Non-carcinogenic Risk For Children Research Articles

Malondialdehyde and heavy metal contents in Piper betel: Possible risks of heavy metals in human health

The content of heavy metals in the food chain has grown due to human activities and rapid industrial growth. The accumulation of heavy metals in P. betel leaves and the related threat to human health were analyzed by using the AAS that was collected from eleven locations inside the city of Dhaka. High MDA contents indicated contamination in P. betel samples and can regulate biochemical activity by different potential toxic elements (PTEs). The P. betel samples revealed the highest mean concentrations of As (2.09 mg/kg), Pb (0.06 mg/kg), Mn (218 mg/kg), Ni (1.55 mg/kg), Cu (10 mg/kg), Zn (2.6 mg/kg), Cr (5.1 mg/kg), and Cd (0.003 mg/kg) and certain metal exceed the guideline value. Mn, Cr, and As mean values at the research sites are higher than the permitted concentration range. Among all metals, Mn was the most accumulated metal in leaves and enhanced hazard index (HI) and non-carcinogenic risk for children. Individual metal THQ values were all less than 1 (except Mn), indicating that consuming only one metal from betel samples would not pose a serious risk to one's health. However, HI value (> 1) indicates a possible non-carcinogenic health risk to urban city people, especially in children. The assessment revealed that the allowable range of Cr and As content in betel leaves may enhance the carcinogenic risk (CR). Among heavy metals, the CR value of Cr indicated an enhanced cancer risk in children at L3, L5, L6, L7, L8, L9, L10, and L11 sites. This study shows from a health perspective that people who eat contaminated betel leaves are continuously exposed to metal pollution, which can have both carcinogenic and noncarcinogenic effects.

Levels of polycyclic aromatic hydrocarbon in the soil around typical automobile repair workshops in Nigeria

Background This study determined the levels of polycyclic aromatic hydrocarbons (PAHs) in the soil around typical automobile repair workshops in Nigeria. Risk assessment associated with human contact with the soil was carried out using hazard quotient (HQ) and incremental life cancer risk (ILCR) from human unconscious ingestion and dermal contact with the soil. Methods Soil samples were obtained at different automobile workshops in Ado-Ekiti, Western Nigeria. The PAHS in the samples were extracted using dichloromethane and extracts were cleaned up using silica-alumina gel open column chromatography. Analysis of PAHs in the soil was done using a gas chromatograph coupled to a mass selective detector operated on electron ionization mode. Results The results showed the mean PAHs concentration at the sampling locations ranged from 5.58 – 6.4 μg/g and the mean ∑ carcinogenic PAHs was 58.4 μg/g, equivalent to 59.39 % of total PAHs observed. The mean Toxicity equivalence (TEQs) ranged from 0.02 - 6.680 μg/g. Benzo (a) pyrene and dibenzo(a,h)anthracene have the highest toxicity equivalent. The total ILCRs from accidental ingestion and dermal contact in adults were 1 ×10^(-3) and 9.8 ×10^(-5), for adults and children respectively; both are higher than the permissible limit stipulated by the World Health Organization.The HQs obtained are several folds higher than 1. This implies high carcinogenic and non-carcinogenic risks for children and adults. Conclusions The study revealed the levels of PAHs and also revealed the risks associated with human contact with the soil around automobile repair workshops.

Health risk assessment of heavy metals based on source analysis and Monte Carlo in the downstream basin of the Zishui

