Nemerow Pollution Index Research Articles

Risk Assessment and Source Identification of Toxic Metals in the Agricultural Soil around a Pb/Zn Mining and Smelting Area in Southwest China.

Mining and smelting activities are the primary sources of toxic metal pollution in China. The purpose of this study was to investigate the pollution risk and identify sources of metals in the arable soil of a Zn/Pb mining and smelting district located in Huize, in Southwest China. Topsoil (346) and profile (three) samples were collected and analyzed to determine the total concentrations of eight toxic elements (Cd, Hg, As, Pb, Cr, Cu, Zn and Ni). The results showed that the mean Cd, Hg, As, Pb, Cr, Cu, Zn and Ni concentrations were 9.07, 0.37, 25.0, 512, 88.7, 239, 1761 and 90.3 mg/kg, respectively, all of which exceeded both the Huize and Yunnan soil background levels. Overall the topsoil was quite acidic, with a mean pH of 5.51. The mean geoaccumulation index (Igeo) revealed that the pollution level was in the order of Pb > Zn > Cd > Hg > As > Ni > Cu > Cr. The ecological risk index (Ei) indicated that there were serious contamination risks for Cd and Hg, high risk for Pb, moderate risk for As, and Cd and Hg were the dominant contributors to the high combined ecological risk index (Er) with a mean parameter of 699 meaning a serious ecological risk. The Nemerow pollution index (Pn) showed that 99.1% of soil samples were highly polluted or worse. Horizontally, high concentrations of Cd, Hg, As, Pb and Zn appeared in the north and middle of the study area, while Cr, Cu and Ni showed an opposite trend. Vertically, as the depth increased, Cd, Hg, As, Pb and Zn contents declined, but Cr, Cu and Ni exhibited an increasing trend. The mobilities of the metals were in the order of Zn > Cd > Hg > As > Pb. Horizontal and vertical distribution, coupled with correlation analysis, PCA and CA suggested that Cd, Hg, As, Pb and Zn mainly came from the anthropogenic sources, whereas Cr and Ni had a lithogenic origin. The source of Cu was a combination of the presence of parent materials as well as human activities. This study provides a base for the local government to control the toxic metal pollution and restore the soil environment system and an effective method to identify the sources of the studied pollutants.

Comprehensive assessment of soil quality for different wetlands in a Chinese delta

AbstractSoil quality is usually considered a powerful tool to reveal soil degradation status and wetland ecosystem health. It is insufficient to reflect actual soil quality based on soil fertility or heavy metal pollution assessment, respectively. A comprehensive assessment was performed to combine soil fertility and heavy metal contamination together, on the basis of 13 soil physical, chemical, biological indicators and six heavy metals, in the Pearl River Delta of China including urban river wetland (URW), ditch wetland (DW), riparian wetland (RiW), and reclaimed wetland (ReW). The moderate fertility level was observed according to the minimum data set, including total nitrogen (TN), microbial biomass carbon (MBC), total phosphorus, total potassium, sand, and salinity. DW soils had significantly higher soil fertility index values than RiW and ReW soils. Low TN, soil organic carbon (SOC), MBC levels, and sandy loam texture revealed potential chemical, biological and physical degradation risks, especially for ReW. In addition, wetland soils were heavily contaminated by heavy metals, particularly for Cd, according to Nemerow Pollution Index. URW soils exhibited significantly higher pollution levels than ReW soils. According to the methodology of comprehensive assessment, soil quality belonged to moderate and low grades because of severe heavy metal pollution, following with moderate nutrition level. Consequently, pollution treatment, fertility (e.g., SOC, N, P, and K), and soil texture improvement are crucial to improving soil quality, preventing further degradation and promoting ecological conservation and sustainability of coastal wetlands in the Pearl River Delta.

