Heavy Metal Status Research Articles

Status of Heavy Metals and Remediation Potential of Indigenous Plants at Contaminated Benin City and Abudu Sites of Edo, Nigeria

Status of Heavy Metals and Remediation Potential of Indigenous Plants at Contaminated Benin City and Abudu Sites of Edo, Nigeria

Pollution Characteristics, Risk Assessment and Source Identification of Heavy Metals in Surface Sediments from the Cage Fish Farm of Poyang Lake, China

ABSTRACT With the development of cage culture, increasing heavy metals concentrations are being taken into sediments. The accumulation of heavy metals in sediments may cause long term environmental issues and pose threat to human health. Fourteen surface sediment samples were collected to assess the contamination status and potential ecological risk of heavy metals, and identify their potential sources from the cage fish farm of Poyang Lake. The concentrations of Cu, Pb, Zn, Cd, Cr, As and Ni in the sediments were measured by ICP-MS. The geo-accumulation index, enrichment factor and potential ecological risk index were implied to evaluate their pollution levels and ecological risk. The principal component analysis was used to identify their potential sources. The results showed that all of the examined heavy metals content exceeded their background values. These heavy metals (except Cd, Cr and As) presented moderately polluted level. Cu showed significant enrichment, Zn, Pb and Ni exhibited moderate enrichment, As and Cd presented minimal enrichment. Cu and Cd posed a moderate ecological risk, and the other heavy metals posed a low ecological risk. The comprehensive potential ecological risk was associated with considerable ecological risk. Cage culture, smelting, mining and agriculture activities were their primary pollution sources.

Machine learning-assisted risk evaluation of heavy metals in the Hainan gold mining region, China.

This study employed machine learning (ML) to thoroughly investigate the impact of informal mining activities on the distribution and pollution status of heavy metals in soils near private gold mines in Hainan Province, southern China, a region known for its ecological sensitivity and economic importance. By systematically collecting surface soil samples and samples at depths of 0.5-1m from 175 drilling sites, a comprehensive quantitative analysis was conducted on major heavy metal elements, including lead (Pb), copper (Cu), cadmium (Cd), nickel (Ni), mercury (Hg), chromium (Cr), arsenic (As), and zinc (Zn). Combined with evaluation methods such as the Pollution Load Index (PLI), Normalized Pollution Index (NIPI), and Ecological Risk Index (ERI), the study revealed a high level of soil pollution at informal mining sites. The findings indicated that the average concentrations of Pb, Cd, Hg, As, and Zn in surface soils significantly exceeded the background values for soils in China, with a pronounced positive correlation observed between these heavy metal elements in both surface and deep soil profiles (r > 0.5). Furthermore, leveraging the heavy metal content in surface soils and the constructed environmental indicators, the predictive accuracy for metal content in deep soils was found to range from R2 = 0.27 to 0.68, suggesting that informal mining activities have led to substantial variations in metal content across different soil profiles. Through the application of a random forest model for predictive analysis of the PLI, NIPI, and ERI, high prediction accuracy was achieved (R2 = 0.78, 0.86, and 0.60, respectively). The study demonstrates that informal mining activities not only elevate the risk of soil pollution but also alter the distribution patterns of heavy metals. Also, this study provides a crucial foundation for the scientific assessment of soil quality and potential environmental hazards, while also affirming the efficacy of ML techniques in forecasting soil quality parameters.

A comparative study between the efficacy of fertigation and spraying procedures in terms of the content of Cadmium (Cd) and Arsenic (As) in greenhouse cucumber.