In this study, stone coal mines in the lower reaches of the Zijiang River were adopted as the research object. To analyze the spatial distribution, sources, and health risks of heavy metals in the surrounding soil of stone coal mines, 82 topsoil samples were collected in the study area, and the contents of 8 heavy metals including Cd, Hg, As, Cr, Pb, Cu, Ni, and Zn were determined. The spatial distribution of heavy metals was analyzed using ArcGIS, and the pollution sources of heavy metals were identified using Positive matrix factorization (PMF). Then, Monte Carlo and health risk assessment models were used to evaluate the health risks of different populations. The results showed that the average content of heavy metals followed the order of Zn > Cr > Pb > Cu > Ni > As > Cd > Hg, and the contents of all heavy metals were higher than the soil background values of Hunan Province. The high-value areas of heavy metals content were mostly concentrated in the central region close to areas with a notable concentration of stone coal mines. PMF identified four pollution sources, namely, mining activities (26.9%), atmospheric deposition (18.8%), natural sources (32.8%) and agricultural sources (21.5%). The carcinogenic and non-carcinogenic risks for children were higher than those for adults, with As and Cd posing higher carcinogenic risks to children. Based on the source of health risks, it was determined that the health risks could be primarily attributed to agricultural sources, and As was the main heavy metal causing health risks. This study provides theoretical support for treating heavy metal pollution in mining basins.

Levels of polycyclic aromatic hydrocarbon in the soil around typical automobile repair workshops in Nigeria

Background: This study determined the levels of polycyclic aromatic hydrocarbons (PAHs) in the soil around typical automobile repair workshops in Nigeria. Risk assessment associated with human contact with the soil was carried out using hazard quotient (HQ) and incremental life cancer risk (ILCR) from human unconscious ingestion and dermal contact with the soil. Methods: Soil samples were obtained at different automobile workshops in Ado-Ekiti, Western Nigeria. The PAHS in the samples were extracted using dichloromethane and extracts were cleaned up using silica-alumina gel open column chromatography. Analysis of PAHs in the soil was done using a gas chromatograph coupled to a mass selective detector operated on electron ionization mode. Results: The results showed the mean PAHs concentration at the sampling locations ranged from 5.58 – 6.4 μg/g and the mean ∑ carcinogenic PAHs was 58.4 μg/g, equivalent to 59.39 % of total PAHs observed. The mean Toxicity equivalence (TEQs) ranged from 0.02 - 6.680 μg/g. Benzo (a) pyrene and dibenzo(a,h)anthracene have the highest toxicity equivalent. The total ILCRs from accidental ingestion and dermal contact in adults were 1 ×10^(-3) and 9.8 ×10^(-5) , for adults and children respectively; both are higher than the permissible limit stipulated by the World Health Organization.The HQs obtained are several folds higher than 1. This implies high carcinogenic and non-carcinogenic risks for children and adults. Conclusions: The study revealed the levels of PAHs and also revealed the risks associated with human contact with the soil around automobile repair workshops.

Evaluation of groundwater for nitrate and fluoride in Alappuzha region from the southwestern coast of India and associated health risks

Nitrate and fluoride are two of the most prevalent pollutants in drinking water and exposure to their high concentrations could cause methemoglobinemia and fluorosis. This study attempted to evaluate the groundwater quality (pH: 4.4–9) from a relatively understudied part of the southwestern coast in India (i.e., Alappuzha, Kerala state) and assessed the associated health risks from exposures to nitrate (0.2–5.8 mg/l) and fluoride (0.2–1.9 mg/l) present in the groundwater. Pollution index (PIG: 0.35–5.43) grouped about 21% samples in high pollution and very high pollution categories because of fluoride content above the WHO guidelines. The total hazard index (THI) for adult male (0.17–1.70; average: 0.75), adult female (0.19–1.85; average: 0.81) and children (0.35–3.40; average: 1.50) suggested more non-carcinogenic risks for children from 41.6% samples compared to adult male and female from 33.3% samples in the absence of any mitigation measure. These results provide additional data from the country with highest population and the largest groundwater use in the context of sustainability in availability and supply of groundwater under the increasing risks of population growth, climate change and industrial development.