Assessment of Heavy Metals Contamination in Agricultural Soil of Southwestern Nile Delta, Egypt

ABSTRACTThe spatial and vertical distributions of heavy metals were quantitatively determined for organic-rich agricultural soils in the Southwestern Nile Delta. This study aims to undertake an assessment of heavy metals contamination in the soils of Quessna district using the inductively coupled plasma-optical emission spectroscopy, remote sensing, and geographic information system techniques. In this study, 24 soil samples were collected at 12 sites representing the main suburbs in the Quessna district. The concentrations of the studied metals decreased in the order of Zn > Cr > Pb > Cu > Ni > Co. The contamination degree and ecological risk assessment for metals in soil samples were evaluated using the enrichment factor, geoaccumulation index, improved Nemerow's pollution index, Pollution load index, and potential ecological risk index. The spatial and vertical distribution of heavy metals concentrations were affected by soil properties such as clay and organic matter content and scavenger metals (Fe and Mn). The intensive urbanization, industrial activity, and agricultural practices are thought to be the main anthropogenic sources of heavy metals contamination. Further studies especially human health risk assessment are recommended to investigate possible risks for humans from heavy metals in this area.

Spatial Variation of Heavy Metals in Soils and Its Ecological Risk Evaluation in a Typical Carya cathayensis Production Area

In recent years, the problem of soil pollution has become more and more serious. The problem of soil heavy metal pollution and its related human health risks has become a hot spot at home and abroad. Carya cathayensis is a unique high-grade woody nut and oil tree from China, and there are few reports on heavy metal pollution in Carya cathayensis plantation soils. Therefore, in order to study the spatial variability of heavy metals and the risk of pollution in Carya cathayensis soil and to promote the sustainable development of the Carya cathayensis industry, Lin'an, a typical Carya cathayensis plantation area, was selected for this study. A total of 188 soil samples were collected from the study area. We systematically studied the spatial heterogeneity of soil heavy metal content in the study area based on GIS technology, geostatistics, Moran's I, and other spatial analysis methods. The single factor pollution index method, the Nemerow comprehensive pollution index method, and the potential ecological risk assessment method were used to evaluate the heavy metal pollution in the study area. The results indicated that the mean content of soil cadmium (Cd), copper (Cu), zinc (Zn), lead (Pb), nickel (Ni), and chromium (Cr) were 0.37, 40.76, 87.61, 30.10, 28.33, 56.57 mg·kg-1, respectively. The average values of Cd and Cu were 1.33 and 2.87 times of the background values, respectively, and the average content of other heavy metals did not exceed the background values. The results of the single factor Nemerow pollution index and potential ecological risk assessment methods showed that heavy metals in the study area exceeded the soil background values in some samples, and the second grade standard of soil environmental quality was exceed for Cd, Cu, Zn, Pb, and Ni in 31.38%, 31.38%, 2.65%, 0.53%, and 17.02% of the samples, respectively. This indicated that the soils in the study area had different accumulation characteristics for Cd, Cu, Zn, Pb, Ni, and Cr, and the local soil had reached pollution levels for Cd, Cu, Zn, Pb, and Ni. Among them, Cd was the most serious, reaching the degree of strong ecological damage, followed by Cu. In general, the heavy metal contents indicated a moderate degree of ecological damage. Based on the analysis of the semi-variance function, the Cd, Cu, and Ni in the soil were best fit with exponential models, the Zn and Pb were better fit with the Gaussian model, and Cr was consistent with the spherical model. Cd, Cu, Pb, Ni, and Cr had the strong spatial autocorrelation, with Nugget/Sill ratios of 12.1%, 4.6%, 14.9%, 2.6%, and 11.2%, respectively, while the Nugget/Sill ratio of Zn was 48.8%, indicating a medium spatial autocorrelation. Moran's I and Kriging interpolation results found that the heavy metals Cd, Cu, Zn, Pb, Ni, and Cr all had obvious spatial distribution patterns and local spatial aggregation phenomena. The high values of heavy metals in soils were mainly found in Taiyang, Daoshi, Qingliangfeng, Heqiao, and Tuankou, and the probability of the risk for contamination by Cd and Cu was higher in the study area. The high values of Cd, Cu, Zn, Ni, and Cr were mainly related to mining, while Pb was closely related to the application of potassium.

