Metal Contamination Status Research Articles

Assessment of heavy metal contamination and trophic status of coral reef sediments of the Lakshadweep Archipelago, Arabian Sea

This study investigated the distribution, contamination status, and ecological implications of heavy metals in the Lakshadweep Archipelago corals and coral reef sediments and the role of labile organic matter on metal accumulation in sediments. Heavy metal concentrations were relatively higher in the inter-tidal sediments than in the lagoon and the corals. The geochemical indices generally indicated the low anthropogenic contribution of heavy metals in sediments, and according to the sediment quality guidelines, there are no adverse effects on the biota. Sedimentary biochemical constituents are dominated by carbohydrates (CHO) followed by Lipids (LPD) and Proteins (PRT), and the low values of PRT: CHO and LPD: CHO ratios indicated aged, refractory organic matter with low nutritional quality. A portion of CHO may be derived from terrestrial sources, and statistical analyses revealed that CHO and LPD are the potential carriers of toxic metals such as Cd, Co and As into the coral reef environment. The biota-sediment accumulation factor (BSAF) showed Cd as a macro concentrator and Zn, Ni, V and As as micro-macro concentrators in Lakshadweep corals.

Response of benthic assemblages to heavy metal contamination from shipbreaking operations in a tropical coastal area

The response of macrobenthic communities to both environmental and anthropogenic pressures serves as a valuable indicator of ecosystem integrity. This study aimed to unravel the benthic community structure, examine the heavy metal contamination status, and explore the response of the microbenthic community to heavy metals in a tropical shipbreaking region. For this, sediment and benthos samples were taken from different sampling stations of the shipbreaking area and the non-shipbreaking sites. The results showed the benthic community consisted of 23 taxa, including Polychaeta, Oligochaeta, Amphipoda, Decapoda, Gastropoda, Bivalvia, and Priapulida, with polychaetes being the predominant group. The benthic community and diversity values were significantly varied between the two sampling sites (p <0.05). Taxa richness was lower in the shipbreaking area, primarily characterized by the dominance of opportunistic benthic groups, particularly Capitella sp. The concentrations of heavy metals (µg. g−1) in the sediment varied within the following ranges: 35.54–258.021 for Zn, 4.84–132.08 for Pb, 22.82–75.25 for Cu, 198.74–764.16 for Mn, 14.57–42.13 for Cr, 4.03–42.23 for Ni, and 3.82–14.85 for Co. Based on concentration levels, Zn, Pb, and Cu were identified as major contaminants with moderate to high potential for adverse effects, particularly evident in the shipbreaking area compared to non-shipbreaking areas. Pollution indices, including enrichment factors and contamination factors, also highlighted contamination by Zn, Pb, and Cu. Among the benthic taxa, Polychaeta demonstrated a high degree of tolerance to elevated concentrations of these heavy metals. Amphipoda density was significantly negatively correlated with Zn, Pb, and Cu concentrations, with significant coefficients of determination (r2= 0.38, p <0.10; r2= 0.64, p <0.01 and r2 = 0.63, p <0.01, respectively). Multivariate analyses (cluster analyses, MDS and CCA) demonstrated both positive and negative relationships among heavy metals and benthic groups. Canonical Correspondence Analysis (CCA) showed the benthic community was negatively correlated with Zn, Pb, and Cu. This finding provided critical insights into the ecological health of aquatic ecosystems, aiding in the development of informed conservation and management strategies.

A Collaborative Approach for Metal Pollution Assessment in Production System of Plastic-Shed Vegetables Near Industrial Areas.

