Health Risks Of Metals Research Articles

Occurrence, contamination evaluation and health risks of trace metals within soil, sediments and tailings in southern Tunisia

Occurrence, contamination evaluation and health risks of trace metals within soil, sediments and tailings in southern Tunisia

Pollution characteristics, sources and health risk of metals in urban dust from different functional areas in Nanjing, China

Urban dust is an important medium of potential toxic metal (PTM) pollution that affects human health and the urban ecosystems. A total of 374 fugitive dust samples were collected in Nanjing, a fast-developing city in southern China, including six sub-types of dust (residential district, commercial district, industrial district, traffic district, cultural and educational district, green land). Chemical analysis of eighteen metal elements by inductively coupled plasma mass spectrometry was carried out to establish the sub-type sources profiles of fine particles for fugitive dust. The results show that these metals (Cu, Zn, Se, Sr, Mo, Cd, Sb, and Pb) are mainly from anthropogenic sources and present a high degree of pollution; Mn, As, and Ba are moderately affected by human activities and present a significant degree of pollution; Ni, Co, Cr, Tl, V, Be, and Ti mainly originate from natural sources and present significant, moderate and minimal degrees of pollution. For the dust types from different functional areas, the differences of enrichment factor (EF) values were relatively small. Metals were highly concentrated in dust from residential, cultural and educational district, which had high density population and would pose higher health risk. In all types of dust, the metals rich in crust (Ti, Mn, Ba, Sr) and the metals (Cu, Zn, Pb) closely connected with city activities were the main components. Factor analysis revealed that there were six main sources of metals in dust collected from Nanjing: industrial activity, building decoration, soil dust, metal smelting, traffic emissions, and brake abrasion. Generally, noncarcinogenic and carcinogenic health risks of metals found in dust are rarely found for children and adults based on health risk assessments. However, the noncarcinogenic risk of Pb in commercial districts for children should be noted because its hazard quotient was higher than the safety threshold level. For the accumulative health risk of eighteen metals, the noncarcinogenic risk values of dust from six functional areas for children were all over the threshold (1.0), whereas below 1.0 for adults. The difference between children and adults was relatively obvious. All accumulative risk values of carcinogenic metals did not exceed the carcinogenic risk threshold of 1 × 10−4, which suggested that no risk prevention measures were needed.

Seasonal variations and risk assessment of heavy metals in PM2.5 from Handan, China

Purpose This study aims to acquire a better understanding on the characteristics and risks of heavy metals (HMs) in PM2.5 from an industrial city – Handan, China. Design/methodology/approach PM2.5 samples were collected on the basis of daytime and nighttime at the state controlling air sampling site in Handan city. Ten metal elements (V, Cr, Mn, Fe, Ni, Cu, Rb, Sr, Cd and Ba) in PM2.5 were determined with an inductively coupled plasma mass spectrometry. The pollution levels of metals were characterized by enrichment factors, and the sources of metals were identified with principle component analysis and cluster analysis. The ecological and health risks of metals were assessed using ecological and health risk indexes. Findings Results showed that the highest and lowest PM2.5 concentration appeared in winter and summer, respectively. The concentration of PM2.5 at night was higher than in the daytime in winter, yet it is the opposite in other seasons. The total mass concentration of detected metals was the highest in winter, and the total mass concentration in the daytime was higher than at night in all four seasons. The elements V, Rb, Sr and Ba exhibited a deficient contamination level; Cr, Ni and Cu exhibited a moderate contamination level; while Fe and Cd were at an extreme contamination level. The metals in PM2.5 originated from a mixture source of fossil fuel combustion and manufacture and use of metallic substances (34.04%), natural source (26.01%) and construction and traffic-related road dust (17.58%). Results from the ecological risk model showed that the ecological risk of metals was very high, especially risks related to Cd. Health risk model presented that both the non-carcinogenic and carcinogenic risk coefficients of metals were above the tolerance level of the human body. Originality/value The significance of the study is to further know the pollution characteristics of PM2.5 and related HMs in Handan city, and to provide references for ensuring local resident health and ecological environment.

