Potential Ecological Risk Level Research Articles

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.

Characteristics of Soil Heavy Metal Pollution and Health Risks in Chenzhou City

The objective of this inquiry is to illuminate the attributes of heavy metal contamination and evaluate the potential ecological hazards inherent in the surface soil of Chenzhou City. A comprehensive analysis was conducted on 600 systematically collected soil samples within the study area, utilizing enrichment factors, geo-accumulation indices, comprehensive pollution indices, potential ecological hazard indices, and health risk assessment models to evaluate the degree of heavy metal contamination in the soil, potential ecological risks, and associated health hazards. The findings reveal that the average enrichment factor (EF) for each heavy metal is below 2, with the hierarchy from highest to lowest being Hg > Cd > Cu > Pb > Ni > Zn > Cr > As. Approximately 78.67% of soil samples exhibit no pollution to weak pollution levels based on heavy metal enrichment factors. Moreover, the comprehensive pollution index (IPIN) indicates that 95.17% of soil samples are within safe and pollution-free levels, indicating an overall environmentally secure setting. However, 2.67% of samples display heightened potential ecological risk levels, primarily concentrated in the southwestern region of the study area, influenced by nearby industrial activities. Additionally, it is noteworthy that both the non-carcinogenic and carcinogenic health hazards emanating from soil heavy metals to adult individuals lie within tolerable thresholds. Among these, arsenic (As), chromium (Cr), and lead (Pb) have been discerned as the principal non-carcinogenic agents. It is of particular significance that only a solitary soil specimen, located in the southwestern quadrant of the investigative region, manifests detectable health perils for children.

Isotopic insights and integrated analysis for heavy metal levels, ecological risks, and source apportionment in river sediments of the Qinghai-Tibet Plateau

The research was carried out to examine the pollution characteristics, ecological risk, and origins of seven heavy metals (Hg, As, Pb, Cu, Cd, Zn, and Ni) in 51 sediment samples gathered from 8 rivers located on the Qinghai-Tibet Plateau (QTP) in China. The contents of Hg and Cd were 5.0 and 1.1 times higher than their background values, respectively. The mean levels of other measured heavy metals were below those found naturally in the local soil. The enrichment factor showed that the study area exhibited significantly enriched Hg with 70.6% sampling sites. The Cd contents at 19.6% of sampling sites were moderately enriched. The other sampling sites were at a less enriched level. The sediments of all the rivers had a medium level of potential ecological risk. Hg was the major ecological risk factor in all sampling sites, followed by Cd. The findings from the positive matrix factorization (PMF) analysis shown agricultural activities, industrial activities, traffic emissions, and parent material were the major sources. The upper, middle, and low reaches of the Quanji river had different Hg isotope compositions, while sediments near the middle reaches were similar to the δ202Hg of the industrial source. At the upstream sampling sites, the Hg isotope content was very close to the background level. The results of this research can establish a strong scientific sound to improve the safety of the natural circumstances of rivers on the QTP.

Potential Ecological Risk Assessment of Soil Heavy Metals in Fengdong New District Based on Information Diffution Model

The large-scale construction of new districts has led to severe soil heavy metal pollution. Therefore, taking Fengdong New District as the target research area, the descriptive statistics of heavy metal content characteristics and Kriging interpolation analysis have been conducted, and the potential ecological risk index and information diffusion theory were further combined to create an information diffusion model based on risk assessment. Finally, the pollution degree, ecological risk, and risk occurrence probability of Pb, Cu, Cd, and Hg were discussed. The findings revealed that the average concentrations of the four heavy metals far exceeded the background value of soil heavy metals by a factor of 1.943 (Pb), 1.419 (Cu), 3.074 (Cd), and 3.567 (Hg), respectively. Moreover, the distribution of soil heavy metals showed strong variability(CV>65%)owing to human interference. The distribution of Pb and Cu pollution were predominantly influenced by industrial production and land development for construction purposes, whereas industrial activities, agricultural practices, and transportation served as the primary sources of Cd contamination. On the other hand, industrial construction emerged as the major factor contributing to Hg pollution. The average values of individual potential ecological risk index for heavy metals of 9.716 (Pb), 7.095 (Cu), 92.292 (Cd), and 142.469 (Hg), coupled with the regional comprehensive potential ecological risk index (RI) average of 251.573, signified that the region was overall characterized by a relatively high potential ecological risk status. The overall potential ecological risk for Pb and Cu in the region were mild, whereas Cd and Hg posed moderate to high risks, indicating that Cd and Hg were the dominant driving factors behind regional heavy metal pollution. The evaluation results of the information diffusion model based on the potential ecological risk indicated that the probability ranking of different levels of comprehensive potential ecological risk was as follows:slightly high (38.98%) > moderate (38.55%) > high (5.89%) > slight (5.15%) > extremely high (3.56%). The exceeding probabilities of potential ecological risk levels for Cd and Hg were significantly higher than those for Pb and Cu. The exceeding probability of different pollution levels of Hg were slight (94.89%), moderate (66.85%), slightly high (23.62%), high (3.9%), and extremely high (2%), of which only the surpassing probability of the slight level was lower than that of Cd. The prediction error of pollution probability of each potential ecological risk level was less than 5%, demonstrating the reliability of the information diffusion model based on the risk assessment. This research will provide technical reference and support for the monitoring and management of potential ecological risks from soil heavy metals in limited sample data regions.

