Level Of Heavy Metal Pollution Research Articles

Assessment of benthic ecological status and heavy metal contamination in an estuarine intertidal mudflat in the Northern Bohai Sea

Evaluating the ecological quality and pollution status of coastal mudflats is crucial for environmental protection and management, particularly when these areas serve as major shellfish production hotspots. In this study, we assessed the benthic ecological quality and heavy metals pollution in Geligang, located in the Northern Bohai Sea using the macrobenthos diversity index and the heavy metal pollution index. The Shannon-Wiener index (H′), AZTI marine biotic index (AMBI), multivariate AMBI (M-AMBI) showed that the benthic ecological quality in Geligang is either good or high. The potential ecological risk index and geoaccumulation index highlighted that cadmium (Cd) and mercury (Hg) as the primary heavy metal pollutants in Geligang. Surprisingly, the biomass of the two dominant species other than these indices serve as reliable indicators of heavy metal pollution. This suggests that the biomass of Mactra veneriformis and Potamocorbula laevis could be used to assess heavy metal pollution levels in Geligang.

Level of Heavy Metals and Potential Ecological Risks in Irrigated Horticultural Farms in the Vicinity of Lake Ziway, Central Ethiopian Rift Valley Region.

Research on heavy metal pollution in horticultural farms located around lakes in the Central Ethiopian Rift Valley Region has focused on measuring the levels of heavy metals and their health implications. However, the ecological risks of horticultural farms contaminated with heavy metals in this region have not been studied. The current study addresses this gap by providing information on the degree of heavy metal contamination and the ecological risk associated with horticultural farms around Lake Ziway, using various pollution indices. An inductively coupled plasma optical emission spectrometer (ICP-OES) was used to measure the concentrations of nine heavy metals (As, Cd, Co, Cu, Cr, Ni, Pb, Hg, and Zn) in a total of 30 composite soil and irrigation water samples, each consisting of a mix of six subsamples. The results indicated that the mean concentrations of Hg, Cd, Pb, and Zn in soils collected from all the sampling sites exceeded the FAO/WHO maximum permissible limit (MPL). The values of both the contamination factor (CF) and contamination degree (Cd) of the heavy metals ranged from 0.04 to 2.66 and 2.81 to 6.14, respectively, indicating a low to medium level of contamination for both indices. The pollution load index (PLI) values of 0.451, 0.449, and 0.157 for sites 2, 1, and 3, respectively, indicate "unpolluted" to "moderately polluted" levels of heavy metal pollution. However, the ecological risk indices (ERIs) at sites 2 and 1 (158.92 and 141, respectively) showed a potentially high ecological risk due to soil pollution. Therefore, close monitoring and early intervention mechanisms must be in place to control pollution in the study area.

Assessment of Heavy Metal Contamination and Ecological Risk in Soil within the Zheng–Bian–Luo Urban Agglomeration

As urbanization accelerates, the contamination of urban soil and the consequent health implications stemming from urban expansion are increasingly salient. In recent years, a plethora of cities and regions nationwide have embarked on rigorous soil geological surveys with a focus on environmental quality, yielding invaluable foundational data. This research aims to develop scientifically robust and rational land-use planning strategies while assessing the levels of heavy metal pollution and associated risks. The urban agglomeration encompassing Zhengzhou, Luoyang, and Kaifeng (referred to as Zheng–Bian–Luo Urban Agglomeration) in Henan Province was designated as the study area. Leveraging the Nemerow comprehensive index method alongside the Hakanson potential ecological risk assessment method, this study delved into the pollution levels and potential ecological ramifications of nine heavy metals, namely Cr, Mn, Ni, Cu, Zn, As, Cd, Pb, and Co. Research indicates that the hierarchy of individual potential ecological risks ranges from most to least significant as follows: Cd > Pb > Cr > Ni > Cu > Zn > As > Mn > Co. The concentrations of Cd in both Zhengzhou and Kaifeng surpassed the established background levels. Furthermore, the mean single-factor pollution index values for the heavy metals Cd and Zn exceeded 1, signifying a state of minor pollution. The Nemerow comprehensive index P of Cd and Zn is between 1 < Pcomp ≤ 2, which is considered mild pollution. The comprehensive P values of the other seven metal elements are all less than 0.7, reaching a clean (alert) level. Predominantly, the primary potential risk factor in the superficial soil of the Zheng–Bian–Luo urban agglomeration is Cd, while the ecological risk implications associated with other heavy metal elements are comparatively minimal. The soil environmental quality within the designated study area remains secure, although certain localized areas pose potential risks of heavy metal pollution. A comprehensive assessment of the current state of soil heavy metal pollution is essential to establish a theoretical foundation and provide technical support for soil environmental protection, pollution mitigation, and sustainable utilization.