A collaborative assessment approach, including impact index of comprehensive quality (IICQ), food pollution index (FPI), and single factor pollution index (PI), was used to simultaneously select priority metal pollutants and assess metal contamination status in the plastic-shed soil (PSS)-vegetable system of the industrial towns situated in the Yangtze River Delta, China. Overall, significant Cr increment as well as Cd and Cu pollution in PSS existed, which was related to anthropogenic activities, especially industrial wastewater irrigation. The evaluation using PI and FPI demonstrated that priority metal pollutants were Cu and Cd in PSS while Cr and Cd in vegetables. Additionally, the estimation using IICQ method revealed that 23.3% and 13.3% of the sampling sites were sub-moderately and heavily contaminated by metals, respectively. These sites especially with heavy pollution need priority pollution management. These data will be beneficial to metal pollution control in PSS-vegetable system around industrial areas.

Metal(loid) contamination in Bangladesh: a comprehensive synthesis in different landscapes with ecological and health implications.

Elevated metal(loid) concentrations in soil and foodstuffs is a significant global issue for many densely populated countries like Bangladesh, necessitating reliable estimation for sustainable management. Therefore, a comprehensive data synthesis from the published literature might help to provide a wholistic view of metal(loid) contamination in different areas in Bangladesh. This study provided a clearer view of metal(loid) contamination status and their associated ecological and health risks in different land use and ecosystems in Bangladesh. Comprehensive analyses were performed on data gathered from 143 published articles using multiple statistical techniques including meta-analysis. Considering the potential loading of metal(loid), the data were summarized under various groups, including coastal, rural, urban and industrial regions. Also, the concentrations of seven metal(loid)s, e.g., cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), zinc (Zn), and arsenic (As) in soil, sediment, cereal, vegetable, fruit, surface water and groundwater were included. Results showed that the relative concentrations of metal(loid)s in comparison to the maximum permissible limit (MPL) were mostly less than one, although they varied significantly for locations and individual metal(loid). However, the normalized cumulative relative concentrations over the MPL for all seven metal(loid)s across different environmental samples were 4.75, 2.97, 1.51 and 2.79 for coastal, industrial, rural and urban areas, respectively, which wasdue to the higher concentration of Cd, Cr and Cu. Similar to the metal(loid) concentrations, the average of cumulative median non-cancer risks for all metal(loid)s was in the order of industrial (6.46) > urban (4.05) > rural (3.83) > coastal (2.41). This research outcome will provide a foundation for future research on metal(loid)s and will help in pertinent policy-making by the relevant authorities in Bangladesh.

An updated ecotoxicological evaluation and health risk assessment of metal contaminants in Perna viridis mussel harvested on March to August 2018 from Pasir Gudang Coastal Area, Malaysia

Perna viridis (P. viridis) is a significant protein source globally but is often contaminated by metals due to its filter-feeding behavior. Given that Kampung Pasir Puteh, Pasir Gudang (Johor) is Malaysia's primary P. viridis harvesting site and the last health risk assessment (2015) was incomplete, the metal contamination status remains uncertain. Graphite furnace-atomic absorption spectroscopy was employed to analyze metal contaminant concentrations in P. viridis samples collected from March to August 2018, as per Malaysian legal requirements. The R2 values varied between 0.9976 and 0.9980 for P. viridis mussels and between 0.9976 and 0.9999 for seawater. The recovery for P. viridis mussels and seawater ranged from 93.95% to 106.80% and 92.73–108.84%, respectively. Precision and accuracy for both intra and inter-day measurements ranged from 0.15% to 5.49% for P. viridis and 0.05–5.58% for seawater. The concentrations of metal contaminants in P. viridis varied significantly among the different months of sampling (p < 0.05). All P. viridis samples had higher concentration of arsenic (3.16–75.80 μg g−1) than that prescribed by the Malaysian law. Higher cadmium concentration was observed during July (2.12 μg g−1) and August (2.05 μg g−1) alone. With target hazard quotients and hazard indices > 1.0, the likelihood of negative health impacts from consuming these mussels cannot be ignored. TCR values for As and Cd exceeded USEPA standards, indicating a potential lifetime carcinogenic risk from continuous P. viridis consumption. Pb (21.20–49.28 µg L−1) in all surface seawater samples was invariably higher than the allowable limit for Class 2 water areas. Metal contaminant concentrations varied significantly between P. viridis and surface seawater (p < 0.05), implying inconsistent bioaccumulation due to pollution differences. Given the significance of P. viridis mussels, concerted scientific efforts are essential to devise effective metal contaminant removal methods.

