Potential Ecological Risk Index Values Research Articles

The influence of water conservancy project on microplastics distribution in river ecosystem: A case study of Lhasa River Basin in Qinghai-Tibet Plateau

Water conservancy projects affect the migration, suspension, and deposition of microplastic (MP). However, its impact on MP pollution of river ecosystem remains elusive. Herein, we investigated the MP characteristics and the influence of water conservancy projects on MPs in the Lhasa River Basin of the Qinghai-Tibet Plateau, China. The results demonstrated that the MPs concentration in surface water decreased from upstream to downstream, as more MPs in surface water were settling down and stored in reservoir sediments in the midstream. It is postulated that reservoir sedimentation of MPs occurs at a greater rate due to the barrier effect of reservoirs, steady hydrodynamics, and weak salinity-induced buoyancy. To evaluate the ecological risk of the Lhasa River Basin, the pollution load index, the polymer hazard index, and the potential ecological risk index were analyzed. The upstream exhibits elevated polymer hazard index values (>100), and the potential ecological risk index values in the Lhasa River Basin showed ecological risk similar to those of pollution load index values. This research represents the initial exploration of MP distribution within the entire Lhasa River basin, providing a foundational framework for investigating the impact of water conservancy projects on MP migration.

Exploring the traits and possible ecological risks of heavy metals in biochars derived from rice husk and sugar beet pulp.

This research investigated the properties and potential environmental hazards associated with biochars derived from rice husk (RH) and sugar beet pulp (SBP), both of which are rich in heavy metals (HMs). The results indicated that the concentration of various HM fractions is significantly affected by the type of feedstock and the pyrolysis temperature. Specifically, the total concentrations of HMs in biochars produced at 600°C were found to be 10-140% higher than those in the original biomasses, a phenomenon attributed to the precipitation of HMs. Cd was a notable exception, exhibiting a reduction of 3-7% in the resultant biochars when compared to biomass, likely attributable to its volatilization. The results also revealed that the F1 + F2 fraction of HMs were largely transformed into F3 + F4 fraction during combustion, indicating that pyrolysis may reduce the ecotoxicity of HMs present in contaminated biomass. However, the process did not effectively diminish the F1 and F2 fractions of Cr and Cd. Elevated pyrolysis temperature significantly enhanced the reduction of HMs phytoavailability. Specifically, the phytoavailability of HMs in biochars produced at 600°C exhibited a decrease ranging from 10 to 92% when compared to the original biomass. Conversely, an unexpected rise in the phytoavailable fractions of Cr and Cd was noted in both RH and SBP biochars as the pyrolytic temperature increased, which correspondingly raised the potential ecological risk index (PERI). All materials analyzed exhibited a very high risk level, with PERI values exceeding 800, primarily due to the significant toxicity of Cd. Excluding Cd from consideration, the biomasses and their resultant biochars displayed PERI values ranging from 7 to 13. It is important to acknowledge that pyrolysis may not effectively diminish the environmental toxicity associated with HMs present in contaminated biomass, thereby limiting its safe application.

Spatial distribution, ecological and human health risks of potentially toxic elements (PTEs) in river Ravi, Pakistan: A comprehensive study