Evaluation of Ceratophyllum demersum as the accumulative bioindicator for trace metals

Ceratophyllum demersum, an ubiquitous submerged aquatic plant, was tested as a passive bioindicator of trace metal pollution. The content and bioaccumulation ability of the wide range of trace metals (Ba, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Pb, Rb, Ti, V and Zn) in this species growing in areas with different type and intensity of anthropogenic activity was analyzed and a synthetic pollution index was calculated to assess the level and spatial distribution of trace metal contamination. The results of Bioaccumulation Factor exceeding index of 103 for Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Rb and Zn showed considerably high trace metal uptake ability of C. demersum and makes it a good metal accumulator. Moreover, multivariate statistics of trace metal content in C. demersum and the Nemerow Pollution Index allowed to indicate the type of land use in the surrounding of reservoirs: recreational; urban and agricultural; or urban with direct impact of industrial pollution. Plants growing in areas with agriculture, intensive housing and vehicle traffic contained significantly more Ba, Cd, Co, Cr, Cu, Fe, Li, Mn, Ni, Pb, Rb, Ti, V and Zn than plants from recreational areas, while the industrial areas distinguished from other urban areas by particularly high content of Li and Ti. The differences in level of pollution between study sites were highlighted by the Nemerow Pollution Index, which was proved to indicate silimar gradient of pollution for water and plants. Therefore, we concluded that the NPI could be a recommended tool helping to analyse ecological condition of the environment and C. demersum may be utilized as a relevant biomonitor of trace metal pollution in areas with diversified and multifactor man-made influence.

Assessing water quality for urban tributaries of the Three Gorges Reservoir, China

Abstract Water quality assessment is essential for water resources management. This paper presents a comprehensive evaluation of water quality conditions in three urban tributaries of the Three Gorges Reservoir, China. The Canadian Council of Ministers of the Environment Water Quality Index (CCME-WQI) and Nemerow Pollution Index (NPI) approach were used in this study. Generally, the assessment results of the NPI approach are consistent with that of the CCME-WQI approach. However, the NPI method overemphasized the influence of the most serious pollutant factor, and thus this method should be used with caution for water resources managers. The CCME-WQI values indicated that the water quality conditions in the Wubu River were quite good during the period 2013–2015. Water quality conditions in the upstream sections of Yipin and Huaxi River are good. However, when the river drains through urban areas, water quality conditions greatly deteriorate due to the excessive release of household and municipal sewage, and industrial wastewater, especially for Huaxi River. Thus, waste water management becomes more and more imperative in urban regions of China. Meanwhile, assessment results indicate that the CCME-WQI approach can provide a reference for decision-makers on water resources management.

Hydrochemical characteristics of surface water and ecological risk assessment of sediments from settlements within the Birim River basin in Ghana

BackgroundGeogenic and anthropogenic activities such as Artisanal and illegal gold mining continue to have negative impacts on the environment and river basins in China. This work studied the hydrogeochemical characteristics of surface water from the Birim River basin and assess the quality of water for human consumption and agricultural activities. In addition, the ecological risk assessment for Cd, Zn, Pb and As in sediment was evaluated using pollution indices.ResultsThe results show that the turbidity, temperature, colour and iron concentration in the water samples were above the World Health Organization guidelines. Multivariate analysis explained five components that accounted for 98.15% of the overall hydrogeochemistry and affected by anthropogenic and geogenic impacts. The surface water was observed to range from neutral to mildly acidic, with the dominance of HCO3−, Cl−, Ca2+, Mg2+, and Na+ in ionic strength. The Piper diagram reveals five major surface water types: Na–HCO3–Cl, Na–Cl–HCO3, Na–Ca–Mg–HCO3, Na–Ca–Mg–HCO3 and Ca–Na–Mg–HCO3. The Gibbs plot showed that the major ion chemistry of surface water was mostly influenced by atmospheric precipitation and the water quality index showed that the majority of the surface water from settlements within the Birim River basin were of poor quality for drinking and other domestic purposes. However, irrigation suitability calculations with reference to sodium adsorption ratio, residual sodium carbonate, and magnesium ratio values, together with Wilcox and USSL models indicated that the surface water within the area under study was suitable for agriculture. The potential ecological risk for single heavy metals pollution and potential toxicity response indices gave low to considerable ecological risks for the sediments, with greater contributions from Cd, Pb and As. Whilst geo-accumulation indices indicated that the sediments ranged from unpolluted to moderately polluted Modified degree of pollution and Nemerow pollution index calculations which incorporate multi-element effects, however, indicated no pollution.ConclusionThere are some levels of both potential ecological risks and health hazards in the study area. Hence continuous monitoring should be undertaken by the relevant agencies and authorities so that various interventions could be put in place to prevent the situation from deteriorating further in order to protect the inhabitants of the settlements within the Birim River basin.

