Geoaccumulation Index Research Articles

Potentially harmful elements in mining sites in Ghana: assessment of their carcinogenic and non-carcinogenic health risks for children and adults

PurposePotentially harmful elements (PHEs) in the soil at gold mining sites can endanger the health and sustainability of the local community. We examined the potential health risks associated with the presence of PHEs (Al, Cd, Cu, Fe, Hg, Mn, Pb, Sb, Se and Ti) in the soils of active, closed/abandoned/former and profile gold mine sites in Ghana.Design/methodology/approachWe collected 102 soil samples from these mine sites, analysed them for their total element contents and calculated the geo-accumulation index, enrichment factor, contamination factor and pollution load index (PLI) (Igeo). We calculated the risks to human health by utilizing the hazard index (HI) and hazard quotient (HQ) for adult males, adult females and children who may ingest contaminated soil particles.FindingsThe average total Cd concentration in the soils was above the global average of 0.2 mg/kg for abandoned (2.86 mg/kg), active (3.93 mg/kg) and profile (4.04 mg/kg) areas. Mercury was detected at elevated concentrations in the soil of active mines (0.92 mg/kg), profiles (0.89 mg/kg) and abandoned mines (0.87 mg/kg). In the active, abandoned and profile soils, titanium concentrations were 14.18, 6.74 and 4.82 mg/kg, respectively, in several folds above the global average of 0.57 mg/kg. The majority of the sites were contaminated with Cd, Hg and Ti based on the calculated PLI values (active = 2.04, abandoned = 1.77 and profile = 2.7). Cadmium, mercury, lead and titanium in mine spoils were found to be correlated with aluminium, iron, manganese, pH, total carbon, clay content and phosphorus in a multivariate analysis using correlation and principal component analysis.Research limitations/implicationsBoth natural and anthropogenic processes contributed to the elevated metal contents in the mining sites, as indicated by the investigation’s results. The children’s hazard index values exceeded the threshold of 1.0, indicating the presence of non-carcinogenic risks.Practical implicationsGreen space technology (e.g. revegetation) may thus be critical for preserving public health and reviving the ecological integrity of the contaminated sites.Originality/valueThis study highlights health risks to local communities in southwest Ghana by investigating the presence of potentially harmful elements in soils from gold mining sites for the first time. It assesses non-carcinogenic and carcinogenic health risks using a methodology recommended by the US Environmental Protection Agency for soil-to-human health risk assessment, especially for children. The study highlights how contamination has been found, making green space technology essential for preserving ecological integrity and protecting public health. The inclusion of geospatial distribution mapping of PTEs offers a visual depiction of the spread of contamination at both active and closed mining sites.

Soil Quality Variations Across Different Land Use Patterns in Central Doon Valley of Dehradun, India: A Comparative Study

Soil is the most basic and yet most complex component of terrestrial ecosystems. It regulates most of the ecosystem processes and provides a large part of the earth’s biodiversity for the physical basis for many human activities. The major objectives of this study are to examine the physio-chemical characteristics of soil in both disturbed and undisturbed areas of Dehradun and to analyze soil pollution indices related to heavy metals in these areas. The study was conducted in the Suddhowala and Selaqui areas of Jhajra Forest Range, Dehradun, India. The soil samples were collected from six different land use patterns of SS1-SS6 from March to May (2024). The Physical parameters such as Moisture Content, Water Holding Capacity, and Electrical Conductivity, and the chemical parameters such as pH, Total Nitrogen, Organic Carbon, Organic Matter, Phosphorus, Potassium, and Sulphur were analyzed and the heavy metals such as Zinc, Boron, Copper, Manganese and Iron were measured. The geo-accumulation index (Igeo), enrichment factor (EF), degree of contamination (CD), and pollution load index (PLI) were studied. The study finds gaps in how micronutrient status is evaluated to meet the soil needs.