Significant quantities of potentially toxic elements have been and are still being discharged into Pakistan's rivers through natural sources and anthropogenic activities. The present study provides a comprehensive study of potentially toxic element contamination in the water and sediment of the Ravi River, Pakistan. The research aims to examine the extent of pollution, its ecological risks, and the potential human health impacts through detailed geospatial analysis and statistical correlation. Water and sediment representative samples were taken and analyzed for potentially toxic elements, including Cobalt (Co), Cadmium (Cd), Zinc (Zn), Nickel (Ni), Arsenic (As), Chromium (Cr), Lead (Pb), Copper (Cu), and Manganese (Mn). Various pollution indices, such as the “Geo-accumulation Index (Igeo), Modified degree of Contamination (mCd), Nemerow comprehensive pollution index (Pt), Contamination factor (CF), Enrichment factor (EF), Pollution Load Index (PLI), and Potential Ecological Risk Index (PERI),” were calculated to determine the contamination levels and ecological risks. The results indicated significant spatial variability in metal concentrations, with higher levels observed in industrial and urban areas (near Lahore). Cd and As were identified as the most critical pollutants, exhibiting high Igeo, CF, EF, and PERI values. The PLI revealed that several regions along the river are heavily polluted. Pt shows high comprehensive pollution near Lahore and moderate to high pollution in surrounding areas. According to mCd, most of the study area, especially sampling points near Lahore, ranges between 8 and 16, indicating a high degree of pollution. The Human Health Risk (HHR) assessment, considering ingestion, inhalation, and dermal contact pathways, highlighted that children are particularly vulnerable, showing higher Hazard Quotient (HQ) and Hazard Index (HI) values for several metals. Correlation analysis revealed significant relationships between certain metals, suggesting common sources of contamination, likely from industrial discharges and urban runoff. The comprehensive mapping and statistical analysis underscore the urgent need for implementing effective pollution control measures to mitigate the risks posed by potentially toxic element contamination in the Ravi River. This study provides critical insights for policymakers and environmental managers to prioritize areas for remediation and to develop strategies to protect both ecological and human health in the region.

Distribution characteristics and ecological risk assessment of heavy metal pollution in seawater near the Yellow River Estuary of Laizhou Bay

To understand the characteristics and pollution status of heavy metals in the intersection areas of Laizhou Bay and the Yellow River Estuary in Shandong Province, the contents of various heavy metals in surface seawater samples collected from this area in August 2022 were detected. The spatial distributions of the heavy metals were analysed, which exhibits a general decreasing trend in the concentrations of Hg, As, Cr, and Pb from west to east, while Cd, Zn, and Cu show the opposite trend. The average single-factor index P values decrease in the following order Pb > Zn > Hg > Cu > As > Cd > Cr, among which Pb, Zn, Hg, and Cu caused pollution in this area. The potential ecological risk index values indicate that the main heavy metal pollutants in study area are Hg and Pb, with Hg having the highest value, accounting for 74.7%, and being the main potential ecological risk factor. Correlation analysis shows that the most significant environmental factor affecting heavy metal content is salinity. According to the interactive heatmap between cluster analysis and station classification, the heavy metals have originated from industrial, agricultural, and domestic sewage discharge, surface runoff, river inputs, seawater aquaculture, maritime transportation, and fuel exhaust emissions. This research hopes to provide some reference value for the protection of marine and estuarine ecosystems.

Soil quality and heavy metal contamination in an open dumpsite in Navrongo, Ghana.

The increasing proximity of the Dudumbia dumpsite, an open dumpsite in Navrongo, Ghana, to human settlements necessitates an investigation of the soil quality to safeguard the environment from heavy metal toxicity. This study examined the impact of waste dumping activities on the physicochemical properties of the soil, as well as the level of heavy metal (Pb, Cd, Ni, Cr, As, Hg, Cu, Mn, and Zn) contamination and associated risks. Various contamination and risk assessment tools were used, including the geoaccumulation index (Igeo), pollution load index (PLI), potential ecological risk (Er), and potential ecological risk index (PERI). The study found significant improvements in notable soil attributes such as phosphorus (P), organic carbon (C), total nitrogen (N), calcium (Ca), magnesium (Mg), potassium (K), sodium (Na), and effective cation exchange capacity, with percentage increases ranging from 50.8 to 2078.3%. Igeo values ranged from 2.07 to 6.20, indicating contamination levels from moderate to extreme. The PLI and PERI values were 16.241 and 1810, respectively. The Er values for the heavy metals ranged from 36 to 607, indicating ecological risk levels from low to very high, with Cd and Hg posing very high risks. These results suggest that while the dumpsite soil shows improvements in some characteristics favourable for plant cultivation, waste dumping significantly contributes to heavy metal contamination. The soil at the dumpsite is deteriorated and poses significant health risks, particularly due to Cd and Hg. Therefore, remediation efforts should prioritise mitigating the risks posed by Cd and Hg.