Health risk assessment of heavy metals in soil and vegetables from major agricultural sites of Ohio and West Virginia

Contamination of soil and crops with heavy metals (HMs) poses a significant environmental challenge in the United States, while the status of metal contamination and associated health risks have been merely studied. Hence, this study aimed to assess metal contamination in major agricultural sites of Ohio and West Virginia, and evaluate the potential health risks associated with consuming metal-contaminated vegetables. Among the agricultural sites studied, Fe was the most predominant contaminant in all the sampling sites, ranging from 28,410 to 67,306 mg/kg of soil, exceeding the permissible limit of the US-EPA. Whereas Cd was the least contaminant, exceeding the permissible limit only in three sampling sites (ME1, ME3, and ME6), ranging from 0.13 to 2.91 mg/kg of soil. Interestingly, range of metals in vegetable samples were within the permissible limits. Principal component and hierarchical cluster analysis indicated the different natural and anthropogenic sources of metals in soil. In noncarcinogenic health risk assessment, the values of EDI, TEDI, THQ and HI levels for all the metals were lower than their daily uptake. However, CR and TCR assessment reveal significant risks associated with Ni exposure for both adults and children, with values of 3.487E-4 and 1.172E-3, and 5.362E-4 and 1.286E-3, respectively, within these agricultural sites. Therefore, regular monitoring of metal concentrations in soil and vegetables, as well as associated health risks, is strongly recommended to prevent potential health hazards in the future.

Health risk assessment and potential sources of metals in riparian soils of the Wujiang River, China.

In order to understand the pollution status of metals in the riparian soils along the Wujiang River, 26 sampling sites in the mainstream and tributary streams were selected for investigation. The geo-accumulation index (Igeo), Nemerow integrated pollution index, and potential ecological risk index were applied to evaluate the contamination status and ecological risks of metals. Results revealed that the average concentrations of As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn were 12.20, 0.51, 84.01, 57.42, 922.57, 38.37, 38.06, and 127.82mg/kg, respectively. The metal contamination degree and ecological risks in the upper reaches were significantly higher than those in the middle and lower reaches of the Wujiang River. Cd was the dominant contamination metal. Significant non-carcinogenic and carcinogenic risks of metals were found in children based on the hazard index and carcinogenic risk. As was the main non-carcinogenic and carcinogenic pollutant metal in both adults and children. According to principal component analysis, hierarchical clustering analysis, and absolute principal component scores-multiple linear regression, anthropogenic sources (mining and agricultural activities) contributed most to Zn, Pb, Cr, Cd, Cu, and Ni, with contribution rates of 89.14, 82.32, 74.46, 72.12, 68.52, and 61.02%, respectively. Natural sources contributed most to Mn, with a contribution rate of 83.07%. Unidentified sources contributed most to As, with a contribution rate of 47.27%.

Geochemical partitioning of Cu and Zn in Pelabuhanratu Bay sediment

Activities such as fishing ports and power plants on the coast of Pelabuhanratu Bay have recently developed and hence, their input of metal-containing waste may influence the seawater quality of the bay as the fishing grounds. This study aimed to determine the potential sources (i.e., anthropogenic and natural) and pollution status in sediments. Sediment samples were collected once at 10 stations in the bay using a Van Veen grab. The geochemical partitioning of non-residual and residual phases of metals was used to assess the anthropogenic and natural sources, respectively. The status of metal contamination was evaluated by determining the geo-accumulation index (Igeo), contamination factor (CF), and pollution load index (PLI). Generally, Cu was dominant in residual fractions ranging 62.79-81.24%, while Zn ranged 39.56-66.02%. This suggests that Cu and Zn in Pelabuhanratu Bay are naturally sourced. Furthermore, the average geo-accumulation index of Cu was categorized as unpolluted (-0.86), and Zn was lightly polluted (0.87). The CF of Cu indicates the uncontaminated category (0.85), whereas Zn indicates a moderate contamination category (CF = 1.54). The pollution level (PLI) in Pelabuhanratu Bay is generally lightly polluted (PLI 1,135).