Bacterial-fungal interactions and response to heavy metal contamination of soil in agricultural areas.

Long-term heavy metal contamination of soil affects the structure and function of microbial communities. The aim of our study was to investigate the effect of soil heavy metal contamination on microorganisms and the impact of different heavy metal pollution levels on the microbial interactions. We collected soil samples and determined soil properties. Microbial diversity was analyzed in two groups of samples using high-throughput sequencing technology. Additionally, we constructed microbial networks to analyze microbial interactions. The pollution load index (PLI) < 1 indicates that the area is not polluted. 1 < PLI < 2 represents moderate pollution. PLI was 1.05 and 0.14 for the heavy metal contaminated area and the uncontaminated area, respectively. Cd, Hg, Pb, Zn, and Cu were identified as the major contaminants in the contaminated area, with the contamination factors were 30.35, 11.26, 5.46, 5.19, and 2.46, respectively. The diversities and compositions of the bacterial community varied significantly between the two groups. Compared to the uncontaminated area, the co-occurrence network between bacterial and fungal species in the contaminated area was more complex. The keystone taxa of the co-occurrence network in the contaminated area were more than those in the uncontaminated area and were completely different from it. Heavy metal concentrations played a crucial role in shaping the difference in microbial community compositions. Microorganisms adapt to long-term and moderate levels of heavy metal contamination through enhanced interactions. Bacteria resistant to heavy metal concentrations may play an important role in soils contaminated with moderate levels of heavy metals over long periods of time.

Health Risk Assessment of Heavy Metals in Soils of a City in Guangdong Province Based on Source Oriented and Monte Carlo Models

Taking a city in Guangdong Province as the research area, the concentration and spatial distribution characteristics of heavy metals in the surface soil were studied to clarify the situation of soil heavy metal pollution and priority control factors, providing basic data for the prevention and control of soil heavy metal pollution in the city. The content characteristics of heavy metals in 221 soil samples in the city were analyzed, and the potential health risk assessment and source analysis were carried out through the Monte Carlo model, the potential health risk assessment (HRA) model, and the PMF receptor model. It was found that heavy metals ω(As), ω(Hg), ω(Cd), ω(Pb), ω(Cr), ω(Cu), ω(Ni), and ω(Zn) in the soil of the city were 18.16, 0.43, 1.46, 68.57, 98.34, 64.19, 26.53, and 257.32 mg·kg-1, respectively, with a moderate to high degree of variation. Except for Ni concentration, the soil concentrations of other heavy metal elements exceeded the background values of soil in Guangdong Province to a certain extent, and the concentrations of Cd and Zn exceeded the national secondary standards, resulting in severe heavy metal pollution; the main sources of heavy metals were industrial sources, and natural parent materials, lead battery manufacturing, transportation, artificial cultivation, and pesticide and fertilizer inputs also had an undeniable impact on the accumulation of heavy metals in the soil. Heavy metals in the soil had a certain degree of tolerable carcinogenic health risk for both children and adults, whereas non-carcinogenic risks could be ignored. The potential health risk of children was greater than that of adults, and the main exposure route was through oral intake. The input sources of pesticides and fertilizers and As should be the main controlling factors for the health risks of heavy metals in the city's soil, followed by mixed sources and Cr. There were differences in the spatial distribution characteristics and relative pollution levels of heavy metals, and it is necessary to deepen zoning monitoring and control, strengthen soil pollution prevention and control, and reduce human input of heavy metals in soil.