Quantifying microplastics in sediments of Jinzhou Bay, China: Characterization and ecological risk with a focus on small sizes

Small-sized microplastics (MPs) pose greater ecological toxicity due to their larger surface area, which makes them more likely to act as carriers for other pollutants and to be ingested by aquatic organisms. However, traditional visual analysis often neglects small-sized MPs and their associated ecological risk. This study utilized Laser Direct Infrared (LDIR) spectroscopy and traditional visual analysis to examine MPs in 31 sediment samples from Jinzhou Bay, a typical semi-enclosed bay located at the economic center of Dalian, China. The results showed significant heterogeneity in MP distribution, with averages of 1192 and 2361 items/kg dry weight reported by visual analysis and LDIR spectroscopy, respectively. LDIR spectroscopy identified MPs as small as 10 μm, with the majority of MPs (89.21 %) within the 10–250 μm range, and a significant proportion (46.45 %) between 10 and 50 μm among them. However, visual analysis was limited to detecting MPs >50 μm, and significant portions were identified between 50 and 100 μm (49.36 %) and 100–250 μm (31.01 %), missing a substantial fraction of smaller MPs. The predominant polymers identified were polyamide (PA), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and acrylonitrile butadiene styrene (ABS). LDIR spectroscopy demonstrated a strong positive correlation between MP abundance and clay content, a relationship not observed with traditional visual analysis. The Potential Ecological Risk Index (PERI) indicated that over 87 % of sites posed an extremely high risk according to LDIR spectroscopy, compared to 51 % by traditional visual analysis. These discrepancy underscores the underestimation of ecological risks by traditional methods, particularly for small-sized MPs. High-risk polymers such as polyvinyl chloride (PVC), ABS, and polyurethane (PUR) significantly influenced PERI values. These findings highlight the critical need for precise identification and thorough risk assessment of small-sized MPs in environmental studies and offer insights for understanding of MP vertical migration in aquatic environments, particularly in the context of co-settlement with sediments.

Ecological and health risk assessments of heavy metals and their accumulation in a peanut-soil system

Heavy metals pollution is a notable threat to environment and human health. This study evaluated the potential ecological and health risks of heavy metals (Cu, Cr, Cd, Pb, Zn, Ni, and As) and their accumulation in a peanut-soil system based on 34 soil and peanut kernel paired samples across China. Soil As and Cd posed the greatest pollution risk with 47.1% and 17.6% of soil samples exceeding the risk screen levels, respectively, with 26.5% and 20.6% of the soil sites at relatively strong potential ecological risk level, respectively, and with the geo-accumulation levels at several soil sites in the uncontaminated to moderately contaminated categories. About 35.29% and 2.94% of soil sites were moderately and severely polluted based on Nemerow comprehensive pollution index, respectively, and a total of 32.4% of samples were at moderate ecological hazard level based on comprehensive potential ecological risk index values. The Cd, Cr, Ni, and Cu contents exceeded the standard in 11.76, 8.82, 11.76 and 5.88% of the peanut kernel samples, respectively. Soil metals posed more health risks to children than adults in the order As > Ni > Cr > Cu > Pb > Zn > Cd for non-carcinogenic health risks and Ni > Cr ≫ Cd > As > Pb for carcinogenic health risks. The soil As non-cancer risk index for children was greater than the permitted limits at 14 sites, and soil Ni and Cr posed the greatest carcinogenic risk to adults and children at many soil sites. The metals in peanut did not pose a non-carcinogenic risk according to standard. Peanut kernels had strong enrichment ability for Cd with an average bio-concentration factor (BCF) of 1.62. Soil metals contents and significant soil properties accounted for 35–74% of the variation in the BCF values of metals based on empirical prediction models.

Pollution Analysis of an Active River Bottom Sediment in Borokiri (Ikpukulu River), Niger Delta, Nigeria

The Niger Delta region, endowed with significant oil and gas resources, faces environmental challenges linked to artisanal petroleum refining activities. This study explores the environmental repercussions of these activities on the ecosystem health of Ikpukulu River bottom sediments in Borokiri, Niger Delta, Nigeria. The study incorporates an assessment of heavy metal and hydrocarbon contamination using geoaccumulation index (Igeo), pollution load index (PLI), and potential ecological risk index (PERI). Three sampling points (X, Y, and Z) along the Ikpukulu River were investigated. While heavy metal concentrations generally fell within background levels, hydrocarbon content, particularly Total Hydrocarbons (THC), exhibited significant pollution. The PERI values for all three points indicated very high ecological risk, demanding immediate attention and remediation efforts. The Ikpukulu River serves as a potential sink for waste from illegal hydrocarbon refining, highlighting severe coastal river pollution in the region. Proactive measures and stringent pollution control regulations are recommended to safeguard the ecosystem's health. The study contributes valuable insights for remediation efforts and policy development in addressing the environmental challenges associated with artisanal petroleum refining in the Niger Delta.

