Risk Assessment Of Heavy Metals 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.

Health risk assessment of heavy metal(loid)s in road dust via dermal exposure pathway from a low latitude plateau provincial capital city: The importance of toxicological verification

The human health risk assessment through the dermal exposure of metal (loid)s in dust from low latitude and high geological background plateau cities was largely unknown. In this study, the road dust samples were harvested from a typical low-latitude plateau provincial capital city Kunming, Southwest China. The total concentration and dermal bioaccessibility of heavy metal (loid)s in road dust were determined, and their health risks as well as cytotoxicity on human skin keratinocytes were also assessed. The average concentrations of As (28.5 mg/kg), Cd (2.65 mg/kg), Mn (671 mg/kg), and Zn (511 mg/kg) exceeded the soil background values. Arsenic had the highest bioaccessibility after 2 h (3.79%), 8 h (4.24%), and 24 h (16.6%) extraction. The dermal pathway when bioaccessibility is considered has a higher hazard quotient than the conventional method using total metal(loid)s in the dust. In addition, toxicological verification suggested that the dust extracts suppressed the cell viability, increased the reactive oxygen species (ROS) level and DNA damage, and eventually activated the mitochondria-mediated apoptosis pathway, evidenced by the upregulation of Caspase-3/9, Bax, and Bak-1. Cadmium was positively correlated with the mRNA expression of Bax. Taken together, our data indicated that both dermal bioaccessibility and cytotoxicity should be considered for accurate human skin health risk assessment of heavy metal(loid)s in road dust, which may provide new insight for accurate human health risk assessment and environmental management.

Occurrence, distribution, and ecological risk assessment of heavy metals in Chao Phraya River, Thailand

Understanding heavy metals in rivers is crucial, as their presence and distribution impact water quality, ecosystem health, and human well-being. This study examined the presence and levels of nine heavy metals (Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn) in 16 surface water samples along the Chao Phraya River, identifying Fe, Mn, Zn, and Cr as predominant metals. Although average concentrations in both rainy and dry seasons generally adhered to WHO guidelines, Mn exceeded these limits yet remained within Thailand’s acceptable standards. Seasonal variations were observed in the Chao Phraya River, and Spearman’s correlation coefficient analysis established significant associations between season and concentrations of heavy metals. The water quality index (WQI) demonstrated varied water quality statuses at each sampling point along the Chao Phraya River, indicating poor conditions during the rainy season, further deteriorating to very poor conditions in the dry season. The hazard potential index (HPI) was employed to assess heavy metal contamination, revealing that during the dry season in the estuary area, the HPI value exceeded the critical threshold index, indicating the presence of heavy metal pollution in the water and unsuitable for consumption. Using the species sensitivity distribution model, an ecological risk assessment ranked the heavy metals’ HC5 values as Pb > Zn > Cr > Cu > Hg > Cd > Ni, identifying nickel as the most detrimental and lead as the least toxic. Despite Cr and Zn showing a moderate risk, and Cu and Ni posing a high risk to aquatic organisms, the main contributors to ecological risk were identified as Cu, Ni, and Zn, suggesting a significant potential ecological risk in the Chao Phraya River’s surface water. The results of this study provide fundamental insights that can direct future actions in preventing and managing heavy metal pollution in the river ecosystem.

Non-carcinogenic risk assessment and sources apportionment of heavy metals in pomegranate in Anhui, China

This study examined the concentrations, sources, and health risks associated with 7 heavy metals in Chinese pomegranates. The results showed that the heavy metal in pomegranates was within standard limits, and the accumulation of heavy metals was low. PCA showed that Cd and Hg in pomegranates originate from irrigation water, Zn, As, and Cu from soil, and Cr and Pb from fertilizers. MLR and Monte Carlo sensitivity analysis showed that soil and irrigation water were the primary sources of heavy metals in pomegranates, with Zn, As, Cu, and Pb primarily originating from soil, and Cd, Cr, and Pb predominantly coming from irrigation water. The presence of organic matter and Ca in soil influenced heavy metal accumulation in pomegranates, other properties (Mg, Fe, and pH value in soil) have minor effects. The TTHQ for both adults and children remained below 1, while the TTRisk exceeded 1×10−4, mainly due to the hazardous impact of As in water. The upper 95% uncertainty limit indicated that residents were exposed to both non-carcinogenic and carcinogenic risks, primarily due to the toxicity of Cr in soil and As in water. Strengthening heavy metal screening in soil and water and enhancing pollution management policies are imperative.