Assessment of heavy metals bioaccumulation and health risk in crops grown in farmlands around mining sites in Gwana, Alkaleri lga, Bauchi state, Nigeria

Analysis was carried out on farm crops (Guinea corn, Millet and Beans) collected from adjourning farmlands around mining area of Gwana in Alkaleri Local Government Area, Bauchi State. Their heavy metal concentrations were determined and quantified using Atomic Absorption Spectroscopy (AAS). The heavy metal characterization revealed the presences copper, iron, lead, manganese, nickel and zinc in the farm crops. The mean values of the elements that where obtain for copper, iron, lead, manganese, nickel, silver and zinc by AAS are 33.90, 12.00, 71.43, 12.56, 4.40, 0.60 and 101.96 mg/kg, respectively. From the Analysis of variance (ANOVA) used to compare these levels of heavy metals in the crops, it showed that there was a significant difference in their concentration. Exposure assessment and risk characterization of the heavy metals present in the farm crops showed that the mean values of the bioaccumulation coefficient for the elements of copper, iron, lead, manganese, nickel, silver and zinc are1.24, 0.03, 1.68, 0.80,1.64, 0.89 and 1.21 respectively. The estimated daily intake rate for the elements of copper, iron, lead, manganese, nickel and zinc are 1.17 to 1.28 mg/kg, 0.03 to 0.04 mg/kg, 0.06 to 0.011 mg/kg, 1.39 to 1.96 mg/kg, 1.92 to 3.14 mg/kg and 1.18 to 1.26 mg/kg respectively. The hazard quotient for the elements of copper, iron, lead, manganese, nickel and zinc are 0.57–1.31, 0.01–0.02, 22.95–32.50, 0.07–0.12, 0.02–0.26 and 0.32–0.40 respectively. The carcinogenic risk for the elements of lead and nickel are 0.0003–0.0011 and 0.0006–0.0089 respectively. It is hereby recommended that the farm crop samples from within the catchment areas understudy should be subjected to clinical trials to evaluate the extent of the damage it can cause on body tissues. Â

Health risk assessment of heavy metals in direct drinking water among middle and primary schools in Huangpi District of Wuhan

Objective To analyze heavy metal health risks of direct drinking water in primary and secondary schools in Huangpi District, Wuhan, so as to provide reference basis for ensuring drinking water safety of teachers and students. Methods Cadmium (Cd), Plumbum (Pb) and arsenic (As) in water samples from primary and secondary schools were detected in accordance with the GB/T 5750–2006 “Standard Examination Methods for Drinking Water”, water quality was evaluated based on the Quality Standard for Fine Drinking Water (CJ 94–2005). Health risk assessment model was used to evaluate the potential risk of heavy metals in direct drinking water in primary and secondary schools. Results The unqualified rates of Pb, Cd and As were 0.95%, 1.22% and 0 in 66 primary and secondary schools in Huangpi District, Wuhan. The risk of noncarcinogens related to the direct drinking water of heavy metals (Pb, Cd, As) were less than 1. The range of carcinogenic risks related to the direct drinking water was within the range of 1.07×10 -8/year–5.58×10 -6/year which were both within the acceptable level. Conclusion Concentrations of cadmium, plumbum and arsenic were not found to be significantly elevated as compared to “Quality Standard for Fine Drinking Water” in Huangpi District of Wuhan. Pb and Cd slightly exceeded the standard, with no significant health risk. Water quality and health risk assessment should be strengthened to ensure the safety of drinking water for teachers and students. 【摘要】 目的 分析武汉市黄陂区中小学校直饮水重金属健康风险, 为保障师生饮水安全提供参考依据。 方法 采集武 汉市黄陂区66所中小学校直饮水, 按照«生活饮用水标准检验方法》(GB/T 5750—2006)检测水中重金属铅(Pb)、镉 (Cd)、砷(AS), 参照《饮用净水水质标准》(CJ 94—2005)进行评价。利用健康风险评价法(HRA)评价水质重金属健康风 险。 结果 检测结果显示, 水质Pb、Cd、As不合格率分别为0.95%, 1.22%和0,水质Pb、Cd、As非致癌风险均<1, 致癌风险 在1.07×10 -8/年~5.58×l0 -6/年范围, 均处于可接受水平。 结论 武汉市黄陂区中小学校直饮水重金属Pb、Cd、As质量体 积浓度符合标准要求, 较少部分水样Pb、Cd轻度超标, 尚未见明显健康风险性。需加强水质卫生管理、监测及健康风险评 价, 确保学校师生饮水安全。

