Distribution Pattern Of Heavy Metals Research Articles

Evaluation of contaminated groundwater for excessive heavy metal presence and its further assessment of the potential risk to public health.

Water plays a significant role in human life. However, the contamination of groundwater by heavy metals (HMs) has profound implications for public health. Industrialization, urbanization, and agricultural activities are turning out to be major causes for the increasing concentration of HMs in rapidly industrializing areas like Rohtak district, Haryana, India. The current study aimed at evaluating and predicting the health hazards associated with the radical rise of HMs in the groundwater of Rohtak district. For this purpose, 45 seasonal-based groundwater samples were collected from five blocks in Rohtak district, namely Kalanaur, Meham, Lakhan Majra, Rohtak City, and Sampla, both during pre- and post-monsoon seasons. Besides physicochemical analysis, these groundwater samples were analyzed for the contamination of HMs. The findings revealed that groundwater samples were relatively more contaminated during the post-monsoon period rather than pre-monsoon. The water quality index (WQI), devised to classify water quality into specific classes, depicted the Kalanaur region as "very poor." Another index named the HM pollution index (HPI) denoted the levels of HMs and categorized Kalanaur as most deteriorated, followed by Meham, Lakhan Majra, Sampla, and Rohtak City. Additionally, principal component analysis (PCA) was employed that showed a significant variation in the distribution pattern of HMs, with the major load being attributed to PC1 and PC2 for both seasons. Pearson's correlation analysis indicated a significant association of pH (R2 = 0.917) with HMs (specifically for Cd and Cr). In terms of health risk assessment, carcinogenic human health risk due to Pb and Cr was found to be higher in children than adults. Non-carcinogenic risk, indicative of harmful human health effects, apart from cancer, was calculated in terms of hazard quotient (HQ) and hazard index (HI). Results of the same, designated "children" as a vulnerable category compared with "adults," especially in the Kalanaur, Sampla, and Rohtak City blocks of the study area. The results thus reiterated that Kalanaur is the most contaminated block among the five blocks chosen and should be given urgent attention. The study holds importance as it provides a framework regarding the methodology that should be adapted for the evaluation, management, and protection of groundwater at a regional level, which could further be replicated by environmentalists and hydrogeologists across the world. PRACTITIONER POINTS: Water logging is one of the most common problems in Kalanaur block of Rohtak district, responsible for causing groundwater pollution. Cadmium and lead pollution was prevalent in Rohtak due to electroplating industries, paint industry, automobile sector, and industrial discharge. Bioremediation is one of the suitable techniques that can be used for the treatment of groundwater that involves the use of microorganisms. Efficient use of groundwater resources is necessary for sustainable development.

Heavy metals and nutrients mediate the distribution of soil microbial community in a typical contaminated farmland of South China

The effects of heavy metals on soil microbial communities have been extensively investigated, whereas the combined effects of heavy metals and nutrients on soil microbial communities and their interactions are rarely understood. In this study, we investigated the distribution patterns of heavy metals, nutrients and microbial communities in a typical contaminated farmland and explored their interaction mechanisms. The results showed that Cd and Pb were the main pollutants in this area, which mainly came from the smelter. Canonical correspondence analysis and variance decomposition analysis showed that the heavy metals played a more important role in restraining the microbial community structure of soils than other soil properties. Soil Cd, Pb, pH and available K content were the most important environmental factors affecting the microbial community structures in soil. Major Cd tolerant bacteria and fungi were detected including Actinobacteriota, Gemmatimonadota, Entorrhizomycota and Mortierellomycota. The analyses of molecular ecological networks showed that there were 84.1 % of negative correlations among microorganisms. Cd could regulate the abundance of key nodes in Cd-tolerant network modules, and these key nodes could improve the adaptability of the whole module to heavy metals through competition with other microorganisms. This study provides insights into the ecological effects of heavy metals and nutrients on soil microbial communities and will help to develop the bio-remediation technologies for contaminated soils.

Composition of heavy metals in sediment, water, and fish of the Ganga and Yamuna Rivers in two major cities of India.