Grey water footprint model of heavy metal based on the hazard quotient

The traditional Grey Water Footprint (GWF) model, rooted in the assumption that the hazard of each pollutant is independent, faces a limitation when dealing with heavy metals, whose hazards to aquatic organisms accumulate. The objective of this study is to develop a GWF model that reflects the cumulative threat posed by heavy metals to aquatic organisms, using the Hazard Quotient (HQ) as a foundation. The model comprises three parts: (i) defining the minimum virtual water volume required to control the HQ within the allowable limits, which includes long-term GWF (L-GWF) and short-term GWF (S-GWF); (ii) calculating the hazard level of heavy metal pollution (HHL); and (iii) determining the contribution rates of each heavy metal to L-GWF and S-GWF. The evaluation results of the heavy metal pollution discharged from the Guixi Smelter show that (i) The GWF of heavy metals from the Guixi Smelter decreases dramatically in 2014, with L-GWF and S-GWF of 2.39 and 0.22 billion m3, respectively, which are only 49.9 % and 47.1 % of L-GWF and S-GWF in 2013. (ii) The HHL values in 2012 and 2013 are 1.52 and 1.43, respectively, with a grade of “moderate.” In contrast, the HHL values in 2014 and 2015 significantly decrease to 0.82 and 0.74, respectively, both with a grade of “low”. (iii) The L-GWF contributors of heavy metals in the Guixi Smelter are Cu > Cd > Pb, and the S-GWF contributors are Cu > Pb > Cd > As. (iv) The GWF model based on HQ overcomes the limitations of conventional GWF and provides an effective assessment of the cumulative heavy metal hazards to aquatic organisms.

Potential risk assessment and occurrence characteristic of heavy metals based on artificial neural network model along the Yangtze River Estuary, China.

Pollution from heavy metals in estuaries poses potential risks to the aquatic environment and public health. The complexity of the estuarine water environment limits the accurate understanding of its pollution prediction. Field observations were conducted at seven sampling sites along the Yangtze River Estuary (YRE) during summer, autumn, and winter 2021 to analyze the concentrations of seven heavy metals (As, Cd, Cr, Pb, Cu, Ni, Zn) in water and surface sediments. The order of heavy metal concentrations in water samples from highest to lowest was Zn > As > Cu > Ni > Cr > Pb > Cd, while that in surface sediments samples was Zn > Cr > As > Ni > Pb > Cu > Cd. Human health risk assessment of the heavy metals in water samples indicated a chronic and carcinogenic risk associated with As. The risks of heavy metals in surface sediments were evaluated using the geo-accumulation index (Igeo) and potential ecological risk index (RI). Among the seven heavy metals, As and Cd were highly polluted, with Cd being the main contributor to potential ecological risks. Principal component analysis (PCA) was employed to identify the sources of the different heavy metals, revealing that As originated primarily from anthropogenic emissions, while Cd was primarily from atmospheric deposition. To further analyze the influence of water quality indicators on heavy metal pollution, an artificial neural network (ANN) model was utilized. A modified model was proposed, incorporating biochemical parameters to predict the level of heavy metal pollution, achieving an accuracy of 95.1%. This accuracy was 22.5% higher than that of the traditional model and particularly effective in predicting the maximum 20% of values. Results in this paper highlight the pollution of As and Cd along the YRE, and the proposed model provides valuable information for estimating heavy metal pollution in estuarine water environments, facilitating pollution prevention efforts.

Heavy metals and radionuclides in Islamabad's industrial area: A comprehensive analysis of soil and water pollution, source apportionment and health effects using statistical and geospatial tools

IntroductionHeavy metal pollution in industrial areas around the world is a significant problem that is worsening day by day. Heavy and toxic metals are detrimental to human health and ecology in a region. Hence, determining their level and potential is critical to form effective pollution control strategies for reducing the risks associated with them. Study areaIslamabad is the capital city of Pakistan with a dedicated industrial zone. PurposeThis study evaluated the heavy metal pollution levels in the soil and water of Islamabad's industrial area and radionuclides activity in the soil using statistical, geospatial tools as well as their subsequent health and ecological hazards. Materials and methodsElemental analysis in this study was performed using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The radionuclides activity in the soil was quantified using High Purity Germanium Detector (HPGe). ResultsThe soil of Islamabad's industrial area is highly polluted with heavy and toxic metals. The risk posed by heavy metals to the eco-system was calculated using Ecological risk factor and was found to be above recommended level. Principal component analysis (PCA), Pearson's correlation and inverse distance weighting interpolation (IDW) revealed that the soil near the steel mills, landfill and marble processing plants is extremely polluted with heavy metals. Health hazards from heavy metal exposure through ingestion, inhalation, and dermal contact were also calculated. Cr posed a carcinogenic risk to children via the three exposure pathways with the value being 4 × 10−4. Natural radioactivity levels for Ra-226, Th-232 and K-40 were found to be 25.96±12.50, 15.84±2.59, 469.48±52.38 Bqkg−1, respectively. Elemental analysis of water samples coupled with geospatial analysis showed that water samples collected near the industrial complexes have elevated levels of Sb. The water quality for irrigation was assessed and the water from Islamabad's industrial area was found to be suitable for irrigation. ConclusionIn conclusion, the soil of Islamabad's industrial area is highly polluted with heavy metals and has lower levels of natural radioactivity. The water near the industries also has elevated levels of some heavy metals.