Heavy metal contamination in Shanghai agricultural soil

As heavy metals in soil could enrich in biomass and pose health risk to human, it is vital to monitor their contaminations to ensure qualified agricultural production. In this study, we collected >4000 soil samples from agricultural fields in Shanghai during 2010∼2020, and unveiled heavy metal contamination status in this metropolitan. We found that although Shanghai has a long industrialization history, the heavy metal levels in agricultural soil are within safe ranges according to national standard. Specifically, the median levels of Cd, Hg, As, Pb, Cr and Cu are 0.11, 0.13, 7.47, 23.80, 41.00 and 28.30 mg/kg, respectively, which are as good as, or even better than national averages. However, there are spatial and temporal heterogeneities for heavy metal contaminations in Shanghai. For example, the levels of Cd, Hg and Cr are relatively higher in some districts with high industry density, which should be further monitored in the future. Moreover, while the levels for Cd, Cr and Pb have decreased, the level for Hg has mildly increased during this period which needs counteractive measures. Correlation analysis of heavy metal levels and soil fertility parameters suggested overuse of fertilizers may be related to heavy metal contamination in some regions. In summary, our study present by far the largest and most comprehensive landscape of heavy metal contamination in Shanghai agricultural soil, which will be useful for future policy-design and land use planning to ensure safe agricultural production.

Assessment of Soil Properties and Heavy Metal Contamination Status in Vegetable Farms along River Sauna

Assessment of Soil Properties and Heavy Metal Contamination Status in Vegetable Farms along River Sauna

Heavy Metal Contamination Status of Water, Agricultural Soil, and Plant in the Semiarid Region of Kandahar, Afghanistan

Agricultural irrigation using wastewater containing heavy metals (HM) might impose risks in bioaccumulation in foods. The current study was performed to assess the status of HM in terms of water-soil–plant systems in Kandahar, Afghanistan, where industrial and domestic wastewater was partially reused for irrigation. Water, soil, and plant samples were collected from wastewater sites in Haji-Arab (HA), Bala-Karz (BKZ), and Mahal-e-Nejat (MN) in comparison with those from a freshwater-irrigated site in Char-Bagh (CB). The HM levels in unfiltered water samples remained lower than the World Health Organization (WHO) and Food and Agriculture Organization (FAO) permissible values, but the HM concentrations in soil and crops were higher at the HA, BKZ, and MN (wastewater-irrigated sites) than those at the CB site (freshwater-irrigated site). Lead (Pb) levels were high in soils (43–83 mg/kg) and crops (18–36 mg/kg) and extremely exceeded the safe limits even for those crop samples cultivated in the freshwater-irrigated site. Continuous wastewater irrigation increased the HM concentration in water, soil, and plants, but the Pb pollution was found to be ascribed to the minerals in that area since the underground water was showing high Pb levels. The bioaccumulation of HM in the studied sites was related to the cultivated crops and correlated with the land use in the watershed area. This study is important in understanding the risks associated with HM and exercising prudence when applying various irrigation resources in Afghanistan.

Trace metal contamination status in soils of the abandoned gold mining district of Bindiba (East Cameroon): Pollution indices assessment, multivariate analysis and; geostatistical approach.

The online version contains supplementary material available at 10.1007/s40201-023-00849-y.