Contamination and health risk assessment of heavy metals in soil surrounding an automobile industry factory in Jiaxing, China

The auto parts industry occupies an important strategic position in our national economy, which brings about the pollution problem in the processing of auto parts, particularly in soil polluted by heavy metals. Soil samples were collected from an automobile parts company in Jiaxing, China, and the data were evaluated using the land accumulation index method. The study found that the heavy metal pollution in the downwind direction of the Automobile Parts Co., Ltd. is mainly As, CD, and Zn mixed heavy metal pollution, and the distribution is uneven. The coefficient of variation of As was the largest, and the regional variation amplitude was large. The coefficient of variation of CD, Cr, and Ni is 50%, that of Zn is 39.38%, and that of PB is the lowest. The accumulative index of AS and CD was 6, which was a very serious pollution level. The content of As was 1994.7 mg/kg, exceeding the standard by more than 44 times, and the distribution of As in soil was uneven. The pollution level of Zn is 3, which belongs to the moderate level. The pollution degree of heavy metals in the soil decreases as the distance from the downwind outlet of the plant increases. According to the health risk assessment, the main route of heavy metals entering the body is through the mouth by breathing. Among exposure routes, oral exposure to heavy metals is the most harmful, so we need to pay special attention to farmland soil heavy metal pollution.

Morphological distribution and risk assessment of soil heavy metals in the Belly of the Three Gorges Reservoir area in Chongqing-A Case Study of Fengdu

The study of the morphological distribution and pollution risk of heavy metals in the hinterland of the Three Gorges Reservoir area in Chongqing can be used to provide data support for soil pollution prevention and control, ecological environment safety risk control and agricultural healthy development in the region. In this paper, Fengdu County, the hinterland of the Three Gorges Reservoir Area in Chongqing, was taken as the study area. The total amount and morphology of 8 heavy metal elements in the surface soil of agricultural land were analyzed and determined. The geocumulative index method was used to evaluate the pollution degree. The risk assessment coding method is used to evaluate the potential risk level. The results showed that the average contents of heavy metal elements As, Hg, Cu and Cr in the soil in the study area were relatively low. The average contents of Cd, Zn, Pb and Ni were higher than those in the Three Gorges Reservoir area. The mean value of Cd content was 1.71 times that of the background value. Cd in the soil heavy metal form is dominated by ion exchange state. The proportion of carbonate-bound state and iron-manganese bound state is relatively high. The proportion of bioavailable state was 46.36%, and the biological activity was strong. The other elements are mainly in the stable residue state. The results of the geoaccumulation index method showed that Cd was mainly mild pollution level. The other elements are mainly clean and pollution-free levels. The evaluation results of the risk assessment coding method showed that the risk of Cd contamination was the highest, and the risk of contamination of other elements was relatively low. On the whole, there is a certain degree of potential pollution risk in the soil Cd in the study area. Attention needs to be paid to the prevention and control of Cd.

Health risk assessment of heavy metals in some vegetables-Erbil City-Kurdistan Region of Iraq.