Spatial Trends of Cadmium and Zinc Concentrations in Water and Enrichments in Surficial Sediments within Nyanza (Winam) Gulf of Lake Victoria (East Africa)

Metal pollution contributes significantly to the environmental degradation of lake ecosystems. The study evaluated the spatial trends in cadmium and zinc concentrations in surface water, un-fractioned and the <63µm grain size fraction (silt and clay) of surficial sediments within Nyanza Gulf, from lake monitoring stations in 2010 and 2012 surveys. Significantly higher Zn total concentrations were found in surface lake water compared to earlier surveys, but cadmium levels were low and not detectable as in previous studies. Variable contents of Zn and Cd were found in un-fractioned and finer sediment fractions. “Much higher sediment Cd contents were found in 2010 compared to other surveys. Major areas under river and urban influences recorded much higher sediment Cd contents than offshore sediments. However, there were no significant differences between Cd and Zn contents between the gulf and main lake zones. Cd sediment enrichment factors were highly variable compared to Zn, which showed a more uniform trend in most of the gulf areas, but Cd sediment enrichment factors appear to increase when compared to previous data. The spatial distribution of Cd and Zn in the surficial sediments show unpolluted to moderate pollution levels, according to geo-accumulation index. Only 4% of Zn samples exceeded the sediment quality threshold effect concentration (TEC) values, but all were below the mid-range effect values. Cadmium is a recognized toxicant and there are potential ecological concerns regarding the variable sediment Cd contents since it has been found previously in bioavailable forms in surficial sediments and 2% of the samples contained Cd (un-fractioned sediment) above the threshold effect concentration during the 2012 survey compared to 51 % in 2010, but none exceeded the severe effect levels”. Continuous monitoring of priority heavy metals is of relevance on the understanding of potential long-term ecological impacts to the lake ecosystem.

Soil pollution with heavy metals in the vicinity of coal-fired power plants in Taean and Seocheon, Chungnam Province, South Korea.

This study investigated the distributions of heavy metals (Cd, Cu, Hg, Ni, Pb, and Zn) in agricultural soils near coal-fired power plants in Taean and Seocheon, South Korea, considering wind direction and distance from the plants. Additionally, pollution assessment for these heavy metals was conducted using the geoaccumulation index (Igeo) and enrichment factor. Results showed that heavy metal concentrations in the studied soil samples were below Korean environmental criteria for agricultural soil (Cd: 4, Cu: 150, Hg: 4, Ni: 100, Pb: 200, and Zn: 300mg/kg). However, a significant proportion of samples exceeded average levels found in uncontaminated soils. Spatial distribution analysis revealed higher concentrations of Cd and Pb southwest of the Taean plant, influenced by prevailing northeast winds. In Seocheon, soils within 4km of the plant exhibited elevated levels of Cd and Ni, suggesting coal combustion as a potential contamination source. Pollution assessment indicated that Cd and Pb in soils near both thermal power plants were more enriched by artificial activity compared to agricultural soils in control areas. Sequential extraction results showed that heavy metals in soils within 4km of the Seocheon plant had higher proportions of exchangeable to organic-associated forms than soils beyond 4km, indicating a risk of high bioavailability near emission sources. This study highlights the significant impact of coal-fired power plant emissions on soil contamination, emphasizing the need for continuous monitoring and management. Environmental policies should consider wind patterns and proximity to emission sources to effectively mitigate contamination risks.

Spatial Distribution, Pollution Assessment, and Source Analysis of Soil Heavy Metals Under Different Land Use Types in the Southern Area of Laizhou Bay

To ascertain the status of the surface soil heavy metal pollution in the southern area of Laizhou Bay, 263 surface soil samples were collected from seven different land use types in the study area and the contents and pH of eight soil heavy metals （As, Cr, Ni, Cu, Zn, Cd, Pb, and Hg） were determined. The pollution assessment was carried out using the geo-accumulation index method, Nemerow comprehensive index method, and potential ecological risk index method. Then, the source of heavy metal pollution was discussed using correlation analysis and the source analysis was carried out through positive matrix factorization （PMF）. The results showed that the surface soil in the study area was weakly alkaline； As, Ni, Zn, and Hg slightly exceeded the background values of Weifang and the spatial distribution of heavy metals showed a trend of low in the north and high in the south. The results of the geo-accumulation index indicated that the study area was pollution free and the geo-accumulation index of different land types was arranged in the order of As>Ni>Zn>Cr>Pb>Hg>Cu>Cd. The results of the Nemerow comprehensive pollution index indicated that the study area was lightly polluted and the Nemerow comprehensive pollution index of different land types was arranged in the order of town>grassland>forest>agricultural land>vegetable land>industrial land>mudflat. The results of the potential ecological risk index indicated that the study area belonged to low ecological risk and the potential ecological risk index of different land types was arranged in the order of agricultural land>town>forest land>grassland>vegetable land>industrial land>mudflat. The results of PMF analysis indicated that the heavy metal pollution sources in the study area mainly included natural sources, transportation sources, agricultural sources, and industrial sources, with contribution rates of 38.06%, 26.38%, 26.21%, and 9.35%, respectively.