The rapid industrial development in the Indian capital region has led to significant waste generation, which, despite undergoing treatment prior to disposal, contributes substantially to water body contamination. Given the diverse nature of these wastes and their potential repercussions across the food chain, a study was conducted to evaluate heavy metal contamination levels in the Ganga and Yamuna Rivers of two major cities. Six heavy metals (Pb, Cd, Hg, Cu, Cr, and Zn) were analyzed in fish, water, and sediment samples by utilizing flame atomic absorption spectrophotometry (Avanta Σ) from March 2019 to February 2020. Results revealed distinct heavy metal distribution patterns, with Cr > Zn > Pb > Cu > Cd > Hg in the Ganga River and Zn > Cr > Pb > Cu > Cd > Hg in the Yamuna River for fish samples. Additionally, levels of Hg in Cyprinus carpio and Sperata oar from the Ganga River, and Pb, Cd, Hg, and Cr in Salmophasia bacaila and Mystus cavasius from the Yamuna River exceeded WHO/FAO permissible limits. In water samples, the predominant heavy metal sequences were Pb > Cu > Zn > Cr > Cd > Hg for the Ganga River and Cr > Zn > Pb > Cu > Cd > Hg for the Yamuna River, with Pb, Cr, Zn, and Cd surpassing WHO standards. Sediment analysis revealed varying heavy metal compositions, with Zn > Cr > Pb > Cu > Cd > Hg in the Ganga River and Cr > Zn > Pb > Cu > Cd > Hg in the Yamuna River. While drinking water and fish from the Ganga River were deemed safe for consumption, those from the Yamuna River were not. Given the toxic nature of heavy metals and their detrimental health impacts, regular monitoring and effective management strategies are imperative.

The impact of heavy metal concentrations on aquatic insect populations in the Asan Wetland of Dehradun, Uttarakhand

This study, centered on the Asan Wetland in Uttarakhand, examines the ecological impact of heavy metals on aquatic insects biodiversity. It highlights the detrimental effects of metals like chromium, mercury, and lead, stemming from natural and anthropogenic sources, on aquatic insects diversity. Aquatic insects, particularly sensitive to water quality, are emphasized as key indicators of environmental health, illustrating the importance of understanding and managing the influences on wetland ecosystems. Wetland ecosystems are vulnerable to various environmental stressors, including pollution from heavy metals. These toxic substances can alter water quality parameters, disrupt nutrient cycling, and negatively impact the biodiversity and ecological balance of the system. This study aimed to evaluate the impact of several heavy metals (namely Cd, As, Cu, Fe, Pb, Ni, Zn, Al, Cr) on the distribution and biodiversity of various aquatic insect species, including Coeleoptera, Diptera, Ephemeroptera, Odonata, Plecoptera, and Trichoptera. The research utilized data collected between November 2021 and October 2022 from specifically chosen sites (S1, S2, S3) within the Asan Wetland in Dehradun, Uttarakhand. After collecting and identifying samples, various statistical (Sorenson, Shannon-Weiner diversity index, Margelef index) and multivariate tests (CCA, PCA, One-way Anova), have been applied to show the effects of these parameters. This study offers significant findings regarding the distribution patterns of heavy metals, the abundance of aquatic insects, and their interconnectedness within the ecosystem of the Asan Wetland. The abundance of aquatic insects, represented by 13 genera belonging to 6 orders, was assessed at three different sites (S1, S2, and S3) within the wetland. It was concluded that the heavy metals concentration and aquatic insects’ density increases and decreases vice-versa in monsoon and winter seasons might be due to unfavourable factors. These findings contribute to the understanding of ecological dynamics and potential impacts of heavy metals on aquatic biota in wetland environments.

Assessment and Review of Heavy Metals Pollution in Sediments of the Mediterranean Sea

The impact of marine sediment pollution is crucial for the health of the seas, particularly in densely populated coastal areas worldwide. This study assesses the concentration and distribution of heavy metals in the marine sediments of the main regions of the Mediterranean Sea. The results underscore high concentrations of mercury (Hg), nickel (Ni), and copper (Cu), whereas chromium (Cr), zinc (Zn), cadmium (Cd), barium (Ba), and vanadium (V) exhibit moderate values. To assess the heavy metal results, sediment quality guidelines and pollution indices (Igeo and Geochemical Signal Type-GST) were employed, revealing a consistent trend of decreasing concentrations from the coastal zone to the open sea. Principal Component Analysis (PCA) emphasizes the significant roles of Cu, Zn, Ba, and Cr in sediment chemistry. The study suggests that the distribution patterns of heavy metals are linked to wastewater discharges in coastal areas, requiring effective management strategies to ensure the health of the Mediterranean Sea.

