Pollution Index Evaluation Research Articles

Nexus between potentially toxic elements’ accumulation and seasonal/anthropogenic influences on mangrove sediments and ecological risk in Sundarbans, Bangladesh: An approach from GIS, self-organizing map, conditional inference tree and random forest models

Mangroves play a vital role in protecting the coastal community from the climate change effect and in the restoration of the coastal ecosystem. This research has been designed to determine the spatial and seasonal changes of potentially toxic elements’ (PTEs) concentration in sediments and their potential source contribution among the different human-driven processes in Sundarbans, Bangladesh. Different pollution evaluation indices, random forest (RF) model, conditional inference tree (CIT), self-organizing map (SOM), geographical information system (GIS), and principal component analysis (PCA) were used for the interpretation of sources and risk assessment of PTEs. The mean concentration of PTEs both in winter and monsoon seasons has fallen below the threshold effect level but exceeded the rare effect level of marine sediments quality standards. Results showed that the PTEs were significantly enriched (EF > 1.00 < 70.00) in sediments, whereas the Cd enrichment (7.00% samples) was very alarming (EF = 60–70). Except for Zn and Cd, other PTEs were enriched in 30–60% samples. The highest geoaccumulation and contamination factors for Cd were observed in 46–72% of samples. The ecological risk (ER) factors showed similar results where Cd showed strong to very strong factors (ER = 110–2218) in 80% of samples. The CIT explained the natural/geogenic and anthropogenic sources of pollution, where the higher CIT values for Cd indicated industrial, aquaculture, and coal-based thermal powerplant. The RF model provided that shrimp firms, power plants, industry, and seaport were recognized as the influential sources for Zn, Pb, Cr, Cd, and As in sediments. Though Pb and As were found as the most significant pollutants, Cd was identified as a severe threat to ecology and public health. Based on CIT, RF, SOM and PCA the order of PTEs in mangroves sediment were:industrial/urban > aquaculture/shrimpfirm > powerplant > seaportoperation > tourism > geogenic/natural. The present study will help the policymakers for effective and sustainable management of the mangrove ecosystem.

Evaluation of pollution indices in Gold Mining communities in the Central Region of Ghana

Evaluation of pollution indices in Gold Mining communities in the Central Region of Ghana

Arsenic, iron, and manganese in groundwater and its associated human health risk assessment in the rural area of Jashore, Bangladesh.

This study investigated groundwater pollution and potential human health risks from arsenic, iron, and manganese in the rural area of Jashore, Bangladesh. Study results show that the mean value of groundwater pH is 7.25 ± 0.31, with a mean conductivity of 633.94 ± 327.41 μs/cm, while about 73, 97, and 91% of groundwater samples exceeded the Bangladesh drinking water standard limits for As, Fe, and Mn, respectively. Groundwater pollution evaluation indices, including the heavy metal pollution index, the heavy metal evaluation index, the degree of contamination, and the Nemerow pollution index, show that approximately 97, 82, 100, and 100% of samples are in the high degree of pollution category, respectively. Spatial distribution exhibited that the study area is highly exposed to As (73%), Fe (82%), and Mn (46%). In the case of non-carcinogenic health risk via oral exposure, about 94% of samples suggest a high category of risk for infants, and 97% of samples are found to be at high risk for children and adults. The carcinogenic risk of arsenic via an oral exposure pathway suggests that approximately 97% of the samples are found to be at high risk for infants, and all of the samples are at high risk for both adults and children.

Assessment of the Anthropogenic Impact and Distribution of Potentially Toxic and Rare Earth Elements in Lake Sediments from North-Eastern Romania.