Assessment of levels of contamination and estimation of ecological risk by potentially toxic elements in Chanchaga River of Minna, Nigeria

This research investigated the geochemical characteristics, contamination indices and ecological risk assessment of stream sediments from Chanchaga area of Minna Metropolis, North-Central Nigeria. Eight samples were collected from River Chanchaga and its tributaries and sieved to less than 2 mm grain size following air drying for 48 hours. The samples were subsequently analysed for the concentration of major and trace elements using X-ray fluorescence (XRF) spectrometry. Contamination indices (enrichment ratio, enrichment factor and index of geoaccumulation) and potential ecological risk index (PERI) were used for assessing the level of risk that exists with respect to potentially toxic elements (PTEs). The research has found significant enrichment of Pb and Cu in stream sediments of Chanchaga area, indicating possible contamination by human activities. Based on the indices of geoaccumulation, the sediments are considered to be moderately to heavily contaminated with respect to these two PTEs. Potential ecological risks exist with respect to PTEs in these sediments, with PERI values in the range of 12.88 to 167.76, averaging 58.63. Pb presented higher monomial ecological risk index, falling within the considerable risk band and contributed significantly to the PERI values, compared to that of Cu. It is therefore concluded that human activities within Chanchaga area of Minna metropolis, Nigeria have had a negative impact on stream sediment quality and there is likelihood of mobilisation of PTEs into the water column from sediments under right environmental conditions. It is recommended that the partitioning of PTEs, especially Pb and Cu in these sediments be studied in order to ascertain their ease of dissolution and eventual biogeoaccessibility.

Ecotoxicological risks of metals in the subsistence food garden soils of Watut River floodplains, Papua New Guinea.

Exorbitant concentrations of toxic metals in the soil from anthropogenic activities are environmental hazards and key health risk concerns to humans. The subsistence food garden soils have minimum anthropogenic interventions. The ecotoxicological risk potentials of the metals in subsistence food garden settings are unexplored. The metals (Cr, Cu, Pb, and Ni) concentration were assessed in the surface soil fractions (2mm and 0.2mm) of food gardens (N = 20) on the floodplains of Watut River, Papua New Guinea. The threshold limits, index of geo-accumulation (Igeo), contamination factor (CF), pollution load index (PLI), and potential ecological risk index (PERI) served as potential risk indicators of metals. Regardless of soil particle size, the descending order of median metals concentration was Cr > Cu > Ni > Pb. The concentration of Cu and Ni in the soil particles exceeded the WHO threshold limits in 100% and 50% of the food garden soils, respectively. Metal enrichment led to severe pollution in 100% gardens (Igeo > 5). Cr, Cu, and Ni contamination factors were > 1 in 95% of the food gardens. The PERI values indicated a lower ecological risk of the metals (PERI < 100). The median concentration of Cu, Igeo, and CF values for Cu in the 2mm soil particles were significantly greater than in 0.2mm. The results suggested exposure of subsistence food gardens soils to geogenic metal contamination and the need to carefully choose appropriate soil particle size for the soil health assessments.