Heavy metals can have significant impacts on human health due to their toxicity and potential to accumulate in the body over time. Some heavy metals, such as lead, cadmium, mercury, and arsenic, are particularly harmful even at low concentrations. The estimation of hazards of vegetable intake to human health as well as explore the of heavy metals accumulation in different vegetables (cucumbers, tomato, eggplant, and bell peppers) collected in Erbil city from different source locally and imported from nearby country are conducted. The heavy metals concentration (cooper, zinc, lead and cadmium) was measured and analyzed by inductively coupled plasma-optical emission spectrophotometry. The maximum concentration of Pb was 27.95 mg/kg and the minimum was 6.49 mg/kg; for Cd, the concentration was 1.43 and 0.99 mg/kg, 74.94 and 5.14 mg/kg for Zn; and for Cu, the result was 56.25 and 8.2 mg/kg for the maximum and minimum, which they are within limits described by Food Agricultural Organization, but more than health limits and health risks calculated by mean of hazard quotient (HQ) techniques for Cu and Pb which they are more than 1. The local sample that collected in Erbil city show less concentration of heavy metals and low HQ in comparison with imported samples. The carcinogenic risk study shows elevated risk of accumulative consuming of edible part of those plant which they exceed the permissible limit that is 10-6.

Health Risk Assessment of Heavy Metals in the Medicinal Plants Ziziphora clinopodioides and Echinophora platyloba in West Islamabad and Sanandaj Regions

Background & Aims: Medicinal plants are part of traditional medicine, which has many uses in the treatment of diseases and human health. This research was conducted to evaluate heavy metals in two species of Ziziphora clinopodioides and Echinophora platyloba. Materials and Methods: In each of the cities of Islamabad and Sanandaj, five sampling stations were determined, and from each station, 5 samples of Kakuti plant and 5 samples of Khosharizeh plant were collected from 3 different places of non-agricultural lands in the summer season of 2021. The mean data of heavy metals were compared with each other using a one-way analysis of variance and Duncan’s test. Results: The average of manganese (Mn) in Z. clinopodioides and E. platyloba (5112.95 and 4258.67 mg/kg) was significantly higher than other heavy metals (P<0.05). In addition, the average of arsenic in Z. clinopodioides and E. platyloba (0.002 mg/ kg and 0.001 mg/kg) had significantly the lowest values among the studied heavy metals (P<0.05). The results of the health risk assessment showed that the highest risk index of heavy metals in Z. clinopodioides and E. platyloba in the age group of children was related to Mn (12.15 and 12.74, respectively). On the other hand, the lowest value of the risk index of heavy metals for the consumption of Z. clinopodioides and E. platyloba for children and adults was obtained for iron (0.48 and 0.32, respectively). The highest carcinogenic risk index of the Kakuti plant was observed in two age groups of children and adults regarding cadmium (0.099 and 0.098, respectively). Conclusion: The analysis of the health risk assessment of heavy metals in the samples of Z. clinopodioides and E. platyloba in two regions of Islamabad and Sanandaj revealed that the consumption of these two plants is dangerous for the health of people of different age groups.

Enrichment Characteristics and Ecological Risk Assessment of Heavy Metals in a Farmland System with High Geochemical Background in the Black Shale Region of Zhejiang, China

Soils derived from black shale enriched in heavy metals pose risks to the environment and human health. Eighty sets of soil–rice samples were collected in northwest Zhejiang, China. The results showed significant enrichment of As, Cd, Pb, and Zn in the studied soil. Sequential extraction data indicated that Cd had relatively high bioavailability. Thirty-four percent of the rice samples exceeded the heavy metal pollution thresholds of national food safety standards. A comprehensive evaluation of soil heavy metals using the potential ecological risk index (RI) revealed low-to-moderate-grade risk. Risk assessment code (RAC) levels decreased as follows: Cd > Ni > Zn > Cr > Cu > Pb > As > Hg. The RAC of Cd was high and very high risk, whereas those of others were no or low risk. Cd was the major contributor to the environmental risk based on the total heavy metal concentration, toxicity, and chemical fractions. The health risk to the local populace was assessed using the method recommended by the USEPA. Local people may experience both non-carcinogenic and carcinogenic health risks, and children face greater health risks than adults. As, Cd, and Pb are the most significant contributors to non-carcinogenic health risks, and Cd is the main carcinogenic risk. In conclusion, special attention should be given to heavy metal pollution in black shale-derived soils.

Ecological risk assessment of heavy metals in desulfurized seawater discharged from a coal-fired power plant in Qingdao.