Chemical analysis was performed on sediment samples collected in two sampling sessions (July and October) from Podu Iloaiei Dam Lake, one of the most important water resources used for aquaculture in north-eastern Romania. The concentration of 15 trace elements (TEs), 8 refractory elements (REs), and 15 rare earth elements (REEs)—determined using inductively coupled plasma mass spectrometry—showed variability largely dependent of the sampling points and collection time. Manganese was the most abundant TE, V and Cr were the most abundant REs, while Ce was one of the most abundant REEs. The cerium negative anomaly and Gd positive anomaly were observed in the Chondrite-normalized distributions. In October, the Ce anomaly showed significant negative correlation with Mn, emphasizing the water body oxidation potential. The identified positive Gd anomaly was most likely associated with the use of Gd-chelating agents in magnetic resonance imaging in Iasi, the largest medical hub in north-eastern Romania. Principal component analysis extracted three factors explaining 96.0% of the observed variance, i.e., rock weathering, leaching from soil surface, contributions from urban stormwater and atmospheric deposition (50.9%), pedological contributions (23.7%), and mixed anthropogenic sources (e.g., traffic, waste discharge, agricultural activities; 21.4%). The evaluation of pollution indices highlighted low and moderate degrees of contamination for most of the elements and a considerable degree of contamination for Cd. Assigned Cd sources included fertilizers and pesticides used in the near agricultural areas or the high traffic road located near the lake. Since contamination of aquatic ecosystems with harmful elements is a human health concern, further monitoring of specific vectors in the food chain of the investigated dam lake will be of the utmost importance.

Spatial Distribution and Influential Factors of Nutrients in Rivers of a Typical Mountainous City: A Case Study of the Qingshuixi River in Chongqing

Surface water pollution seriously restricts the development of the city and results in the citizens yearning for a better life. Mountainous cities have their own characteristics in surface water environment and pollution compared with those of plain cities due to their unique topography. In August and October 2019, surface water and sediments were collected in a typical river (Qingshuixi River) in the main urban area of Chongqing. These samples were analyzed for nutrients such as carbon, nitrogen, and phosphorus as well as other basic physicochemical indicators. The results showed that the surface water of the Qingshuixi River was inferior to Category V at present, and it was also at a serious pollution level according to the comprehensive pollution index evaluation system. Among all the water quality indices, NH4+ and TP showed the most serious pollution. The tributaries of the Qingshuixi River exhibited higher surface water quality than that of the main stream, and the water quality during the rainfall season was better than that during the non-rainy season. Pollution sources, tailwater/tributary inflow, and river self-purification capacity determined the spatial distribution of nutrients in the surface water of the mainstream of the Qingshuixi River. Point sources such as the direct discharge of source sewage and pollution overflow in the middle and lower reaches were the most important sources of surface water pollution in the mainstream of the Qingshuixi River. Non-point source pollution had a limited impact on water quality. The "sink" or "source" role transformation of river sediments would occur under different water volume conditions in the river, reflecting the complexity of endogenous pollution. Surface water quality of the main stream showed a gradual improvement tendency along the downstream due to the dilution of the tail water/tributary inflow and the increased self-purification capability of the surface water in the mountainous rivers due to the increased DO content. To summarize, this study suggests that the water environment of the Qingshuixi River should be improved in comprehensive ways, which might be reducing the input of point source pollution by the deployment of the municipal pipe network in key areas, upgrading the sewage treatment plants to decrease pollutant concentrations or fluxes or channel dredging at the reaches with low DO content, etc.

Evaluation of pollution indices, health hazards and source identification of heavy metal in dust particles and storm trajectory simulation using HYSPLIT model (Case study: Hendijan center dust, southwest of Iran)

Atmospheric dust is one of the most recent environmental pollutions in Iran. This study examines the concentration of heavy metals and the assessment of environmental and human health risk in the dust samples of Hendijan region as one of the most important centers of wind erosion in the southwestern of Iran. ICP-MSS analysis was performed on 18 samples of fine dust to specify the concentration of heavy metals. Studies showed that the highest concentrations of metals in these fine dust samples belong to Cr, Ni, Zn, Cu, As, Pb and Cd, respectively. Examining fine dust's pollution assessment showed that the highest enrichment and geo-accumulation index belong to As, Ni and Cr metals. Environmental risk assessment shows the low environmental risk of these fine dusts. The hazard quotient in children and adults belongs to Cr, As and Ni, respectively. Human health risk assessment also showed that the highest absorption of metals in both children and adults is through ingestion. The non-carcinogenic risk of heavy metals of dust samples in children is about 9 times more than adults. The highest risk of cancer in the adult group belongs to Ni metal and in the group of children belongs to As and Ni metal. PCA analysis showed that As, Cu, Cd, Cr and Ni are of anthropogenic origin and Zn and Pb are of geogenic origin. The source of the dust phenomenon with the HYSPLIT model and the backward method indicates the tracking of this dust mass through Iraq, and its probable origin was assessed in the centers of northern Iraq and southeastern Syria.