Exposure to arsenic and other potentially toxic elements: health risk assessment and source analysis in the Wuming Basin, Guangxi Province, China

Guangxi, China, is one of the world's largest karst regions where potential toxic elements tend to accumulate, resulting in high soil background values. This study explores the ecological risk, elemental baseline values, and sources of potential toxic elements in karst regions, expanding the research to include 21 common elements. The significance of this research lies in its implications for the management of potential toxic element pollution, the formulation of environmental quality standards, and soil remediation in karst areas. In this study, 12,547 topsoil samples (0–20 cm) were collected in the study area. Pollution assessment and ecological risk evaluation of eight potential toxic elements (Zn, Ni, Cu, Pb, Cd, Hg, Cr, and As) were conducted using the geo-accumulation index method and potential ecological risk index method. Multivariate statistical analysis was applied to analyze the total content of 21 common elements (Zn, Ni, Cu, Pb, P, Cd, Hg, Co, Mn, Cr, V, I, S, As, pH, Se, N, CaO, Corg, Mo, and F). Additionally, the potential sources of 21 soil elements were preliminarily quantitatively analyzed using the principal component analysis-absolute principal component scores-multiple linear regression receptor model. The results showed that (1) Zn, Ni, Cu, Pb, Cd, Cr, V, and As were enriched in the research area and Ca, Cd, Mn, Mo, Hg, As, and Cu might have been influenced by human activities; (2) Cr, Pb, As, and Zn were generally lightly polluted, with Hg having a moderate potential ecological risk level; and (3) Ni and Zn have contributions of 37.99% and 35.07% from geological sources, agricultural fertilization, and pesticides. Mo, V, Cr, Se, Hg, and As exhibit contributions ranging from 39.44 to 59.22% originating from geological backgrounds and human activities. Corg, S, N, and P show contributions of 45.39% to 80.33% from surface vegetation. F, Co, Mn, and Pb have contributions ranging from 31.63 to 47.93% from acidic rocks in the soil parent material, mining activities, and transportation. Cd and CaO derive 31.67% and 40.23%, respectively, from soil parent material and industrial sources. I has 31.94% from geological background and human activities, and 31.95% from soil parent material and atmospheric sources. Cu has 30.56% from geological sources. The study results can serve as a scientific basis for element research in karst areas domestically and internationally.

Temporal change of potential toxic element contamination, ecological and toxicological risk in holocene in Southern Black Sea coasts (Türkiye)

This study was carried out to evaluate the temporal variation of the potential toxic element concentration and ecological risk level during the Holocene along the Southern Black Sea coasts. Ecological and ecotoxicological indices such as enrichment factor (EF), modified ecological risk index (mRI), modified potential ecological risk index (mPER) and toxic risk index (TRI) were used in the study. Anthropogenic effects were determined to be more dominant in the western and middle parts of the Southern Black Sea Region. As, Cu, Pb, Zn, Cd, Hg, Ni enrichments were observed in the last 200 – 300 years and the potential risk index values related to them increased. Source of enrichment detected in the cores was found to be related to the volcanic activities that occurred in different geological periods. It was determined that the increases in PTE concentration observed specifically in the middle parts of the cores coincided with the dates of the volcanic activities observed in Anatolia.

