Comprehensive Ecological Risk Research Articles

Ecological risk assessment of toxic metal(loid)s for land application of sewage sludge in China

Sewage sludge, including those after biological or thermochemical treatments, has the potential to be used as fertilizers for recycle of resources. However, its potential ecological risk is also of great concern to policy making. This study employed comprehensive ecological risk assessment (ERA) methods to evaluate the risk caused by the toxic metal(loid)s in sewage sludge throughout China. The conventional geo-accumulation index and potential ecological risk index revealed that cadmium (Cd) and mercury (Hg) were of significant concern in treating sewage sludge before land application, but chromium (Cr) and zinc (Zn) were preferred by potential affected proportion (PAF) and overall risk probability (ORP) of species sensitivity distribution (SSD). Because SSD considered both the community and the ecotoxicity of toxic metal(loid)s, it was more advantageous and promising in assessing ecological risks caused by land application of sewage sludge. Based on the predicted no-effect concentration (PNEC) of toxic metal(loid) calculated by hazardous concentration that cause death of 50% of species (HC50) by SSD, the maximum allowable disposal amount (MADA) of sewage sludge in the whole China indicated that chromium (Cr) should be totally eliminated because of its high risks in the present background soil. After excluding Cr, the MADA of sewage sludge in China was 3.24 × 106 t and 6.47 × 107 t under land application scenarios with high and low ecological risks, respectively. Additionally, the MADA could be increased by mixing sewage sludge with deeper soil in wider areas. This study emphasized that local laws and regulations on land application of sewage sludge and the subsequent ERA system need to be addressed in the future.

Ecological and Health Risk Assessments Based on the Total Amount and Speciation of Heavy Metals in Soils Around Mining Areas

Topsoil and supporting crop samples around a mining area were collected in Longyan City, and the total amounts and speciation of Pb, Cd, and As in the samples were determined. The ecological risk and human health risk assessment of soil heavy metals Pb, Cd, and As were carried out using the Hakanson potential ecological risk assessment method, the ecological risk classification method based on the principle of geochemical statistics, and the health risk assessment method in accordance with the characteristics of human exposure parameters in China. The results indicated that the heavy metal elements in the soil in the study area exceeded the environmental quality standards for Pb and Cd, and the heavy metal contents in cereal grains exceeded the food limit value mainly for Pb. The proportion of the four bioavailable forms except the residue state followed the order of Pb>Cd>As. The ecological risk assessment results based on the total amount of heavy metals and bioavailable forms showed that Cd was the most important ecological risk factor. The single potential ecological risk of Cd and the comprehensive ecological risk of Pb, Cd, and As in the soil based on bioavailable forms were significantly reduced compared with that based on the total amount. The proportion of medium and superior samples decreased from 100% and 50.0% to 17.2% and 7.81%, respectively, and the divided risk zone basically contained all the warning points of exceeding the standard of crops. Oral ingestion was the main carcinogenic and non-carcinogenic exposure route of heavy metals. In terms of carcinogenic risk, the risk of human carcinogenic health exposure to Cd and As was within the acceptable range, regardless of whether bioavailability was considered. Among the non-carcinogenic risks, the non-carcinogenic risk of the heavy metal Cd was negligible. When only the total amount of heavy metals was considered, the non-carcinogenic risk index of Pb and As under the three exposure pathways ranged from 0.14 to 8.65 and from 0.04 to 2.85, respectively. After considering the adjustment of bioavailability, the non-carcinogenic risk of As was greatly reduced and could be considered to no longer have non-carcinogenic risk. Although the non-carcinogenic exposure risk index of Pb was reduced by 84.7%, the maximum value still reached 1.69, which would cause non-carcinogenic harm to the population and was the key to soil remediation in mining areas.

Monitoring, Source Identification and Environmental Risk of Potentially Toxic Elements of Dust in Isfahan Province, Central Iran.