Assessment of potential ecological risk based on the vertical characteristics of potential toxic elements in sediments from a high-density cage culture reservoir in China

The pollution of sediments around Lu Ban Island is a serious environmental issue that is threatening human health. The concentration of As, Cd, Cu, Cr, Hg, Ni, Pb, and Zn at 73 layer points were investigated, vertical distribution characteristics, correlation among potential toxic elements and potential ecological risks of sediments at different depth were analyzed. The following results were obtained, (1) the hypothesis that there was a linear relationship between concentration of potential toxic elements and the reciprocal of deep was reasonable. Based on hypothesis, the ultimate value of concentration by making depth go to infinity was regarded as the background concentration. The background concentration of As, Cd, Cu, Cr, Hg, Ni, Pb, and Zn are respectively 4.94 mg/kg, 0.20 mg/kg, 15.48 mg/kg, 58.41 mg/kg, 0.062 mg/kg, 26.96 mg/kg, 20.29 mg/kg, and 53.31 mg/kg. (2) But correlation between Ni and As was relatively weak, high degree of correlation among other potential toxic elements were found. Based on their correlation, eight potential toxic elements were classified into three groups. First group included Ni and Cr, mainly releasing by coal burning; Cu, Pb, Zn, Hg, and Cd were grouped together, possibly due to their shared source of fish cage culture; Arsenic with relatively weak correlation with other potential toxic elements was classified as a separate class, which was usually one important mineral resource associated with phosphate. (3) Potential ecological risk index (PERI) of sediment above − 0.40 m belonged to moderate risk, the PERI of sediment in − 0.10 m, − 0.20 m, and − 0.40 m were 289.06, 254.33, and 201.44, respectively. Sediment below − 0.40 m belonged to low risk with average PERI value 112.82, with no significant changes in PERI values. The order of contribution to PERI was Hg > Cd > As > Cu > Pb > Ni > Cr > Zn. (4) According to result of cluster analysis and potential ecological risk, the potential ecological risk of sediment above − 0.40 m mainly contributed by potential toxic elements of Cu, Cd, Hg, Pb, and Zn sharing source of fish cage culture.

Accumulation characteristics and risk of heavy metals and microbial community composition in bioretention systems: A case study of a university campus

Bioretention systems have proven to be an effective stormwater treatment technology for reducing runoff pollution. However, the accumulation risk of heavy metals and characteristics of the microbial communities in the filter media is still unclear under long-term runoff infiltration. This paper reports on a field study that investigated the ecological impact of common heavy metals and the structures of microbial communities in nine bioretention systems during two seasons. Samples were collected from the filer media to determine the concentrations of heavy metals and the microbial information was obtained by high-throughput sequencing technology. The results indicated that Cr, Ni, Cu, and Zn accumulated significantly in the bioretention system, with mean concentrations 2–3 times higher than the corresponding background values. Heavy metals were mainly trapped in the surface media (0-10 cm) and concentrations varied with season. The comprehensive pollution status of the bioretention systems was at a light to medium level. In particular, Ni accounted for the majority of the potential ecological risk index values, with an ecological hazard of above moderate levels. The results of high-throughput sequencing showed that Actinobacteria (22.51–42.16%) and Proteobacteria (19.67–34.46%) are the dominant phyla in the bioretention media under the long-term pollutants accumulation. Microbial diversity was negatively correlated with the heavy metals content of the media (p < 0.05). Heavy metals inhibited the growth and reduced the diversity of media microorganisms to varying degrees, with Ni contributing the most to microbial community changes. Our findings are expected to help in controlling the heavy metals pollution in the bioretention systems and provide practical guidance regarding the systems operation and media micro-ecosystem maintenance.

Qualitative Assessment of Soil and Sediment Pollution with Some Heavy Metals: A Case Study of Duhok Valley in The Kurdistan Region of Iraq

The current study was conducted on the valley of Duhok and the agricultural lands irrigated from it, where three sites were identified for collecting samples quarterly from soil and sediment using clean plastic bags for the purpose of measuring lead, nickel, cobalt and copper. Pollution load index (PLI), Nemerow pollution index (PIN), Potential Ecological Risk (PER) and Geo-accumulation Index (Igeo) were also calculated according to the internationally approved methods. The results indicated that most of lead, nickel and copper concentrations in soils and sediments exceeded the limits allowed by WHO, reaching annual rates (96.758, 168.746 and 29.88) , (111.25, 219.65 and 48.162) mg.kg-1, respectively. This fluctuation in concentrations was reflected in the values of the studied indicators for both soil and sediment, where 50% and 58% of the studied specimen are of the polluted grade and the remnant are of the non-polluted grade according to the PLI values. So is the case with PIN where 58% of the soil specimen and 41.6% of the sediment samples were of the severe pollution grade, while 25% and 33.3% of the specimen were of the heavy pollution grade and the remnant were slightly pollution grade. The same applies to the results of the PER index values, where 50% and 41.67% of the specimen were from the Medium ecological risk category, and the rest were from the low ecological risk category, likewise for the (Igeo) values, 100% and 96% of the soil and sediment samples were from the Weakly polluted category.