Chemometric analysis and risk assessment indices to evaluate water and sediment contamination of a tropical mangrove forest

BackgroundMangroves are among the utmost productive forest residing at the interface amid terrestrial and marine environments. They play an essential role in carbon storage, nutrient cycling, and the marine food web's sustenance. Rapid land use and land cover changes have severely affected these ecosystems worldwide. Material and methodsThe present study was carried out in the mangrove forest of Kachchh district in Gujarat. This area is one of India's most swiftly growing industrialized coastal regions, embracing several ports, thermal power plants, salt production units, textile, petrochemical, cement, and fertilizer manufacturing industries. Therefore, this study aims to investigate nutrients and trace metal contamination status in mangroves. A total of 25 physicochemical parameters for water and 16 parameters for surface sediment were analysed using standard protocols. Trace metals were determined using Flame Atomic Absorption Spectrophotometry. Results and discussionImmensely higher chloride (20,116 ± 1929 mg L −1) and sulfate (2315 ± 679 mg L −1) concentrations were observed, suggesting high seawater and saltpan brine mixing in this coastal region. High tidal influx and arid-climate of the area are responsible for higher salinity (52.7 ± 5.0 PSU) in water. Cluster analysis depicts that sites M2, M3, M5, and M6 incorporate higher nutrient levels, indicating the anthropogenic origin of nutrients. The results depict the role of granulometric composition in controlling carbon, nitrogen, sulfur, and metal biogeochemistry in sediments. Results showed that mean trace metal (Fe, Cu, and Ni) content in sediment was higher than the world average shale value, indicating anthropogenic sources. Geo-accumulation index (Igeo) and Enrichment factor (EF) indicates sediment samples were moderately polluted with Cu, Zn, and Ni. ConclusionThe findings revealed that anthropogenic activities have affected the hydrogeochemistry of mangroves in the studied region, which will eventually impact flora and fauna. Therefore, there is a pressing necessity to implement pollution control, mitigation, and restoration policies for the endurable management of the mangroves.

Mercury and other trace elements distribution and profiling of microbial community in the surface sediments of East Siberian Sea

In this study, total mercury (THg), methylmercury (MeHg), various trace elements, and microbial communities were measured in surface sediments of the East Siberian Sea (ESS). The results showed that the average values of THg and MeHg were 58.8 ± 15.21 μg/kg and 0.50 ± 0.22 μg/kg, respectively. The notable levels of trace elements present in both surface sediment and porewater were Al, Fe, and Mn. The enrichment factor and geoaccumulation index analyses found that both natural phenomena and anthropogenic activities contributed to elevated concentrations of metals in the ESS. The redox proxy metals, pH, and SO42− were the major factors influencing the THg and MeHg distributions. Microbial profiles were substantially affected by metals and other abiotic factors. Proteobacteria and Thaumarchaeota were the most abundant phyla. Overall, the findings presented here facilitate the understanding of the current status of metal contamination, its influencing factors, and metal-microbiota-interactions in ESS.

Ecological Risk Assessment of Heavy Metals and Environmental Quality of Tunisian Harbours

Harbours are one of the most disturbed coastal ecosystems due to intensive anthropogenic pressures. This study aimed for the first time to compare anthropogenic impacts in three harbours from the central coast of Tunisia (Mediterranean Sea) employing analysis of heavy metal contamination and ecological quality status (EcoQS). Sampling was carried out in spring 2019 in the fishing harbour of Teboulba, the marina of Monastir, and the commercial harbour of Sousse. The high levels of concentration in heavy metals and organic matter were closely related to the fine-grained fraction of the sediment in the fishing and commercial harbours. A total of 94 macrobenthic species, including five nonindigenous species, were identified belonging to six zoological groups. Multivariate analyses highlighted a strong influence of the harbour activity on the diversity of macrozoobenthic communities. Three benthic assemblages were identified according to their environmental characteristics such as sediment type, organic matter content, and heavy metal contamination. Benthic and biotic indices (H′, J′, AMBI, and BO2A) showed that the EcoQS varied from poor (commercial harbour) to good (marina), and was significantly influenced by harbour activity, organic matter, and heavy metal contamination of the sediment. The present work could be considered as providing important baseline data for the implementation of national environmental policies and management plans in the future.