Current water pollution status at an important wintering site of the black-faced spoonbill Platalea minor in Xinghua Bay, south China

Xinghua Bay is one of the largest wintering sites of the black-faced spoonbill Platalea minor in mainland China. The ecosystem of Xinghua Bay has shown a deteriorating trend with the increasing pressure of economic development in recent decades. To understand the current conservation status of the wintering spoonbills in Xinghua Bay, we collected water samples along the coast of Xinghua Bay and important spoonbill habitats during the wintering period to analyze the pollution degree of 7 target heavy metals and organics. The Nemerow pollution index (NPI), heavy metal pollution index (HPI) and contamination degree (CD) were used to assess the heavy metal pollution levels. The ecological risk index of a target heavy metal (Efi) and potential ecological risk index of all target heavy metals (RI) were used to assess the ecological risk of heavy metals levels in Xinghua Bay. Positive matrix factorization (PMF) was used to determine the sources of heavy metals in coastal waters with the EPA PMF5.0 model. The results showed that there was moderate to very heavy pollution by heavy metals and moderate associated ecological risks in Xinghua Bay, in which Hg and Cd were the major heavy metal pollution sources, and the level of organic pollution was of serious concern. The use of fertilizers for cultured shellfish and aquaculture in and around the bay were the major cause of the excessive nitrogen and phosphorus levels, and factories surrounding Xinghua Bay were the major sources of heavy metals and organic pollution. We propose conservation measures to increase black-faced spoonbill population and enhance its habitats.

Water Resources, Pollution, Integrated Management and Practices in Nigeria – An Overview

This paper provides a comprehensive overview of Nigeria’s water landscape, focusing on its abundant surface and underground water sources and the agencies responsible for water resources development and management. Findings reveals that the country boasts vast freshwater reserves, encompassing surface and groundwater, intricate river drainage systems, numerous dams, and managed aquifer formations, primarily overseen by River Basin Development Authorities. Despite these resources, Nigeria faces severe pollution challenges, especially in the Niger Delta, resulting from oil-related activities and causing environmental degradation, health crises, and enduring ecosystem consequences. Approximately 13 million barrels of oil spills have adversely impacted coastal wetlands, mangroves, and agricultural lands. Elevated levels of heavy metal pollution, exceeding recommended guidelines, pose significant threats to public health, emphasizing the lasting impact of persistent oil spillage on fishery production and aquatic organisms. River Basin Development Authorities have made substantial contributions, challenges persist in catchment management and the indiscriminate disposal of hazardous substances. The absence of effective environmental policies necessitates urgent, coordinated action from federal and state governments. Nigeria must prioritize integrated water management practices to strike a delicate balance between resource utilization and preservation for the benefit of current and future generations. This manuscript relies on secondary sources, utilizing key search terms such as “water resources in Nigeria,” “water pollution in Nigeria,” “water supply and demand in Nigeria,” “water management in Nigeria,” and “integrated water practices in Nigeria.” Data were sourced from reputable institutions, including the Federal Ministry of Water Resources, The World Bank, United Nations Environmental Protection (UNEP), USAID’s Sustainable Water Partnership, and various scientific publications, ensuring the reliability of the presented data.