Quantification and characterisation of microplastic pollution and its ecological risk in the coastline of Tuticorin, India

Microplastics (MPs) are present practically everywhere in the coastal ecosystems, including the sediment of beaches and wetlands as well as the columns of surface and subsurface waters. Marine MPs are most frequently found in the near shore zones. Due to their potential negative impact on ecosystem functions, MPs have become a significant environmental problem worldwide. Contamination by microplastics has been well-documented around the world and it has drawn the attention of the scientific community, governmental and international organisations and the general public. In the present study, involving the isolation, assessment and characterisation of MP debris collected from six coastlines with recreation and fishing activities in Tuticorin district, the most common MP polymers identified are polypropylene, polyethylene, polyamide and polystyrene. The maximum number of MPs are found in the sediment samples of Tiruchendur (with an average of 8.33 5.3), and the least number of MPs are observed in the water samples of Aalanthalai (2 1.0). To assess the quality of water and sediment, we calculated the polymer hazard index (PHI), pollutant load index (PLI) and potential ecological risk index (PERI). Because of the presence of high-hazard polymers like polyamide (PA) and polystyrene (PS), the study areas have high PHI values (&gt;1000). According to PLI values, water and sediment samples from Tiruchendur and Manapad are highly contaminated with MPs (PLI: 6.98 to 13.85), whereas samples from Aalanthalai, Kayalpattinam and Roche Park are less contaminated (PLI: 1.87 to 3.43). The PERI values of sediment samples from Tiruchendur show the highest ecological risk (PERI: 416.783). On the basis of anthropogenic activities, centres with recreational activities have substantially greater MP concentrations than the fishing locations, and the sediment samples are considerably more polluted with MPs than the water samples taken from the same locations, according to PLI values.

Bioaccumulation of Heavy Metals in a Soil–Plant System from an Open Dumpsite and the Associated Health Risks through Multiple Routes

Screening various plant species to act as hyperaccumulators and associated health risks could serve as a sustainable solution for the bioremediation heavy metals (HMs). For the first time, the present study explored the phytoremediation potential of native plants, soil enrichment, and human health risks associated with the contamination of HMs in soil and plant samples collected from a municipal solid-waste open dump site. Soil and plant samples (n = 18 + 18) from the dumpsite and (n = 18) from the control site were analyzed for selected HMs, i.e., Chromium (Cr), Lead (Pb), Nickel (Ni), Iron (Fe), and Zinc (Zn). The phytoremediation potential of plants was assessed using the bioaccumulation factor (BAF), bioaccumulation coefficient (BAC), and translocation factor (TF), while soil pollution levels were evaluated using the contamination factor (CF), geoaccumulation index (Igeo), enrichment factor (EF), potential ecological risk index (PERI), and human health risk indices. The results revealed that based on TF and BAC values, Alhagi maurorum Medic., Astragalus creticus Lam., Cichorium intybus L., Berberis lycium Royle, and Datura stramonium L. were hyperaccumulators for Cr while Parthenium hysterophorus L. was a promising species for both Ni and Cr. Similarly, CF values for Fe, Ni, Pb, and Cr were &gt;6, thereby showing very high contamination, while Igeo values for Fe, Ni, Pb, and Cr were (class 6, &gt;5), showing that the soil was extremely polluted. Furthermore, EF values for Fe, Ni, Pb, Cr, and Zn were 2 &lt; EF ≤ 5, depicting moderate enrichment, while PERI values were in the range of 91.31–195.84, employing moderate ecological risks (95 &lt; PERI &lt; 190) from the dumpsite’s soil. Moreover, for non-carcinogenic exposure, none of the analyzed metals exceeded the threshold limit HRI values &gt; 1 in both adults and children. Likewise, in the case of carcinogenic effects, the CRI values were lower than the tolerable limits (1 × 10−6–1 × 10−4) in both adults and children. Moreover, almost all studied plants could be utilized for the phytoextraction of mentioned HMs. In future, the present study can help in the implementation of public policies to ensure sustainability and developmental activities in contaminated sites. Based on these results, it is concluded that there is a dire need of monitoring solid waste dumpsites due to various types of potential risks associated with the contamination of HMs. Moreover, to minimize the potential health problems arising from the dumpsite, it is substantive that special attention should be paid to work on sustainable and eco-friendly remedial measures.