Contamination Characteristics and Source Apportionment of Soil Heavy Metals in an Abandoned Pyrite Mining Area of Tongling City, China

To investigate the impact of pyrite mining on the heavy metal pollution in the surrounding soil in Tongling City, 50 surface soil and sediment samples were collected from mining fields, farmland, forests, villages, and the river. The contents of Zn, Cr, Cu, Pb, Ni, Cd, and As in soils and sediments were analyzed. Then, the spatial distribution characteristics of heavy metals in soil were analyzed, and the degree of heavy metal pollution and potential ecological risk level were assessed. Finally, the sources of soil heavy metal pollution were identified. In general, the soil in the study area was weakly acidic (average pH=6.32), and the contents of other heavy metals except Ni exceeded the background values of the soil in Tongling City. Moreover, Ni and Cd were enriched in the river sediments. According to the Nemerow pollution index, Pb and As reached heavy pollution levels, Cu and Cd reached moderate pollution levels, and other elements belonged to light or non-pollution levels. The comprehensive pollution index of different land types was ranked in the order of mining field > river > forest > farmland > village. Mining fields and the river were heavily polluted, forest land was moderately polluted, and farmland and villages were mainly mildly polluted. Pb, As, and Cd belonged to the medium ecological risk category. The contribution rates of the potential ecological risk index were 33.27%, 27.39%, and 20.22%, which were much higher than the other four elements. The ranking results of the potential ecological risk index of different land types was the same as that of the comprehensive pollution index. Mining fields and the river were at a high-risk level, forest land reached moderate risk, and the rest were at a slight risk level. The consistent results of correlation analysis, principal component analysis (PCA), and positive definite matrix factor analysis (PMF) indicated that Zn, Cu, Pb, Cd, and As were mainly derived from pyrite mining activities, Cr mainly came from the parent material and agricultural production, and Ni was mainly affected by soil-forming parent material and pyrite mining activities.

Phenolic compounds occurrence and human health risk assessment in potable and treated waters in Western Cape, South Africa.

Phenolic pollutants from industrial and agricultural activities pose a major threat to the world's potable water supply. The persistent micro-pollutants often find their way into drinking water sources with possible adverse human health implications. In this study, bottled water, tap water, and wastewater treatment plant (WWTP) effluent samples from the Boland region of the Western Cape, South Africa were assessed to determine 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP) levels using HPLC/DAD instrumentation. The selected area is known for its vast agricultural ventures and wineries. Evaluation of the human health risk (cancer risk) for the pollutants was conducted using the hazard quotient (HQ). The Ames mutagenicity test was also conducted using the Salmonella typhimurium T98 and T100 strains and the S9 activation enzyme. Trace levels of the phenolics were detected in the samples with a range of 9.32 × 10-7-1.15 × 10-4mg/L obtained for 4-CP, and 8.80 × 10-7-1.72 × 10-4mg/L recorded for 2,4-DCP. Both compounds had levels below the limit of 0.01mg/L prescribed by South African legislation. The assessed HQ for the phenolic concentrations indicates a low level of potential ecological risk and none of the samples had a cancer risk value that exceeded the regulatory limit. The possibility of the analyzed samples causing cancer is unlikely, but non-carcinogenic adverse effects were found. Strong mutagenicity was observed for the T98 strains with a potential ability to cause mutation toward the insertion or deletion of a nucleotide. The T100 bacterial strain showed very slight mutagenicity potential, however, it is unlikely to cause any mutation. The levels of phenolics in the potable water samples may pose a significant threat to human health. Hence, screening persistent organic chemicals in potable water sources and evaluating their potential human health effects is pertinent to prevent associated health challenges.

Spatial-temporal evolution of ecological risks in a typical urban lake in Southwestern China