Risk assessment and source analysis of heavy metals in soil around an asbestos mine in an arid plateau region, China

Asbestos is widely used in construction, manufacturing, and other common industrial fields. Human activities such as mining, processing, and transportation can release heavy metals from asbestos into the surrounding soil environment, posing a health hazard to the mining area's environment and its surrounding residents. The purpose of the present study was to determine the extent of ecological and human health damage caused by asbestos pollution, as well as the primary contributors to the contamination, by examining a large asbestos mine and the surrounding soil in China. The level of heavy metal pollution in soil and sources were analyzed using methods such as the geo-accumulation index (Igeo), potential ecological risk index (RI), and positive matrix factorization (PMF) model. A Monte Carlo simulation-based health risk model was employed to assess the health risks of heavy metals in the study area’s soil to human beings. The results showed that the concentrations of As, Pb, Cr, Cu, and Ni in the soil were 1.74, 0.13, 13.31, 0.33, and 33.37 times higher than the local soil background values, respectively. The Igeo assessment indicated significant accumulation effects for Ni, Cr, and As. The RI evaluation revealed extremely high comprehensive ecological risks (RI ≥ 444) in the vicinity of the waste residue heap and beneficiation area, with Ni exhibiting strong individual potential ecological risk (Eir ≥ 320). The soil health risk assessment demonstrated that As and Cr posed carcinogenic risks to adults, with mean carcinogenic indices (CR) of 1.56E − 05 and 4.14E − 06, respectively. As, Cr, and Cd posed carcinogenic risks to children, with mean CRs of 1.08E − 04, 1.61E − 05, and 2.68E − 06, respectively. Cr also posed certain non-carcinogenic risks to both adults and children. The PMF model identified asbestos contamination as the primary source of heavy metals in the soil surrounding the asbestos mining area, contributing to 79.0%. According to this study, it is recommended that management exercise oversight and regulation over the concentrations of Ni, Cr, Cd, and As in the soil adjacent to asbestos mines, establish a designated control zone to restrict population activities, and locate residential zones at a safe distance from the asbestos mine production zone.

Assessment of the accumulation level and ecological risk of heavy metals in surface sediments of Bong Mieu River, Quang Nam Province, Vietnam.

This study assessed the accumulation levels and ecological risks associated with seven heavy metals (As, Pb, Cd, Hg, Cu, Cr, Zn) in the surface sediments of the Bong Mieu River in Quang Nam Province, Vietnam. The sampling encompassed 10 locations (S1-S10), considering areas both impacted and less impacted by gold mining activities. The findings revealed elevated levels of heavy metal pollution and associated ecological risks attributable to gold mining. Heavy metal content varied within specific ranges: As (70.6-341.2 mg/kg), Pb (216.3-504.1 mg/kg), Hg (0.138-0.252 mg/kg), Cd (0.91-1.51mg/kg), Cu (18.3-45.5 mg/kg), Cr (10.5-19.1 mg/kg), and Zn (49.3-84.1 mg/kg). Among these elements, Hg, Cu, Cr, Zn, and Cd adhered to the acceptable limits of VNTR 43:2017/MONRE (VNTR 43:2017/MONRE: National Technical Regulation/Ministry of Natural Resources and Environment of Vietnam). However, As and Pb content at all locations exceeded these limits significantly, with As being 4.1-20 times higher and Pb 2.3-5.5 times higher. The pollution of Pb and As was attributed to waste discharge from gold mining activities, which carry substantial amounts of these metals in various forms. The Igeo indicated heavy pollution of As and Pb in the sediments. Ecological risk factors were ranked as follows: (As) > (Pb) > (Hg) > (Cd) > (Cu) > (Cr) > (Zn). The potential ecological risk (RI) due to combined heavy metal impact varied across locations, with S2 > S8 > S9 > S6 > S7 > S10 > S1 > S3 > S4 > S5, exhibiting low to moderate risk (RI values ranging from 73.4 to 252.8). The study area demonstrated high contamination levels for As and Pb, coupled with low to moderate potential ecological risks.