The aim of this study was to identify potentially toxic elements (PTEs) associated with airborne particulate matters (PMs) and their source identification and environmental risk in Isfahan Province, central Iran. Dust samples were collected from various locations included three urban and four rural locations. Results revealed the eastern part of the region as the main source of dust and showed that the highest monthly atmospheric dust deposition was in July (5.53g m-2). The mean concentrations of Zn, Pb, Cu and Cd were respectively 279, 63, 49 and 0.5mg kg-1 in dust samples, whereas Cd showed the highest ecological risk index. Dust samples of urban areas showed considerable and very high levels of pollution indices for Pb and Zn, respectively. Among the metals, Zn showed the highest enrichment factor (>5), mainly due to anthropogenic sources. The comprehensive ecological risk index of PTEs revealed the moderate and considerable risk of Isfahan and Najafabad cities, respectively.

重庆市生态风险预警等级划分及演化趋势模拟

PDF HTML阅读 XML下载 导出引用 引用提醒 重庆市生态风险预警等级划分及演化趋势模拟 DOI: 10.5846/stxb202108032116 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 重庆市自然科学基金杰出青年基金项目（cstc2020jcyj-jqX0004）；国家社科基金后期资助项目（20FJYB035）；教育部人文社科一般项目（20YJA790016） Classification of ecological risk warning levels and simulation of evolutionary trends in Chongqing Municipality Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:生态风险预警等级评估和演化趋势模拟，可为生态风险管理提供可靠的辅助决策。以重庆市为研究对象，基于驱动力-压力-状态-影响-响应模型，构建重庆市生态风险预警指标体系，采用正态云模型和集对分析法，定量分析重庆市生态风险时空分异特征和演化趋势。研究结果表明：（1）2013-2019年，重庆市生态风险值呈"上升-下降"的波动趋势，综合生态风险隶属于重警等级，生态风险综合值从0.295下降到0.278，生态环境逐年好转；（2）重庆市生态风险有下降、不变、先上升后降低、先降低后上升以及一直升高5种演化趋势，分别占比39%、16%、5%、21%、24%；（3）重庆市生态风险转移分为两个方向，2013-2016年生态风险空间分异性增大，中警、轻警和无警风险等级不断向东北、东南和西部四周分散转移；2016-2019年生态风险分布格局变化较小，重警风险区在东部聚集；（4）演化趋势模拟结果表明，未来重庆市生态风险降低的区县有13个，占比34%，生态环境有向好发展的趋势；生态风险上升的区县有25个，占比66%，生态环境会有所恶化，但是恶化程度较低。将生态风险等级划分与预警演化趋势相结合，能为城市生态风险管理提供科学依据。 Abstract:The level assessment on the ecological risk early warning and the simulation on evolutionary trend can provide reliable auxiliary decision making for the ecological risk management. Taking into account the Driving-Pressure-State-Impact-Response model, this paper establishes an index system for ecological risk early warning to quantitatively analyze the temporal and spatial differentiation characteristics and evolution trend of ecological risk in Chongqing Municipality, using the normal cloud model and the set-pair analysis method. The results demonstrate that:(1) from 2013 to 2019, the ecological risk value of Chongqing presented a "rise-decline" fluctuation trend, and the comprehensively ecological risk was ranked as heavy warning level, while the comprehensive ecological risk value decreased from 0.295 to 0.278, denoting that the ecological environment had been improved. (2) There were five evolutionary trends of ecological risk in Chongqing:decreasing, unchanged, increasing-decreasing, decreasing-increasing and always increasing, accounting for 39%, 16%, 5%, 21% and 24% of all regions, respectively. (3) The ecological risk transferred to ward two orientations in Chongqing. From 2013 to 2016, the medium-alert, light-alert and no-alert risk areas continued to spread to the northeast, southeast and west of Chongqing, which intensified the spatial differentiation of ecological risks; whereas from 2016 to 2019, the high-alert risk areas were concentrated in the east, suggesting the little change in the ecological risk distribution pattern. (4) The simulation results of evolution trend revealed that 13 counties, accounting for 34% of all areas, would experience the declining ecological risk and subsequently improving ecological environment in Chongqing in the future; additionally 25 counties, accounting for 66%, would maintain the deterioration of ecological environment to small extent. The combination of ecological risk classification with early warning evolutionary trend can contribute a scientific basis to urban ecological risk management. 参考文献 相似文献 引证文献