During urbanization, excessive development and utilization pose varying risks and challenges to the ecosystems of many urban lakes. Sediments are invaluable archives of past ecosystem changes. By analyzing variations in 210Pb and other geochemical indicators in sediment cores, it is possible to assess how susceptible lakes are to the impacts of climate change and human-induced pollution, which is crucial for urban planning and the management of lake environments. This study investigated the status of heavy metal pollution in Lake Longquan, Chengdu City, and reconstructed the historical evolution of its ecological environment using 210Pb dating. Three main conclusions are drawn. (1) Currently, Cd, Cu, Pb, Zn, Cr, and organic matter in the surface sediments of Lake Longquan are highly enriched in the southeastern, central, and northeastern regions. Cd levels even reach 1.54 mg/kg in the southeastern part of the lake near the town. The high overlap of heavy metal distribution with historical aquaculture areas and some tourist areas indicates that aquaculture and tourism are important sources of heavy metals that increase their bioavailability. (2) Lake Longquan is currently at a high potential ecological risk level, and the high potential risk level of Cd may cause ecological safety problems. The biological toxicity of As should be considered, too. (3) The risk evolution in Lake Longquan can be divided into six stages: (i) Before 1977, the ancient river. With the destruction of forest vegetation and the intensification of rock weathering, ecological risks increased. (ii) 1977–1989, construction and development. Due to human factors and the joint influence of heavy precipitation events, ecological risks increased; and (iii) 1989–2010, development prioritized protection. Due to the ineffective implementation of protection policies, aquaculture increases risks. (iv) 2010–2017, development. As a provincial resort and tourism area, the significant increase in human activities has led to constantly rising sedimentation rates and heavy metal concentrations, resulting in an ecological risk peak. (v) 2017–2020, protection. The efficient implementation of lake protection and restoration policies proved to be effective, and the ecological risk started to decrease. (vi) After 2020, protective development. The government's plan to reduce fertilizer usage and increase forest cover will help control ecological risks. It is necessary to continue controlling tourism and aquaculture activities, and transitional areas should be established around lakes for city residents to engage in lakeside sightseeing and recreational sports. This study provides valuable references for controlling and preventing heavy metal pollution in urban lakes.

Heavy Metal Pollution in a Lake: An Assessment of the Ecological Threat

The purpose of this study was to investigate and evaluate the presence of different heavy metals in sediment samples collected from water of Durgam Cheruvu . The concentrations of six heavy metals, namely arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), and zinc (Zn), were quantified using the technique of inductively coupled plasma-atomic emission spectroscopy (ICPAES). The investigation employed relative enrichment factors and prospective ecological risk indices to examine the contamination levels of heavy metals in sediment samples and evaluate their potential ecological impact on the surrounding ecosystem. The order of heavy metal sediment enrichment factors was determined to be as follows: chromium (Cr) exhibited the highest enrichment factor, followed by arsenic (As), cadmium (Cd), zinc (Zn), copper (Cu), and lead (Pb). Several potential ecological risk indices for heavy metals were identified. The order of decreasing reactivity of the elements is as follows: Cadmium (Cd) > Arsenic (As) > Chromium (Cr) > Copper (Cu) > Lead (Pb) > Zinc (Zn). The prospective ecological risk indices, as determined through calculations, indicate that the lake has been low contaminated by heavy metals. Cadmium (Cd) exhibited a moderate level of potential ecological risk within the ecological environment and emerged as the primary factor contributing to the possible toxicity response indices associated with different heavy metals in Durgam cheruvu. The application of analysis of variance was employed to determine the statistical significance of the observed fluctuations in heavy metal concentrations. The analysis of mean seasonal concentrations of metals revealed statistically significant variations across different seasons and sampling sites. The pollution in Durgam Cheruvu may be attributed to industrial and anthropogenic activity. We have put up a series of techniques that can be implemented to mitigate the accumulation of heavy metals in the lake.

Assessment of Zn, Pb and Cd in Soil around an MSW Incineration Plant: Using Risk Assessment and Multivariate Statistical Techniques

To investigate and evaluate the spatial distribution of Zn, Pb and Cd in the soil around a municipal solid waste incineration plant and its ecological risks, Zn, Pb and Cd were analyzed in soil samples around a municipal solid waste incineration plant in Chengdu, Sichuan Province, China. The results revealed that the average content of Zn and Pb did not exceed the soil environmental quality value for the risk control standard for soil contamination of agricultural land (GB15618-2018), but the average content of Cd in the soil was higher than this standard. Multivariate statistical analysis indicated that Cd was the predominant pollutant and had strong correlations with Zn and Pb. The Cd content was most impacted by human activities, which also explained that this municipal solid waste incineration plant has little effect on Zn, Pb and Cd in the surrounding soil. The geo-accumulation index decreased in the order of Cd > Zn > Pb, and the geo-accumulation index of Cd was greater than 5, indicating that the pollution level for Cd was extremely heavy. The comprehensive potential ecological risk index (RI) of various heavy metals was greater than 1200, And the potential ecological risk level of the study area was high. The contribution rate of Cd to RI was relatively large, and Cd pollution should be paid more attention to.