Despite the prevalence of discharge of large volumes of heavy-metal-bearing seawater from coal-fired power plants into adjacent seas, studies on the associated ecological risks remain limited. This study continuously monitored concentrations of seven heavy metals (i.e. As, Cd, Cr, Cu, Hg, Pb, and Zn) in surface seawater near the outfall of a coal-fired power plant in Qingdao, China over three years. The results showed average concentrations of As, Cd, Cr, Cu, Hg, Pb, and Zn of 2.63, 0.33, 2.97, 4.63, 0.008, 0.85, and 25.00 μg/L, respectively. Given the lack of data on metal toxicity to local species, this study investigated species composition and biomass near discharge outfalls and constructed species sensitivity distribution (SSD) curves with biological flora characteristics. Hazardous concentrations for 5% of species (HC5) for As, Cd, Cr, Cu, Hg, Pb, and Zn derived from SSDs constructed from chronic toxicity data for native species were 3.23, 2.22, 0.06, 2.83, 0.66, 4.70, and 11.07 μg/L, respectively. This study further assessed ecological risk of heavy metals by applying the Hazard Quotient (HQ) and Joint Probability Curve (JPC) based on long-term heavy metal exposure data and chronic toxicity data for local species. The results revealed acceptable levels of ecological risk for As, Cd, Hg, and Pb, but unacceptable levels for Cr, Cu, and Zn. The order of studied heavy metals in terms of ecological risk was Cr > Cu ≈ Zn > As > Cd ≈ Pb > Hg. The results of this study can guide the assessment of ecological risk at heavy metal contaminated sites characterized by relatively low heavy metal concentrations and high discharge volumes, such as receiving waters of coal-fired power plant effluents.

Water Quality and Risk Assessment of Selected Heavy Metals in Tilapia Oreochromis niloticus from Pulangi Lake, the Philippines

Regular monitoring of the water quality and heavy metal concentration in edible fish from the Pulangi Lake – an artificial lake in Bukidnon, the Philippines – has not yet been established. This study analyzed the water quality of the Pulangi Lake and assessed the associated risks of heavy metals cadmium (Cd), chromium (Cr), and lead (Pb) in Nile tilapia (Oreochromis niloticus) harvested from the lake during the dry season. Key informant interviews (KII) were also conducted to gather relevant information about the lake. The physico-chemical analysis of the surface water revealed high fecal coliform levels, exceeding the standard limit by more than 100%, but the concentrations of Cd, Cr, and Pb were below the standard limit. However, the Cr concentration in tilapia (0.2430–1.7870 mg/kg) exceeded the permissible limit of 0.05 mg/kg set by the Food and Agriculture Organization and the World Health Organization. Low concentrations of Cd (0.0270–0.1140 mg/kg) and Pb (0.0360–0.4350 mg/kg) were observed. The risk assessment of these individual heavy metals measured from tilapia and its combined impacts showed no potential non-carcinogenic effects based on the estimated target hazard quotient (THQ < 1) and hazard index (HI < 1). However, based on the permissible target cancer risk (1 x 10–6 to 1 x 10–4), tilapia from the Pulangi Lake should be reexamined as it appears that – in terms of Cd and Cr – the probability relating to contamination problem can occur. The present study can be used as baseline data for risk management.

Risk assessment and source analysis of heavy metals in soil around an asbestos mine in an arid plateau region, China