Urban green space area mitigates the accumulation of heavy metals in urban soils

Despite that the heavy metals in urban soils pose a threat to public health, the critical factors that influence their concentrations in urban soils are not well understood. In this study, we conducted a survey of surface soil samples from urban green spaces in Shanghai, to analyze the concentrations of the key heavy metals. The results showed that Zn was the most abundant metal with an average concentration of 122.99 mg kg−1, followed by Pb (32.72 mg kg−1) and Cd (0.23 mg kg−1). All concentrations were found to be below the risk screening values defined by the National Environmental Quality Standards for soils of development land in China (GB36600-2018), indicating no current risk in Shanghai. However, there was a clear accumulation of heavy metals, as the mean concentrations were significantly higher than the background values. Furthermore, we explored the relationships between key heavy metals with population density, GDP and green space area. Both Spearman correlation and Random Forest analysis indicated that per capita green space area (pGSA) and population density were the most crucial factors influencing the status of heavy metals in urban soils, unlike edaphic factors e.g. SOM content in farmland soils. Specifically, there was a significantly positive linear correlation between heavy metal concentrations and population density, with correlation coefficients ranging from 0.3 to 0.4. However, the correlation with pGSA was found to be non-linear. The nonlinear regression analysis revealed threshold values between heavy metals concentrations and pGSA (e.g Zn 22.22 m2, Pb 24.92 m2, and Cd 25.92 m2), with a sharp reduction in heavy metal concentrations below the threshold and a slow reduction above the threshold. It suggests that an increase in per capita green space area can mitigate the accumulation of heavy metals caused by growing population density, but the effect is limited after the threshold. Our findings not only provide insights into the distribution patterns of heavy metals in the urban soils at the local scale, but also contribute to the urban greening at the global scale and offer guidance for city planning in the face of increasing population densities over the coming decades.

Spatial patterns of PM2.5-bound heavy metals and analysis of their influencing factors in China

This study investigates the relationship between the spatial distribution patterns of heavy metals (HMs) in atmospheric fine particulate matter (PM2.5) and their influencing factors in China, in order to address air pollution problems. Using HM data from PM2.5 collected from 88 Chinese cities between 2012 and 2020, the study employed a combination of enrichment factor (EF) analysis, standard deviation ellipses and hot spot analysis to assess spatial distribution patterns; geographical detectors to identify influencing factors; and hybrid single-particle Lagrangian integrated trajectory models (HYSPLIT) to determine air mass movement. The results reveal that the spatial distribution of PM2.5-bound HMs in China is characterized by high levels in the north and interior and low levels in the south and along the coast. Anthropogenic activities affect HM levels in China's interior more strongly than on the coast. Moreover, the distribution of PM2.5-bound HMs in China exhibits a northeast-southwest spatial pattern, with significantly higher levels observed in central and northern regions than in eastern regions, particularly along the coast. Industrial waste emissions and energy consumption are key factors contributing to high PM2.5-bound HMs. In central China, the summer air mass movement predominantly follows a southeast direction, while in winter, it follows a northwest direction, originating from inland. In contrast, in eastern China, summer air mass movement predominantly follows a southeast direction, while in winter, it follows a northeast direction, originating from the ocean. Overall, our findings suggest that HMs in PM2.5 display high clustering values in central China, due primarily to industrial waste emissions, energy consumption, and air mass movement.

Pollution Level, Ecological Risk Assessment and Vertical Distribution Pattern Analysis of Heavy Metals in the Tailings Dam of an Abandon Lead–Zinc Mine

Tailings dams in mining areas frequently experience the phenomenon of haphazard dumping and stacking of a large amount of tailings waste. Under the influence of surface runoff and groundwater infiltration, heavy metals from tailings waste can migrate to the surrounding areas and underground soil, resulting in extensive heavy metal pollution. To analyze the pollution level and ecological risk of heavy metals in an abandoned lead–zinc mine tailings dam, this study first employed X-ray fluorescence analysis to determine the vertical distribution patterns of heavy metals with depth. Then, the pollution levels of heavy metals were analyzed based on the Nemerow comprehensive pollution index and geoaccumulation index. Subsequently, the ecological risk of heavy metal pollution was further assessed using the potential ecological risk (PER) index. Finally, the sources and potential hazards of heavy metal pollution were investigated. The results reveal that (1) heavy metal pollutants are identified as lead (Pb), zinc (Zn), copper (Cu) and arsenic (As), displaying enrichment at the interface layer between the reclaimed zone and tailings layer with the highest concentrations; (2) the pollution degrees in each zone follow the order of interface layer > tailings layer > deep zone > reclaimed zone, and the pollution levels for the four heavy metals in decreasing order are Pb > Zn > As > Cu; (3) after considering the toxic effects of heavy metals, the potential ecological risk in each zone remains consistent with the ranking of pollution levels, and the contribution of the four heavy metals to PER changes to Pb > As > Zn > Cu, corresponding average Eri values of 913.928, 416.900, 96.462 and 47.998, respectively; (4) ecological risk of heavy metals originates from lead–zinc ore extraction, and heavy metal pollution poses potential risks to public water security and surrounding ecological resources.

