongs to strong pollution - extremely strong pollution. The heavy metal pollution of Zn was universal, however, the toxicity response parameter of Zn is low, Tr i=1, so the ecological risk was not significant. The detection rate of Cd was only 11.5%, but the value was much higher than background value, which should be paid attention to. The results showed that there are different degrees of heavy metal pollution and potential ecological risks in the research area, which supported the safe use of land in urban fringe areas.

Assessment of Heavy Metals in Sediments of Different Functional Areas along the Yangzong Lake Coast, Yunnan Province

Contents of Cu, Zn, Ni, Cr, Fe, Mn, V, Mo, Co, Sr, Li, Be, Cd, As, Pb, Al, Ba and Ti in 40 coast sediment samples collected from the industrial, tourism and agriculture area adjacent to Yangzong Lake Coast were analyzed. Enrichment coefficient method and potential ecological risk index method have been adopted to evaluate heavy metal pollution and ecological risk. The results showed that pollution degree of Cu, Zn, Ni, Cr, Mn, Co, V from high to low was as follows: agriculture area > tourism area > industrial area. The enrichment performance of Be, As, Cd, Al, Ti, Li, Fe from high to low was as follows: agriculture area>industrial area>tourism area. The pollution degree of Mo, Pb, Sr from high to low was as follows: industrial area > tourism area > agriculture area. The pollution degree of Ba from high to low was as follows: tourism area > industrial area > agriculture area. According to the potential ecological risk coefficients, Cd, As, Cu, Co were the most hazardous elements in industrial area, tourism area and agriculture area. The request potential ecological risk index indicated that industrial area and tourism area were low-moderate potentical ecological risk, agriculture area was moderate-considerable potentical ecological risk.

Distribution and Assessment of Cr, Pb, Ni and Cd in Topsoil of the Modern Yellow River Delta, China

Modern Yellow River Delta (MYRD) is a typical petrochemical and agricultural industrial area of China. To effectively assess the current status of the four heavy metals (Cr, Pb, Ni and Cd) of topsoil residues, soil samples (0 ~ 20 cm) (n = 104) in the MYRD were collected and analyzed. The results showed that the contents of the four heavy metals were all below or equal to the level 1 background content as specified in the National Environmental Quality Standard for Soils, while the content of Cd and Pb were 1.68 and 1.41 times higher than the background value of soil in Shandong province, respectively. The difference of four heavy metal contents between different kinds of land types existed. Geoaccumulation index and potential ecological risk index methods were used to evaluate the risk of the four heavy metal pollution in the MYRD. The results showed that there was a light or moderate pollution of heavy metals Cd and Pb, which were a strong ecological hazard. Therefore, it is necessary to enhance the monitoring and controlling of heavy metal Cd and Pb pollution in the MYRD.