Asbestos is widely used in construction, manufacturing, and other common industrial fields. Human activities such as mining, processing, and transportation can release heavy metals from asbestos into the surrounding soil environment, posing a health hazard to the mining area's environment and its surrounding residents. The purpose of the present study was to determine the extent of ecological and human health damage caused by asbestos pollution, as well as the primary contributors to the contamination, by examining a large asbestos mine and the surrounding soil in China. The level of heavy metal pollution in soil and sources were analyzed using methods such as the geo-accumulation index (Igeo), potential ecological risk index (RI), and positive matrix factorization (PMF) model. A Monte Carlo simulation-based health risk model was employed to assess the health risks of heavy metals in the study area’s soil to human beings. The results showed that the concentrations of As, Pb, Cr, Cu, and Ni in the soil were 1.74, 0.13, 13.31, 0.33, and 33.37 times higher than the local soil background values, respectively. The Igeo assessment indicated significant accumulation effects for Ni, Cr, and As. The RI evaluation revealed extremely high comprehensive ecological risks (RI ≥ 444) in the vicinity of the waste residue heap and beneficiation area, with Ni exhibiting strong individual potential ecological risk (Eir ≥ 320). The soil health risk assessment demonstrated that As and Cr posed carcinogenic risks to adults, with mean carcinogenic indices (CR) of 1.56E − 05 and 4.14E − 06, respectively. As, Cr, and Cd posed carcinogenic risks to children, with mean CRs of 1.08E − 04, 1.61E − 05, and 2.68E − 06, respectively. Cr also posed certain non-carcinogenic risks to both adults and children. The PMF model identified asbestos contamination as the primary source of heavy metals in the soil surrounding the asbestos mining area, contributing to 79.0%. According to this study, it is recommended that management exercise oversight and regulation over the concentrations of Ni, Cr, Cd, and As in the soil adjacent to asbestos mines, establish a designated control zone to restrict population activities, and locate residential zones at a safe distance from the asbestos mine production zone.

Human and ecotoxicological risk assessment of heavy metals in polymer post treatment sludge from Barekese Drinking Water Treatment Plant, Kumasi

The disposal of polymer post-treatment sludge (PTS) from Barekese Water Treatment Plants (WTPs) as organic fertilizer and aquatic feed is a common practice in Ghana, necessitating a thorough evaluation of its ecological and human health risks. This study aims to assess the suitability of PTS samples for soil amendment and fish feed, scrutinizing potential hazards to consumer health and soil. PTS samples were collected from five distinct lateral sections of three clariflocculator tanks. Potentially toxic metals such as Cd, Zn, Pb, Cu, Ni, and Cr were determined using a flame atomic absorption spectrophotometer. The mean concentration of 7.82 ± 2.43, 0.31 ± 0.021, and 0.78 ± 0.042 mg/kg for Mn, Zn, and Pb respectively. The concentrations of Ni, Cr, and Cd were below their detection limits (BDL) in all PTS samples. Upon detailed exposure assessment, ingestion emerged as the primary exposure route for both adults and children, with non-cancer risks (NCR) determined to be below 1 for both age groups. Additionally, an exploration of potential cancer risks (CR) associated with heavy metal exposure in the PTS samples revealed values below the tolerable intake levels ranging from 10−4 to 10−6 for both adults and children (10−8 and 10−9, respectively). This study also employs various ecological indices, such as Nemerow's synthetic pollution index (PN), single factor pollution index (PI), geo-accumulation index (Igeo), contamination factor (CF), potential ecological risk index (PERI), pollution load index (PLI), polymetallic contaminant index (IPD), and ecological risk index (ERI). These indices consistently highlight a low contamination status and ecological sensitivity. Consequently, the study indicates that the presence of metals in the PTS samples does not pose a significant threat to the surrounding environment and human health. Furthermore, this research underscores the inadequacy of relying solely on regulatory limit values in assessing the health risks of waste materials. Such comprehensive assessments are crucial for safeguarding aquatic and human populations.

Environmental Contamination and Health Risk Assessment of Heavy Metals in the Stream Sediments of Oued Kasseb (Northerwest of Tunisia) in the Vicinity of Abandoned Pb–Zn Mine

Environmental Contamination and Health Risk Assessment of Heavy Metals in the Stream Sediments of Oued Kasseb (Northerwest of Tunisia) in the Vicinity of Abandoned Pb–Zn Mine

Source-specific probabilistic health risk assessment of heavy metals in surface water of the Yangtze River Basin