Heavy Metal Pollution Characteristics and Ecological Risk Assessment of Kafang Tin Tailings Pond

To study the pollution characteristics and ecological risks of heavy metals in tailings ponds is an important prerequisite for protecting the surrounding environment and human health. The total amount and morphology of five "toxic" heavy metals （As, Cr, Cd, Pb, and Hg） in Kafang tin tailings pond were determined. Based on the aforementioned, we analyzed the distribution characteristics of heavy metals. The potential ecological risks of heavy metals in tailings ponds were studied from the aspects of total amount and morphology. Sample data were analyzed using the geo-accumulation index method, potential ecological risk assessment method, and risk assessment criteria. The results showed that, from the perspective of the total amount of heavy metals, the spatial distribution of As was different, and the pollution was serious； the spatial distribution of Cd, Hg, Cr, and Pb was relatively uniform； the pollution of Cd and Hg was slight； and the pollution of Cr and Pb was controllable. From the perspective of the morphology of heavy metals, As, Cr, Pb, and Hg in tailings were mainly in the residual state and had low environmental pollution risk, whereas Cd in tailings was mainly in an oxidizable state and had high environmental pollution risks. Therefore, Kafang tin tailings pond should strengthen the control of As in tailings and pay attention to the potential pollution risks of Cd in tailings and the overall pollution risks of Hg, Pb, and Cr in the entire reservoir were controllable.

Heavy Metals and Associated Risks of Wild Edible Mushrooms Consumption: Transfer Factor, Carcinogenic Risk, and Health Risk Index

This research aims to investigate the heavy metals (i.e., Cd, Cr, Cu, Ni, and Pb) in the fruiting bodies of six indigenous wild edible mushrooms including Agaricus bisporus, Agaricus campestris, Armillaria mellea, Boletus edulis, Macrolepiota excoriate, and Macrolepiota procera, correlated with various factors, such as the growth substrate, the sampling site, the species and the morphological part (i.e., cap and stipe), and their possible toxicological implications. Heavy metal concentrations in mushroom (228 samples) and soil (114 samples) were determined by Inductively Coupled Plasma—Mass Spectrometry (ICP-MS). In the first part of the study, the soil contamination (index of geo-accumulation, contamination factor, and pollution loading index) and associated risks (chronic daily dose for three exposure pathways—ingestion, dermal, and inhalation; hazard quotient of non-cancer risks and the carcinogenic risks) were calculated, while the phytoremediation capacity of the mushrooms was determined. At the end of these investigations, it was concluded that M. procera accumulates more Cd and Cr (32.528% and 57.906%, respectively), M. excoriata accumulates Cu (24.802%), B. edulis accumulates Ni (22.694%), and A. mellea accumulates Pb (18.574%), in relation to the underlying soils. There were statistically significant differences between the stipe and cap (i.e., in the cap subsamples of M. procera, the accumulation factor for Cd was five times higher than in the stipe subsamples). The daily intake of toxic metals related to the consumption of these mushrooms with negative consequences on human health, especially for children (1.5 times higher than for adults), was determined as well.

Ecological risk and chemical speciation of heavy metals in surface sediments of the Pearl River Estuary for comprehensive assessment

The Pearl River Estuary, a vital ecological and economic zone in Southern China, has been heavily impacted by industrial discharges, leading to significant heavy metal contamination. To address the ecological implications of different chemical forms of heavy metals, this study systematically evaluated the total concentrations and chemical speciation of Cu, Zn, Cd, and Pb in surface sediments (0–2 cm) collected from 17 sites. Chemical speciation was determined using a modified BCR sequential extraction procedure, and pollution and ecological risks were assessed via the geo-accumulation index (Igeo), potential ecological risk index (RI), and risk assessment code (RAC). The results showed that all four metals exceeded background values, with Cd presenting the highest enrichment (39 times) and contributing 97% of the ecological risk. Speciation analysis revealed that Cd predominantly exists in bioavailable forms, posing severe ecological threats. This study highlights the urgent need for targeted remediation strategies to mitigate Cd contamination and its ecological impact on the estuary.