Components of sludge from municipal wastewater treatment plants and its evaluation for land application in JiUJiang city of China

Municipal sewage sludge has a potential for widespread application on land, but the implementation of new standards for the agricultural use of sludge in China support a cautious approach. The organic matter, nutrients, and heavy metals in sewage sludge from four municipal wastewater treatment plants in Jiujiang City of China were continuously monitored. The feasibility for its land use was analyzed from three aspects such as sludge nutrients, heavy metal pollution levels, and potential ecological risks in soil. The average content of Cd, Cu, Zn, Cr, Ni, Pb, Hg and As in the sludge of Jiujiang City are 1.85, 305.25, 764.48, 170.57, 42.45, 42.27, 0.59, 28.79 mg∙kg-1, which are less than or close to mean value of heavy metals in China (except As), and all meet the minimum standards of heavy metal content in the sludge according to Chinese Quality of sludge from municipal wastewater treatment plant (GB24188-2009). The maximum content of Cu, Zn, Cr, and As exceed the control standards of pollutants in sludge for agricultural use, and the maximum value of Cu and Cr are close to the limit of landscaping standards. The average contents of organic matter, total nitrogen, total phosphorus, total potassium, and total nutrients in sludge are 385.16, 34.14, 11.05, 7.87, 53.06 g∙kg-1, respectively. The organic matter content meets the limit value (no less than 200 g∙kg-1) of Chinese Control standards of pollutants in sludge for agricultural use (GB 4284-2018), and the total nutrients content meets certain content limit (no less than 40 g∙kg-1) of total nutrients in China’s organic fertilizer. The single-factor pollution index and Nemerow’s synthetic pollution index methods were used to assess the pollution of heavy metals. The heavy metal pollution indexes (PI) are in descending order: Cd > Cu > Zn > Cr > As > Ni > Pb > Hg. The PI shows that Cd and Cu are in strong pollution level, Zn is in moderate pollution level, and As, Ni, Pb, Hg are in absolute safe level. The potential ecological risk levels of heavy metal are ranked in the following order: Cd> Cu> As> Ni> Zn> Cr > Pb. The monomial potential ecological risk coefficients reveal that Cd is in extremely strong ecological risk, Cu is in medium ecological risk and other heavy metals are in slight ecological risk. The results indicate that Cd and Cu are the main contributors to the pollution and potential ecological risks of heavy metals in soil, to which more attention should be paid during sludge disposal. Being rich in organic matter and inorganic plant nutrients，sewage sludge in Jiujiang City may be widely used on soil, but availability of potential toxic metals exceeding the limit value often restricts its uses. Before being harmlessly treated, the sludge in Jiujiang City should not be used on agricultural land and may be applied with highly caution on landscaping and land improvement, but it can be used as cover materials for co-landfilling.

Distribution Characteristics, Source Analysis and Potential Ecological Risk Assessment of Soil Heavy Metals in Typical River Source Areas of Northeastern Hunan Province

Soil environmental quality in water source areas related to the residents' life, health and safety, has been the hotspot issues in science of ecological environment protection. A total of 87 surface soil samples were collected from typical river source areas in northeastern Hunan Province, using GIS technique and potential ecological risk assessment index to study the spatial distribution characteristics and Potential ecological risk of soil heavy metals (Cd, Pb, Cr, Hg and As), and the means of multivariate statistical analysis and positive definite matrix factor analysis models (PMF) were used to explain the possible sources and its contribution rates of heavy metals. The results show that:① The soil located in the typical river source area of northeastern Hunan Province was acidic, and the meant of ω(Cd), ω(Pb), ω(Cr), ω(Hg), and ω(As) in soil was 0.20, 41.07, 130.51, 0.29, and 11.63mg·kg-1, respectively. And except As, all of them had enrichment tendency. ② The comprehensive potential ecological risk of soil heavy metals was at a medium level, among which Cr, Pb and As were at a slight level of potential ecological risk, and Cd and Hg all reached a strong level of risk. ③ Cd and Pb of soil had significant homology, which were derived from agricultural activity, Cr and As of soil were affected by both domestic waste discharge and natural parent material, and Hg of soil was mainly derived from fossil combustion and transportation. ④ There were four pollution sources which included household waste discharge source, natural parent material source, Fossil burning and transportation sources, as well as sources of agricultural activities in typical river source area in northeastern Hunan Province, which contributed the rates of heavy metals were 21.36%, 35.92%, 19.30% and 23.42%, respectively, and the contribution rate of man-made sources was higher than that of natural sources. To sum up, this study has reference value for pollution prevention, ecological restoration and beautiful village construction in river source area of northeastern Hunan Province.