Regional distribution patterns of heavy metals and radionuclides in the East European Plain

Identification of stable regularities in the distribution of heavy metals and radionuclides in soil profiles of the East European Plain is an important scientific and practical task. Heavy metals are easily included in the biological cycle, getting into the human body, are accumulated in the bones, tissues, causing incurable disease, which may subsequently proceed unnoticed. The peculiarity of radioactive pollutants is that they usually do not change the level of soil fertility, but accumulate in crops. Therefore, maximum permissible concentrations (MPC) of radionuclides have been established for human food and animal feed. When analyzing the results of the study, it was revealed that soil horizons are well traced by the content of heavy metals, which makes it possible to get an idea of the soil profile structure by the content of heavy metals in them. The content of natural radionuclides in carbonate yellow-brown clays was established for the first time. According to the obtained correlation data of radionuclides and gross content of heavy metals and a number of oxides of heavy metals with a sufficient degree of reliability we can determine the content of this or that radionuclide, being aware of the percentage content of the element or oxide in the soil.

Contents and spatial distribution patterns of heavy metals in the hinterland of the Tengger Desert, China

The desert in northern China is one of important sources of loess and one significant source of material for sandstorms in Asia. The sand/dust that is transported from desert when sandstorms occur can destroy the growth of crops, cause serious losses and great harm to the economic construction and life safety, and cause natural environment pollution. Hence, it is very important to deepen the research into heavy metals in surface deposits at vulnerable ecological region of arid land of northern China to guide local industrial and agricultural development and improve environmental protection. In this research, 10 heavy metal elements (Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb, and Th) were tested and analyzed in 33 soil sample sites collected from the hinterland of the Tengger Desert, northern China. The results showed that the average abundance of Th exceeded its background soil value of China by more than 5.2 times, which suggests that the Tengger Desert is polluted by Th. In addition, based on principal component analysis, spatial differentiation, and correlation analysis, we identified the source of element with a coefficient of variation in abundance of greater than 0.5 or exceeding the background soil value of China. Principal component analysis and correlation analysis showed that the sources of heavy metals of Cr, Mn, Fe, Co, Ni, Cu, and Cd were similar, while those of Th and Zn were different. Moreover, based on the contents and spatial distribution characteristics of those heavy metal elements, we found that the formation of heavy metal elements enrichment areas is caused by industrial pollution, development of irrigated agricultural, geological, and geomorphic conditions, and the sedimentary environment in the study area. Our result can provide information on the environmental background values of soils in the hinterland of the Tengger Desert.

Particle collection and heavy metals migration during high-temperature electrostatic precipitation in copper smelting: A pilot-scale study

Recently, large amounts of particulate matter (PM) and heavy metals (HMs) have been generated in the processes of non-ferrous metal smelting (NFMS). High-temperature electrostatic precipitator (HT-ESP) was the key method to capturing PM while extensive HMs enriched. In this work, the PM collection and migration of HMs in the HT-ESP process of copper smelting were investigated through an established pilot-scale platform. The excellent performance of the pilot-scale HT-ESP could achieve a particle collection efficiency of 99.5 %. The distribution patterns of HMs in various particle sizes revealed that the volatile heavy metals, arsenic (As) and selenium (Se) were predominantly distributed in PM1.0 and PM1-2.5 with a moderately dispersed distribution, whereas copper (Cu) and lead (Pb) were densely concentrated on particles. When the temperature difference between the inlet and the outlet of the HT-ESP narrowed to 23 K, the original As and Se enriched in hopper particles partially volatilized and migrated into the gas phase and adhered to tiny size particles. The enrichment ratio in the gas phase (ERG) of As and Se increased by 2.7 % and 18.5 %, respectively. The results were beneficial to reducing the enrichment of volatile HMs in copper smelting ash and provided guidance for resource utilization of the copper smelting industry.