Heavy metal characteristics and ecological threat assessment in water and sediments of Eniong Creek, Niger Delta, Nigeria

Heavy metal characteristics and ecological threat assessment in water and sediments of Eniong Creek, Nigeria was studied between August 2022 and January 2023 in 3 stations. Seven heavy metals were analyzed with standard methods and compared with quality Standard. Ecological threat was assessed in water using two metal pollution indices while six sediment quality assessment indices were used to access the sediment quality. Results showed that the mean concentrations of nickel, copper, cadmium and zinc in water sample exceeded the permissible limits set by National environmental (surface and groundwater) quality regulations for aquatic life, while copper and cadmium exceeded the permissible limits set by Canadian sediment standards quality for the protection of aquatic life in sediments in all the stations. The heavy metal pollution index (HPI) values exceeded the threshold (100) across the stations, ranging between 469.53 and 686.74 while comprehensive pollution index (CPI) ranged between 1.405 and 1.854, indicating moderate contaminated water. The sediment indices indicated that cadmium and copper were the major metallic pollutants. The indices indicated the following –contamination factor: copper (moderate) and cadmium (very high), degree of contamination (very high); ecological risk: cadmium and copper (high) while lead and zinc were moderate; potential ecological risk (high); quantification of contamination: cadmium and copper (anthropogenic); geo-accumulation index: cadmium (very highly polluted). The study revealed that the water body and sediments were polluted, attributed to anthropogenic activities.Keywords: Eniong Creek; Heavy Metals, Nigeria; Sediment; Water

Assessment of Carcinogenic and non-carcinogenic risk indices of heavy metal exposure in different age groups using Monte Carlo Simulation Approach

Dermal contact, ingestion and inhalation of heavy metal poses significant health risk in human subjects. The exposure could be via potable water, soil or air. The current experiment design focuses on soil media and exposure. Advanced probabilistic and geospatial methods are used in this study which evaluates contamination levels and health risks associated with iron (Fe), arsenic (As), zinc (Zn), copper (Cu), nickel (Ni), chromium (Cr), lead (Pb), and cadmium (Cd) in soil samples. The samples were collected and analysed using ICP-OES after tri-acid digestion, and indices such as Geoaccumulation Index (Igeo), Contamination Factor (CF), Pollution Load Index (PLI), Hazard Quotient (HQ), Hazard Index (HI), and Carcinogenic Risk (CR) were used to assess environmental impacts and health risks across the age groups via oral ingestion, inhalation and dermal contact. The current study indicates heavy metal concentrations follow the order Ni > Zn > Pb > Cu > Cr > As > Cd, with more than 60% of samples demonstrating significant pollution levels. The computational method used in the study revealed substantial non carcinogenic risk (HQ > 1) and carcinogenic risk (33%) in the population related to As exposure. Geospatial analysis and Monte Carlo simulations helped in identifying the hotspots in the tropical coastal area emphasizing need for targeted remediation focusing on As and Pb.

The Evaluation of heavy metal contamination in soil samples in the region of Mitrovica

The industry is crucial for the economic development of the country, but at the same time, it is one of the biggest influences on the environment. The Mitrovica region faces numerous environmental problems due to the mining-industrial processes applied in the facilities of the industrial complex "Trepça". As a result of these processes, industrial waste with a toxic composition is created, which is considered a potential polluter of soil, air, water, and vegetation in this area. The study aims to determine the concentration of heavy metals including Pb, As, Zn, Ni, Co, Cr, Cd, and Cu in soil samples. Also, the level of soil pollution with heavy metals was examined, using pollution indicators, such as contamination factor (CF), degree of contamination (Cd), modified degree of contamination (mCd), pollution load index (PLI), and geo-accumulation index (Igeo). To carry out this research, we selected 6 sampling sites in the period May - August 2024, which were characterized and evaluated as the most critical points. The concentration of heavy metals in soil samples was determined using inductively coupled plasma-optical emission spectrometry (ICP–OES Optima 2100 DV, Perkin-Elmer) by standard method US EPA 6010C. From the obtained results it was found that the level of heavy metals analyzed in this work, respectively the level of zinc (197.84 - 3456.14 mgkg-1), lead (204.75 - 3458.16 mgkg-1), and arsenic (30.76 – 634.56 mgkg-1) is relatively high and exceeds the allowed values ​​recommended by Kosovo and European Legislation.