Spatial Distribution and Pollution Assessment of Dissolved Heavy Metals in Chaohu Lake Basin During the Wet Season

The spatial distribution characteristics of the mass concentration of V, Cr, Mn, Ni, Cu, Zn, Pb, Cd, Fe, and Sb in the Chaohu Lake basin and ten surrounding rivers during the wet season were explored. The results showed that the average mass concentration of heavy metals in the western and northwestern Chaohu Lake surrounding rivers was higher than that in the central and eastern regions. The correlation analysis showed a significant positive correlation between the concentrations of Cu, Ni, Zn, Pb, and Cd, which indicated a similarity of spatial distribution among the five elements. The single-factor pollution index evaluation results classified Cr in the ten surrounding rivers as Grade I based on the Environmental Quality Standards for Surface Water. Pb was classified as Grade Ⅰ-Ⅱ; Cu and Zn as Grade Ⅰ-Ⅴ; Fe, Sb, and V were far below the standard limit; Ni slightly exceeded the standard at some sampling points of the Nanfei River; Mn slightly exceeded the standard at some points of the Shiwuli and Pai River; Cd exceeded the standard at some points of the Nanfei River. Except Mn at one point of the Tangxi River, V, Cr, Ni, Cu, Zn, Pb, and Fe were all<1, which indicated clean and pollution-free level. The integrated pollution index of the rivers surrounding the lake in the northwestern part was the highest compared to the southwestern, central, and eastern parts.

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.

Spatial and Temporal Distribution and Pollution Evaluation of Soluble Heavy Metals in Liujiang River Basin

In the Liujiang River, soluble heavy metals Zn, Al, Co, As, Ni, Cr, Cu, Mn, Pb, Hg, and Cd were monitored day and night to determine their temporal and spatial distribution as well as the sources of this pollution. The Nemerow comprehensive pollution index method was then used to evaluate the environmental quality of the Liujiang River water body. The results showed that: ① For each river section (Lutang and Luowei), the amounts of soluble Al, Co, As, Ni, Cr, Mn, Pb, and Cd all met the Class Ⅲ water quality standard limit, as defined in the National Surface Water Quality Class Ⅲ Standard. The concentration of Zn and Cu was far below the standard limit, while the Hg content slightly exceeded the standard; the concentration of heavy metals in Liujiang River basin was highest in the normal season and lowest in the wet season. In terms of spatial distribution, the Luowei section had a higher heavy metal concentration. ② The single factor pollution indexes for elemental Hg, Cd, and As were higher in the Liujiang River basin. The Nemerow comprehensive pollution index evaluation shows that the risk of heavy metal pollution in the water body exhibits certain seasonal variations (March > November > June), indicating that rainfall in different seasons may result in reduced drinking water safety in the study area. The water of the Lutang and Luowei sections generally exhibited a moderate level of heavy metal pollution. The comprehensive pollution index of the Luowei section was higher than that of the Lutang section, and the pollution level was relatively severe. Therefore, the Luowei section should be listed as a priority control section of the Liujiang River basin by the water environment management department; ③ After assessing the difference in heavy metal pollution between annual and monthly rainfall periods, it was found that the selection of rainy season or conventional season has no significant impact on the assessment of heavy metal pollution in rivers, when the mass concentration of Cu in the river is used. However, the presence of As, Mn, Pb, Al, Cr, and Ni elements in the river will cause significant differences in the evaluation of heavy metal pollution on an interannual scale; ④ Multivariate statistical analysis results show that Cd, Cr, Ni, Co, and Pb in the Liujiang River are mainly derived from industrial production activities; As and Zn are mainly derived from rainwater leaching of domestic pollution waste; Mn, Al, and Cu are mainly derived from the application of pesticides and fertilizers.