Geodetector based identification of influencing factors on spatial distribution patterns of heavy metals in soil: A case in the upper reaches of the Yangtze River, China

With the acceleration of urbanization and industrialization, soil heavy metal pollution has become a serious problem threatening ecological security. Identification of influencing factors on the variations and distribution of heavy metals in soils becomes a critical problem to be solved. Here, the geographical detector (geodetector) method was applied to study the influencing factors on the spatial distribution pattern of heavy metals (As, Cd, Cr and Hg) in soils in the upper reaches of the Yangtze River, China. Based on the geodetector model, eight influencing factors were selected, including 5 natural factors of pH, precipitation, soil type, rock type and landform, 2 anthropogenic factors of land use and road density, and 1 comprehensive factor of deposit density). The influence of each factor on the spatial distribution of 4 heavy metals shows that 1) for As, the dominant influencing factors were pH and deposit density, and the secondary influencing factors were precipitation and rock type, 2) for Cd, precipitation had the greatest explanatory power, while pH, land uses, road density and deposit density also had significant effects, 3) for Cr, the main influencing factors were rock type and soil type, and the secondary factors were pH and deposit density, 4) for Hg, the deposit density and rock type dominated its distribution. Compared with single factors, the interaction between factors significantly improved the explanatory power of heavy metals. Taking Cd as an example, the single factor contributions of road density and precipitation are 12.4% and 13.2%, respectively, while the explanatory power of their interaction was as high as 49.8%. This finding indicated that the geodetector can be a helpful method for us to understand the factors affecting the distribution patterns of heavy metals in soil, and it can further service for land management and pollution remediation.

Health risk assessment of heavy metals in drinking water leaching through improperly managed dumpsite waste in Kurata, Ijoko, Sango area of Ogun State, Nigeria

Groundwater contamination by leachate from dumpsites is a major health issue of public concern in developing nations of the world. The present study assessed the health risk of the scavengers and residents exposed to different heavy metals (HMs) in drinking water contaminated through leaching from improperly managed dumpsite waste in Kurata, Ijoko, Sango area of Ogun State, Nigeria. The data of groundwater parameters and biological (nails and urine) samples of scavengers and the residents around the dumpsite were evaluated for descriptive and inferential statistics. The HMs observed in samples varied significantly (p < 0.05) across the sampling sites. However, 74 and 63% of the nail samples had Pb and Co levels below the detection limit (BDL) of the analytical instrument, respectively, The HM concentrations (mg/L) in groundwater followed the decreasing order of Fe (16.66 ± 13.98) > Zn (2.46 ± 1.80) > Pb (0.55 ± 0.59) > Cu (0.03 ± 0.01) > Cd (0.01 ± 0.01). Positive correlations were observed for Cu and Pb, and Cu and Cd at p < 0.05 in groundwater. The distribution patterns of HMs followed the decreasing trends of Zn > Ni > Mn > Cu > Pb > Co for nails; and Ni > Zn > Mn > Co > Cr > Pb > Cd for urine. The hazard quotient values estimated for HMs (except Zn and Pb) in groundwater consumed by adults were greater than the permissible limit of 1.0, indicating adverse health effects. The cancer risk data for Cd and Pb were generally higher than the acceptable limit of 1.0 × 10−4; suggesting the possible development of cancer on exposure to groundwater through ingestion. The ∑CRs of HMs in groundwater samples were 114, 76, and 14 times higher than the acceptable limit of 1.0 × 10−4 for infants, children, and adults, respectively. Cd (94%) was the major contributor to the total cancer burden of HMs in the groundwater. The HMs were observed at higher concentrations in biological samples than in groundwater. This study, therefore, established the deleterious health effects of the dumpsite on the vicinity groundwater and the scavengers.

Apportionment of heavy metals in a soil-water-plant system via brick kiln emissions in heavily industrialized city of Pakistan.