Assessment of accumulation of heavy metals in soil, irrigation water, and vegetative parts of lettuce and cabbage grown along Wawan Rafi, Jigawa State, Nigeria

Human exposure to heavy metal toxicity has been linked to the consumption of vegetables grown on polluted soils. The goal of this study was to see how much heavy metals accumulated in the soil, irrigation water, and vegetative sections of lettuce and cabbage planted in Wawan Rafi, Jigawa State, Nigeria. The concentrations of potentially harmful metals in soil, water, and crops are in the order Mn > Pb > Zn > Ni > Cd > Cu, except for lettuce, where Pb was found to be greater than Mn. Furthermore, the majority of the hazardous elements analyzed were below the allowed limit. Nevertheless, the presence of high levels of metals revealed evidence of contamination, which was attributed to human activities. The potential ecological risk index values for lettuce and cabbage are 86.488 and 225.463, respectively, and both are considered safe because the RI values for both lettuce and cabbage are below or within the range of 200 ≤ RI ˂ 400. This implies consumption of these vegetables may not pose a high health risk to the local public when individual heavy metal is considered, but the risk could multiply when all of the heavy metals are considered together.

Metal Contents and Pollution Indices Assessment of Surface Water, Soil, and Sediment from the Arieș River Basin Mining Area, Romania

The current study was conducted to assess the level and spatial distribution of metal pollution in surface water, soil, and sediment samples from the Arieș River basin, located in central Romania, an area impacted by various mining and industrial operations. Several pollution indices, spatial distributions, cluster analyses, principal component analyses, and heat maps were applied for evaluating the contamination level with Ni, Cu, Zn, Cd, Pb, Mn, As, and Hg in the area. Based on the results of the Heavy-Metal Pollution Index and of the Heavy-Metal Evaluation Index of the surface-water samples, the middle part of the Arieș River basin, near and downstream of the gold mine impoundment, was characterized by high pollution levels. The metal concentration was higher near the tailing impoundment, with increased levels of Cu, Ni, Zn, and Pb in the soil samples and As, Cd, Pb, Na, K, Ca, Mn, and Al in the sediment samples. Ca (23.7–219 mg/L), Mg (2.55–18.30 mg/L), K (0.64–14.70 mg/L), Al (0.06–22.80 mg/L), and Mn (0.03–22.40 mg/L) had the most remarkable spatial variation among the surface-water samples, while various metal contents fluctuated strongly among the sampling locations. Al varied from 743 to 19.8 mg/kg, Fe from 529 to 11.4 mg/kg, Ca from 2316 to 11.8 mg/kg, and Mg from 967 to 2547 mg/kg in the soil samples, and Al varied from 3106 to 8022 mg/kg, Fe from 314 to 5982 mg/kg, Ca from 1367 to 8308 mg/kg, and Mg from 412 to 1913 mg/kg in the sediment samples. The Potential Ecological Risk Index values for soil and sediments were in the orders Cu &gt; Ni &gt; Pb &gt; Hg &gt; Cr &gt; As &gt; Mn &gt; Zn &gt; Cd and As &gt; Cu &gt; Cr &gt; Cd &gt; Pb &gt; Ni &gt; Hg &gt; Mn &gt; Zn, respectively, and the highest values were found around the gold mine impoundment.