Geochemistry pollution status and ecotoxicological risk assessment of heavy metal(oid)s in soil influenced by co-landfilling of MSW and sewage sludge, Morocco

Landfilling activities are one of themajorsources of heavy metal(loid)s contamination. Thus, assessing the spatial distribution ofthese elementsand evaluatingtheirpotentialhazards to public health in the areas surrounding landfills is of utmost importance. In this paper, the synergistic effects of co-landfilling of Municipal Solid Waste (MSW) and Sewage Sludge (SS) were assessed using pollution indicators, PCA, HCA, and Montecarlo probabilistic human risk assessment. To do so, 19 soil, leachate, and sewage sludge samples were collected around the landfill and their content of heavy metal(oid)s was analyzed using Inductively Coupled Plasma (ICP-AES). The average concentrations of As, Cd, Cu, Pb, Zn, Cr, Ni, Co, and Fe were 0.98, 3.14, 36.87, 41.90, 148.43, 21.64, 32.07, 4.02, and 3143.74 mg/kg dry weight, respectively. The concentration of all metal(oid)s was higher than the geochemical background and the highest amount was observed at the first 100 m from the landfill and the sampling sites affected directly by sewage sludge. The values of pollution indexes (geo-accumulation index, enrichment factor, pollution load index, ecological risk index) showedthat soils in the vicinity of the landfill displayed moderate to high contamination level, with a strong potential ecological impact. Furthermore, multivariate statistical analysis demonstrated that anthropogenic sources related to disposal practices of MSW and SS are the main responsible behind the revealed pollution. In addition, the deterministic and probabilistic human risk assessment highlighted that the non-carcinogenic risk for children and adults still within the acceptable limits. However, carcinogenic risk was well above the threshold values (10−4) for children. The elevated pollution level reflected the dangerousness of synergistic dumping of SS and MSW, which renders the avoidance of their co-landfilling mandatory.

Levels of polycyclic aromatic hydrocarbon in the soil around typical automobile repair workshops in Nigeria

Background: This study determined the levels of polycyclic aromatic hydrocarbons (PAHs) in the soil around typical automobile repair workshops in Nigeria. Risk assessment associated with human contact with the soil was carried out using hazard quotient (HQ) and incremental life cancer risk (ILCR) from human unconscious ingestion and dermal contact with the soil. Methods: Soil samples were obtained at different automobile workshops in Ado-Ekiti, Western Nigeria. The PAHS in the samples were extracted using dichloromethane and extracts were cleaned up silica gel open column chromatography. Analysis of PAHs in the soil was done using a gas chromatograph coupled to a mass selective detector operated on electron ionization mode. Results: The results showed the mean PAHs concentration at the sampling locations ranged from 5.58 – 6.4 μg/g and the mean ∑ carcinogenic PAHs was 58.4 μg/g , equivalent to 59.39 % of total PAHs observed. The mean Toxicity equivalence (TEQs) ranged from 0.02 - 6.680 μg/g . Benzo (a) pyrene and dibenzo(a,h)anthracene have the highest toxicity equivalent. The total ILCRs from accidental ingestion and dermal contact in adults were 1 ×10^(-3) and 9.8 ×10^(-5) , for adults and children respectively; both are higher than the permissible limit stipulated by the World Health Organization. The HQs obtained are several folds higher than 1. This implies high carcinogenic and non-carcinogenic risks for children and adults. Conclusions: The study revealed the levels of PAHs and risks associated with human contact with the soil around automobile repair workshop.