Evaluation of Ecological Environmental Pollution in Green Building Construction

The long-term extensive development mode of China’s construction industry has resulted in the enormous consumption of energy resources, increasingly severe environmental pollution, and serious ecosystem degradation. Green construction is an essential route to implement the ecological civilization construction policy and achieve green building in China’s construction industry. However, enormous environmental pollution has been generated because of a series of problems in China’s green building construction, such as the lack of a scientific evaluation system for green building construction, loose field construction management, and weak awareness of environmental protection among constructors. Therefore, in this study, a pollution evaluation index system for green building construction was established from three aspects, namely, resource utilization, environmental load, and environmental management, to evaluate the class of ecological environmental pollution triggered by green building construction. Next, a model combining the analytic hierarchy process (AHP) and fuzzy comprehensive evaluation was built, followed by a case study. The results revealed that resource utilization was the main factor causing ecological environmental pollution in green building construction, accounting for 63.70%. Energy conservation and application of new pollution control technology were level III factors that should be given considerable attention. In the fuzzy comprehensive evaluation, the degree of membership of “good” was 0.4855, which was the maximum, indicating that the ecological environment of green building construction in this study was at “good” level, thereby indicating the environmental friendliness of green building construction. This study will be of positive reference values for identifying the ecological influencing factors of green building construction, reducing the waste of resources of green buildings, promoting green construction technologies, and innovating green con

Pollution and Health Risk Assessment of Heavy Metals in Farmlands and Vegetables Surrounding a Lead-Zinc Mine in Yunnan Province, China

ABSTRACT To investigate the contaminant characteristics of heavy metals in soils and vegetables surrounding a lead-zinc mine in Huize County, Yunnan Province, thirty surface soil samples and vegetable samples were collected to measure the contents of heavy metals, including lead (Pb), zinc (Zn), copper (Cu), and cadmium (Cd). The potential risk was evaluated by using the single factor pollution index, Nemerow comprehensive pollution index, and target hazard index. The results showed that the contents of Pb, Zn, Cu, and Cd in the soil were 954.1, 2236.5, 151.1, and 4.83 mg·kg−1, respectively. Compared with the soil background values in Yunnan Province, the soil surrounding the lead-zinc mine was polluted by Pb, Zn and Cd. The Nemerow comprehensive pollution index evaluation indicated that the soil was heavily polluted. The contents of Pb, Zn, Cu, and Cd in vegetables were 117.5–778.6, 430.3–2212.4, 16.8–89, and 1.28–34.3 mg·kg−1, respectively. Among them, the contents of Pb and Cd in vegetables exceeded the pollutant limit in food products of China’s National Standard for Food Safety (GB 2762–2017). The contents of Pb, Zn and Cd in the soil were extremely significantly or significantly correlated with the contents of Pb, Zn and Cd in the edible parts of vegetables. The results indicated that there was serious heavy metal pollution and significant health risk for the soil and vegetables surrounding the lead-zinc mine. The research results not only reveal the contaminant characteristics of heavy metals in soils and vegetables surrounding a lead-zinc mine in Huize County, Yunnan Province, but also could provide a scientific evidence for reasonable utilization and ecological remediation.

Water quality assessment, multivariate analysis and human health risks of heavy metals in eight major lakes in Kenya

This study evaluates water quality, concentrations and health risks of heavy metals (HMs) in eight major lakes in Kenya namely Naivasha, Elementaita, Nakuru, Baringo, Bogoria, Turkana, Victoria and Magadi. Water quality was assessed using water quality index (WQI) and pollution evaluation index (PEI), while human health risk associated with ingestion and dermal contact of HMs was assessed using hazard quotients (HQ) and hazard index (HI). Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to deduce the probable sources of the HMs. The average concentration of aluminium (Al), molybdenum (Mo), manganese (Mn), nickel (Ni), arsenic (As), zinc (Zn), selenium (Se), lead (Pb), chromium (Cr), mercury (Hg), cobalt (Co) and cadmium (Cd) in the eight lakes was 824.6, 66.1, 58.9, 16.2, 8.40, 7.84, 6.91, 4.65, 2.66, 0.86, 0.78 and 0.46, respectively, all in μg/L. Al, Mn, As, and Mo were relatively high in Rift Valley lakes and exceeded the maximum permissible levels for drinking water. Notably, high HM concentrations were recorded at the entry points of rivers and areas with high human activities. Lake Magadi had the highest average WQI of 158.8 followed by lake Elementaita (128.4), Bogoria (79.5), Nakuru (73.3), Turkana (57.6), Victoria (52.3), Baringo (42.6) and Naivasha (25.5). Lake Magadi also had the highest average PEI of 40.0 followed by Elementaita (30.1), Bogoria (16.2), Nakuru (15.7), Victoria (10.8), Baringo (9.57), Turkana (9.53) and Naivasha (5.12). Based on WQI, Lake Naivasha water was excellent for drinking, Lake Victoria, Turkana, Baringo, Nakuru, and Bogoria had good water, but water from Lake Elementaita and Magadi was of poor quality. PEI classified the lakes as minimally polluted except Lake Magadi. Multivariate analysis concluded that Pb, Cr, Ni and Se had anthropogenic sources, mainly agricultural and urban runoff, but other HMs had natural influence. Although the HMs did not pose any health risks through dermal contact, HQingestion was >1 for adults and children consuming water from Lake Elementaita, Nakuru, Bogoria and Magadi due to non-carcinogenic risks associated with As, Zn and Mo. These results are important for formulating the necessary remediation policies to improve water quality in the eight lakes.