Characteristics and Source Analysis of Soil Heavy Metal Pollution in a Mining Area

It is of great significance to study the degree and source of soil heavy metal pollution in geological high background value area for remediation of local contaminated soil. The 0 - 20 cm topsoil was taken around the mining area, and the contents of Pb, Zn, Ni, Cd, Hg, Cu and As in the soil were measured. Single-factor pollution index, Nemeiro comprehensive pollution index and potential ecological risk index were used to evaluate the degree of heavy metal pollution and ecological risk. Finally, multivariate statistical analysis was used to analyze the sources of soil heavy metals. The results show that the measured elements are polluted to different degrees, mainly due to the ecological environment problems caused by extensive mining development methods and inefficient utilization of resources. The key link is the release of pollutants at the source. Effectively blocking the release at the source can cut off the possibility of pollutants entering the food chain and the circulation of materials in the ecosystem. The results of potential ecological risk index showed that the potential ecological damage of seven heavy metals was ranked as follows: Cd (97.67) > Hg (68.97) > As (14.29) > Pb (11.55) > Ni (4.62) > Zn (1.61) > Cu (1.45) had a high ecological risk coefficient, and the potential comprehensive ecological risk index was 200.16 and the degree was medium. Principal component analysis shows that the sources of heavy metals are divided into Pb, Cd, As, Zn and Hg mainly from human activities such As mining, while Ni and Cu mainly come from soil parent materials, mining and agricultural activities.

Characteristics of nutrients pollution and ecological risk assessment of heavy metal in sediments of Fenhe River, Taiyuan section, China

AbstractThis study aimed to reveal the characteristics of nutrients and heavy metals associated with ecological risks in the sediments of Fenhe River, Taiyuan section. The concentrations of nutrients (total nitrogen, total phosphorus, total organic matter) and heavy metals (As, Cu, Zn, Pb, Cr, Ni, Hg, Cd) were investigated. Spatial distribution, correlation analysis and source identification were facilitated to indicate nutrient and heavy metal pollution characteristics. Evaluations of heavy metals’ contamination degree were achieved by comprehensive ecological risk indexes including Igeo, Iin, Cf, pollution load index and risk index. The results showed that nutrients accumulated in the middle region and were mainly from embryophyte, zooplankton and phytoplankton or algae, based on C/N values. Large spatial variabilities existed in heavy metal distribution patterns; source identification for heavy metals revealed they were from natural sources and anthropogenic activities based on a principal component analysis model. Results of different ecological risk indexes showed that pollution associated with Hg was rated as a moderate ecological risk but was significant contamination, higher ecological risks mainly existed in the middle region.

Evaluation of potential ecological risks in potential toxic elements contaminated agricultural soils: Correlations between soil contamination and polymetallic mining activity

Extensive mineral exploitation activities in history have aggravated potential toxic elements (PTEs) contamination in agricultural soils in China. Comprehensive ecological risk assessment is of great significance to orientate the restoration of contaminated soils, especially for those with high background values and multiple sources. The study area is located in the major rice producing area of China. Historically, there was a silver mine and a lead-zinc mine in the area, which were successively closed during the investigation. The intensive mining activities caused serious PTEs pollution in the agricultural soils around the mining area. In this study, five PTEs (As, Cd, Cr, Hg and Pb) selected to assessed the potential of geoaccumulation index in assessing agricultural soil potential risk assessment by identifying ecological risk sources. 315 of soil samples collected in 2009, 2014, 2018 were comprehensively analyzed by single pollution index evaluation (single factor index, geoaccumulation index), comprehensive evaluation (Nemerow index, potential ecological risk index) and trend analysis. Single factor index analysis showed that geoaccumulation index considered the impact of natural diagenesis of background values and human activities on the environment, ensuring high evaluation accuracy comparing to other methods used in typical complex agricultural soils. The modified potential ecological risk index revealed that the high background area did not represent high risk area, which was consistent with the implementation effect of governance measures. This study can provide important insights for policymakers and environmental engineers to quantitatively recognize the soil pollution and the effectiveness of governance based on applicable and reasonable evaluation methods.