Heavy metal concentrations in soils and two vegetable crops (Corchorus olitorius and Solanum nigrum L.), their transfer from soil to vegetables and potential human health risks assessment at selected urban market gardens of Yaoundé, Cameroon

ABSTRACT Soil contamination by heavy metals has received considerable attention in recent years. In this study, heavy metal accumulation in two vegetable crops (Corchorus olitorius and Solanum nigrum L.) was studied. Assessment of soil properties and seven heavy metals (Zn, Cu, Cd, Ni, Pb, Cr and Mn) in soils and vegetables was done. Heavy metal transfer from soil to plant parts, translocation from roots to leaves and estimated potential health risks of heavy metal to humans via consumption of vegetable crops were studied. The ANOVA test showed that variations in the soil characteristics and heavy metal concentrations were statistically significant at level 0.05. Pearson correlation coefficients showed that the concentration of heavy metals has significant relationships with some soil properties like cation exchange capacity (CEC), organic carbon (OC) and soil texture. Bioconcentration factor (BCF) for both leaves and roots for Zn, Cu, Cd, Ni Cr and Mn were found to be greater than one, indicating the hyperaccumulation nature of vegetables. High translocation (TF) from root to leaves (TF>1) was recorded for Zn, Cu, Cd and Mn. The Health Risk Index (HRI) was found generally less than 1, suggesting that it is not risky for the Yaoundé city inhabitants to consume vegetable crops, except for Cd and Mn in Solanum nigrum L. Total Hazard Health Risk Index (THRI) expressed to know the overall harmful effects on health posed by several heavy metals taken together showed that the value for vegetables studied was higher than 1, suggesting the probability of adverse effects. The health risk is likely to occur for vegetable consumers.

Potential health risks of metals in skin care products used by Chinese consumers aged 19–29 years

Metal contamination of skin care products that occurs during their production poses potential health risks, which are of increasing concern, to consumers. Here, we collected 570 responses to an online survey to analyze the usage pattern of skin care products across China. Then a total of 30 commonly used skin care products with various prices and applications were purchased. The concentrations of metals (Al, Zn, Cu, Ni, Cr, Pb, Hg, and Cd) and metalloid As, were determined. Next, we improved the frequency calculation method and used the weighted exposure frequency to calculate the dermal absorption dose (DAD). The amounts of Zn, Cr, and Al that were assimilated by the human body via uptake were approximately 2 orders of magnitude greater than those of Pb, Hg, Cd, Ni and metalloid As. In addition, younger consumers were at higher risk of metals exposure than older consumers because of their higher frequency of use of skin care products. Al and Zn posed higher risk to consumers because of its high DAD. There was no significant chronic non-carcinogenic health risk (hazard index < 1) posed by skincare product use.

The sources-specific health risk assessment combined with APCS/MLR model for heavy metals in tea garden soils from south Fujian Province, China

Limited comprehensive information is available on the source-specific health risks for heavy metals (HMs) in tea plantation soils. In this study, the concentrations of HMs in tea leaves and their corresponding topsoils (0–20 cm) collected from South Fujian (including the three regions of Xiamen, Zhangzhou, and Quanzhou) were determined by inductively coupled plasma mass spectrometry (ICP-MS). Factor analysis and absolute principal component score/multiple linear regression (APCS/MLR) were used to quantify the pollution sources of HMs in tea garden soils. The human health risks of the HMs from different specific sources were further quantified by the health risk assessment model. Agricultural activities and natural sources were the largest contributors to the non-carcinogenic risk of HMs in soils for adults. Natural sources accounted for 80.29% and 80.31% of the carcinogenic risk to adults and children, respectively. Furthermore, the relative contributions of different sources to non-carcinogenic and carcinogenic risks were similar for adults and children. Co and Cr were the major contributors to the non-carcinogenic and carcinogenic risks of HMs in tea leaves by soaking, respectively. Generally, this study highlights the need to control and manage agricultural activities in tea plantation bases to mitigate health risks.