INVESTIGATION OF THE IMPACT OF POTENTIALLY TOXIC ELEMENTS FROM URBAN FLOODED AREAS IN PORT HARCOURT CITY, NIGERIA

Flooding transports significant environmental contaminants in soils especially potentially toxic elements (PTEs). The prevalence of PTEs in the environment poses serious threat to human health. Anthropogenic activities contribute to elevation of PTEs contents in soils. In this study, a total of 24 soil samples collected from six study areas within Port Harcourt city were analysed to determine level of some elements (As, Cd, Cr, Pb and Ni) following the acid digestion methods. Samples were taken from different soil profiles ranging from topsoil (0 – 30 cm) to sub-soil (30 – 60 cm). Each sample was subjected to three acid digestion procedures namely: aqua regia, reversed aqua regia and multi-acid attack. For purposes of quality control, levels of the elements of interest in the digested samples along with blanks were measured using atomic absorption spectrometer (AAS). A wide range of total concentrations of the toxic elements was found, with high level of concentration obtained in the topsoil. The proportion of elements released by the multi- acid attack method was higher than those of aqua regia and reversed aqua regia methods. This finding suggests that the heavy metals bound to silicate minerals are not easily dissolved in simple mineral acids. A correlation analysis revealed a strong association between Pb and total organic carbon (r = 0.950012), indicating that the source of Pb contaminants may be derived from organic matter contents. The potential health risk associated with PTEs indicated non-carcinogenic risk for children and carcinogenic risk for adults living in the flooded areas. Further monitoring of flooded areas in Port Harcourt metropolis is recommended for other environmental contaminants beside the PTEs monitored.

Oral and inhalation bioaccessibility of mercury in contaminated soils and potential health risk to the kidneys and neurodevelopment of children in Taiwan.

Health risk assessments of exposure to mercury (Hg) from soils via ingestion and inhalation are indispensable for Taiwanese people living in the vicinity of Hg-contaminated sites. In this study, anthropogenic soils were collected from various polluted sources in Taiwan. In vitro oral and inhalation bioaccessible fractions of Hg were analyzed to avoid from overestimating the exposure risk. Discrepancies in oral and inhalation bioaccessible levels of Hg in soils were found using different in vitro assays with different pH levels and chemical compositions. The freshly contaminated soil (soil S7) polluted by chlor-alkali production activity sampled before the site was remediated had the highest total Hg concentration of 1346mg/kg, with the highest oral bioaccessibility of 26.2% as analyzed by SW-846 Method 1340 and inhalation bioaccessibility of 30.5% as analyzed by modified Gamble's solution. The lesser extent of aging of Hg in soil S7 increased the Hg availability for humans, which was also found based on results of a sequential extraction procedure. Results of the hazard quotient showed that soil ingestion was the main pathway causing non-carcinogenic risks for children and adults. Children were also exposed to higher risks than were adults due to higher frequencies of hand-to-mouth behaviors and lower body weights. Furthermore, hazard index results adjusted for oral and inhalation bioaccessible Hg were lower than those obtained based on the total Hg content; however, an unacceptable value of the non-carcinogenic risk (> 1) for children living near soil S7 was still observed. This study suggests that children living near sites polluted for a short period of time may suffer potential renal effects regardless of the bioaccessibility. Our findings provide suggestions for decision makers on setting new strategies for managing risks of Hg-contaminated soils in Taiwan.

Characteristics and Risk Evaluation of Heavy Metal Contamination in Paddy Soils in the Three Gorges Reservoir Area

Soil Cd, Hg, Pb, As, Cr, Cu, Zn, and Ni of 12 districts in the Three Gorges Reservoir area (Chongqing section) were analyzed, and different evaluation methods were used to assess the degree of contamination, potential ecological risk, and human health risk of soil heavy metals in paddy soils. The results showed that the average values of all heavy metals except Cr in paddy soils in the Three Gorges Reservoir area exceeded the background values of soils in the Three Gorges Reservoir area, and the contents of Cd, Cu, and Ni in 12.32%, 4.35%, and 2.54% of the soil samples exceeded the screening values, respectively. The variation coefficients of the eight heavy metals were 29.08%-56.43%, which belonged to the medium and above-intensity variation levels and were influenced by anthropogenic activities. The eight heavy metals were contaminated in the soil, and 16.30%, 6.52%, and 2.90% of the soil Cd, Hg, and Pb were heavily contaminated. At the same time, the potential ecological risk of soil Hg and Cd were in the medium risk level on the whole. Wuxi County and Wushan County had relatively high pollution levels among the 12 districts, the Nemerow pollution index showed a moderate pollution level, and the comprehensive potential ecological risks were also at a moderate ecological hazard level. The results of the health risk evaluation showed that hand-mouth intake was the main exposure path of non-carcinogenic risk and carcinogenic risk. Soil heavy metals presented no non-carcinogenic risk for adults (HI<1), but 12.68% of the sites had non-carcinogenic risk for children (HI>1). As and Cr were the main influencing factors for non-carcinogenic and carcinogenic risks in the study area, and their total contributions to non-carcinogenic and carcinogenic risks were more than 75% and 95%, respectively, which was cause for concern.