Ecological Indices of the Heavy Metals in the Soil of Shewasoor Sub-Basin, Kirkuk NE Iraq

The current research aimed to assess contamination levels in the soil of study area by heavy metals. Eight sites were selected for the collection of soil samples. The eight heavy metals namely As, Pb, Cd, Cr, Co, Cu, Ni, and Zn were analyzed in each soil samples by using ICP-MS technology. The measured concentrations of heavy metals were compared with Geochemical Background values, EPA Sediment Quality Guidelines, Ecological Screening values, and WHO Guidelines. The spatial distribution maps of ecological indices were performed using ArcGIS software (version 10.2), which provides an idea of the geographical distribution of heavy metals contamination levels in the soil of Shewasoor sub-basin. The soil contamination by heavy metals assessed using Potential Ecological Risk Index (RI), Nemerow Pollution Index (P_N), Hazard Index (HI), and Cancer Risk. The RI showed there are high risk of heavy metals in soil and according to P_N the soil has been moderate to severely contaminated by heavy metals. The hazard index of all soil samples was within acceptable range for adults and showed unacceptable risk for children. While the total cancer risk values of As and Cr were within acceptable limits, whereas of Pb, Cd, Co, and Ni were lower than acceptable risk range at all sites for adults and children. Ecological indices which are used to assess the contamination levels in the soil by heavy metals refers to the soil of study area was contaminated moderate to heavily by heavy metals, this attributed to the natural and anthropogenic pollution sources around and within the study area.

Contamination source apportionment and health risk assessment of heavy metals in soil around municipal solid waste incinerator: A case study in North China

Few studies have comprehensively taken into account the source apportionment and human health risk of soil heavy metals in the vicinity of municipal solid waste incinerator (MSWI) in high population density area. In this study, 8 elements (Cr, Pb, Cu, Ni, Zn, Cd, Hg, and As) in fly ash, soil samples from different functional areas and vegetables collected surrounding the MSWI in North China were determined. The single pollution index, integrated Nemerow pollution index, principal component analysis (PCA), absolute principle component score-multiple linear regression (APCS-MLR) model and dose-response model were used in this study. The results showed that the soils around the MSWI were moderately polluted by Cu, Pb, Zn, and Hg, and heavily polluted by As and Cd. MSWI had a significant influence on the distribution of soil heavy metals in different distances from MSWI. The source apportionment results showed that MSWI, natural source, industrial discharges and coal combustion were the four major potential sources for heavy metals in the soils, with the contributions of 36.08%, 29.57%, 10.07%, and 4.55%, respectively. MSWI had a major impact on Zn, Cu, Pb, Cd, and Hg contamination in soil. The non-carcinogenic risk and carcinogenic risk posed by soil heavy metals surrounding the MSWI were unacceptable. The soil heavy metals concentrations and health risks in different functional areas were distinct. MSWI was the predominate source of non-carcinogenic risk with the average contribution rate of 36.99% and carcinogenic risk to adult male, adult female and children with 4.23×10−4, 4.57×10−4, and 1.41×10−4 respectively, implying that the impact of MSWI on human health was apparent. This study provided a new insight for the source apportionment and health risk assessment of soil heavy metals in the vicinity of MSWI.