Bioaccessibility and source-specific health risk of heavy metals in PM2.5 in a coastal city in China

Heavy metals in PM2.5 (a global pollutant) are bio-accessible and highly toxic. Health risk assessment of bioaccessible heavy metals in PM2.5 was analyzed in the present study to relate the bioaccessibility with health outcomes. Then source-specific health risk was used to find out the major health abuser, which could provide reliable evidence for accurate pollution control. PM2.5 samples were collected in four seasons included spring, summer, autumn, and winter in urban and suburban areas in Xiamen, China. The order of heavy metals’ concentrations in PM2.5 was Cu > Zn > Mn > Ni > Pb> V > Co > Cr, urban area > suburb. Heavy metals in PM2.5 were mainly from anthropogenic sources that contributed more than 69.30%, 56.51%, 69.70%, 58.99% in spring, summer, autumn, and winter, respectively. Bioaccessibility of V, Pb, and Zn was relatively high, Co, Ni, Mn was relatively low after extracting by an artificial lysosomal fluid at pH=4.5. Bioaccessibility of Cr in spring and summer was higher than that in autumn and winter (60.4%–90.7% vs. 16.1%–69.2%) due to different sources and species in various seasons. Bioaccessibility of Cu after 1 d extraction was higher than that after 15 d extraction (69.6%–78.4% vs. 33.8%–48.2%) because of reverse adsorption of filter membranes and particulate matter. Health risks of bioaccessible heavy metals were lower than those of total heavy metals. However, both total and bioaccessible Cr and Cd had carcinogenic risks. Based on the combined positive matrix factorization-health risk (PMF-HR) model, industry, combustion, and traffic emission contributed the most to the health risk of Cr and Cd, followed by soil parent material layer. Our study provided a reliable method to calculate the bioaccessible heavy metal health risk and determine each potential source's contribution to health risk.

Do trace metal(loid)s in road soils pose health risks to tourists? A case of a highly-visited national park in China

Nowadays, more people tend to spend their recreational time in large national parks, and trace metal(loid)s in soils have attracted long-term attention due to their possible harm to human health. To investigate the pollution levels, potential sources and health risks of trace metal(loid)s in road soils, a total of eight trace metal(loid)s (including As, Cd, Cr, Cu, Ni, Pb, Zn and Hg) from 47 soil samples along roads were studied in the Huangshan National Park in Southeast China. The results showed that the concentrations of As, Cd, Pb, Zn and Hg appeared different degrees of pollution compared with their corresponding background values. According to the pollution indices, Hg and Cd were recognized as significant pollutants presenting moderate to high ecological risk. Combining principal component analysis and positive matrix factorization model, the results showed that traffic, industrial, agricultural and natural sources were the potential origins of trace metal(loid)s in this area, with contribution rates of 39.93%, 25.92%, 10.53% and 23.62%, respectively. Non-carcinogenic risks were all negligible, while the carcinogenic risk of As was higher than the limit (1 × 10−6). Moreover, children were more susceptible to trace metal(loid)s by ingestion which appeared to be a more important exposure pathway than dermal contact and inhalation. The contribution rates of different sources to non-carcinogenic risks and carcinogenic risks were similar among children and adults, while traffic and industrial sources have a significant impact on health risks. This study will give more insights to control the environmental risks of trace metal(loid)s in national parks.

Health Risk Assessment of Heavy Metals Through Cow Milk Consumption in Trans-Himalayan High-Altitude Region.