Distribution and Ecologica Risk of Sediment Heavy Metals in the Water-Level-Fluctuation Zone of the Shawan River Section of Yelang Lake

With the aim of revealing the potential ecological risk and distribution characteristics of heavy metals on the surface sediment at the Shawan River section of Yelang Lake, the following three analyses were first performed: (1) analysis of grain-size composition on sediment samples collected at seven different sites in the water-level-fluctuation zone (WLFZ); (2) analysis of bulk sediment content of six heavy metals, namely, Cd, Cr, Pb, Mn, Zn, and Cu; and (3) the correlation analysis of grain-size composition and heavy metal content in the sediment. Afterwards, the approach of Hakanson potential ecological risk index was employed to analyze the risk of heavy metal pollution in sediments of seven WLFZ plots. The outcomes indicate that (1) the mean sediment grain size at each sampling site was generally >0.063 mm, with gravel grains (>1 mm) and sand grains (0.22–1 mm) accounting for the largest proportions; (2) the site-averaged mean sediment content of each of the six heavy metals was significantly higher than their respective geochemical background contents in the sediment of Guizhou Province, and the grain-size dependence of the bulk sediment content of heavy metals was not significant; (3) the distribution of Cr was relatively independent of other metals, which was in contrast to notable positive correlations observed between other metals; and (4) in accordance with the approach of Hakanson potential ecological risk index, for these heavy metals, their potential ecological risk reduced by the order of Zn < Cr < Cu < Pb < Cd, with Cd having a mean potential risk index (Ei) of 566.13, suggestive of a very high level of potential ecological risk, Zn, Cr, and Cu having a mild potential ecological risk, and Pb having moderate potential ecological risk. Cd largely contributes to the comprehensive ecological risk index RI is the largest, thereby having important environmental implications.

Heavy metal pollution levels, source apportionment and risk assessment in dust storms in key cities in Northwest China

In this study, the potential hazards of heavy metals in dust storms were investigated by collecting dust storm samples, measuring their heavy metal concentrations, and using index evaluation, spatial analysis, positive matrix factorization (PMF) model and risk assessment model. Heavy metals in dust storms were contaminated by anthropogenic sources leading to their concentrations being higher than the background values. The enrichment factors and geoaccumulation indices showed that the heavy metals came from both natural and anthropogenic sources, Cu, Ni, Zn and Pb are strongly influenced by anthropogenic sources. Heavy metals in dust storms were divided into four sources: Cu and Ni were attributed to industrial sources mainly from local mining and metal processing; Cr was mainly contributed by industrial sources related to industrial production such as coal combustion; Pb and Zn were mainly contributed by transportation sources; and Ti, V, Mn, Fe, and As were from natural and agricultural sources. The level of comprehensive ecological risk of heavy metals in dust storms were low, but there were moderate and above risks at individual sites. Both adults and children had the highest carcinogenic and non-carcinogenic risks from the ingestion route, and the risk for children was higher than that for adults.