One of the major environmental problems is the fast accumulation of brick kiln emissions near the peripheries of almost all urban centers. An enormous quantity of substandard coal, wood, rubber tires, or saw wood is used as fuel in these brick kilns, creating environmental pollution through carbon and heavy metals present in the emissions. The present study was designed to determine the distribution pattern of heavy metals in a soil-water-plant system under the influence of brick kiln emissions. Ash, soil (0-15cm), water, and plant samples were collected from the adjacent areas of the brick kilns. Geo-accumulation index and contamination factors were used to assess the toxicity of metals to soil and plants. It was found that the concentrations of Cd in water, soil, coal, and plant samples were found in the range of 0.004-0.024mg L-1, 0.02-0.66, 0.002-0.042, and 0.06 to 0.07mgkg-1, respectively, while Pb concentration was found within the range of 0-0.08mg L-1, 0.30-8.60, 0.011-0, and 0.01-0.08mgkg-1 in water, soil, and plant samples, respectively. The concentration of Cd in brick kilns ash was in the range of 0-0.04mgkg-1 while Pb was found within the range of 0.01-0.05mgkg-1 for ash. Geo-accumulation index and contamination factor values for Cd were found higher suggesting proper pollution prevention measures to be implemented. Based on the results, it was concluded that Cd concentrations in soil, plants, and water samples were higher in the subject area due to brick kiln emissions and higher Cd concentrations in the fuel material.

Spatiotemporal distribution patterns and risk characteristics of heavy metal pollutants in the soil of lead\u2013zinc mines

BackgroundThe current soil environmental assessment system is inadequate in terms of the spatiotemporal distribution of heavy metal pollutants. This study employed the numerical simulation technique to predict spatiotemporal distribution patterns of heavy metals within 50 days and to assess the soil risk characteristics of heavy metal pollution near a lead–zinc mine in Hunan Province, China.ResultsThe spatiotemporal distribution results indicate that the soil in the sewage plant and mining areas served as the pollution center, exhibiting a ladder-shaped pollution diffusion trend outward. When the pollution migration time reached 20 days, pollutant migration and changes tended to remain stable, high-pollution areas exhibited no drastic changes within 10 m, and low-pollution and medium-pollution areas revealed obvious changes. Moreover, the low-pollution area width approached 2 m, the depth reached 2 m, the medium-pollution area width was close to 2.5 m, and the depth approached 4 m. The percentage of areas containing lead–zinc mine soil with high to extremely high risks reached 82.88%, and extremely high-risk farmland, mining and residential areas accounted for up to 100%, 95% and 90%, respectively, of the total area. Among the pollution sources, high-risk and extremely high-risk areas in regard to heavy metal Cd accounted for 13.51 and 49.55%, respectively, of the total area.ConclusionThis study provides new insights into the migration patterns and risk characteristics of pollutants to address soil environmental assessment system problems.

Spatio-temporal distribution of heavy metals in sediments of Biyyam Backwater, Kerala, Southwest India; its environmental implications

Biyyam backwater is a developing eco-tourism hub and prone to increased pollution due to urbanization and agricultural waste disposal. This study investigates the distribution, temporal variation, enrichment and accumulation of heavy metals in the surface sediments from Biyyam backwaters. Samples were collected from four locations during post-monsoon (December 2017), pre-monsoon (March 2018) and monsoon (July 2018) seasons. Sediment texture, organic matter and heavy metals such as Mn, Co, Zn, Ni, Cr, Pb, Sc, Cd, and As were analyzed. The metal concentration in surface sediments decreased in the following order, i.e., Mn > Cr > Zn > Ni > Pb > As > Co > Sc > Cd. Spatio-temporal variability in distribution pattern of heavy metals show higher concentrations in upstream region. Heavy metal concentrations in surface sediments show relatively higher Igeo factors indicating contribution of heavy metals from agricultural and urban waste disposal. These relatively high values indicate that the Biyyam backwater is threatened by metal contamination, specifically by As, Cd, Cr and Ni. Biyyam backwater is an eco-tourism hub and a beautiful aquatic ecosystem, thus our results would help the local environmental managers to develop strategies to conserve the natural state of the kayal via managing the sources of pollution and sediment remediation in the area.

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.