The pollution of microplastics in sediments of the Yangtze River Basin: Occurrence, distribution characteristics, and basin-scale multilevel ecological risk assessment.

Microplastics (MPs) pollution in the Yangtze River Basin (YRB) of China has grown to be a serious issue, yet there is a lack of understanding of the environmental risks of MPs in the sediment of the entire basin. This work revealed the spatial distribution characteristics of MPs in YRB sediments, and it methodically assessed the ecological risks of MPs by taking into consideration their abundance, toxic effects, and polymer types. The results showed a high heterogeneity in the abundance of MPs in YRB sediments, with an average of 611 particles/kg dry weight (DW) sediment. Small-sized MPs (<1mm), fibrous, transparent-colored and polypropylene (PP) accounted for the majority with 71.6%, 68%, 37% and 30.8%, respectively. Correlation analysis indicated significant influences of human activities such as population, industrial structure, and urban wastewater discharge on the abundance and morphological types of MPs in sediments. Based on chronic toxicity data exposed to sediments, a predicted no-effect concentration (PNEC) of 539 particles/kg DW was calculated using the species susceptibility distribution (SSD). Multiple deterministic risk assessment indices indicated that MPs in YRB sediments exhibited primarily low pollution load levels, moderate-to-low potential ecological risk levels, and high levels of polymer pollution. However, probabilistic risk assessment revealed an overall low risk of MPs in YRB sediments. Monte Carlo simulation results demonstrated that polyvinyl chloride (PVC) and polycarbonate (PC) made a great contribution to ecological risk and should be considered as priority control pollutants in MPs. In addition, various assessments showed that the ecological risk of MPs in river sediments was higher than that in lake reservoir sediments. This is the first study to comprehensively assess the ecological risk of MPs in sediments of the YRB, which improves the understanding of the basin-wide occurrence characteristics and environmental risks of MPs in freshwater systems.

Accumulation Pattern and Risk Assessment of Potentially Toxic Elements in Permafrost-Affected Agricultural Soils in Northeast China.

The accumulation of potentially toxic elements (PTEs) in agricultural soils is of particular concern in China, while its status, ecological risks, and human health hazards have been little studied in the permafrost areas of Northeast China. In this study, 75 agricultural soil samples (0-20 cm) were collected from the Arctic Village, Mo'he City, in the northernmost part of China. The average concentration (mean ± standard deviation) of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn were 12.11 ± 3.66 mg/kg, 0.11 ± 0.08 mg/kg, 52.50 ± 8.83 mg/kg, 12.08 ± 5.12 mg/kg, 0.05 ± 0.02 mg/kg, 14.90 ± 5.35 mg/kg, 22.38 ± 3.04 mg/kg, and 68.07 ± 22.71 mg/kg, respectively. Correlation analysis, cluster analysis, and principal component analysis indicated that As, Cu, Ni, and Zn likely originated from geogenic processes, Hg and Pb from long-range atmospheric transport, Cd from planting activities, and Cr from Holocene alluvium. The geo-accumulation index and enrichment factor showed that As, Cd, Hg, and Zn are enriched in soils. The Nemerow pollution index showed that 66.67%, 24%, and 1.33% of soil samples were in slight, moderate, and heavy pollution levels, respectively, with Hg being the most important element affecting the comprehensive pollution index. The potential ecological risk index showed that 48.00% and 1.33% of soil samples were in the moderate ecological risk and high potential ecological risk levels, respectively. The non-carcinogenic and carcinogenic human health risk index for adults and children were both less than 1, which was within the acceptable range. This study revealed the accumulation pattern of PTEs in agricultural soils of permafrost regions and provided a scientific basis for research on ecological security and human health.