Preliminary environmental assessment of metal-contaminated sediment dredging in an Urban River, New Jersey, USA.

While several studies have reported success with remedial sediment dredging, the sustainability of these impacts remain unclear. This preliminary study aimed to investigate the short- and long-term effects of remedial dredging on metal contamination, dredging efficacy and ecological status of the Lower Passaic River. To accomplish this, pre- and post-dredging data were statistically analyzed and evaluated using geochemical indices. Short-term results showed effective heavy metal reduction although their concentrations became elevated in water column, increasing bioaccumulation risk in aquatic biota. On the long-term, metal concentrations increased in surface sediments. Ecological assessment revealed that Cu, Hg and Pb pose greater risks while Ag remained abundant despite dredging. Further investigation suggests that post-dredging residuals, surface runoff and sewage pollution may contribute significantly to recontamination and continued pollution. Depletion in long-term dredging efficacy from spring to summer suggest that season-influenced changes in temperature, algae growth and stormwater discharge may have played a role.

Heavy metal contamination assessment and probabilistic health risks in soil and maize near coal mines.

ObjectiveCoal mining activities have continuously introduced heavy metals into the soil–crop system, causing increasing damage to crops. This study integrated the analysis of the heavy metal contamination status and human health risk in soil and maize near coal mines to help formulate control strategies for soil quality, maize production, and safe consumption.MethodThis study was carried out on maize agricultural land near a coal mining plant. Heavy metal contamination was assessed by the geo-accumulation index (Igeo), enrichment factor (EF), and bioaccumulation factor (BCF). The Monte Carlo simulation was used to estimate the probabilistic health risk of heavy metals exposure in soil and maize. The relationship between the concentration of heavy metal in the soil and that in maize was further visualized by correlation analysis and random forest analysis.ResultsThe results revealed that the mean concentrations of soil Ni, Cu, As, Cd, Sn, Zn, Pb, and Hg were all above the local background level. Ni was the most severely polluted heavy metal in maize and had a concentration higher than the risk control standard for corn in China (NY 861-2004). The Igeo values of all heavy metals were low, and EF values showed enrichment in V, Cr, Ti, Ni, and As. The assessment of probabilistic health risk exposed by heavy metals in soil and maize indicated that 1.16 and 1.46% of residents exceeded the carcinogenic risk level due to heavy metal exposure from soil and maize, respectively. Children were the most sensitive to maize and soil heavy metal exposure in the contaminated area. Ingestion of heavy metals was associated with the highest health risk to residents, followed by dermal contact and inhalation. As and Cr in soil and Cr and Ni in maize had the greatest impact on human health risk. Furthermore, maize heavy metals were affected the most by soil Cr, Cd, and V.ConclusionThese results may provide useful information for human carcinogenic risk associated with soil and maize heavy metal exposure due to coal mining activities.

Investigation of pollutant metals in road dust in a post-industrial city: Case study from Detroit, Michigan