Identification of spatial patterns and sources of heavy metals in greenhouse soils using geostatistical and positive matrix factorization (PMF) methods

AbstractGreenhouse vegetable products are important dietary sources. Heavy metals in greenhouse soils are associated with food safety and public health. Therefore, heavy metals in greenhouse soils are of significant concern. This study used positive matrix factorization (PMF) and geostatistical analyses to assess possible sources and spatial distribution patterns of heavy metals in 248 greenhouse soil samples obtained from southern Hebei Province, China. The results showed that the mean arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), and zinc (Zn) concentrations in the greenhouse soil samples were 13.5, 0.16, 74.3, 31.4, 0.03, 26.0, 156, and 98.0 mg/kg, respectively. Approximately 97.18%, 32.26%, 25.81%, 22.98%, 8.06%, 6.45%, 2.02%, and 0.40% of sample sites were contaminated with Cd, Cu, Hg, Zn, Cr, As, Pb, and Ni, respectively. The PMF indicated that Cd and Pb was mainly influenced by metal smelting activity; Cu and Zn accumulation in greenhouse soils was mainly from manure and chemical fertilizer application, while Ni, Cr, and As were strongly derived from natural sources. The spatial distribution patterns varied among metals, with Ni and Pb mainly controlled by natural factors, whereas Cd, Cu, Cr, and Zn were moderately to strongly influenced by fertilizer application. However, Pb is also affected by atmospheric deposition caused by industrial emissions. The spatial distribution of As is controlled by both natural and anthropogenic factors.

Ecological Risk Assessment of Heavy Metals in Adjoining Sediment of River Ecosystem

The present study was focused on heavy metal distribution patterns and the associated ecological risk assessment in the adjoining sediment of the Hindon River in Muzaffarnagar Region (U.P.), India. Lead (Pb), zinc (Zn), copper (Cu), cadmium (Cd), nickel (Ni), iron (Fe), aluminum (Al), sodium (Na), and potassium (K) were estimated from six sediment samples (Atali A and B, Budhana A and B, and Titavi A and B). The concentration of the heavy metals Zn, Pb, Cu, Ni, and Cd ranged from 25.5–74.7 mg kg−1, 29.8–40.6 mg kg−1, 7.0–29.2 mg kg−1, 14.7–21.8 mg kg−1, and 0.96–1.2 mg kg−1, respectively and followed the sequence Zn &gt; Pb &gt; Cu &gt; Ni &gt; Cd, while major elements followed the sequence Na &gt; Fe &gt; Al &gt; K. The enrichment factor (EF) and geo-accumulation index (Igeo) revealed that Atali A showed the highest enrichment and followed the sequence Zn &gt; Cu &gt; Pb &gt; Ni &gt; Cd. Contamination factor (CF) and contamination degree (CD) depicted that all of the sites (except Titavi B) were moderately to considerably contaminated. The highest degree of contamination (CF, CD, and PLI, pollution load index) was observed at Titavi A followed by Atali A and Budhana A. Eco-toxicological risk assessment (RI) indicated that the sites were moderately contaminated, predominantly by Ni and Pb and Zn. The results revealed that the metal contamination in sediment is alarming and might pose an adverse threat to ecosystem health.

APPLICATION OF SOME SINGLE AND INTEGRATED INDEX EQUATION TO ASSESS HEAVY METAL IN DIFFERENT SOILS IN ERBIL GOVERNORATE

The aim of this study was to application of some single and integrated index equation to assess heavy metal in different soil within Erbil governorate. The 15 different locations (Bahare new, Newroz, New Hawler, Hesarok, Azadi1, Zen city, Atconz city, Pank village, Binaslawa, Darato, Qushtapa, Shaways, Kasnazan, Bahirka, Pirzin) were specifically selected to identify the effects of traffic activities on soil properties. Different heavy metal distribution patterns (As, Cd, Cu, Cr and Zn) were determined from distance 5, 25, 50m roadside. Soil pollution was assessed using many indices including: contamination factor (CF), degree of contamination (Cdeg), Ecological Risk Factor and Potential Ecological Risk Index.The results showed that concentrations of As, Cd, Cr, Cu, and Zn in street dust ranged from (4.60, 1.80, 217.83, 62.14 and 215.18) mg.kg-1 which recorded in Qushtapa, Kasnazan, Atconze city, Hasarok5 and Zen city respectively. The contamination factor and degree of contamination of the trace elements As, Cd, Cr, Cu ,and Zn of soil samples was indicating considerable contamination factor for Qushtapa moderate contamination factor for Kasnazan, while Atconze city, Hasarok5, Zen city showed very high contamination factor, while degree of contamination considerable low degree of contamination. According to the ecological risk factor and RI results Qwshtapa was indicate as low potential ecological risk, Kasnazan had moderate potential ecological risk while Hasarok5 and Zen city considerable high potential ecological risk, except Atconze considerable very high ecological risk, on the other hand for RI index shown considerable very high ecological risk recorded in Hasarok 5 soil samples.