Assessment of Potential Human Health Risk Associated With Heavy Metals in Soil – Vegetables System Irrigated by Rift Valley Lake Ziway, Ethiopia

Metal contamination of vegetables is a major concern, especially in areas where irrigation has been used for a long time. The Central Ethiopian Rift Valley Region is highly affected due to the heavy use of agrochemicals throughout the year. Although some studies have been conducted on the concentration and level of heavy metal pollution, little attention has been paid to their impact on human health. This study determined the concentrations of nine metals (As, Cd, Cr, Co, Cu, Hg, Ni, Pb, and Zn) in a soils and vegetables (tomatoes and onions) irrigated by Lake Ziway, Ethiopia. An inductively coupled plasma optical emission spectrometer (ICP-OES) was used to determine the heavy metal levels. Moreover, the study evaluated the health risks associated with consuming contaminated vegetables by employing major indices, including non-carcinogenic and carcinogenic risks. The results showed that the mean concentrations of Pb, As, Hg, and Cr in all tomato and onion samples and the average Zn, Pb, Cd, and Hg levels in all soil samples exceeded the FAO/WHO threshold. Non-carcinogenic health risk estimates showed that As, Pb, Hg, and Co for children and Pb and Co for adults had THQ values greater than 1, indicating the possibility of systemic health risks. Carcinogenic health risk showed that Ni posed a risk of developing cancer for both adults and children, with values ranging from 10−3 to 10−1. In addition, children are likely to have a higher cancer risk due to exposure to As and Cr. Therefore, it is crucial to raise awareness among stakeholders and implement effective monitoring policies to safeguard public health both within and beyond the study area.

Geochemical baseline establishment, pollution level and health risk assessment of soil heavy metals in the upper Xiaowen River Basin, Shandong Province, China.

This study analyzed the distribution and content of eight heavy metals (Cu, Pb, Zn, Ni, Cr, As, Cd, and Hg) in 221 surface soil samples from the upper reaches of the Xiaowen River. Environmental geochemical baselines were established for the eight heavy metals, and the pollution status was assessed on the basis of these baselines and the soil background value of Weifang City. The calculation results of Nemerow pollution index and the potential ecological hazard index (PEHI)-Ri showed that the overall pollution degree and ecological hazard in the study area were at a slight level. 49% (calculated by baseline value) and 24% (calculated by background value of Weifang City) samples were at moderate or above pollution level. 9% (calculated by baseline value) and 42% (calculated by background value) samples were at the level of moderate potential ecological hazards or above. According to the calculation results of Igeo and PEHI-Ei, the main pollutant in the study area was Hg, followed by Cd. 3% (calculated by baseline value) and 12% (calculated by background value) of Hg samples were at moderate or above contamination levels. 5% (calculated by baseline value) and 38% (calculated by background value) of Hg samples were at the level of strong potential ecological hazard or above. The western, central, and eastern parts of the study area were mainly the primary areas of pollution and ecological hazards. The non-carcinogenic risk was at an acceptable level, the carcinogenic risk was at a tolerable level, and the main risk pathway was oral intake, with Cr being the main contributor. Source apportionment indicated that soil heavy metals primarily originate from soil parent material, transportation, agricultural fertilization, and industrial emissions (waste gas, waste water and solid waste).

Concentration levels and pollution status of selected heavy metals in active dumpsites in Port Harcourt, Rivers State, Nigeria