A comprehensive approach to quantify the source identification and human health risk assessment of toxic elements in park dust.

In this research, enrichment factor (EF) and pollution load index were utilized to explore the contamination characteristics of toxic elements (TEs) in park dust. The results exhibited that park dust in the study area was mainly moderately polluted, and the EF values of dust Cd, Zn, Pb, Cu and Sb were all > 1. The concentrations of Cr, Cu, Zn and Pb increased with the decrease of dust particle size. The investigation results of chemical speciation and bioavailability of TEs showed that Zn had the highest bioavailability. Three sources of TEs were determined by positive matrix factorization model, Pearson correlation analysis and geostatistical analysis, comprising factor 1 mixed sources of industrial and transportation activities (46.62%), factor 2 natural source (25.56%) and factor 3 mixed source of agricultural activities and the aging of park infrastructures (27.82%). Potential ecological risk (PER) and human health risk (HHR) models based on source apportionment were exploited to estimate PER and HHR of TEs from different sources. The mean PER value of TEs in the park dust was 114, indicating that ecological risk in the study area was relatively high. Factor 1 contributed the most to PER, and the pollution of Cd was the most serious. There were no significant carcinogenic and non-carcinogenic risks for children and adults in the study area. And factor 3 was the biggest source of non-carcinogenic risk, and As, Cr and Pb were the chief contributor to non-carcinogenic risk. The primary source of carcinogenic risk was factor 2, and Cr was the cardinal cancer risk element.

Assessment of heavy metals leachability characteristics and associated risk in typical acid mine drainage (AMD)-contaminated river sediments from North China

Acid mine drainage (AMD) is a worldwide environmental problem, characterized by low pH values and high concentrations of heavy metals. Heavy metal pollution of sediments caused by AMD has attracted widespread attention. However, research works on the leachability and distribution characteristics along with the ecological and health risks assessment of AMD-polluted sediment are limited. 15 sediments samples were collected from an AMD-polluted river, Shandi River, North China to analyze the leachability concentration, potential sources, and associated risk of eight metals, namely Ni, Cd, Cu, Zn, Fe2+, Fe3+, Pb, and Mn. Our results showed that Mn, Ni, Fe3+, and Fe2+ were the main leachate pollutants in the Shandi river. Certain levels of ecological risks existed in AMD-polluted stations and Ni was the common key metal that caused the high ecological risk factor in S1, S2, and S4. Cu, Ni, and Zn were the three metals that caused high or moderate risk to zebrafish. Mn and Fe were the main heavy metals that caused non-carcinogenic risks both for adults and children and Ni was another main heavy metal that caused non-carcinogenic risks for children. Ni and Cd can induce carcinogenic risks in these areas. Pearson's correlation and PCA results supported that these metals possibly originate from common AMD–polluted sources. The technology of “gravitational settling-neutralizing filter-aeration-coagulation-filtration” (GSNFACF) was an effective strategy to amend AMD and could be used for future cleaner production and environmental sustainability. These results suggested that the main contaminants in the sediments of the Shandi River should be preferentially treated by the government.

Heavy metal content in soil-like fractions on the landfills within Volgograd boundaries and assessment of health risk connected to its presence in the environment.