Application of Nemerow Index Method and Integrated Water Quality Index Method in Water Quality Assessment of Zhangze Reservoir

[Objective] Based on the water quality historical data from the Zhangze Reservoir from the last five years, the water quality was assessed by the integrated water quality identification index method and the Nemerow pollution index method. The results of different evaluation methods were analyzed and compared and the characteristics of each method were identified.[Methods] The suitability of the water quality assessment methods were compared and analyzed, based on these results.[Results] the water quality tended to decrease over time with 2016 being the year with the worst water quality. The sections with the worst water quality were the southern and northern sections.[Conclusion] The results produced by the traditional Nemerow index method fluctuated greatly in each section of water quality monitoring and therefore could not effectively reveal the trend of water quality at each section. The combination of qualitative and quantitative measures of the comprehensive pollution index identification method meant it could evaluate the degree of water pollution as well as determine that the river water was black and odorous. However, the evaluation results showed that the water pollution was relatively low.The results from the improved Nemerow index evaluation were better as the single indicators and evaluation results are in strong agreement; therefore the method is able to objectively reflect the water quality of each water quality monitoring section and is more suitable for the water quality evaluation of the reservoir.

Ecological and health risks assessment and spatial distribution of residual heavy metals in the soil of an e-waste circular economy park in Tianjin, China

Ziya Circular Economy Park is the biggest e-waste recycle park in North China before 2011, its function was then transformed in response to regulations and rules. In this paper, investigation was conducted to research the residual concentrations of 14 analytes (12 heavy metals and 2 non-metals) in the surface soil of Ziya Circular Economy Park and surrounding area. Both ecological and health assessments were evaluated using GI (geo-accumulation index) and NPI (Nemerow pollution index), and associated health risk was assessed by using USEPA model. According to the ecological risk assessment, Cu, Sb, Cd, Zn and Co were seriously enriched in the soil of the studied area. The health risk assessment proposed by USEPA indicated no significant health risks to the population. Soil properties, such as pH and organic matter, were found to correlate with the enrichment of heavy metals. Arsenic concentrations in the soil were found positively correlated to dead bacteria concentrations. Spatial distribution of heavy metals revealed that Ziya Circular Economy Park was the dominant pollution source in the studied area. Findings in this study suggest that enough attention should be payed to the heavy metal pollution in Ziya Circular Economy Park.

Biomonitoring of nutrient and toxic element concentrations in the Sarno River through aquatic plants

The Sarno River is considered the most polluted river in Europe and one of the ten most polluted rivers in the world. So far, its quality has been usually evaluated by water and sediment analyses of either inorganic or organic pollutants. However, a biomonitoring approach would be of paramount importance in the evaluation of river quality, since it integrates pollutant temporal fluctuations, as in the case of discontinuous inputs from urban, industrial and agricultural activities. To this end, a passive biomonitoring study of the Sarno River was carried out, using two native aquatic plants accumulators of inorganic pollutants. The spring area was monitored analysing the roots of the semi-submerged Apium nodiflorum, whereas the whole river course was monitored analysing the shoots of the submerged Potamogeton pectinatus. The information on the four macronutrient (Ca, K, Mg, P), the six micronutrient (Cu, Fe, Mn, Na, Ni, Zn) and the four toxic element (Cd, Cr, Pb, V) concentrations were separately combined in the Nemerow Pollution Index. Results evidenced a severe pollution degree of the Sarno River, attributable to toxic elements > micronutrients > macronutrients. In particular, the spring area showed high K concentrations, as well as high concentrations of several micronutrients and toxic elements. A generalized Zn contamination and a progressive macronutrient (above all Ca and P), micronutrient (above all Ni, Cu and Fe) and toxic element (above all Cr and Pb) accumulation toward the mouth was related to pollution from agricultural and urban activities. Industrial sources, especially tanneries along the Solofrana tributary, accounted for high Mn concentrations, whereas the volcanic origin of the substrate accounted for a generalized V contamination.

Railway transportation as a source of soil pollution

Surface soil (0–10cm) samples from 60 sampling sites along the length of railway tracks on the territory of Srem (the western part of the Autonomous Province of Vojvodina, itself part of Serbia) were collected and analyzed for seven polychlorinated biphenyls (PCBs) and ten heavy metals in order to see how the distance from the railroad affects the concentration of some organic and inorganic pollutants in the soil. Samples were taken at a distance of 0.03–4.19km from the railway. For the soil extraction was used USEPA 3540S method. The extracts were purified on a silica-gel column (USEPA 3630C). The analysis of the extracts was performed by gas chromatography with tandem mass spectrometry. PCBs were not detected only at two locations. Mean total concentration of PCBs for all other sampling locations was 0.0043ppm dry weight (dw) with a range of 0.0005–0.0227ppm dw. According to values of Nemerow pollution index Cu, Co, Zn and Ni were the most ubiquitous heavy metals in the area near railroad. Based on these results, it can be said that railway transport is a potential source of PCBs and some heavy metals.