Impact of heavy metals on water quality and indigenous Bacillus spp. prevalent in rat-hole coal mines.

The present study reports pollution evaluation indices employed to assess the intensity of metal pollution in water systems affected by acid mine drainage from rat-hole coal mines prevalent in North-east India. The concentration of seven eco-toxic metals was evaluated from coal mine waters which showed concentration order of Iron (Fe) > Manganese (Mn) > Zinc (Zn) > Chromium (Cr) > Lead (Pb) > Copper (Cu) > Cadmium (Cd). The water samples were acidic with mean pH 2.67 and burdened with dissolved solids (924.8mg/L). The heavy metal pollution index (HPI) and heavy metal evaluation index (HEI) displayed high and medium range of pollution level in majority of the water samples. Statistical correlation suggested strong positive correlation between metals such as Cr with Mn (r = 0.780), Mn with Fe (r = 0.576), Cr with Fe (r = 0.680), Pb with Mn (r = 0.579) and Cr with Pb (r = 0.606), indicating Mn, Pb, Fe and Cr to be major metal contaminants; an unequivocal affirmation of degradation in water quality. The sampled waters had lower heavy metal concentration during monsoon and post-monsoon seasons. The commonly occurring bacterial species Bacillus pseudomycoides and Bacillus siamensis were chosen to understand their behavioral responses toward metal contamination. Findings demonstrated that Bacillus spp. from control environment had low tolerance to metals stress as evident from their MTC, MIC and growth curve studies. The survival of the native isolates across varying pH, salinity and temperature in the coal mine areas suggest these isolates as promising candidates for reclamation of rat-hole coal mining sites.

Soil Contamination Assessment by Trace Elements in Barapukuria Coal Mine Region, Bangladesh

Coal mining areas in Bangladesh are exposing to extreme environmental problems due to the mobilization of heavy metals in the surrounding region. To assess the persisting risk, several soil samples were collected from the nearby coal mine areas. The amount of pollution of heavy metal has been calculated to determine the extent of the contamination. Soil contamination assessment was carried out using pollution evaluation indices such as heavy metal pollution index (HPI), the degree of contamination (Cd), and the contamination factor (CF). The concentration of S, As, Ba and, F exceeded the maximum concentration level in some soil samples. The HPI and the Cd yield similar results. The CF shows strong similarities with the Cd and gives a better evaluation of pollution levels. HPI indicates that about 71.42% of samples exceed the high level. Cd and CF show that about 71.42% sample is highly contaminated by trace element and 14.28% sample is highly contaminated by S, Cl, and F. Based on radioactive element analysis about 14.28% samples show medium contamination level. The findings of this research help us to assess the level of soil contamination and the extent of environmental and health concerns in the region of the Barapukuria coal mine.