Inhalation and/or ingestion of toxic heavy metals enriched in road dust have toxic effects on humans. From inhalation and ingestion of dust, release of readily bioavailable elements sorbed on to dust, could lead to health issues such as lung or skin cancer, kidney dysfunction, hypertension, dermal lesions, peripheral neuropathy, and vascular disease. On 49 road dust and soil samples collected in the Metro Detroit area, we analyzed a suite of trace metals in &amp;lt;63 μm and size-separated fractions to quantify the extent of metal enrichment and contamination status. We evaluated Enrichment Factor (EF), Pollution Index (PI), Geoaccumulation Index (GI), and Pollution Load Index (PLI). The average Chromium (Cr) concentration of 198 ppm is the highest reported for any global city in literature while in ∼80% samples, Barium (Ba), Cr, Lead (Pb), and Zinc (Zn) concentrations exceeded the USEPA limit. The EF for Barium (Ba) was found to be ≥9 in all samples, and for the rest of other elements was &amp;gt;1.5. The PI values for Cr, Ba, Zinc (Zn), Lead (Pb), and Selenium (Se) indicate elevated levels and for Ba, Cr, and Zn up to a moderate level. PLI values in &amp;gt;50% of road dusts were ≥3, indicating many sites are ‘heavily polluted’. The PLI value in Detroit road dust is higher than those reported for some other global cities including Shanghai. Observed strong correlations between Cr-Zn and Cadmium (Cd)-Silver (Ag) likely indicate a common metal source. Cluster analysis of data for Cd, Arsenic (As), Pb, and Zn appears to be distinct between different proximally related clusters, while Nickel (Ni) and Ba are potentially more distinct between property type clusters. In general, metal concentrations of industrial samples are more commonly distinct with over half of metals (≥6 of 11) differing from residential and/or soil samples. Three generalized “groups” were identified from the combination of hierarchical cluster and PCA analyses followed by varimax rotation: Group 1 characterized by Cr, Cd, Ni, Ag, Zn, and Copper (Cu); Group 2 characterized by Pb, As, Mercury (Hg), and minor Ba; and Group 3 characterized by Se. This is the first study to report all four metrics of metal pollution along with rigorous statistical analysis.

Heavy metal contamination status in the soil-water-rice system near coal-fired power plants in Cilacap, Indonesia

Indonesia is intensively developing plenty of coal-fired power plants to support electricity demand growth. Some research showed the utilization of coal as an electrical energy source may produce anthropogenic contaminants (ACs) that can bioaccumulate in plants. This research was carried out to investigate the severity of the heavy metals contamination problem, for instance, arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) in soil, water, rice, and rice bran using ICP-MS and ICP-OES. This research demonstrated the metal contamination levels of arsenic, cadmium, mercury, and lead in the soil, water, rice, and rice bran were below the maximum limit, according to SNI, Codex, and FAO/WHO. However, only a rice sample showed the lead (Pb) level above the safe limit. Coal-fired power plant activities in Cilacap did not indicate clear evidence of soil, water, rice, and bran heavy metal contamination. Therefore, transformation to green energy (e.g., solar and geothermal) is highly recommended to minimize the potential health risks of environmental pollution due to the coal-fired power plant's by-product activities.

Sedimentation of metals in Sundarban mangrove ecosystem: Dominant drivers and environmental risks.

Metal contamination from upstream river water is a threat to coastal and estuarine ecosystem. The present study was undertaken to unveil sedimentation processes and patterns of heavy metal deposition along the salinity gradient of a tropical estuary and its mangrove ecosystem. Sediment columns from three representative sites of differential salinity, anthropogenic interference, and sediment deposition pattern were sampled and analyzed for grain size distribution and metal concentrations as a function of depth. Sediments were dominantly of silty-medium sand texture. A suite of fluvial and alluvial processes, and marine depositional forcing control the sediment deposition and associated heavy metal loading in this estuary. The depth profile revealed a gradual increase in heavy metal accumulation in recent top layer sediments and smaller fractions (silt + clay), irrespective of tidal regimes. Alluvial processes and long tidal retention favor accumulation of heavy metals. Enrichment factor (0.52-15), geo-accumulation index (1.4-5.8), and average pollution load index (PLI = 2.0) indicated moderate to higher heavy metal contamination status of this estuary. This study showed that alluvial processes acted as dominant drivers for the accumulation of metals in sediments, which prevailed over the influence of marine processes. Longer tidal retention of the water column favored more accumulation of heavy metals. Metal accumulation in the sediments entails a potential risk of bioaccumulation and biomagnification through the food web, and may increasingly impact estuarine ecology, economy, and ultimately human health.