Analysis and Risk Assessment of Seven Toxic Element Residues in Raw Bovine Milk in China.

The object of this study is to analyze the levels of seven toxic elements residues in raw bovine milk in China and assess the potential health risk of those residues. The 178 raw bovine milk samples were collected from eight main milk-producing provinces and from three types of milk stations in China, and were analyzed for arsenic (As), lead (Pb), cadmium (Cd), chromium (Cr), mercury (Hg), aluminum (Al), and nickel (Ni) using inductively coupled plasma-mass spectrometry (ICP-MS). Al, Pb, Hg, Ni, Cr, and As were detected in 47.8, 29.2, 28.1, 23.6, 12.4, and 9.0% of total milk samples, respectively, and Cd were not detected in all samples. The raw bovine milk samples with high levels of toxic elements were found in industrial areas, such as Heilongjiang and Shanxi. Nemerow pollution index analysis showed that the levels were lower in the samples from the processing plants than that from the large-scale farms and small farm cooperatives. The margin of exposure (MOE) values suggest that the levels of As, Pb, Hg, Cr, Al, and Ni in the raw milk samples are not causing a health risk for Chinese consumers, including adults and children. Nevertheless, the risk of Pb for infant and young children was more serious than adult.

Erratum to: The Extent of Heavy Metal Pollution and Their Potential Health Risk in Topsoils of the Massively Urbanized District of Shanghai.

Urbanization and industrialization increase the concentrations of heavy metals in soils, which affect human health. A total of 127 topsoil samples were collected from the massively urbanized and industrialized district of Shanghai: Baoshan District. The sampling sites were isolated based on the land-use practice: industrial area, roadside area, residential area, and agricultural area. The absolute concentrations of heavy metals (Zn, Cr, Ni, Mn, Cu, Pb, and Cd) were determined using atomic absorption spectrometry and compared with Shanghai and the National soil background values. The geoaccumulation index (Igeo) and Nemerow pollution index were used to determine the existence and severity of the pollution of heavy metals. Enrichment factor (EF) analysis, spatial variability of pollution, and multivariate statistical analyses also were employed to determine the anthropogenic loading of heavy metals, their spatial dependency, and correlation among their sources, respectively. Moreover, potential ecological risk and human health risk [carcinogenic risk (RI) and noncarcinogenic hazard (HI)] were evaluated. The average concentration of all the metals (accounted as 229, 128, 56, 719, 55, 119, and 0.3 mg kg-1 for Zn, Cr, Ni, Mn, Cu, Pb, and Cd, respectively) was many folds higher than the background values. The indices depicted that the pollution exists in all the sites and severity decreases in the following order: industrial soils > roadside soil > residential soils > agricultural soils. However, Zn, Pb, and Cd showed high levels of pollution in all the soils. The EF values suggested that the majority of heavy metals are anthropogenically loaded; spatial variability showed that the pollution is more concentrated in Songnan town; Pearson's correlation, principal component analysis (PCA), and cluster analysis suggested different sources of origin for the majority of the heavy metals. RI of Cr and Pb ranged between 2.8E-04 and 2.7E-07. However, HI was site-specific (only for Cr, Pb, Mn), and most of the sites were in Songnan town. This study could be used as a significant piece of information for management purposes to prevent heavy metal pollution and to protect human health.

The Extent of Heavy Metal Pollution and Their Potential Health Risk in Topsoils of the Massively Urbanized District of Shanghai.