The detrimental effects of heavy metal accumulation on both ecosystems and public health have raised widespread concern. Source-specific risk assessment is crucial for developing effective strategies to prevent and control heavy metal contamination in surface water. This study aims to investigate the contamination characteristics of heavy metals in the Yangtze River Basin, identifying the pollution sources, assessing the risk levels, and further evaluating the health risks to humans. The results indicated that the average concentrations of heavy metals were ranked as follows: zinc (Zn) > arsenic (As) > copper (Cu) > chromium (Cr) > cadmium (Cd) > nickel (Ni) > lead (Pb), with average concentrations of 38.02 μg/L, 4.34 μg/L, 2.53 μg/L, 2.10 μg/L, 1.17 μg/L, 0.84 μg/L, and 0.32 μg/L, respectively, all below the WHO 2017 standards for safe drinking water. The distribution trend indicates higher concentrations in the upper and lower reaches and lower concentrations in the mid-reaches of the river. By integrating the Absolute Principal Component Scores-Multiple Linear Regression (APCS-MLR) receptor model and Positive Matrix Factorization (PMF) model, the main sources of heavy metals were identified as industrial activities (APCS-MLR: 41.3 %; PMF: 42.1 %), agricultural activities (APCS-MLR: 30.1 %; PMF: 27.4 %), and unknown mix sources (APCS-MLR: 29.1 %; PMF: 30.4 %). The calculation of the hazard index (HI) for both children and adults was <1, indicating no non-carcinogenic or carcinogenic risks. Based on the source-specific risk assessment, agricultural activities contribute the most to non-carcinogenic risks, while industrial activities pose the greatest contribution to carcinogenic risks. This study offers a reference for monitoring heavy metals and controlling health risks to residents, and provides crucial evidence for the utilization and protection of surface water in the Yangtze River Basin.

Source Distribution and Ecological Risk Assessments of Heavy Metals from the Soils of Riruwai Mining Area, North-Western Nigeria

Mining is an important global economic driver, contributing to human civilization’s advancement and foreign exchange revenues. However, it causes significant environmental contamination, particularly in developing nations with inadequate waste management and ineffective mining legislation. In the present study, the source distribution and ecological risk of heavy metals (HMs) from the soils of the mining area around Riruwai town, northern Nigeria, were assessed. Soil samples were obtained from active and abandoned mining sites, farmlands, and control sites and were analyzed for physicochemical characteristics and HM contents. The measured concentrations of HMs were used to evaluate the source distribution and ecological risks. The study’s findings indicated that, with the exception of Mn, Hg, and Ni, all HM concentrations were above threshold levels in all sample locations aside from the control sites. The results of the correlation analysis showed that there was a significant correlation between the HMs, indicating that they came from comparable origins. Principal component analysis and hierarchical cluster analysis results indicated that As, Cr, Hg, Ni, and Zn might originate from similar anthropogenic sources, possibly mining activities, while Cd, Mn, and Pb might come from natural sources (parent material). Results of an ecological risk assessment revealed that the soils from active and abandoned mining sites were severely polluted by HMs. The degree of pollution has begun to extend onto farmland, signifying a critical need for adequate HM pollution control in the study area.

Ecological and human health risk assessment of tungsten and other heavy metal(loid)s in farmland around a typical tungsten mining area in southern Jiangxi, China

Ecological and human health risk assessment of tungsten and other heavy metal(loid)s in farmland around a typical tungsten mining area in southern Jiangxi, China

Pollution status and health risk assessment of heavy metals in the soil of Sahibzada Ajit Singh (SAS) Nagar district of Punjab, India and its source apportionment

The threat of heavy metals in soil due to rapid urbanization, intensive agricultural practices, vehicular emission, and industry-related activities is increasing day by day, causing high risk to environmental health. The present study assessed the heavy metal pollution (Cr, Co, Ni, Co, Zn, As, Cd, and Pb) in the soil of Sahibzada Ajit Singh Nagar District, Punjab, India, through the index of geoaccumulation (Igeo), contamination factors (CF), degree of contamination (DC), pollution load index (PLI), ecological risk factor (Er) and potential ecological risk indices (PRI). The results showed the concentration of heavy metals in the soil in the order of Pb > Zn > Ni > Cr > Cu > As > Co > Cd. The pollution risk assessment indices: Igeo, CF, and Er indicated that most soil samples were moderately contaminated with Pb. The village Majra showed considerable contamination as evidenced by the Cd. The multivariate statistical analysis revealed the anthropogenic sources (agricultural practices and discharges from micro, small and medium enterprises (MSME) industries) to be the possible sources of Cr, Co, Ni, Cu, Zn, and Pb. The health risk assessment studies indicated that carcinogenic risks were higher for children than the adults. The cancer risk (CR) for all heavy metals in decreasing order is As > Cr > Pb > Ni > Cd. Likewise, the non-carcinogenic risks calculated as HQ followed the order of Pb > As > Cr > Cd > Ni > Cu > Co > Zn. The significant disparities in heavy metal concentrations underscore the necessity of establishing appropriate baseline levels for toxic trace metals in soils.