A comparative study between fertigation and spraying procedures in terms of the status of Cadmium (Cd) and Arsenic (As) in greenhouse cucumber was conducted as a two-factor split plot based on a randomized complete block design with three replications at the Soil and Water Research Institute, Karaj, Iran in 2023. The main and sub-factors were respectively fertigation and spraying that were used in two levels [the maximum permissible concentration of Cd and As in granular triple super phosphate fertilizer (25ppm Cd and 50ppm As) and the minimum permissible concentration of these metals in granular triple super phosphate fertilizer (5ppm Cd and 5ppm As)]. Spraying was done in three modes (spraying of leaves, leaves and fruit, and fruit). On average, the results showed that the order of the concentration of Cd in plant tissues (DW) was as leaf (0.284mg/kg) > fruit peel (0.102mg/kg) > fruit peel + flesh (0.054mg/kg) > fruit flesh (0.044mg/kg). This order for As was as leaf (0.608mg/kg) > fruit flesh (0.127mg/kg) > fruit peel + flesh (0.109mg/kg) > fruit peel (0.072mg/kg). Based on the measurements, the spraying procedure accumulated more amounts of Cd and As in the fruit (i.e., peel + flesh) than the fertigation procedure. In general, it is concluded that under soilless culture, the status of heavy metals in plant tissues of greenhouse cucumber is related to the nature of the metal, the organ exposed to the metal, and the fertilization procedure. Because there is the risk of contamination of vegetables grown in the areas fertigated and sprayed with poor-quality nutrient solutions in terms of the content of heavy metals, the frequency of fertigation and spraying needs to be monitored continuously for the quality of the vegetables cultivated in greenhouses.

Status, Sources, and Risks of Heavy Metals in Surface Sediments of Baiyangdian Lake and Inflow Rivers, North China

Baiyangdian Lake, recognized as the largest freshwater body in northern China, plays a vital role in maintaining the regional eco-environment. Prior studies have pointed out the contamination of sediments with heavy metals, raising concerns about eco-environmental challenges. Therefore, it is imperative to evaluate the current pollution levels and ecological threats related to heavy metals found in the sediments of Baiyangdian Lake as well as in its inflow rivers. In May 2022, surface sediments with a depth of less than 20 cm were analyzed for Cu, Zn, Pb, Cr, Ni, As, Cd, and Hg to determine the pollution status, identify sources of pollution, and evaluate potential ecological risks. A range of evaluation methods used by predecessors such as geo-accumulation index (Igeo), enrichment factor (EF), ecological risk index (RI), sediment quality guidelines (SQGs), positive matrix factorization (PMF), absolute principal component score-multiple linear regression model (APCS-MLR), chemical mass balance (CMB), and UNMIX model were analyzed. After comparison, multi-methods including the geo-accumulation index (Igeo), absolute principal component score-multiple linear regression model (APCS-MLR), ecological risk index (RI), and sediment quality guidelines (SQGs) were utilized this time, leading to a better result. Findings reveal that pollution levels are generally low or non-existent, with only 1.64% of sampling sites showing close to moderate pollution levels for Cu, Pb, and Zn, and 4.92% and 1.64% of sites exhibiting close to moderate and moderate pollution levels for Cd, respectively. The main contributors to heavy metal presence are pinpointed as industrial wastewater discharge, particularly Cu, Zn, Pb, Cd, and Hg. The ecological risks are also relatively low, with 4.92%, 1.64%, and 1.64% of sampling sites demonstrating close to moderate, moderate, and strong risks in the inflow rivers, respectively. Additionally, only one site shows moderate potential biological toxicity, while the rest display non-toxicity. These findings will update our cognition and offer a scientific basis for pollution treatment and ecosystem enhancement for government management.

The Natural Habitats, Nutrients, and Heavy Metal Status of Wild Steppe Peony Populations in Serbia

Steppe peony (Paeonia tenuifolia L.) is a strictly protected herbaceous species in Serbia, yet its growing conditions, nutrient needs, and heavy metal status are under-researched. This research is vital for conservation, as it supports sustainable cultivation, genetic diversity, and habitat restoration. This study addresses the gap in understanding how climate and soil characteristics affect P. tenuifolia, particularly regarding nutrient availability and heavy metal accumulation. Despite its recognized medicinal value, insufficient data on environmental impacts limit effective conservation and cultivation strategies. Addressing this gap will help determine optimal growth conditions and ensure the species’ survival and medicinal use. Data on P. tenuifolia natural habitats in Serbia were collected following the Descriptor List for medicinal plants. Field and laboratory analyses assessed climatic and soil characteristics, as well as macro- and microelement contents and heavy metals in soil and plant organs. In Serbia, P. tenuifolia thrives in a semi-arid steppe climate on light, sandy loam soils with a pH of 6.9–7.4. The soils are rich in humus (4.36–5.76%) and nitrogen (0.34–0.37%), but low in phosphorus (1.16–3.50 mg/100 g) and variable in potassium (12.5–52.4 mg/100 g). Soil microelements are abundant, and harmful heavy metals are below critical levels. Plant organs, including flowers, seeds, leaves, and stems, show high phosphorus and magnesium levels, while potassium, manganese, and copper are generally low. The levels of potentially harmful elements like cadmium and chromium are near the maximum-allowed limits, suggesting avoidance of highly acidic soils for the cultivation of P. tenuifolia. Among the examined soils, Arenic chernozem is recommended for preserving the species’ natural resources.