This study was carried out to assess the extent of concentration exposure of As, Cu, Cr, Ni and Mn in the soils of five active dumpsites located at (Eliozu, Oyibo, Eneka, Eleme and Woji) in the city of Port Harcourt Rivers State, Nigeria to evaluate the pollution indices of heavy metals. Soil samples were collected randomly at the quadrant from the dumpsite while control samples were collected from farmland 25 km away from the dumpsite. Some physiochemical parameters (pH, TOC and CEC) of the soils were evaluated using standard techniques, while the heavy metal concentrations were evaluated using Atomic Absorption Spectroscopy (AAS). The pollution levels of soil heavy metals were assessed using several pollution indices. The mean concentration of heavy metals (mg/kg) ranged between As (ND – 0.45), Cr (ND – 2.21), Cu (6.05 – 51.87), Mn (3.24 – 37.91), Ni (ND – 13.50) across the studied dumpsites. The heavy metal levels in soil samples observed were in the order of Cu &gt; Mn &gt; Ni &gt; Cr &gt; As (Eleme), Cu &gt; Mn &gt; As &gt; Ni &gt; Cr (Eliozu), Cu &gt; Mn &gt; Ni &gt; Cr &gt; As (Eneka), Cu &gt; Mn &gt; Cr (Oyigbo), Cu &gt; Mn &gt; Ni &gt; Cr &gt; As (Woji), Cu &gt; Mn &gt; Ni &gt; Cr &gt; As (Control Site). The pH results were relatively acidic across the studied dumpsites ranging from 5.7±0.58 to 6.63± 0.02, while the TOC levels were low to moderate showing no wide disparity in the values. The Cation exchange capacity (CEC) showed a range of 13.98±0.186 (Eneka) to 20.98±0.061 cmol/kg (Woji) across the studied dumpsites. The Igeo values except for Ni, Cu and Mn at Eneka dumpsite, Cr and As in all the studied dumpsites revealed moderate to heavy contamination. Pollution load index (˃ 1) was in the studied dumpsites which implies that there is heavy metal pollution across the studied dumpsites. Anthropogenicity indicates that human activity is mostly responsible for the increase in metals in the studied area. Low ecological risk indices for the heavy metals (Ni, Cu, Cr, Mn, As) were found in all the sampling locations except for copper in Oyibo dumpsite. According to the findings, there is a low to moderate level of heavy metal pollution in the soils from the dumpsite, which can deteriorate the food ecosystem if adequate measures are not put in place.

Background levels of heavy metals in the water of Khadzhibey estuary

In the Odesa region, heavy metal contamination of fishery water bodies is a pressing problem. The accumulation of heavy metals in fish depends on the physiological and biochemical activity of the organism and the physical and chemical parameters of the water body. Most heavy metals enter the fish's body through the gills, skin, and digestive organs. Copper, zinc, and plumbum accumulate in the skin, gills, and liver, while cadmium and mercury accumulate in the kidneys. The level of heavy metal pollution in the water of the Khadzhibey estuary was measured and determined in 2022–2023. The following methods were used to determine the content of heavy metals in water: atomic emission spectroscopy using an EMAS-200 CCD instrument to determine cadmium, copper, zinc, and plumbum; cold vapor atomic absorption spectroscopy using the “Julia-2M” method to determine the content of mercury. Toxicological studies of water were carried out in the water hygiene and ecology laboratory of the Ukrainian Research Institute of Transport Medicine and at the Department of Veterinary Hygiene, Sanitation, and Expertise of Odesa State Agrarian University. The study found that the content of heavy metals in the water of the Khadzhibey estuary is not constant and fluctuates depending on the season. The maximum levels of heavy metals are observed in summer (plumbum and cadmium) and autumn (zinc, copper and mercury). It was found that cadmium, plumbum, copper, and mercury content does not exceed the maximum permissible levels for marine fisheries. The zinc content in the water of the Khadzhibey estuary exceeds the maximum permitted concentration by 2.65%. The zinc content in the studied water samples is a stress factor affecting the meat quality of common carp (Cyprinus carpio) and round goby (Neogobius melanostomus).

Surface water-groundwater interactions drive the spatial variability of dissolved heavy metals and interfacial fluxes in mangrove intertidal zones

The intertidal aquifer is a crucial area that significantly influences the transport of heavy metals and the health of coastal environment. In this study, we used a 3-dimensional sampling method to analyze the spatial variability of heavy metals in the groundwater of the mangrove intertidal zone in China. The pollution level of heavy metals and their release processes into coastal waters through groundwater discharge were also explored. Our findings revealed high spatial heterogeneity of heavy metals occurred along the cross-shore, parallel-shore, and depth directions. Specifically, heavy metals exhibited inconsistent variation trends between the seawater infiltrated zone and groundwater discharge zone along the cross-shore direction. Fe, Cr, Cu, Zn, and Pb exhibited a similar variation trend along the cross-shore direction, but were opposite to that of Hg and As. In addition, most heavy metals showed higher concentrations in mangrove groundwater compared to inland pond water and coastal seawater, indicating that mangrove intertidal zone played a crucial role in sequestering heavy metals. The spatial variability of heavy metals can be attributed to different exchange types and magnitudes between the surface water and groundwater, as well as the complex biogeochemical reactions. Our study also identified a slight pollution level of Zn and Hg, and high groundwater discharge-derived fluxes of Hg and As compared with other study sites in the world. In addition, this study highlights the importance of considering different groundwater end-member, especially for redox sensitive heavy metals, when determining groundwater discharge-derived fluxes into the surface water in mangrove intertidal zone.