Potentially toxic elements contamination and health risk assessment of coastal sediments in Betoya Bay, Morocco.

This study investigated the potentially toxic elements (PTEs) contamination of Betoya Bay surface sediments to assess the degree of pollution and identify the source of these contaminants. Average PTE levels as mg/kg in Betoya Bay are ranked in descending order as Zn (22.68) > Cr (8.64) > Pb (7.24) > Ni (6.82) > As (6.62) > Cu (5.78) > Co (2.45) > Cd (0.20). The sampling sites show an increase in PTEs at station 5, probably due to runoff from the wadi, and at the first station, where fishing activity is particularly intense. At all stations throughout the year, PTE levels were unpolluted as evaluated by the geoaccumulation index (Igeo) and the pollution load index (PLI). Almost all PTEs showed a "low contamination factor" according to the contamination factor index (CF). As assessed by the contamination degree (CD), all PTE levels at all stations and seasons were "low contamination degree". The ecological risk indices (Eir and RI) indicated low to moderate ecological risk. In line with sediment quality requirements, the M-ERM-Q calculation suggests there is only a 9% chance that this particular combination of metals poses a threat. The non-carcinogenic health risk assessment showed that beach sand in the study area is entirely safe, presenting no additional health risk to children or adults. However, the carcinogenic risk showed a low to moderate carcinogenic risk for adults and a moderate to high carcinogenic risk for children. In addition, statistical analysis revealed that all PTEs are likely to have common sources, which may be related to the geology of the area.

Effect of heavy metals contamination due to leachate migration from uncontrolled dumpsites: A comprehensive analysis on soil and groundwater

In the contemporary era, the widespread practice of open dumping persists as a major method for municipal solid waste (MSW) disposal, contributing significantly to global environmental degradation and posing severe health risks. Deficient waste management systems result in over 90% of waste being openly discarded or burned at numerous unregulated dumpsites, particularly in developing nations like India. This research focuses on the active waste dumping site, Bhandewadi Dumpsite in Nagpur, Maharashtra, India, aiming to assess soil and groundwater contamination caused by the release of toxic elements into the surrounding region. Various parameters, such as the index of geoaccumulation, contamination factor, potential ecological risk, heavy metal pollution index, and water metal index were employed to evaluate the impact of the dumpsite. Results indicated heavy contamination in soil and groundwater samples, particularly from Bidgoan Road and Pardi, with elevated levels of metals, such as Cr, Ni, and Pb within 2 km radius of Bhandewadi dumpsite, Nagpur (India). The principal component analysis confirmed these locations as highly polluted, emphasizing the influence of leachate migration from the uncontrolled dumpsite. The findings underscore the urgent need to improve waste management strategies at municipal landfills and highlight the importance of policy measures to control environmental pollution and the introduction of scientific methods to curb the migration of metals into the environment.

Spatial distribution and migration characteristics of heavy metals at an abandoned industrial site in the Southwest of China

The rapid acceleration of global industrialization has rendered heavy metal contamination at abandoned industrial sites a severe challenge, particularly in geologically complex and fragile karst regions of Southwest China, posing significant threats to ecosystems and public health. However, existing research lacks a comprehensive understanding of the spatial distribution and migration mechanisms of heavy metals in this region. In this study, 523 soil samples and 30 groundwater samples were collected, and the pollution levels were systematically assessed using the Geo-Accumulation Index, Single Pollution Index, and Nemerow Integrated Pollution Index. Horizontal and vertical spatial heterogeneity was explored through Moran's I and Voronoi polygon analysis. Furthermore, 3D geological modeling and groundwater flow simulations were employed to investigate the influence of hydrogeological conditions on contaminant migration. The results indicate elevated concentrations of Cd, Hg, Pb, and As in the surface layer, with concentrations initially decreasing and then increasing with depth, likely due to the presence of discontinuous clay layers. Moran's I revealed significant clustering effects at depths of 0.2 meters and 4 meters, while Voronoi analysis confirmed vertical heterogeneity. This study provides a scientific basis for pollution assessment and targeted remediation in karst regions.