Pollution Assessment and Source Apportionment of Heavy Metals in the Surrounding Soil of Typical Mining Areas in Tongling, Anhui Province

To study the level of heavy metal pollution and ecological risks in the soil around typical mining areas in Tongling, a total of 150 soil samples were collected from the study area. The content characteristics of 10 elements, namely, As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Fe, and Zn, in the soils were analyzed. Methods including enrichment factor, the geo-accumulation index, single-factor pollution index, Nemero comprehensive pollution index, and potential ecological risk index were used to evaluate the pollution status of heavy metals in the soil of the study area. The pollution sources of heavy metals in the soil were also analyzed using correlation analysis, cluster analysis, and principal component analysis. The results showed that except for Cr and Fe, the average contents of the other eight heavy metal elements were higher than the soil background values in the study area. Pb, Zn, As, Cu, and Cd had a high degree of variation and were significantly affected by external interference. The spatial distribution showed that both Cr and Ni showed a decreasing trend from the edge to the central region, whereas the other eight heavy metals showed a decreasing trend from the central region to the surrounding areas. The pollution level of Cd and Cu in the soil of the research area was relatively severe. The overall ecological risk was at a medium to low level. Cd and Hg were the main contributing factors. As, Cd, Cu, Fe, Mn, Pb, and Zn mainly came from agricultural, industrial, and transportation sources, whereas Cr and Ni were mainly from natural sources. However, the sources of Hg were relatively complex. The research results can provide a scientific basis for the prevention and control of soil heavy metal pollution in metal mining areas, as well as the remediation of mine pollution.

Present Status Of Trace Elements And Heavy Metals In AyurvedicMedicines

The therapeutic benefits of Ayurvedic medicines are historically well known. Sometimes the concentration of trace and heavy metals can vary depending on their geographical sources, whichcan cause extremely harmful effects. Thus, one of the most important topics nowadays is the assessment of toxicity and safety of these Ayurvedic medicines. The presence of these constituents in the soil of the study area can be linked to the formation of toxicants of these harmful elements. They should be used with caution in the field as their uncontrolled ingestion can have harmful dangerous consequences on their consumers. Analysis by atomic absorption spectrometry allowedthe detection of trace and heavy metals. This paper discusses the current status of trace elements and heavy metals in Ayurvedic medicine. Along with this, the effects of trace elements and heavymetals on human health have also been explained. This research paper also contains about in whatway to determination of Trace element and heavy metal from ayurvedic medicines specially “Ras

Determination and contamination status of mercury and other heavy metals in artisanal and small-scale gold mining at Banyumas region, Central Java, Indonesia, using ICP-OES

ABSTRACT The determination of mercury and other heavy metals (As, Cd, Cr, Ni, and Pb) has been carried out as toxic metals for the human body. Sample preparation was carried out by the microwave digested assist. The determination of heavy metals was carried out using the ICP-OES. The validation parameters used were linearity, Limit of Detection (LoD), Limit of Quantitation (LoQ), precision, and accuracy. Mercury, Arsen, Cadmium, Chromium, Nickel, and Lead average content in sediment gold ore processing waste was 1617.64, 5525.09, 20.24, 484.96, 259.67, and 1210.27 μg/kg, respectively. Linearity used a standard solution of 10–1000 μg/kg, and it produced a regression equation with r2 > 0.9992. The Limit of Detection (LoD) and the Limit of Quantitation (LoQ) was below 1.56 μg/kg and 6.27 μg/kg, respectively. The precision was calculated by the repeatability method, with a result of %RSD below 2.30%. Accuracy was obtained by recovering a spiked standard. The recovery value was found to be between 83% and 118%. Geoaccumulation Index (Igeo), Metal Pollution Index (MPI), Degree of Contamination (Cdeg), and Potential Ecological Risk Index (PERI) in this study was −8.62–1.43, 0.02–5.33, 8.80, and 168.59, respectively. The waste processing site at Artisanal and Small-Scale Gold Mining is generally contaminated by mercury and other heavy metals. All the validation parameters of the method are in the acceptability range, so the method can be used as a routine method for determining mercury and other heavy metals (As, Cd, Cr, Ni, and Pb) levels in gold ore processing waste.