Risk assessment and management of PM2.5-bound heavy metals in the urban area of Kitakyushu, Japan

The sampling campaign of PM2.5 was carried out in Kitakyushu City on the western edge of Japan from 2013 to 2019, and 29 heavy metals loaded in PM2.5 were measured in this study. During the whole sampling period, the PM2.5 mass concentration ranged from 6.3 μg·m−3 to 57.5 μg·m−3, with a median value of 21.3 μg·m−3, and the sum concentration of heavy metals only accounted for 3%. According to the enrichment factor (EF) and geo-accumulation index (Igeo) analysis, it can be known that Se, Mo, Pb, As, Zn, W, Sb, Cu, V, Cr, Ni, and Cs were mainly from anthropogenic sources, which had EF values larger than 10 and Igeo values larger than 0. The comprehensive ecological risk index for these 12 anthropogenic metals was far greater than 600. This large index showed severe metal pollution and very high ecological risk in the urban area of Kitakyushu, Japan, which should be paid great attention. The human health assessment result further revealed that children living at the sampling site faced severe non-carcinogenic risk (HI = 7.8) and moderate carcinogenic risk (CR = 1.2 × 10−4), and oral ingestion was basically the most important exposure pathway, followed by dermal contact and inhalation. The priority control metals included Mo, Se, As, Pb, Sb, and Cr; moreover, the concentration-weighted trajectory analysis (CWT) indicated that Mo, Sb, and Cr were from ship emissions because some shipping routes around the Kyushu area were identified as their potential pollution source regions, while Se, As, and Pb were carried by the air masses from the Asian landmass. Overall, although the PM2.5 concentration in the urban area of Kitakyushu, Japan was not high, the heavy metal risk cannot be overlooked; it is necessary to strengthen the source control of high-risk metals and raise public protection awareness.

Surface sediment enrichment with trace metals in a heavily human-impacted lagoon (Bizerte Lagoon, Southern Mediterranean Sea): Spatial distribution, ecological risk assessment, and implications for environmental protection

Although several studies previously assessed the contents of trace metals in the sediments of the heavily human-impacted lagoon of Bizerte (northern Tunisia), multi-analytical approaches have not been, so far, used to assess the ecological risks in this water body. This study attempts to provide a comprehensive ecological risk assessment related to the enrichment of the lagoon sediments with seven metals (As, Cd, Cr, Cu, Hg, Pb, and Zn). Significant spatial variations were found in the metal concentrations in sediments, in relation to the degree of coastal human activities and hydrodynamics. This was confirmed with the results of the three pollution indices, Cf, PLI, and Igeo. Concordant results were found with most of the indices used to assess the ecological risks (PERI, PEL, ERL, ERM, M-ERM-Q, TU), indicating higher risks in the southern part of the lagoon. These findings can help to improve the environmental management plan of the socio-economic important lagoon of Bizerte.

Characteristics of Sludge and Associated Risk Assessment of Urban Sewage Treatment Plants

In urban solid waste management, the scientific and reasonable disposal and utilization of sewage sludge is becoming more and more important. It can be said that the pollution status and chemical properties of sewage sludge in urban sewage treatment plants can provide a basis for the scientific disposal and utilization of sludge. In this study, the characteristics of pH, moisture content, Cd, Cr, Cu, Zn, Pb, As, Hg, Ni, mineral oil, volatile phenol, PAHs, organic matter, nitrogen, phosphorus, and potassium were evaluated in sewage sludge collected from 49 sewage treatment plants in a certain city. The pollution status of heavy metals and organic pollutants, the frequency distribution of pollutant concentrations, and changes in the nutrient content were analyzed. The Nemero index and Hakanson potential ecological hazard index were used to assess the potential ecological risks of heavy metals in the agricultural utilization process of sludge. The results showed that under the condition of neutral pH values and high moisture content, the order of heavy metal content was Zn > Cu > Cr > Pb > Ni > As > Hg > Cd. The principal component analysis (PCA) results indicated that Cd, Pb, Hg, Ni, and As constituted the main load factors of the first main component of heavy metal sources. The most concentrated contents of 8 heavy metal frequency distributions among the 49 samples were 38.9-1380.0, 62.6-182.7, 63.6-181.3, 0.0-97.8, 19.3-68.4, 0.8-29.2, 0.3-8.7, and 0.01-0.96 mg·kg-1. In addition, the most concentrated frequency distribution of mineral oil, volatile phenol, and PAH concentration were 87.0%, 87.9%, and 77.6%, respectively. Moreover, the nutrient content of sludge was higher than the average level in China, and the organic matter content was 67.4%, 75.9%, and 92.5% of that of pig manure, cow dung, and chicken manure, while the content of nitrogen, phosphorus, and potassium was not very different. The Nemero index and Hakanson ecological hazard index results showed that the sludge of urban sewage treatment plant in the city has certain ecological risks. However, four sewage treatment plants were heavily polluted or highly ecologically hazardous among the 44 plants in this study, which were in line with the Standards for pollutant control of agricultural sludge. In summary, there are certain potential ecological risks for the agricultural utilization of sludge in the city, and it is necessary to reduce the heavy metal content before resourcing. More importantly, on the premise that the sludge meets the agricultural standards, a comprehensive ecological risk assessment is required to select a reasonable sludge recycling method.