Comprehensive analysis and risk assessment of fine road dust in Abbottabad city (Pakistan) with heavy traffic for potentially toxic elements

Human activities have far-reaching impact on natural ecosystems, causing increasing disturbances and disruptions to the delicate balance of the environment. Poor land use planning, urbanization, infrastructure development, and unplanned tourism exacerbate contamination and degradation in tourist destinations, yet the pollution of potentially toxic elements (PTEs) in these environments remains inadequately explored. To address this issue, we investigated the concentrations of acid-digested PTEs in road dust in Abbottabad city (Pakistan) with heavy traffic. The current study also evaluated PTE associated pollution, ecological and health risks, and potential sources of these elements. The average concentrations (in mg kg–1) of PTEs in road dust were highest for Fe (15540), followed by Mn (304), Zn (139), Cu (50.0), Pb (21.5), Cr (13.0), Ni (10.3), Co (6.66), and Cd (0.236). The levels of Co, Cr, Mn, Ni, and Fe were below the upper continental crust (UCC) averages, while Cd, Cu, Pb, and Zn exceeded them. Spatially, Cd, Cu, Pb, and Zn were found at higher levels near traffic hotspots, bus stands and automobile workshops. Road dust in Abbottabad exhibited unpolluted to moderate pollution levels (geo-accumulation index), with Cd, Cu, Zn, and Pb at 23% of the sites. The enrichment factor results indicated a significant anthropogenic influence, with Cd being significantly enriched and Zn, Cu, and Pb moderately enriched. The contamination factor results revealed moderate contamination by (Cd: 2.62, Zn: 2.08, Cu: 1.79, Pb: 1.27). Single metal risk index showed that 61% of the sites posed considerable to very high ecological risks due to Cd, which was highlighted as a significant concern. The absolute principal component scores-multiple linear regression model identified three factors contributing to PTE pollution: lithogenic (Co, Fe, Mn, Ni), traffic-related (Cd, Cu, Pb, Zn), and mixed sources (Cr), with contributions of 52.8%, 35.8%, and 11.4%, respectively. The PTE hazard quotient and total hazard index values for children and adults were below the safe risk level of 1, indicating no non-carcinogenic health risks. The cumulative carcinogenic risk values to the residents were also within acceptable limits. However, children's susceptibility to non-carcinogenic risks is higher due to their behavior and lower body weight. This study highlights the accumulation of PTEs in Abbottabad's environment, which poses challenges to long-term sustainability, particularly amid unplanned tourism. Therefore, urgent measures are necessary to mitigate PTE pollution and preserve tourist spots and public health.

Analysis and Risk Evaluation of Soil Microplastics in the Rohingya Refugee Camp Area, Bangladesh: A Comprehensive Study

The global concern over the pollution-induced by microplastics (MPs) has intensified due to its adverse effects on the environment, particularly in terrestrial ecosystems, where it poses potential threats to soil quality and resident species. However, there is a noticeable research gap regarding soil MPs in dumping sites, specifically within the Rohingya Refugee Camp (RRC), the world's largest humanitarian crisis located in Bangladesh. The main objective of this study is to assess soil MPs' abundance, spatial distribution, and inherent risks in the RRC. The investigation involved extracting MPs from ten soil sampling sites in Kutupalong RRC, home to Rohingya refugees who sought refuge in Bangladesh following the 2017 ethnic atrocities in Northern Rakhine State, Myanmar. Stereomicroscopy and Fourier transform infrared spectroscopy were employed for identification purposes. The concentration of MPs in the study area varied from 67 to 126 (items/kg) (dry weight), with a mean concentration of 103.80 ± 20.671 (items/kg). MPs with sizes <0.5mm constituted the majority at 83%, with fragments (68%) being the prevailing shape, and transparent (63%) as the most abundant color. Predominant polymers included polyethylene (53%) and polypropylene (46%). Negative correlations were observed between MP abundance and pH and moisture content (p<0.05), while a positive correlation was found between MP abundance and organic matter. PCA results suggested that human-induced inappropriate waste and air deposition are the primary sources of soil MP pollution. Contamination factor values suggested moderate pollution with MPs in the study area. According to the geo-accumulation index (Igeo), the area was classified as pollution grade II, signifying 'uncontaminated to moderately contaminated.' However, pollutant load index and potential ecological risk index indicated Hazard Level-I and Pollution Grade-I, respectively. This study illuminates the contamination scenario with MPs, underscoring concerns for eco-environmental safety and providing crucial data for future investigations into MPs in terrestrial dumping habitats.