Assessment and Source Analysis of Heavy Metal Pollution in Farmland Soil Around Tin Mine

Studying the status and source analysis of heavy metal pollution in farmland in typical mining and processing areas is an important prerequisite for promoting farmland soil ecological restoration and farmland protection in concentrated mining areas. In this study, the heavy metal content of farmland soil around a mining area in southwest China was detected, and the pollution status, distribution law, health risks, and sources of heavy metals were studied by using the land accumulation index method, comprehensive pollution index method, kriging interpolation method, health risk assessment method, and PMF receptor model on the sampling data. The results showed that the mean values of eight heavy metals in farmland soil except Ni exceeded the local soil background values, and the results of the ground accumulation index evaluation showed that Cd and Hg were extremely polluted； Pb and As showed medium pollution-heavy pollution； and Cr, Zn, Ni, and Cu were lightly polluted. In the health risk assessment, oral ingestion was the main exposure route posing a health risk to the human body； the main element that constituted non-carcinogenic health risks was As, and the carcinogenic risks were from As and Cd. PMF model analysis showed that the contribution rate of weathering natural sources of iron-bearing ore was 28.02%, and the main factors were Ca and Fe. The contribution rate of agricultural sources was 3.02%, and the main factors were Pb and As. The contribution rate of industrial and atmospheric deposition composite sources was 33.09%, and the main factor was Hg. The contribution rate of the parent material source was 17.27%, and the main factor was Ca. The contribution rate of mining activities such as mining and smelting was 18.60%, and the main factors were Zn and Cd.

Identification Priority Source of Heavy Metals in Urban Soils Based on Source-specific Ecological Risk Analysis in a Typical Tourist City

To understand the pollution status, distribution characteristics, and pollution sources of soil heavy metals in tourist cities in northwest China, the soil content of heavy metals As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in the main areas of Dunhuang City was collected and analyzed. The soil heavy metal pollution level was quantitatively evaluated by the methods of the geo-accumulation index and improved Nemerow pollution index, and the sources of heavy metal pollution were quantitatively analyzed using cluster analysis and the positive matrix factorization （PMF） model. The contribution rate of each pollution source to ecological risk was determined by combining the PMF model and comprehensive ecological risk index. The results showed that except for the mean contents of As and Ni, the mean contents of Cd, Cr, Cu, Hg, Pb, and Zn were all higher than the background values in Gansu Province. However, the average content of the eight elements was lower than the screening value of construction land in the Standard for Soil Pollution Risk Control of Soil Environmental Quality Construction Land （trial） （GB 36600-2018）. Among them, the enrichment of Cd, Pb, and Hg was more serious, and the exceedance rate was higher than 90%. The results of the geo-accumulation index indicated that urban soils were mainly polluted by Hg in the study area, and Cd, Cr, Cu, Pb, and Zn pollution also existed in different degrees. The improved Nemerow pollution index illustrated that the comprehensive pollution degree of the soil was clean to moderate pollution, and the overall pollution was light pollution. Based on the PMF model, we could conclude that soil heavy metals in the study area were affected by natural sources, industrial deposition sources, industrial sources, traffic sources, and comprehensive sources, and the contribution rates were 29.28%, 25.86%, 20.13%, 16.5%, and 8.23%, respectively. The specific source-integrated ecological risk assessment model found that the industrial deposition source contributed the most to the ecological risk in the study area and could be regarded as the priority control pollution source, and Hg was considered to be the priority control pollution element for ecological risk.