Consumption of heavy metals contaminated dairy milk may affect human health. No such studies have been carried out at the high-altitude region to assess the human health risk after consuming dairy milk. To this end, this study reveals the evaluation of selected heavy metals in dairy milk in the summer and winter seasons, followed by the assessment of heavy metals health risk. Analysis of Jersey crossbred cattle's milk showed that only the zinc level was significantly higher in the summer season. All the non-carcinogenic and carcinogenic parameters were below the permissible limits. However, the carcinogenic risk (CR) level of arsenic and cadmium showed near the threshold level. Based on these findings, it might be concluded that all the studied metals do not have any significant role in health risk. In the near future, CR could be a health concern due to cow milk consumption at a high-altitude region.

Environmental levels and human health risks of metals and PCDD/Fs near cement plants co-processing alternative fuels in Catalonia, NE Spain: a mini-review

This paper was aimed at reviewing recent studies related with the impact on environment and human health of metals and PCDD/Fs near cement plants. It has been particularly focused on the impact of cement plants located in Catalonia, Spain, which have been monitored by our research for more than ten years. Environmental monitoring studies were performed under different cement plant conditions. While some of our studies examined temporal trends of the levels of the above indicated pollutants, the main goal of other surveys was to assess the impact of implementing alternative fuels in the facilities. Even one of the studies was performed before and after the cement plant temporally ceased its industrial activity. The impact of cement plants burning alternative fuels on the emissions of metals and PCDD/Fs elsewhere was also reviewed. Regarding the cement plants in Catalonia, no significant differences were found, neither in the long-term follow-up studies, nor when alternative fuels are used, nor when a cement plant temporally stopped its activity. These results are in agreement with those reported for several stack emissions of other cement plants working under different conditions. We conclude that emissions of metals and PCDD/Fs by cement plants working with the best available techniques (BAT), should not cause a significant negative impact neither on the surrounding environment, nor on the human health of the population living in the neighborhood.

Distribution, bioaccessibility and human health risks of toxic metals in peri-urban topsoils of the Kumasi Metropolis

The occurrence of heavy metals in urban soils is of great environmental concern due to the unwanted health effect associated with their excessive exposure. The study assessed levels of heavy metals (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sn, V, and Zn) in peri-urban communities of the Kumasi metropolis and evaluated sources and potential health risk associated with exposure to these metals. Soil samples collected from topsoils at a depth of 0–10 cm were subjected to x-ray fluorescence (XRF) spectroscopy analysis for total metal quantification. The XRF results were then confirmed by inductively coupled plasma mass spectrometry. Soil pH, conductivity, and total organic carbon were determined using standard procedures. The mean concentrations (mg/kg) of metals were As (10.11), Cd (12.91), Cr (77.97), Cu (20.20), Fe (23031), Pb (18.60), Mn (158.68), Ni (29.33), Sn (8.83), V (78.21) and Zn (49.27). The pH and electrical conductivity were in a range of 6.5 - 8.5 and 153 - 8990 µS/cm respectively. The mean total organic carbon was 8.85%. Pollution indicators such as enrichment factor, contamination factor, and pollution load index all showed that soil in the study area is of low degree of contamination. The potential ecological risk index projected a low-risk effect. In contrast, the hazard index and carcinogenic risk index indicated no significant human health risk associated with exposure to the metals presently. However, to regulate bioaccumulation effects, constant monitoring is essential.

Appraisal of pollution scenario, sources and public health risk of harmful metals in mine water of Barapukuria coal mine industry in Bangladesh