Spatial distributions, potential sources, and ecological risks of heavy metals in stream sediments in Zambia

The ecological risk assessment and source identification of heavy metals (HMs) are significant for resource utilization and food security. This study aims to assess the spatial distributions, potential sources, and ecological risks of HMs in stream sediments in Zambia. Using 735 samples collected from stream sediments across the country and methods such as inductively coupled plasma mass spectrometry (ICP-MS), atomic fluorescence spectrometry (AFS), and X-ray fluorescence spectrometry (XRFS), this study determined the concentrations of the seven HMs, i.e., arsenic (As), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), and zinc (Zn). The spatial distributions of these HMs were determined using a Geographic Information System (GIS), and their ecological risks were accessed based on the analytical results of their potential sources. Additionally, this study explored the relationships between mining activities and regions with high heavy metal (HM) concentrations based on the statistical analysis of the HM concentrations and geology of the study area. The results indicate the stream sediments in Zambia exhibit average As, Cr, Cu, Hg, Ni, Pb, and Zn concentrations of 1.49 × 10−6, 19.34 × 10−6, 12.12 × 10−6, 12.70 × 10−9, 7.13 × 10−6, 12.52 × 10−6, and 16.30 × 10−6, respectively. The analytical results of the geoaccumulation index (Igeo) and potential ecological risk index (PERI) reveal the presence of relatively high As and Cu concentrations, especially in Copperbelt and North-Western provinces and areas surrounding Lusaka—the capital of Zambia. The HM contamination in stream sediments in Zambia is primarily caused by Cu and gold (Au) mining. This study exemplifies how to determine potential sources and ecological risks of HMs in stream sediments, holding important implications for nation-scale environmental contamination prevention and land utilization planning.

Spatial distribution of heavy metal in sands and sediments of Parki Beach, Chattogram, Bangladesh.

To assess the sources, levels, spatial distributions and exposure to human health, the concentration of heavy metals Pb, Cu, Mn, Zn, and Fe in the sand/sediment of the Parki Beach area of Anowara, Chattogram, Bangladesh are determined using Atomic Absorption Spectroscopy (AAS) for the first time. A total of 40 surface and subsurface sand and sediment samples were collected from 20 different sampling points along the 15km long Parki Beach area, Bangladesh. Average concentrations of Pb, Cu, Mn, Zn and Fe in surface samples are 14.60, 10.10, 283, 407 and 25,256 mg/kg respectively and 9.95, 4.20, 193, 156.6 and 24,404 mg/kg for sub-surface samples, respectively, which shows that the values are higher in surface samples than those in sub-surface samples. According to the Consensus-Based Sediment Quality Guidelines (CBSQG), the northern part of the beach becomes moderately polluted by Mn and Fe, and a smaller area of the southern part is highly polluted by Zn.The average Contamination Factor (CF) of Zn was greater than 1(CF > 1), while the CF of other metals was less than 1(CF < 1). CF of Zn in some sampling points was exceptionally high. Geo-accumulation Index (Igeo) also shows that Zn slightly pollutes some sampling points. The enrichment Factor (EF) of Fe and Mn in samples in the northern part of the study area is quite high and the study reveals that high values of Fe and Mn are mainly derived from geogenic sources. Ecological risk factor (Er) indicates low ecological risk for all sampling points. The Pollution Load Index (PLI) was measured at all sampling stations, and the results showed that the overall level of heavy metal pollution is low. The health quotient (HQ), health index (HI), total health index (THI) and incremental life time cancer risk (ILCR values suggest that adults are safe from any health risk while children may experience non carcinogenic health risk due to the combined effect of the metals. Reduction of heavy metal in the beach is possible with the adaptation of multiple strategies. This data can be used by policymakers to develop strategies to reduce the potential impacts of soil contamination on the environment and public health.