Analysis of heavy metal and arsenic sources in mangrove surface sediments at Wulishan Port on Leizhou Peninsula, China, using the APCS-MLR model

Mangrove forests are sources and sinks for various pollutants. This study analyzed the current status of heavy metal and arsenic (As) pollution in mangrove surface sediments in rapidly industrializing and urbanizing port cities. Surface sediments of mangroves at Wulishan Port on the Leizhou Peninsula, China, were analyzed using inductively coupled plasma emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) for the presence of Cr, Pb, Ni, Zn, Cd, Cu, As, and Hg. The Pollution load index, Nemerow pollution index, and Potential ecological risk index were employed to evaluate the pollutant. Multivariate statistical methods were applied for the qualitative analysis of pollutant sources, and the APCS-MLR receptor model was used for quantification. This study indicated the following results: (1) The average content of eight pollutants surpassed the local background level but did not exceed the Marine Sediment Quality standard. The pollution levels across the four sampling areas were ranked as Ⅲ > Ⅳ > Ⅰ > Ⅱ. The area Ⅱ exhibited relatively lower pollution levels with the grain size of the sediments dominated by sand, which was not conducive to pollutant adsorption and enrichment. (2) The factor analysis and cluster analyses identified three primary sources of contamination. As, Cr, Ni, and Pb originated from nearby industrial activities and their associated wastewater, suggesting that the primary source was the industrial source. Cd, Cu, and Zn stem from the cement columns utilized in oyster farming, alongside discharges from mariculture and pig farming, establishing a secondary agricultural source. Hg originated from ship exhaust burning oil and vehicle emissions in the vicinity, representing the third traffic source. (3) The APCS-MLR receptor model results demonstrated industrial, agricultural, and traffic sources contributing 47.19 %, 33.13 %, and 13.03 %, respectively, with 6.65 % attributed to unidentified sources.

Impact of biochar produced at different pyrolysis conditions on heavy metal contaminated soil.

This study aimed to assess the effectiveness of urban derived biochars such as Sugarcane bagasse (SB), Brinjal Stem (BS), and Citrus Peel (CP) produced at two different pyrolysis conditions (450 and 600°C for 60min) for soil heavy metal bioremediation potential. An ex-situ study was conducted to remediate single heavy metal-contaminated SoilRite with lead (Pb), copper (Cu), chromium (Cr) and cadmium (Cd), with biochars applied at different rates. Heavy metal status in soilrite was evaluated using various extraction methods (water-soluble, exchangeable, TCLP (Toxicity Characteristic Leaching Procedure), and PBET (Physiologically Based Extraction Tests)) to determine the biochar treatments' efficacy. The findings show that SB biochar at 450-60 are more effective in immobilizing heavy metals in water-soluble (Cd-100% Pb and Cu-70%), exchangeable (Pb:91%, Cd and Cu by 70-80%) and PBET-extracted forms (Cd-91%, Pb-80%, and Cu-75%), whereas biochar derived from BS (84%) and CP (90%) at 600-60 are more effective in immobilizing TCLP-extracted form of Pb and Cu. Urban derived biochars significantly reduced the toxicity of Pb, Cu, and Cd in various extractable forms and can stabilize and convert them into less accessible forms except for Cr. These extraction methods aid in evaluating environmental risks and influencing remediation strategies for soil heavy metal pollution. Urban biochar, as a cost-effective and eco-friendly solution, significantly solves this issue, facilitating sustainable waste management.

Status of Heavy Metals in Soil and Vegetables Grown in Peri-Urban Areas of Jabalpur District, Madhya Pradesh, India

Status of Heavy Metals in Soil and Vegetables Grown in Peri-Urban Areas of Jabalpur District, Madhya Pradesh, India

Distribution Characteristics and Assessment of Heavy Metal Pollution in Sediments of Fengyuan River, Guangdong