Heavy metal contamination risk assessment and correlation analysis of heavy metal contents in soil and crops.

Heavy metal pollution is a notable threat to agricultural production. Soil heavy metal pollution can cause potential ecological risk (ERI), and crop heavy metal pollution can cause human health risk (HRI). However, most previous studies partially focused on heavy metal pollution in soil or crop but often neglected the relationship between them. Actually, soil heavy metal can pollute crops to some extent, while not all heavy metal pollution in crops comes from soil. The inner relationship of pollution risk in soil-crop system is worth attention. In this study, we selected Ningbo as the study region and used sample data to assess both soil and crop heavy metal risks, in order to explore the differences between heavy metal contamination risks in soil and crops as well as the relationships between heavy metal contents in soil and crops. Our results showed that Hg was the most polluted heavy metal in soil, which led to the highest ecological risk in Jiangbei (Comprehensive ERI=567) with the maximum ERI of Hg (430). However, As in crops contributed the most to health risk and caused the highest health risk in Fenghua (HRI=10) with the largest contribution of 64.5%. Such differences of pollution risk assessment indicated that the contents of the same heavy metal were inconsistent in soil and crops. Our results further showed that the heavy metals in soil had the greatest influence on Zn in crops. Pb and Cr in soil had synergistic effects on the crop absorption of Zn, whereas As, Hg and Cu played antagonistic roles in the crop absorption of Zn. Our study confirms that heavy metals in soil would variously influence heavy metals in crops and the interaction of heavy metals is very important for pollution risk control, which have been largely ignored yet.

Ecological risk assessment of coal mine area based on “source-sink” landscape theory – A case study of Pingshuo mining area

Coal mining play a fundamental role in promoting economic and social progress. However, intensive mining operations have brought enormous ecological risks, such as landform destruction, vegetation degradation and biodiversity loss. Based on the “source-sink” landscape and ecological risk assessment theories, this study proposes a new methodology to comprehensively analyze the mechanism of ecological risk and makes quantitative evaluation taking Pingshuo coal mine area as an example from 2000 to 2017. The results prove that the “source-sink” landscape theory is more consistent with the nature of ecological process to distinguish the ecological risk in mining area. Within the study period, the main risk source of mining areas is the environmental disturbance brought by mining production with a spreading trend, while the pollution risk caused by residents’ life is relatively low but the scope is large. The ecological niche of risk sink (a place where ecological risks disappear) in the study area improved as a whole, the ecological vulnerability and exposure coefficient of risk sink shows a decreasing trend from core mine area to outside, and the trend was not obvious at the end stage, testifying the protective effect of environmental governance. The striking increase areas of comprehensive ecological risk are mostly concentrated in the surroundings of mining production expansion, testifying mining practice has a significant adverse impact on the contiguous natural ecosystem. Any kind of pressure from coal mine operation, residents’ production and natural erosion in mining area should not be ignored, and the high risk areas are markedly clustered around the risk sources.