Urbanization and industrialization increase the concentrations of heavy metals in soils, which affect human health. A total of 127 topsoil samples were collected from the massively urbanized and industrialized district of Shanghai: Baoshan District. The sampling sites were isolated based on the land-use practice: industrial area, roadside area, residential area, and agricultural area. The absolute concentrations of heavy metals (Zn, Cr, Ni, Mn, Cu, Pb, and Cd) were determined using atomic absorption spectrometry and compared with Shanghai and the National soil background values. The geoaccumulation index (Igeo) and Nemerow pollution index were used to determine the existence and severity of the pollution of heavy metals. Enrichment factor (EF) analysis, spatial variability of pollution, and multivariate statistical analyses also were employed to determine the anthropogenic loading of heavy metals, their spatial dependency, and correlation among their sources, respectively. Moreover, potential ecological risk and human health risk [carcinogenic risk (RI) and noncarcinogenic hazard (HI)] were evaluated. The average concentration of all the metals (accounted as 229, 128, 56, 719, 55, 119, and 0.3mgkg-1 for Zn, Cr, Ni, Mn, Cu, Pb, and Cd, respectively) was many folds higher than the background values. The indices depicted that the pollution exists in all the sites and severity decreases in the following order: industrial soils>roadside soil>residential soils>agricultural soils. However, Zn, Pb, and Cd showed high levels of pollution in all the soils. The EF values suggested that the majority of heavy metals are anthropogenically loaded; spatial variability showed that the pollution is more concentrated in Songnan town; Pearson's correlation, principal component analysis (PCA), and cluster analysis suggested different sources of origin for the majority of the heavy metals. RI of Cr and Pb ranged between 2.8E-04 and 2.7E-07. However, HI was site-specific (only for Cr, Pb, Mn), and most of the sites were in Songnan town. This study could be used as a significant piece of information for management purposes to prevent heavy metal pollution and to protect human health.

Shallow groundwater quality assessment: use of the improved Nemerow pollution index, wavelet transform and neural networks

Shallow groundwater is generally of great interest to the community due to its easy availability. However, it is very sensitive to external stimulus. In this paper, shallow groundwater quality is assessed and classified with improved Nemerow pollution index, multi-layer perceptron artificial neural network (MLP-ANN) optimized with a back-propagation algorithm and wavelet neural network (WNN) methods in a coastal aquifer, Fujian Province, South China. The data used in three models were collected during the pre-monsoon over the period 2004–2011. The eight parameters, total dissolved solids, total hardness, chemical oxygen demand, chloride, sulphate, nitrate, nitrite and fluorides, were selected to characterize groundwater quality classification based on the National Quality Standard for Groundwater (GB/T 14848-93). The results of MLP-ANN and WNN are interpreted by mean absolute error, root mean square error and R2 (determination coefficient) criteria. The results obtained from three methods demonstrate that WNN has a higher accuracy compared with the other two methods. The study reveals that these methods are efficient tools for assessing groundwater quality.

Contamination, ecological risk and source apportionment of heavy metals in sediments and water of a contaminated river in Taiwan

Houjing River, located in Kaohsiung City, is one of the most seriously contaminated rivers in Taiwan. This study analyzed the concentrations of heavy metals (As, Cd, Cr, Cu, Pb, Ni, Zn and Hg) in sediments and water samples collected from this river. Analysis of contamination factor (Cfi) and potential ecological risk factor (Efi) of heavy metals in water showed that there were low grades of contamination and potential ecological risk for all heavy metals, suggesting that heavy metals in water were less likely to pose risks to the ecosystem. However, sentiment samples were found to have severe contamination levels based on ranges found in sediment quality guidelines (SQG). The average Cu concentration was almost twice as high as the upper standard values in all the guidelines. Multi-element indices were used to evaluate the synergistic effects of different metals at the sampling sites. The calculated results of different indices, the modified degree of contamination (mCd), Nemerow pollution index (PN) and potential ecological risk index (RI), were in good accordance. ‘Heavy’ contamination and ‘severe’ ecological risk were found at three sites, Demin, Zhuwai and Renwu. Cadmium and copper contributed the highest to the ecological risk there. Results of positive matrix factorization modeling identified four sources of heavy metal pollution in both sediments and water. Heavy metal contamination in the Houjing River is attributed to companies carrying out various industrial processes along the riverbank, including traditional metal-plating, plastic manufacture and semi-conductor packaging. Therefore, future pollution control and management plans should emphasize the strict regulation of discharge from these industrial activities.