This study was conducted to assess the accumulation and sources of harmful metals and associated public health risk from the usage of underground mine water of Barapukuria coal mine in Bangladesh, keeping in mind the optimum reuse. Thirty underground mine water samples had been analyzed for assessing temperature, pH, EC, TC, DO, BOD, COD, Ca, K, S, Ti, Mn, V, Fe, Co, Ni, Cu, Zn, Br, Rb, Sr, and Pb. Numerous pollution evaluation and health risk assessment indices along with multivariate statistical tools were employed in this study to apprise the pollution scenario, controlling factors, and probable health risk. The chronic or persistent health risk of metals via oral and dermal exposure of adults and children was determined using the hazard quotient (HQ) and hazard index (HI). The results showed that the content of physicochemical parameters and potentially harmful elements in water samples was many folds higher than the national and international standards. The results of pollution evaluation indices indicate that coal seam-leached mine water is highly concentrated by potentially harmful metals and not suitable for drinking, agriculture, and aquatic lives. The correlation coefficients and multivariate analysis illustrate both the geological and anthropogenic factors controlling the variability of metals in mine water. Results of HQoral value suggest that V, Co, and Pb are significant health risk for adults and Mn, V, Co, Cu, and Pb are for children. Vanadium is found potential for dermal effects, and HIdermal value directs 33%, and 70% samples exceed the safe limit for adults and children, respectively. The HI value suggests that oral exposure to harmful metals creates more harm than dermal absorption, and children are more vulnerable than adults. It is anticipated that the outcomes of this study would deliver expedient insights to initiate necessary steps to minimize the public health risk by applying appropriate environmental protocols.

Human Health Risks of Heavy Metal in Wells and Streams Water in the Vicinity of a Lead Mining in Nasarawa State, North Central, Nigeria

The quality of surface and ground water in mining communities is uncertain since metals associated with acid mine drainage are known to saturate these waters. A total of two (2) hand dug wells, two (2) stream water and six (6) mine waste water samples were collected in March 2019. The water samples were analyzed in triplicate for As, Pb, Hg, Cu, Zn, Ni, Cr and Cd using AAS. The toxic metals concentration sequence was such that Pb > Zn >Cu > Cd > Cr > Ni > Hg > As. Pb, Cd and Cr concentrations were higher than WHO and NESREA Standard limits. Measured concentrations of these heavy metals were used to calculate the health risk for human population. The Hazard Index (HI) value for all pathways was found to be 236.8 in mine waste water, 23.39 in stream water 1, 12.91 in stream water 2, 11.1 in well water 1 and 45.07 in well water 2. Among all the studied metals, Cr and Cd has the highest chances of cancer risks with ILCR values of 1.8 x 10–3 and 5.17 x 10–3 while Pb and Ni has the lowest chances of cancer risks with ILCR values of 1.69 x 10–4 and 5.9 x 10–4.

Evaluation of Heavy Metal Pollution in Shallow Groundwater of Farmland in Huaibei Plain, China

In order to understand the characteristics of heavy metal pollution in shallow groundwater in farmland in Huaibei Plain, 69 samples were collected from typical farmland areas in Xiaoxian County to determine the content of heavy metal elements such as Cr, Zn, Cu, Cd, and Ni. The single-factor pollution index method and Nemerow comprehensive index method are used to evaluate and analyze the pollution degree and the health risk assessment method is used to explore the health risk level. The results show that the concentrations of Cr, Zn, Cu, Cd and Ni were respectively 1.27μg∙L-1~268.78μg∙L-1, 0.45μg∙L-1~ 266.1μg∙L-1, 1.77μg∙L-1~ 29.8μg∙L-1, 0.10μg∙L-1~ 21.54μg∙L-1 and 0.9μg∙L-1~ 252.85μg∙L-1. The Nemerow comprehensive index of each heavy metal element is 0.031~5.507, and the pollution degree is Ni&gt;Cr&gt;Cd&gt;Zn&gt;Cu. The Nemerow comprehensive pollution index of each sampling point is 0.251~9.325, with an average value of 1.934. The overall value is 9.523, and the pollution level is extremely poor. The overall health risk is at a risk-free health level. There are 19 samples which the carcinogenic risk index of the Cr is greater than 10-4, and the number of samples with health risks accounts for 27.5%. Cr is the main source of heavy metal health risks in shallow groundwater in farmland.

Concentration and potential health risks of trace metals in warty crab (Eriphia verrucosa Forskal, 1775) from Southern Coasts of the Black Sea, Turkey.