Spatial distribution and the ecological risks posed by heavy metals and total petroleum hydrocarbons (TPHs) in the sediments of mangrove and coral habitats of Northeast Persian Gulf

BackgroundHeavy metals and total petroleum hydrocarbons (TPHs) are important pollutants in the aquatic ecosystem, and their long-term resistance, bio-accumulation, and bio-magnification during the food chain may cause adverse ecological and health risks. MethodsIn here, the distribution and risk assessment of six heavy metals Cd, Pb, Ni, Cu, Zn, Cr, and TPHs were performed in the sediments of 32 regions situated in two mangroves (Tiab and Azini estuaries, Hara Mangrove forest protected area) and coral habitats (Larak and Hengam Islands) in Northeast of the Persian Gulf during 2020–2021. An atomic absorption device was used to determine the concentrations of heavy metals. Ecological risk of heavy metals is assessed through indices contamination factor (CF), contamination degree (CD), modified contamination degree (MCD), pollution load index (PLI), potential ecological risk index (PERI), and geoaccumulation index (Igeo). The spatial distribution of heavy metals was mapped through the inverse distance weighting (IDW) method in ArcMap. ResultsThe concentration of heavy metals indicated significant differences in spatial distribution. The maximum concentration of Cd 1.64 ± 0.001, Cr 18.41 ± 0.41 and Cu 40.5 ± 0.28 µg/g was observed at the regions situated in the Hara Mangrove forest protected area. Azini estuary had the maximum value of Zn 94.61 ± 30.74 and TPHs 4.47 ± 1.93 µg/g and finally, the highest value of concentration Ni 135.22 ± 1.85 µg/g and Pb 17.87 ± 2.17 g/gµ was found in Tiab estuary. The studied regions in the Tiab estuary and Hara Mangrove forest protected area were more contaminated than others and had considerable risks of Ni and Cd. Average ecological indices indicated the sediments of these areas especially Tiab, Hara Mangrove forest protected area, and Azini are moderately to considerably contaminated with Cd and Ni. Tiab was identified as the most contaminated area and all stations except Hengam Island were exposed to considerable ecological risks. Cadmium was found to be the riskiest heavy metal in the investigated region. The distribution of TPHs indicated there is no pollution of TPHs in the region. In all studied stations, the PELq (Toxicity of TPHs) and CF values showed the absence of potential risks of TPHs in sediments. ConclusionsThe findings indicated considerable contamination of Cd and Ni in the mangrove areas, especially Tiab, and it seems necessary to identify, manage, and control possible sources of contamination.

Assessment of heavy metal concentrations, environmental risks and human health implications in marine sediments along the coastal ecosystems of the Republic of Congo.

The aim of this study is to assess the level of heavy metals (HMs) in surface sediments along the coastal estuaries of the Republic of Congo. A variety of approaches were employed, integrating elemental analysis (Atomique Absorption Spectroscopy), environmental, ecological, health risk assessment, and source identification techniques to evaluate the distribution, origin, environmental, ecological and health risks of potentially toxic element (PTE) contamination in sediments. The ascending mean concentration (mg/kg) of Cd (0.4) < Cu (18.6) < Pb (28.8) < Zn (62.1) < Mn (107) < Mg (569.6) complied with the local background, except for Cd and Pb. However, notable variations across sampling points and sites were observed, with a strong relationship between metals and organic matter. The comparing of PTEs with USEPA international standards and sediment toxicity guidelines showed compliance. The assessment of environmental risk parameters, based on the calculation of the geo-accumulation index, concentration factor and pollutant load indices showed low pollution of sediments. The ecological risk assessment, on the other hand, revealed a low level of pollution of biota and a low toxicity risk of ecosystems related to Cd and Pb and then to Cu in some sites. Regarding human health risk assessment, related to the PTEs, the cancerogenic effect indices were calculated for Cd and Pb through ingestion and inhalation pathways, and the non-cancerogenic effect indices were calculated for all HMs through ingestion, inhalation, and cutaneous contact routes, for children and adults, and showed that the results comply with the international standards set by USEPA, ranging from 10-4 to 10-6 and less than 1, respectively, where children were more sensitive and vulnerable than adults to the effects of the PTEs. Ultimately, this study revealed sediment lithology, anthropogenic activities, and mixed origins of HMs, with a large contribution from industrial activities. However, no significant impacts are discernible in the study area. In addition to the importance of this study, it forms part of the region database and could serve as a reference for future monitoring studies, since no data are available in th Congolese coastal environment.