Multivariate statistical and lead isotopic analyses approach to identify heavy metal sources in topsoil from the industrial zone of Beijing Capital Iron and Steel Factory.

Heavy metals are considered toxic to humans and ecosystems. In the present study, heavy metal concentration in soil was investigated using the single pollution index (PIi), the integrated Nemerow pollution index (PIN), and the geoaccumulation index (Igeo) to determine metal accumulation and its pollution status at the abandoned site of the Capital Iron and Steel Factory in Beijing and its surrounding area. Multivariate statistical (principal component analysis and correlation analysis), geostatistical analysis (ArcGIS tool), combined with stable Pb isotopic ratios, were applied to explore the characteristics of heavy metal pollution and the possible sources of pollutants. The results indicated that heavy metal elements show different degrees of accumulation in the study area, the observed trend of the enrichment factors, and the geoaccumulation index was Hg>Cd>Zn>Cr>Pb>Cu≈As>Ni. Hg, Cd, Zn, and Cr were the dominant elements that influenced soil quality in the study area. The Nemerow index method indicated that all of the heavy metals caused serious pollution except Ni. Multivariate statistical analysis indicated that Cd, Zn, Cu, and Pb show obvious correlation and have higher loads on the same principal component, suggesting that they had the same sources, which are related to industrial activities and vehicle emissions. The spatial distribution maps based on ordinary kriging showed that high concentrations of heavy metals were located in the local factory area and in the southeast-northwest part of the study region, corresponding with the predominant wind directions. Analyses of lead isotopes confirmed that Pb in the study soils is predominantly derived from three Pb sources: dust generated during steel production, coal combustion, and the natural background. Moreover, the ternary mixture model based on lead isotope analysis indicates that lead in the study soils originates mainly from anthropogenic sources, which contribute much more than the natural sources. Our study could not only reveal the overall situation of heavy metal contamination, but also identify the specific pollution sources.

Heavy metals pollution assessment in correlation with magnetic susceptibility in topsoils of Shanghai

This study investigated the heavy metal accumulation, magnetic susceptibility, and their correlation in urban soils of Baoshan District, Shanghai. A total of 127 topsoil samples were collected from industrial (n = 28), roadside (n = 38), residential (n = 21), and agricultural (n = 40) areas. The absolute concentration of heavy metals: lead (Pb), zinc (Zn), chromium (Cr), nickel (Ni), cadmium (Cd), and copper (Cu), was measured using an atomic absorption spectroscopy (AAS). Nemerow pollution index was applied to estimate the pollution level in respective areas. The results showed an excess of heavy metals in the urban topsoil of Baoshan District, among which, Pb, Zn, and Cd were most prominent. The average values of Pb, Zn, and Cd were obtained as 118.5, 228.6, and 0.56 mg kg−1, respectively, which are 5.6, 3.0, and 2.8 times higher than the Shanghai soil background values. Kriging interpolation was employed (according to the pre-evaluated fitted model variogram values of nugget, sill, and range) to assess the spatial distribution of heavy metals. Kriging interpolation depicted that the industrial sites were heavy metal-centric locations. Complimentary to AAS detection method, magnetic susceptibility tool was also applied to evaluate the presence of magnetic particles and their correlation with heavy metals. The magnetic susceptibility of the topsoil in Baoshan District was 148 × 10−8 m3 kg−1, which is ~5 times higher than the background value of Shanghai soil (29.1 ± 9.8 × 10−8 m3 kg−1). In most of the samples, the percentage frequency-dependent magnetic susceptibility (χ fd%) values in the topsoil of Baoshan District were less than 4%, suggesting the absence of pedogenic ultrafine superparamagnetic grains and the presence of anthropogenic multidomain and stable single domain grains. A significantly positive correlation (industrial: r = 0.81, P < 0.01; roadside: r = 0.65, P < 0.01; residential: r = 0.56, P < 0.01; agricultural: r = 0.6, P < 0.01) was found between magnetic susceptibility and heavy metal pollution irrespective of the type of anthropogenic activities at a particular land. The results suggested the reliability of magnetic susceptibility measurement to interpret the heavy metal pollution of the soils.