The heavy metal content (Cu, Ni, Pb, Zn, and Cd) in a soil-like fraction from two landfills located within the boundaries of Volgograd was described using pollution indices and health risks. The calculated pollution index (PI) values have shown a lack of Pb and Zn pollution in the soil-like fraction from both landfills. For landfill No.1, the pollution level was determined as very high for Cd and as low for Cu and Ni, and for landfill No.2, this level was determined as very high, low, and non-polluted, respectively. The Nemerov integral pollution index (NIPI) values (25.24-43.90 for landfill No. 1 and 10.37-40.38 for landfill No. 2) indicated a high level of pollution in a soil-like fraction with studied elements in both landfills. According to the calculated values of the hazard index (HI), which are significantly lower than 1 in all samples, there is no non-carcinogenic risk for children and adults associated with the presence of a soil-like fraction in the environment. The total potential carcinogenic risks (TCR) associated with the heavy metals in a soil-like fraction were determined to be high for both target groups. The health of a child target group (TCR = 1.30E-03 and 4.87E-04) was found to be more exposed to carcinogenic risk than an adult target group (TCR = 1.40E-04 and 5.21E-05). Because the risk of a carcinogenic effect is high, the use of a soil-like fraction from both landfills for territory reclamation without prior detoxification is not allowed.

Concentration, source apportionment and human health risk assessment of elements in PM2.5 at Agra, India

The present study determined the concentration, seasonal variation, source identification and the human health risk of elements (V, Cr, Mn, Fe, Ni, Cu, Zn, As, Cd, Pb and Si) in fine particulate matter (PM2.5). Samples of PM2.5 were collected at the urban site (Bhagwan Talkies) of Agra, India during January to December 2021. The result showed that the average annual PM2.5 concentration at the urban site was 144.32 ± 57.18 μg m−3 which exceeded the air quality guidelines. Seasonal variation of PM2.5 shows high concentration in winter followed by post-monsoon, summer and monsoon. Among the elements analysed, Si showed the highest concentration and V had the lowest concentration. The concentration of Cr, Ni, As and Cd exceeded the WHO limit, whereas V, Mn and Pb concentrations were below the WHO limit. The significant seasonal variations of elements were observed during the study period. An enrichment factor (EF) was applied to assess the level of the contamination. The possible sources of elements were determined using principal component analysis (PCA). The non-carcinogenic risks for children and adults due to Ni and Cu were higher than the safe level (= 1). The HI values for studied metals for both children and adults were 7.02. The carcinogenic risks for both children and adults due to Pb while for children due to Cd were lower than 1 × 10−6. The carcinogenic risks for other studied metals were higher than 1 × 10−6. The total carcinogenic risks for adults and children were higher than the acceptable limit (1 × 10−6).

Health Risk Assessment of Heavy Metals in Sediment of Tropical Freshwater Stream

An investigation of the heavy metals in the bed sediment of Asunle stream was carried out to assess how seriously the sediment is polluted using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The potential health risk assessment was calculated for a lifetime exposure (ingestion) based on the United State Environmental Protection Agency (USEPA) models to determine the carcinogenic and noncarcinogenic risks for children and adults. The range of values (mg/kg) of heavy metals in bed sediment were: Fe (2850 – 7260), Mn (58 – 209), Co (0.7 – 33), Ti (21.6 – 67), Ba (1.61 – 9.81), Zn (7.5 – 79), Cu (5.6 – 25), As (8 – 137), Al (273 – 2160), Y (24 – 49), and Sr (0.10 – 5.3). As and Sr, values were below the background values for typical soil. The health risk assessment of heavy metals in the bed sediments revealed that carcinogenic risk was almost insignificant while the non-carcinogenic risk was significant since their values were above the recommended minimal risk level. The results also revealed that children are more vulnerable to hazards than adults. The chronic hazard quotient index for exposure to these metals through ingestion exceeded the acceptable USEPA value of 1.0.

Potentially Harmful Elements Associated with Dust of Mosques: Pollution Status, Sources, and Human Health Risks.