Mining activities and industrial production discharges often generate heavy metal pollution and pose serious environmental impacts. It is of great significance to study the pollution status and sources of heavy metals in polluted rivers for environmental pollution control. This paper determines the concentration of 34 heavy metals, including As, Cd, Cr, Cu, Ni, Pb, and Zn, in the Fengyuan River and tailing pond in Yunfu City, Guangdong Province. The potential ecological risk index (RI) and integrated pollution index (IPI) were used to evaluate the spatial distribution and pollution levels of heavy metals, and the possible source and enrichment of heavy metal were identified and assessed using enrichment factor (EF). The results showed that Cd and Tl in the slag of the tailings pond were the most serious; The potential ecological risk index indicates that Cd in the sediment of the Fengyuan River is a very severe ecological risk, As and Pb caused heavy and moderate ecological risk, respectively, while, Co, Cr, Cu, Mn, Ni, V, and Zn constituted mild ecological risks; The integrated pollution index shows that all the sampling sites are above high pollution. The average enrichment factor of Cd in surface sediments reached 28.11. The EF values of As, Cu, Mn, Pb, and Zn were all greater than 1. The RI, IPI, and EF produced similar levels of heavy metal pollution in sediments, thereby confirming each other’s results, indicating that the Fengyuan River is heavily contaminated, and As, Cd, Mn, Pb, and Zn were likely to have an effect on the aquatic ecosystem. According to principal component and hierarchical cluster analyses, the Fengyuan River may contain heavy metals from a variety of sources, such as tailings ponds, industrial parks, chemical effluent, and more. In addition, correlation analysis indicates that total organic carbon is significantly correlated with the concentrations of As and Cr, respectively, and combining EF suggests that cluster 1 containing As, Mn, and Pb and cluster 2 containing Cd and Zn may be derived from similar anthropogenic sources. This study can provide meaningful basic information for environmental development planning and decision-making associated with human health in the region.

Assessment of Microplastic Pollution in Surface Water and Sediments of Otammiri River, Imo State, Nigeria

This study analyzed the physicochemical and heavy metal status and also quantified microplastics from Otammiri River, Imo state, Nigeria. The physicochemical and heavy metal analysis were carried out using procedures of Federal Environmental Protection Agency. The quantification of the microplastics from Otammiri River was carried out according to the National Oceanic and Atmospheric Administration (NOAA) protocol for surface water trawling for microplastics. The microplastics quantified in this study were at the range of 0.3 mm to 5mm that were resistance to wet oxidation and exhibited flotation in a 5M NaCl. The result of the physicochemical parameters showed that the parameters were within the Federal Ministry of Environment (FMEV) permissible limits with exception to lead and mercury. The microplastics concentrations at the surface water of Otammiri River was between 0.12 g to 2.50 g and in sediments samples, between 0.01 g to 1.37 g.

Potentially Toxic Metals: Their Effects on the Soil-Human Health Continuum

As the foundation of nutritious foods lies in the soil, the consumption of crops grown in contaminated soils may pose an elevated risk of health issues through the soil-plant-human pathway. The impact of heavy metals (HMs) and metalloids on the physiological and biochemical responses of plants can have adverse effects on both growth and yield. The excessive accumulation of these substances in plant tissues poses a significant challenge to public health. HMs possess the capability not only to function as carcinogens but also to act as co-carcinogens, thereby activating specific chemical compounds. According to the World Health Organization (WHO) reports, the target values, representing the desirable maximum concentrations of HMs in the soil, follow the order: Cr>Pb>Zn>Cu>Ni>Cd. This implies that Cd poses the highest potential risk, given its target value of 0.8 mg/kg, while Cr carries the lowest potential risk, with a target value of 100 mg/kg. Various agricultural management practices are recognized as significant pathways that induce the accumulation of metals in the soil and the surrounding environment. Hence, understanding the origin and status of HMs in the environment, along with assessing their potential risks and developing strategies to mitigate these risks, becomes crucial. This study aims to evaluate different facets of the soil-human health continuum concerning potentially toxic metals.

Bioaccumulation of Lead and Mercury in Water, Sediment, and Fish Samples of Baraila Lake, Vaishali, Bihar.