Multi-elemental composition and toxicity of bottom sediments from Panama Canal watershed

The Panama Canal is a milestone in the history of interoceanic communication. Despite its importance, environmental data regarding this important ecosystem is scarce. The aim of this work was to quantify trace-element levels in bottom sediments from 11 sites along the Canal watershed using ICP-MS, and in the case of mercury, employing a direct Hg Analyzer. These data were associated with the biological activity of aqueous sediment extracts tested on wild type and mutant strains of Caenorhabditis elegans, measuring physiological and molecular markers. The levels of trace elements in bottom sediments decreased in the order Sr > V > Ba > Cr > Li > Sc > Ce > Ni > Y > Co > Ga > Pb > Rb > Nd > La > Gd > Dy > Sm > Pr > Er > Hf > Yb > U > Th > Eu > Ho > Be > Tb > Tm > Ta > Hg. The Pollution factor and Pollution Load Index showed that 36% of the sites presented strong sediment pollution by V, Li, Pb, and Sr. Moreover, the Comprehensive Ecological Risk Index based on Cr and Ni levels was exceeded in all stations. Toxicity tests revealed that sediment extracts, despite not being highly lethal against C. elegans, did significantly reduce its mobility and activated toxicity mechanisms associated with the expression of metallothionein and oxidative stress-related genes. These last three endpoints were statistically related to Cr, Ta and Ba concentrations in sediments, respectively. Data suggest elements present in sediments from Panama Canal may be impacting benthonic organisms, and therefore, stronger management regulations should be considered in order to ensure its sustainability.

Concentrations, distribution, and risk assessment of heavy metals in the iron tailings of Yeshan National Mine Park in Nanjing, China

For the first time, a field survey was conducted to investigate the present situation, vertical distribution and ecological risks of heavy metals (Cu, Zn, Mn, Cr, Pb and As) from 21 in-situ samples drilled out from Yeshan iron mine tailings in the Jiangsu Province of China. The heavy metal contents obtained for the tailing wastes in decreasing order were as follows: Mn > Cu > Zn > As > Cr > Pb. The contents of heavy metals varied with depth, and the variation trends were not completely consistent. Vertical distribution profiles showed that heavy metals accumulated in certain strata. Both the monomial potential ecological risk factor (E) and the risk quotient (RQ) showed a high ecological risk for Cu, Mn and As. The comprehensive ecological risk index (RI) also indicated that the wastes presented a high ecological risk level, to which Cu, Mn and As were the key contributors. Our study showed that the health of individuals, especially children, living in the mining-impacted areas could be affected by the potential noncarcinogenic risk of copper, manganese and the carcinogenic risk of arsenic.

Characteristics and influencing factors of heavy metal pollution in surface dust from driving schools of Wuhu, China

To investigate the characteristics and influencing factors of the heavy metal pollution in surface dust of driving schools, 128 dust samples have been collected from 22 driving schools in Wuhu city, Anhui province. The distribution characteristics, sources and ecological risks of Co, Cr, Cu, Ni, Pb and Zn in the surface dust of driving schools are under detailed analysis. The results showed the elements of Cu, Pb, Zn and Cr in the surface dust of driving school from Wuhu appear pollution. The training environment of driving school, emission mode of training car and density of training car have a great influence on the content of Cr, Cu, Zn and Pb in surface dust of driving schools. The contents of Cr, Cu and Pb in the surface dust of driving schools as the following: reverse parking stall and side orientation > S bend as well as ramp and right angle bend > control point, Zn: reverse parking stall and side orientation > right angle bend > S bend and ramp > control point. Cr, Cu, Pb and Zn mainly come from exhaust emission, friction of automobile parts and tire wear during motor vehicle driving training. Co and Ni mainly come from natural sources. Although the comprehensive ecological risk index of surface dust in driving schools reaches slight ecological risk, and the elements of Pb, Zn and Cu are the main risk factors. But all above shows that enough attention should be paid to heavy metal pollution brought by training activities.