Potentially harmful elements (PHEs) associated with dust generated from anthropogenic sources can be transported into mosques and deposited on the filters of the air-conditioners (AC); thereby, children and adults are exposed to such PHEs while visiting mosques. Data dealing with the assessment of PHEs pollution and its human health risk in mosques dust in Saudi Arabia are scarce. Therefore, this work aims to examine the levels and pollution status of PHEs in AC filter dust (ACFD) of mosques and their associated human health risk in three Saudi cities: Jubail, Jeddah, and Dammam metropolitan. A similar concentration pattern of PHEs is observed in three cities' mosques with noticeably higher concentrations than both global crustal and local background values for Zn, Cu, Pb, As, and Cd only. Except for Fe, Al, and Mn, the highest PHEs concentrations were found in Jeddah (1407 mg/kg), followed by Dammam (1239 mg/kg) and Jubail (1103 mg/kg). High PHEs' concentrations were also recorded in mosques located near workshops and suburban areas compared to urban areas. Based on the spatial pattern, enrichment factor, geo-accumulation index, pollution load index, and ecological risk values, Jubail, Jeddah, and Dammam have shown moderate pollution levels of Cd, As, Pb, and Zn. On the other hand, Cu. Zn, Cu, Cr, Pb, Ni, As, and Cd had degrees of enrichment levels that varied from significantly enriched to extremely highly enriched in the ACFD of the three cities. Heavy pollution is found in Jubail, which posed a higher potential ecological risk than in Jeddah and Dammam. Cd presents the highest ecological risk factors (ER) in the three cities. Carcinogenic and non-carcinogenic risks for children and adults follow the order: Jeddah > Dammam > Jubail, and the ingestion pathway was the main route for exposure. Carcinogenic and con-carcinogenic risks in the mosques of the various studied cities were generally within the acceptable range.

Pollution characteristics and human health risk of potentially toxic elements associated with deposited dust of sporting walkways during physical activity

Sporting walkways are planned features designed to facilitate physical exercise in urban areas. Potentially toxic elements (PTEs) associated with deposited dust (DD) of urban sporting walkways (USWs), suburban sporting walkways (SSWs) and residential sporting walkways (RSWs) in Jeddah, Saudi Arabia, were measured and interpreted in relation to concentration, spatial distribution, pollution level and human health risk. The elemental concentrations followed a similar pattern, but were generally lower than those in road dust. Pb, Zn, Cu, Cd, and As had elevated Crustal Enrichment Factors (>10), ranging up to 185 for Cd. Except for Fe, ∑PTE concentrations were in the following order: USWs (1431 mg/kg) > SSWs (1073 mg/kg) > RSWs (892 mg/kg). Based on the spatial pattern and enrichment factor, and ecological risk values, sporting walkways (SWs) had moderate to heavy pollution levels of Cd, As, Pb, Zn and Cu, and heavy to extreme pollution level of Cd in USWs. Cd presented a high ecological risk, accounting for 85% of the summed ecological risk indices of the elements with elevated concentration. Carcinogenic and non-carcinogenic risks for children and adults follow the order: USWs > SSWs > RSWs. Ingestion was the main pathway for carcinogenic and non-carcinogenic risks, well exceeding that for the dermal and inhalation pathway. Most risks to human health were generally within the acceptable range, although risks to children were generally higher than those to adults, by a factor of 5.5 for non-carcinogenic risk. Incremental Lifetime Cancer Risks for individual elements did not exceed 10−4 for any element.

Levels, origins and probabilistic health risk appraisal for trace elements in drinking water from Lhasa, Tibet.