In the current study, a protected subtropical wetland in Bihar (India), Baraila Lake, was investigated for heavy metal (Pb and Hg) status. These metals tend to bioaccumulate in fish, posing a concern to human health. This study reported the concentration of lead and mercury in water, sediment, and fish muscles of Baraila Lake in the year 2022. The samples were collected from pre-monsoon and post-monsoon seasons at four sampling locations, i.e., Loma, Dhulwar, Chakaiya, and Kawai Baraila, and were analyzed in triplicates. Lead concentration in water samples of all four sites of Baraila Lake observed during pre-monsoon and post-monsoon season exceeded the permissible limit for drinking water, while the mercury concentration of all sites was under the permissible limit in both seasons as prescribed by WHO. The extent of elemental pollution was evaluated using the Geo-accumulation index (Igeo), contamination factor (CF), contamination degree (Cd), ecological risk factor (Er), and the potential ecological risk index (Ri). Lead concentration in fish muscles of both seasons exceeded the permissible limit, while the concentration of mercury exceeded in Xenentodon cancila (0.55 ± 0.07µg/g) during the pre-monsoon season. Also, estimated daily intake (EDI), target hazard quotient (THQ), and hazard index (HI) were calculated in different fish muscles to assess potential human health risks. A higher THQ value of 1.303 was observed in carnivore fish during the pre-monsoon season.

Ecological risk and spatial distribution, sources of heavy metals in typical purple soils, southwest China

The identification and quantification of the ecological risks, sources and distribution of heavy metals in purple soils are essential for regional pollution control and management. In this study, geo-accumulation index (Igeo), enrichment factor (EF), pollution index (PI), potential ecological risk index (RI), principal component analysis (PCA) model and geographical detector (GD) were combined to evaluate the status, ecological risk, and sources of heavy metals (HMs) in soils from a typical purple soil areas of Sichuan province. The results showed that the average contents of As, Cd, Cr, Cu, Hg, Ni, Pb and Zn in purple soil were 7.77, 0.19, 69.5, 27.9, 0.077, 30.9, 26.5 mg/kg and 76.8 mg/kg, and the Igeo, EF and RI of topsoil Hg and Cd in designated area was the highest, and the average contents of Hg and Cd in topsoil were obviously greater than respective soil background value in Sichuan province and purple soil. The hot spots for the spatial distribution of 8 HMs were mainly focused in the southwest and northeast of the designated area, and there were also significant differences for 8 HMs distribution characteristics in the profile soil. Cu comes from both anthropogenic and natural sources, Zn, Ni and Cr mainly come from natural sources, but As, Pb, Hg and Cd mainly derived from human activities. GD results showed that soil texture (X18), altitude (X4), total nitrogen (TN), clay content (X3), sand content (X2) and silt content (X1) had the greatest explanatory power to 8 HMs spatial differentiation.This study provides a reference for understanding the status and influencing factors of HM pollution in typical purple soil, and lays a theoretical foundation for the environmental treatment of purple soil in China.

Surface water pollution by some heavy metals in a remote island, Hatiya, northern Bay of Bengal

IntroductionMetal contamination in surface water in urban cities has become a common scenario in underdeveloped and developing countries. Nowadays, the extent of this contamination is suspected to be traced in remote islands due to the transportation of metals with downward water flow. Unfortunately, we found a dearth of research on our remote island, where thousands of people live and use surface water for their daily needs. ObjectivesThe current study aims to investigate the status of heavy metals in surface water from a remote island, Hatiya Coast, to determine the existence of heavy metals and their risks to human health. Ten surface water samples were collected, and their concentrations were measured using AAS. Later, various pollution indices were analyzed to understand their pollution level. ResultsThe mean metal concentrations were ranked in descending order of Mg (65.44 mg.L−1)> Fe (0.375 mg.L−1)> Zn (0.139 mg.L−1)>Mn (0.016 mg.L−1)> and Cu was below the detection limit (BDL). According to different metal pollution indexes, the surface water of the Hatiya coast is low to moderately polluted. The standard HEI value was 1.58, and the range was 1.29–2.25, indicating that all sampling stations had a low level of metal contamination. The mean and range of HPI values were found at 44.58 and 34.33–69.33, respectively. All of the sampling stations indicated low pollution levels except sampling station 6. NPI values revealed moderate contamination in stations 2, 3, and 7. According to the hazard quotient (HQ) and hazard index (HI) for adults and children, heavy metals were found to have no carcinogenic risks for children and adults through dermal exposure. ConclusionAlong with the metals coming from upstream, several local sources of heavy metals were identified during fieldwork, including metallurgical businesses, oil spills from the ship, and some trawlers associated with fishing activities. Overall, these findings would be valuable for aquaculture sectors and future researchers to compare, correlate, and understand the pollution level of the island and serve as a foundation for conducting further investigations in similar island environments, both locally and globally.