Assessment of arsenic and its associated health risks due to mining activities in parts of North-central Nigeria: Probabilistic approach using Monte Carlo

This study evaluates health risks associated with Arsenic due to mining activities in parts of North-central Nigeria. 306 samples of soil, water and guinea corn were collected for analysis using Atomic Absorption Spectrometry. The analysis reveals varying concentration of Arsenic that is in most cases, above the acceptable limits of consumption, signifying evidence of pollution. The estimated pollution evaluation indices indicates evidence of pollution due to the mining activities. The estimated values of the bioaccumulation factors are very low. The Average Daily Intake reveals that ingestion pathway is the dominant pathway of exposure. While most of the Hazard Index (HI) estimated for the soil and grain samples are « 1, the HI estimated for the water is ≈1. This therefore, means that the probable non-cancerous effect of Arsenic in the drinking water is high. Based on the Delphii method of classification, the Incremental Lifetime Cancer Risk ranges between level II and level III for the soil and grain samples and between level VI and level VII for the water samples within the study sites. This high cancer risks was confirmed by the mean, 5th and 95th percentiles of the cumulative probabilities using the Monte Carlo simulation.

Appraisal of pollution scenario, sources and public health risk of harmful metals in mine water of Barapukuria coal mine industry in Bangladesh

This study was conducted to assess the accumulation and sources of harmful metals and associated public health risk from the usage of underground mine water of Barapukuria coal mine in Bangladesh, keeping in mind the optimum reuse. Thirty underground mine water samples had been analyzed for assessing temperature, pH, EC, TC, DO, BOD, COD, Ca, K, S, Ti, Mn, V, Fe, Co, Ni, Cu, Zn, Br, Rb, Sr, and Pb. Numerous pollution evaluation and health risk assessment indices along with multivariate statistical tools were employed in this study to apprise the pollution scenario, controlling factors, and probable health risk. The chronic or persistent health risk of metals via oral and dermal exposure of adults and children was determined using the hazard quotient (HQ) and hazard index (HI). The results showed that the content of physicochemical parameters and potentially harmful elements in water samples was many folds higher than the national and international standards. The results of pollution evaluation indices indicate that coal seam-leached mine water is highly concentrated by potentially harmful metals and not suitable for drinking, agriculture, and aquatic lives. The correlation coefficients and multivariate analysis illustrate both the geological and anthropogenic factors controlling the variability of metals in mine water. Results of HQoral value suggest that V, Co, and Pb are significant health risk for adults and Mn, V, Co, Cu, and Pb are for children. Vanadium is found potential for dermal effects, and HIdermal value directs 33%, and 70% samples exceed the safe limit for adults and children, respectively. The HI value suggests that oral exposure to harmful metals creates more harm than dermal absorption, and children are more vulnerable than adults. It is anticipated that the outcomes of this study would deliver expedient insights to initiate necessary steps to minimize the public health risk by applying appropriate environmental protocols.

Daily water quality evaluation of reservoir and cyanobacteria pollution index calculation

Abstract Water quality evaluation is the most direct and quantitative description of a reservoir water environment. Due to the lack of biological factor evaluation in water quality evaluation at present, the conventional pollution index evaluation system was used to evaluate water quality and the correlation between the evaluation indexes and the concentration of cyanobacteria was studied. After determining the correlation, a novel calculation method using the cyanobacteria pollution index was determined by principal component analysis (PCA). The results showed that the eutrophication index and nitrogen phosphorus index of the water body were high. Biological pollution in reservoirs cannot be ignored. The correlation between eutrophication index and cyanobacteria concentration was weak (Pearson correlation = 0.242). For the reservoir, it was necessary to establish a special cyanobacteria pollution index. Five variables were used for the cyanobacteria pollution index calculation by the PCA method. The total variance of the two main components was 77.107%, which reflected most of the data information. In the reservoirs of other areas, similar parameters can also be selected to calculate the cyanobacteria pollution index. This research provides a reference for the biological factor evaluation of similar reservoirs in the world.