Risk assessment of heavy metals in a typical mangrove ecosystem - A case study of Shankou Mangrove National Natural Reserve, southern China

Mangroves bear enormous ecosystem value, while the ecosystems are facing increasing environmental pressures. In this study, 73 samples of soil sediments in mangroves, paddy fields, grasslands, forests, and shrimp ponds were collected from Shankou Mangrove National Nature Reserve (SKMNNR), Guangxi Zhuang Autonomous Region, China. The pollution status and ecological risks of heavy metal elements of Cr, Ni, Cu, Zn, As, Cd, Pb, V, and Co were determined using the enrichment factor (EF), geoaccumulaton index (Igeo), and potential ecological risk index (PERI). The average concentration is shown to be substantially lower than the background value. In general, the Igeo values indicated that the pollution conditions of different land use types in SKMNNR are relatively minor. Most of the PERI values were at the moderate level. This study demonstrates that the current status of sediment quality in SKMNNR is relatively good, and the pollution level is relatively low. Large-scale coastal aquaculture development and industrial expansion should not no longer be permitted there.

Source apportionment and risk assessment of soil heavy metals around a key drinking water source area in northern China: multivariate statistical analysis approach.

With the intensive urbanization and industrialization in recent years, lots of products containing heavy metals (HMs) have brought in severe environment problems. Yuqiao Reservoir (YQR) is an important drinking water source area in Tianjin of China, and the soil environmental quality of YQR is vital for human health. The goal of this study was to identify the priority control pollutants and hotspots of HMs contamination of YQR catchment. Thus, an integrated field investigation was conducted to analyze the major elements such as As, Cd, Cr, Cu, Hg, Ni, Pb and Zn in soils around YQR. Geoaccumulation index (Igeo), enrichment factor (EF) and potential ecological risk index (PERI) were employed to assess the contamination status of HMs. The average contents of these elements were given as follows: As 7.97mg/kg, Cd 0.31mg/kg, Cr 86.1mg/kg, Cu 24.7mg/kg, Hg 0.044mg/kg, Ni 30.7mg/kg, Pb 27.3mg/kg and Zn 76.7mg/kg. According to geoaccumulation index (Igeo) and enrichment factor (EF) values, Cd, Cr, Pb and As showed a prominent enrichment. The result of multivariate statistics showed that Cd, Cr, Cu, As, Ni, Pb and Zn concentrations were mainly affected by human activities, whereas Hg was mainly from natural release. The anthropogenic activities were the major sources with a contribution of 91.46%, while natural origins only contributed 8.54%. And agricultural fertilization, mining and traffic activities are the most probable sources of these heavy metals in the soil. The PERI values indicated that 65.7% of total HMs were at low risk, 22.5% in moderate risk and 11.8% in considerable risk. To ensure soil environmental quality and human health, cadmium should be listed as a priority control pollutant. Spatial maps of HMs and their integrated PERI provided clear hotspots that indicated lower risk in the region close to YQR but higher risk in the region far from YQR.

Imposed by urbanization on soil heavy metal content of lake wetland and evaluation of ecological risks in East Dongting Lake

The properties of heavy metals in soil hold key to effectively protecting the urban ecosystem and predicting the environmental risks. In this study, we selected the wetland of East Dongting Lake as the study area, and measured the contents of their physicochemical properties. We adopted the methods of multivariate statistical analysis and inverse distance weighted (IDW) interpolation, so as to reveal the sources and distribution characteristics of heavy metal content in soil in the study area. By adopting the potential ecological risk index (PERI) method, we assessed the PERI values of heavy metals. The research findings indicate that: (1) As shown by the analysis of correlation matrix, the elements of As, Hg and Zn are positively correlated with SOC (P < 0.01). (2) As shown by the rotation factor load matrix, Factor 1 (F1) accounts for 18.03% of the total variance, which includes As, Fe, Mn, Zn and soil organic carbon. Factor 2 (F2) mainly includes nitrate ammonia, Pb and soil particles, and the factor load all exceeds 0.50. (3) There is a significantly higher level of contents of the elements of Cd, Zn, Pb and Hg in the agricultural land than other types of land use (P < 0.05). (4) Judging from the potential ecological risk coefficient of single heavy metal Eir, Cd features the highest risk coefficient with the mean value of 292, whereas the sampling points that have their E.56ir ≥ 320 account for 36.51% of the total, indicating strong ecological risks. The average value of the comprehensive PERI in heavy metals amounts to 555.03, representing a strong degree of ecological risks.