Analyzing environmental risk, source and spatial distribution of potentially toxic elements in dust of residential area in Xi’an urban area, China

A comprehensive study on concentration, spatial distribution, pollution, ecological–health risk and source of potentially toxic elements (PTEs) in dust of residential area in Xi’an, China were conducted to explore the environmental quality of residential area in urban district. The results show that the concentrations of V, Ni, and Mn in the dust were less than, while the contents of Cr, Zn, Pb, Cu, and Ba in the dust were obviously larger than, the soil background values of Shaanxi. The high–value area of PTEs primarily concentrated in densely populated areas, heavily trafficked areas and the surroundings of plants. Cr, Pb and Zn posed moderate enrichment and Pb possessed moderate ecological risk in the dust. The comprehensive pollution levels of PTEs in the dust were uncontaminated to moderately contaminated and their comprehensive ecological risk were moderate. The non–carcinogenic risks of the PTEs for adults and children were in the safe level and the carcinogenic risks of Ni and Cr were under the current acceptable value. Four major sources were discriminated on basis of the multivariate statistical analysis results and the content characteristics, enrichment degrees, and the spatial distribution features of the PTEs, viz. Mn, V, and Ni primarily came from natural source; Pb, Zn, and Cu mainly originated from traffic source; and Ba and Cr were respectively from construction source and coal–fired power plant source, which respectively contributed 22.8%, 28.3%, 47.3%, and 1.6% to the total content of PTEs determined in the dust.

Evaluating the distribution and potential ecological risks of heavy metal in coal gangue.

The heavy metals, which derived from accumulated coal gangue, are important source of environmental pollution. In this study, coal gangue dumps, collected in Shaanxi Province, China, were used to evaluate the potential ecological risks and release characteristics of heavy metals, including the chemical forms, release characteristics, and potential ecological risks by using the methods of Tessier's sequential extractions, leaching experiments, gray GM (1, 1) forecasting mode, and potential ecological risk index. The results indicated that gangue samples contained high levels of metals, especially of Pb, which was the 20-31 times of the background value, whereas the sum of exchangeable and carbonate fractions in Co and Cu was a large proportion (4-11%) of the total. Potential ecological risks were at strong level regardless of the type of the coal gangue because of Mo and Pb and the comprehensive ecological risk index of 351.51-412.27. Weathering promotes the release of heavy metals in the gangue. Furthermore, the contents of Cu and Pb in leaching solution and their release times in weathered gangue were significantly higher than those of the fresh one. This research provides a scientific basis for the prevention and control of heavy metal pollution in coal-containing areas.

Copper ecological risk assessment using DGT technique and PNEC: A case study in the Brazilian coast

Estuarine systems are vulnerable to metals stress, such as copper (Cu). Thus, the development of applicable tools to improve routine monitoring programs is increasingly necessary. In the present work a comprehensive Ecological Risk Assessment (ERA) was implemented by coupling the Measured Environmental Concentration (MEC), based on labile Cu (DGT) and the total dissolved Cu concentration. Additionally, toxicity data related to site-specific Predicted No Effect Concentration (PNEC) were used. As case study, estuarine areas were selected on Brazilian coast, previously reported as Cu release in shipyard areas. The results indicated an increase in concentrations of dissolved and labile Cu during the application of antifouling paints. In locations where more vessels in maintenance were found, the concentration of Cu-DGT exceeded the PNEC value (0.16 μg.L−1) and represented an important part of the total dissolved fraction (>93 %). The MEC/PNEC quotients, showed that shipyard areas represent a high ecological risk. Thus, it is highlighted the need for site-specific environmental assessments to manage complex ecosystems and set in environmental legislation. Consequently, the novel coupling of DGT technique and the derivation of a site-specific PNEC represent an easily applicable tool as an alternative to classical ERAs.