Assessment of heavy metal pollution in groundwater of an industrial area: a case study from Ramgarh, Jharkhand, India

ABSTRACT In the present study, pollution evaluation indices were carried out to assess the intensity of pollution in Marar industrial area of Ramgarh in Jharkhand. Fifteen groundwater samples were collected from the study area in May 2016. The physicochemical parameters (pH and EC,, HCO3 −, Cl−, SO4 2-, NO3 −, F−, Ca2+, Mg2+, Na+, K+) and heavy metals (Fe, Mn, As, Zn, Cu, Cr, Ni, Se, Al, Ba, Pb and Cd) were analysed. Measured concentration of heavy metals in the study area in decreasing order is as follows: Fe> Zn> Mn > Al> Ba > Ni> Cu > Pb> Cr > Se> As > Cd. Fe concentration was found beyond desirable limit in each sample. In the study area 73%, 60% and 21% water samples surpass desirable limit of Al, Mn and Ni respectively as per BIS,10,500 (2012). Concentration of As, Cu, Cr, Se, Pb, Ba and Cd was within the desirable limit in each sample. The analysed data was then applied for the calculation of Heavy Metal Pollution Index (HPI), Heavy Metal Evaluation Index (HEI) and Degree of Contamination (Cd). HPI values have not surpassed the critical value of 100 in any of the sample despite of various industrial activities. Fe is the prominent contributor for all the three pollution indices followed by Ni, Cr, Pb, Cu and Mn. According to multiple of mean value approach 100%, 93% and 80% of the samples belong to low and medium classes of HEI, HPI, and Cd respectively. Cluster analysis results advocate that heavy metal concentration in groundwater resources are contributed by both lithogenic as well as anthropogenic inputs such as large number of ferro alloys, non-ferrous alloys, sponge iron, foundry, instrument manufacturing and welding industries in the study area.

Evaluation of surface water quality after mine closure in the coal-mining region of Guizhou, China

In this study, we used pollution evaluation indices, principal component analysis (PCA), and hierarchical cluster analysis (HCA) to assess the pollution status of surface water systems after mine closure in an intensive coal-mining area of Guizhou. The concentrations of Fe, Al, Mn, Hg, total nitrogen, volatile phenols, sulfide, and petroleum in most of the water samples exceeded the limits set by China and the World Health Organization. The surface water in this region was characterised as near-neutral-high metals and near-neutral-low metals. The metal elements showed high spatial variability as inferred from their high variation coefficients. In contrast, most non-metallic pollution elements were not considered dominant polluters and generally showed low spatial variability. Modifications to the existing heavy metal pollution index and degree of contamination scheme showed comparable results to that of the heavy metal evaluation index, where 76.92%, 7.69%, and 15.38% of the water samples showed low, medium, and high pollution, respectively. Combined, the results of the HCA, PCA, and pollution indices inferred highest surface water contamination at sites closest to the coal mines (G1, G4, G9), while distal sites were less contaminated. Our results highlight the need to assess the pollution status of surface water systems after mine closure in intensive coal-mining areas in order to prevent severe ecological and environmental degradation.

Distribution, contamination status and source of trace elements in the soil around brick kilns

This study reports the distribution, contamination level, and possible sources of 54 metal (oid)s in the soils found around brick kilns in south-western Bangladesh. In total, 40 soil samples were collected from the vicinity of five brick kilns in four directions at 250 m intervals. This study reveals that the mean respective concentrations of caesium (Cs), beryllium (Be), lead (Pb), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), dysprosium (Dy), holmium (Ho), terbium (Tb), erbium (Er), thulium (Tm), ytterbium (Yb), thorium (Th), germanium (Ge), yttrium (Y), zirconium (Zr), niobium (Nb), silver (Ag), hafnium (Hf), tantalum (Ta), and tungsten (W), were 7.83, 3.19, 22.93, 85.93, 9.61, 36.86, 7.30, 1.23, 5.76, 1.13, 0.99, 3.14, 0.45, 2.91, 17.72, 3.04, 30.07, 185.13, 13.99, 0.30, 5.34, 1.26, and 2.61 μg g−1. Furthermore, those amounts exceeded their respective shale values. The pollution evaluation indices indicated a moderate level of contamination by Cs, Pb, Th, Ag, Hf, Ta, W, and lanthanides but excluding lanthanum (La) and lutetium (Lu). The pollution load index revealed pollution at two brickfields. Multivariate statistics reported that coal combustion in the brick kilns is the primary source of lanthanides, actinides, Y, Zr, and Hf in the soil, while other elements derived mostly from natural sources. A portion originated from coal combustion in brick kilns and agricultural activities. Changes in metal (oid)s concentrations were non-linear with the distance between the kilns and sampling points. Consequently, further studies are required and should consider meteorological factors and severity of human impact in the study area.