Spatial Distribution, Risk Assessment and Sources of Heavy Metals in Roadside Soils Exposed to the Zhengzhou-Kaifeng Intercity Railway in Huanghuai Plain, China

ABSTRACT Heavy metal accumulation in soil can seriously harm human health, and it is necessary to identify the accumulation status and access the potential risks for local pollution control and sustainable economic development. This study evaluated the pollution level, spatial distribution, potential risk and sources of soil heavy metals along the Zhengzhou-Kaifeng intercity railway and compared pollution characteristics in north side soils with south side soils of the railway. A total of 260 soil samples were collected from a section along the railway. In practice, only the average Zn and Pb contents in soils were slightly higher than their corresponding risk screening values. The heavy metal enrichment in the north side soils was marginally lower than that in the south side soils. The spatial distribution of soil heavy metals except Pb could be mainly influenced by the different land use types. The geoaccumulation index and potential ecological risk of a single heavy metal indicated that Cd was the major contaminant with moderate pollution and high ecological risks in the south side soils and none to moderate pollution and moderate ecological risks in the north side soils. However, the mean multimetal potential ecological risk values suggested that the north side soils were at low ecological risks and the south side soils were at moderate ecological risks. The comprehensive non-carcinogenic risks and total carcinogenic risks for adults were low and acceptable, respectively. Pearson correlation analysis, PCA, and APCS-MLR analyses identified that the contributions of natural sources, mixed sources of industrial and traffic activities, agricultural activities, and other sources were 57.49%, 21.44%, 12.67% and 8.40%, respectively, and the major soil pollution Cd was mainly related to mixed sources of industrial and traffic activities. Therefore, continuous soil heavy metal monitoring is essential to elucidate the long-term railway operation effect on soil heavy metal accumulation.

Pollution Level and Sources of Heavy Metals in Indoor Dust from College of Science, University of Anbar Campus, Iraq

This research aims to evaluate the level of heavy metal pollution [Cadmium (Cd), Cobalt (Co), Chromium (Cr), Copper (Cu), Lead (Pb) and Zinc (Zn)] in indoor dust samples taken from the College of Science at the University of Anbar in Iraq and their likely sources. Atomic absorption spectrophotometer was used to evaluate the dust samples that were taken from 39 locations (classrooms, offices, and laboratories). Zn > Pb > Cr > Co > Cu > Cd was the order in which the heavy metal concentrations were found. The findings showed that all metal concentrations at various times exceeded background values. Using the geo-accumulation index (Igeo) and contamination (CF), the pollution level was calculated. The values of Igeo and CF indicate that the indoor dust in the College of Science is heavily polluted with Pb and Cd and is unpolluted to moderate polluted with the other metals. Pb, Cd, and Zn may be released from anthropogenic sources, while Co, Cr, and Cu may come from a combination of sources, according to the coefficient of variation (CV) comparison of the heavy metal concentrations with background values, Pearson’s correlation, cluster analysis (CA), and principle component analysis (PCA).

Heavy metals assessment of farmland soil in Bagega mining community, Zamfara State, Northwestern Nigeria

The present study was conducted to examine the level of heavy metals pollution of farmlandsoil at Bagega community, Anka Zamfara State as a result of artisanal and illegal mining activities going on in the community. Soil samples were collected from farmland soil at thedepth of 15cm, acid digestion was carried out and the solution was subjected to Atomic Absorption Spectrophotometer model Varian AA240FS for the metal analysis. The level of soil contamination were assessed by Geo-accumulation Index (Igeo) and Pollution Load Index (PLI). The Geo-accumulation studies show that the soil was moderately polluted by Pb (1.21 mg/kg), Fe (0.9 mg/kg), Zn (0.91 mg/kg) and Cu (1.46 mg/kg). The Pollution Load Index result shows that farmland soil was polluted, with PLI value of 2.1. Also, the geochemical distribution of the metals in the soil samples was revealed by sequential extraction procedures which show that 90 % of the metal concentrations were found in the residual fractions. This signified high level of heavy metals contamination of the farmland soil is associated with the anthropogenic activities such as the mining activities going on in the community.