Comprehensive assessment of metals and organic pollutants in pelagic fishing port sediments

Fishing ports are among the environments that accumulate pollutants along the coast but often lack environmental data and scientific research. This study investigated 8 metals, 16 polycyclic aromatic hydrocarbons (PAHs), 10 phthalate esters (APs), and 2 alkylphenols (APs) in the surface sediments of Qianzhen Fishing Port, the largest pelagic fishing port in Taiwan. Indicator compounds, pollution hotspots, potential ecological risk levels, and pollution sources were evaluated. Results showed that copper, zinc, and bis(2-ethylhexyl) phthalate (DEHP) in surface sediments were pollution indicators posing potential toxicological risks. Metals and PAHs in sediments were mainly from ship-related sources, while PAEs and APs were related to dockland activities. Combining metal and organic pollutants, the sediments had a moderate potential ecological risk, with metals higher than organic pollutants. Cluster analysis and color geographic map of risks indicate sediment pollution hotspots and areas requiring immediate intervention. In the future, sustainable operation and management can be carried out by using metal-free antifouling paint, improving sewage treatment rate, and regular environmental dredging of fishing port.

Spatial distribution and ecological risk assessment of heavy metal elements in rock‐soil in the mountainous areas of Southwest China: A case study of Xichang

This study employs the Muller geological accumulation index method and the Hakanson risk assessment method in combination with ArcGIS technology to assess the potential heavy metal pollution in soil. The study aims to investigate the geochemical characteristics, pollution degree, and potential ecological risks associated with soil heavy metal element content and distribution across various geological formations. The concentrations of eight heavy metals, namely Cu, Cd, Ni, Pb, Zn, Hg, As, and Cr, were analysed by collecting samples of the soil layer, parent material layer, and parent rock layer. The proportions of samples with different risk levels are accurately calculated to locate areas with high pollution risks. The findings are as follows: Firstly, the soil pH value in the study area is low, and the Cd and Cr concentrations are 1.38 and 1.20 times the background concentrations in soil in Sichuan Province, respectively. Moreover, Cu, Cd, Ni, Zn, and Cr concentrations are 1.23, 1.10, 1.20, 1.10, and 1.55 times the background concentrations in soil in China. Secondly, the distribution of heavy metal elements varies across different geological formation units, and the heavy metal contents of different samples from the same formation also varies significantly. The concentrations of heavy metal elements are influenced by different geological formations, with the pedogenic parent rock in the soil determining the initial concentrations of heavy metal elements. Thirdly, the spatial distribution of heavy metal elements indicates a good spatial distribution coupling relationship among the soil layer, parent material layer, and rock layer. The study suggests that the contents of the eight heavy metal elements in the soil inherited the characteristics of the parent material to a large extent and are influenced and controlled by the pedogenic parent rock (geological formation). Finally, the evaluation results reveal that all eight heavy metal elements exhibit moderate pollution, with a relatively large distribution area exhibiting moderate Cd, Hg, and As pollution and above. The overall study area exhibits a mild potential ecological risk level, with some areas at a moderate potential ecological risk level, distributed in patches across the study area. Cd and Hg exhibit relatively high potential ecological risks. The potential ecological risks of heavy metals are relatively high in the JKms and Tss units. While the overall quality of the soil in the study area is good, heavy metal pollution and potential ecological risks of some elements are still above ideal levels.

Ecological Risk Assessment and Source Apportionment of Heavy Metals in Mineral Resource Base Based on Soil Parent Materials

Mineral resource bases have dual properties, e.g., mineral resources and environmental pollution. The latter could be classified into natural and anthropogenic pollution based on identifying the spatial distribution characteristics and sources of heavy metals in the soil. The Hongqi vanadium titano-magnetite mineral resources base in Luanping County, Luanhe watershed, was taken as the research object. The geo-accumulation index (Igeo), Nemerow comprehensive pollution index (PN), and potential ecological risk (Ei) were utilized to assess the soil heavy metal pollution characteristics, and redundancy analysis (RDA) and positive determinate matrix factorization (PMF) were employed to identify sources of the soil heavy metals. The results revealed that the mean contents of Cr, Cu, and Ni in the parent material of medium-basic hornblende metamorphic rock and medium-basic gneisses metamorphic rock were 1-2 times that in other parent materials in the concentrated area of mineral resources. However, the mean contents of Pb and As were lower. Fluvial alluvial-proluvial parent materials had the highest mean content of Hg, and the mean content of Cd was higher in the parent materials of medium-basic gneisses metamorphic rocks, acid rhyolite volcanic rocks, and fluvial alluvial-proluvial facies. The Igeodecreased in the following order:Cd>Cu>Pb>Ni>Zn>Cr>Hg>As. PN ranged from 0.61 to 18.99, and the sample proportion of moderate and severe pollution reached 10.00% and 8.08% respectively. Pishowed that the contents of Cu, Cd, Cr, and Ni were relatively higher in the parent material of intermediate-basic hornblende metamorphic rocks and intermediate-basic gneiss metamorphic rocks. Ei decreased in the order of Hg(58.06)>Cd(39.72)>As(10.98)>Cu(6.56) >Pb(5.60)>Ni(5.43)>Cr(2.01)>Zn(1.10). Samples whose RI was lower than 150 accounted for 84.27%, showing that the research area was predominantly at a slight potential ecological risk level. The sources of soil heavy metals were dominated by parent material weathering, followed by the mixed sources of agricultural activities and transportation, the exploitation of mining, and fossil burning, which accounted for 41.44%, 31.83%, 22.01%, and 4.73%, respectively. The risks of heavy metal pollution in the mineral resource base were characterized as multi-source instead of the single source from the mining industry. These research results provide the scientific basis for regional green mining development and eco-environmental protection.