Due to the lack of monitoring systems and water purification facilities, residents in western China may face the risk of drinking water pollution. Therefore, 673 samples were collected from Lhasa's agricultural and pastoral areas to reveal the status quo of drinking water. We used inductively coupled plasma-mass spectrometry to determine trace elements concentrations for water quality appraisal, source apportionment, and health risk assessment. The results indicate that concentrations of V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Ba, and Pb are below the guidelines, while As concentrations in a few samples exceed the standard. All samples were classified into "excellent water" for drinking purpose based on Entropy-weighted water quality index. Thereafter by principal component analysis, three potential sources of trace elements were extracted, including natural, anthropogenic, and mining activities. It is worth noting that geotherm and mining exploitation does not threaten drinking water safety. Finally, health risks were assessed using Monte Carlo technique. We found that the 95th percentiles of hazard index are 1.80, 0.80, and 0.79 for children, teenagers, and adults, indicating a non-carcinogenic risk for children, but no risks for the latter two age groups. In contrast, the probabilities of unacceptable cautionary risk are 7.15, 2.95 and 0.69% through exposure to Cr, Ni, As, and Cd for adults, children, and teenagers. Sensitivity analyses reveal As concentration and ingestion rate are most influential factors to health risk. Hence, local governments should pay more attention to monitoring and removal of As in the drinking water.

Pollution characteristics of soil heavy metals around two typical copper mining and beneficiation enterprises in Northwest China.

In order to investigate the situation of heavy metal pollution in the heavy metal industry in Gansu Province, a large copper mining province, two large and typical copper mining and beneficiation enterprises with differences in topographic features, climatic conditions, and soil types were selected as the target of this study based on similar ore types and beneficiation processes. Around these two enterprises, geochemical baselines of the six heavy metals were established, while the degree of local soil heavy metal pollution and potential hazards to humans were assessed based on statistical analysis, single-factor and multi-factor index analysis, and health risk evaluation models. In addition, Spearman's correlation analysis and hierarchical cluster analysis were used to explore the intrinsic association between each heavy metal in the two mining industries to reveal the pattern of soil heavy metal pollution in the copper mining and beneficiation industry and to propose targeted measures to improve and prevent soil heavy metal pollution. The results showed that the heavy metal pollution in the soil around Shengxi Mining Co., Ltd. of Subei County (SX enterprise) was higher than that around Yangba Copper Co., Ltd. of Gansu Province (YB enterprise), but the two enterprises had similar patterns of pollution, with an overall medium level of pollution. The carcinogenic and non-carcinogenic risks for children and adults were within acceptable limits for both enterprises. Besides, the correlation between the different heavy metals to similarity in their sources of contamination and the different degrees of association between the soil heavy metals of the two enterprises due to their environmental characteristics.

Potentially Toxic Elements in Urban Soils from Public-Access Areas in the Rapidly Growing Megacity of Lagos, Nigeria.

Rapid urbanization can lead to significant environmental contamination with potentially toxic elements (PTEs). This is of concern because PTEs are accumulative, persistent, and can have detrimental effects on human health. Urban soil samples were obtained from parks, ornamental gardens, roadsides, railway terminals and locations close to industrial estates and dumpsites within the Lagos metropolis. Chromium, Cu, Fe, Mn, Ni, Pb and Zn concentrations were determined using inductively coupled plasma mass spectrometry following sample digestion with aqua regia and application of the BCR sequential extraction procedure. A wide range of analyte concentrations was found—Cr, 19–1830 mg/kg; Cu, 8–11,700 mg/kg; Fe, 7460–166,000 mg/kg; Mn, 135–6100 mg/kg; Ni, 4–1050 mg/kg; Pb, 10–4340 mg/kg; and Zn, 61–5620 mg/kg—with high levels in areas close to industrial plants and dumpsites. The proportions of analytes released in the first three steps of the sequential extraction were Fe (16%) < Cr (30%) < Ni (46%) < Mn (63%) < Cu (78%) < Zn (80%) < Pb (84%), indicating that there is considerable scope for PTE (re)mobilization. Human health risk assessment indicated non-carcinogenic risk for children and carcinogenic risk for both children and adults. Further monitoring of PTE in the Lagos urban environment is therefore recommended.