Health risk assessment of soil heavy metals in a typical mining town in north China based on Monte Carlo simulation coupled with Positive matrix factorization model

The accumulation of heavy metals (HMs) in soil caused by mineral resource exploitation and its ancillary industrial processes poses a threat to ecology and public health. Effective risk control measures require a quantification of the impacts and contributions to health risks from individual sources of soil HMs. Based on high-density sampling, soil contamination risk indexes, positive matrix factorization (PMF) model, Monte Carlo simulation and human health risk analysis model were applied to investigate the risk of HMs in a typical mining town in North China. The results showed that As was the most dominant soil pollutant factor, Cd and Hg were the most dominant soil ecological risk factors, and Cr and Ni were the most dominant health risk factors in the study area. Overall, both pollution and ecological risks were at low levels, while there were still some higher hazard areas located in the central and south-central part of the region. According to the probabilistic health risk assessment (HRA), children suffered greater health risks than adults, with 21.63% of non-carcinogenic risks and 53.24% of carcinogenic risks exceeding the prescribed thresholds (HI > 1 and TCR>1E-4). The PMF model identified five potential sources: fuel combustion (FC), processing of building materials with limestone as raw materials (PBML), industry source (IS), iron ore mining combined with garbage (IOG), and agriculture source (AS). PBML is the primary source of soil HM contamination, as well as the major anthropogenic source of carcinogenic risk for all populations. Agricultural inputs associated with As are the major source of non-carcinogenic risk. This study offers a good example of probabilistic HRA using specific sources, which can provide a valuable reference for strategy establishment of pollution remediation and risk prevention and control.

Health risk assessments of heavy metals and trace elements exposure in the breast milk of lactating mothers in the Northeastern Iran.

Mother's breast milk is a natural and complete food for infants but can be a main source of exposure to toxic pollutants. These pollutants can negatively affect the health of the infant. Therefore, conducting biomonitoring surveys is essential to evaluate such health effects in toxicological research. This study aimed to estimate the probable health risks for infants exposed to essential and non-essential trace elements through breast milk ingestion. This descriptive-analytical, cross-sectional study was performed on 90 breastfeeding mothers referred to the health centers in Mashhad, Iran in January 2021. The health risk assessments (carcinogenic and non-carcinogenic risk) were estimated using chronic daily intake (CDI), hazard quotient (HQ), hazard index (HI), and lifetime carcinogenic risk (CR), which were recommended by the US Environmental Protection Agency (US EPA). The results of the HQ values of trace elements through ingestion exposure for arsenic (90%), copper (90%), zinc (40%), and iron (10%) exceeded the threshold of HQ, and arsenic (66.59%), copper (16.91%), and zinc (9.68%) and iron (4.57%) had the highest contribution to increasing the HI index. The average value of CR was 5. 08 × 10-3. Chromium and iron showed significant relationships (P<0.05) with education level and disease background in this study, and the concentration of chromium, iron, and zinc in the breast milk samples significantly changed during lactation stages (P<0.05). Overall, the risk of carcinogenicity through exposure to breast milk for infants was higher than the safety level of US EPA risk. Therefore, there could be a potential health risk of trace elements, particularly arsenic, copper, and zinc for infants in Mashhad, Iran through the consumption of mothers' breast milk. More efforts are required to control and reduce routes of receiving trace elements in breastfeeding mothers by the competent authorities.