Distribution Characteristics, Ecological Risks, and Source Identification of Heavy Metals in Cultivated Land Under Non-grain Production

The purpose of this study was to explore the distribution characteristics and potential ecological risks of soil heavy metal pollution of cultivated land under non-grain production. Taking a typical area around Hangzhou Bay as an example, 254 topsoil samples (0-20 cm) of cultivated land were collected, and the content of eight soil heavy metals in four different cultivated land use types, including grain, seedlings, vegetables, and fruits, was analyzed. The ecological risk was assessed by the Nemerow pollution index and the potential ecological risk index, and the PMF model was used to identify the source of soil heavy metals in the study area. The results showed that the average contents of As, Cr, Cd, Cu, Hg, Ni, and Zn were all higher than the soil background value, except for Pb, but were lower than the national risk control standard for soil contamination of agricultural land. Non-grain production had a significant impact on the accumulation of heavy metals in soil. The content of heavy metals in nurseries and orchards was relatively high, followed by vegetable fields, and the lowest in grain fields. The Nemerow index showed that the cultivated land in the study area was in a light pollution level as a whole, and the single-factor pollution risks of Hg, Cd, and As were relatively high. The potential ecological risk levels of heavy metals in different cultivated land use types were:nurseries>orchards>vegetable fields>grain fields. The PMF results showed that the main sources of soil heavy metals in the study area were mixed sources of industrial emissions (36.8%), natural parent material sources (28.4%), atmospheric deposition sources (21.4%), and agricultural activity sources (13.4%). In conclusion, the increase in the application of chemical fertilizers and pesticides was the direct reason for the increase in soil heavy metal content caused by non-grain production of the cultivated land, whereas the industrial and mining emissions and atmospheric deposition accelerated the increase in soil heavy metal content in the study area.

Changes in ecological and health risk assessment indices of potentially toxic elements associated with ambient air particulate matters (PM2.5) in response to source, land use and temporal variation in Isfahan city, Iran

Fine particles and their associated compounds such as potentially toxic elements (PTEs) are critical pollutants in ambient air of industrialized urban areas that adversely affect human health. The aim of this study was to determine the pollution, ecological and human health risk assessment of potentially toxic elements in PM2.5 using various indices spatiotemporally, in case of Isfahan city, Iran. Besides, the manuscript objective was to identify an overview and a comprehensive perspective of the potentially toxic elements pollution and risk in PM2.5, affected by anthropogenic and natural source and inversion time using various ecological and health risk assessment indices. The concentrations of 17 PTEs associated with PM2.5 from 40 sampling sites in ambient air of Isfahan city, Iran, were measured. Then their ecological risks (including individual and overall indices) and human health risks (carcinogenic and non-carcinogenic) were assessed. The results of the ecological risk analyses revealed traffic (particularly diesel vehicles) and industrial activities (metal smelting plants, brick and cement factories) together with natural sources (dust storms) affected the risk of PTEs. Among the elements, As, Pb, Cr, and Cd showed the highest health risk, respectively, and only As, Pb, and Cd crossed the carcinogenicity threshold in some sites. Cu, As, and Cd showed the level of highest, average, and potential ecological risk, respectively. Although fall was the most critical season in terms of PTEs ecological risk due to temperature inversion, the human health risk was the highest in summer mainly because of PTEs associated with dust storms. This revealed that health and ecological risk indices vary depending on the source of PM2.5, type and concentration of associated PTEs at different times. The risk trend for different sampling sites was urban > industrial > bus terminal showing the necessity of air pollution control in urban areas with a high population density.