The drastic increase of human population and industrial wastes mostly affects coastal areas. Crabs with limited mobility, especially in benthic regions of the coasts, are more affected by metal pollution. Monitoring of trace metals in terms of food safety and potential health risks is important for consumers. Warty crab (Eriphia verrucosa) samples were collected with trammel nets between July 2015 and June 2016. The crab extracts were analyzed by an ICP-MS optical emission spectrophotometer. Trace metal densities of crab meats in the present study were determined in the order of Zn > Cu > Fe > As > Al > Mn > Hg > Pb ≥ Cd. These levels were below the acceptable values reported by the Turkish Food Codex and the EU Commission. The target hazard quotient (THQ) was above 1 in terms of As, Cu, and Hg trace metals in both groups. This study showed that although the level of trace metal was below allowable values, consumption of warty crab more than once a month may cause metal toxicity according to potential health risk analyses.

Metalliferous content of drinking water and sediments in storage tanks of some schools in Erbil city, Iraq.

The present study was conducted to evaluate the quality of drinking water in randomly selected schools in Erbil city, Kurdistan Region, Iraq. The water quality indices such as the Heavy metal Pollution Index (HPI) and Heavy metal Evaluation Index (HEI) were applied to characterize water quality. Eighteen schools were incorporated and sampled for their water storage tanks available to students. Water samples and sediment samples from tanks floor were analyzed by Inductively Coupled Plasma Optical Emission Spectrometer for the determination of twenty-two metal elements. In drinking water samples, all detected metals did not exceed the permissible limits of the World Health Organization. The results of this study showed that the average values of HPI and HEI for As, Cd, Cr, Cu, Fe, Pb, Mn, Ni, and Zn were 54.442 and 0.221, respectively. According to data of the water quality indices, the schools drinking water quality are good and suitable for drinking in terms of heavy metals. However, sediments samples contained high concentrations of all elements including the toxic heavy metals (As, Cd, Cr, and Pb). Re-suspension of sediments into water column after refilling storage tanks can pose a serious threat to students drinking water from such vessels. It is therefore recommended that proper storage tanks are provided to the schools accompanied by continuous sanitation and hygiene practice to mitigate the corrosion of tanks to avoid health risks of toxic metals.

Spatial distribution, pollution index, receptor modelling and health risk assessment of metals in road dust from Lagos metropolis, Southwestern Nigeria

This study assessed the spatial distribution, pollution index, receptor modelling and health risk of metals in road dust samples from Lagos metropolis, Southwestern Nigeria. Paved and unpaved road dust samples were collected from twenty locations for three consecutive months. Seventy two samples (including control soils) were collected and analysed for metals using inductively coupled plasma - optical emission spectrophotometry. Dust and control soil data were manipulated for descriptive and inferential statistics. Road dusts and control soil revealed high concentrations of Ca (758-2509 mg kg−1), Mg (693-1461 mg kg−1), Fe (583-2493 mg kg−1), Ti (189-785 mg kg−1) and Zn (42-1255 mg kg−1). The geospatial map identified pollution hotspots for Ca, Cd, Cr, Cu, Fe, Mg and Mn at the mainland parts of Lagos state. The receptor models (positive matrix factorization and principal component analysis) identified emission sources from steel industry, traffic emission, crustal matter and combustion processes. The pollution assessment (pollution index, ecological risk index, Nemerov integrated pollution index and enrichment factor) indicated high contamination levels for As, Cd, Pb and Zn in dust/soil. The health risk of metals evaluated for non-carcinogenic [average daily dose (ADD), hazard quotient (HQ), hazard index (HI)] and cancer risk (CR) revealed the HQs greater than 1.0 for As and Ca, an indication of adverse health effects. The CRs of As, Cr, Cd and Ni were higher than the acceptable limit of 1.0 × 10−4, suggesting probable development of cancer.

Occurrence and Health Risks of Organic Micro-Pollutants and Metals in Groundwater of Chinese Rural Areas.

Background:Groundwater is a main drinking-water source for Chinese rural residents. The overall pollution status of organic micropollutants (OMPs) and metals in the groundwater and corresponding health risks are unknown.Objectives:Our objective was to comprehensively screen for and assess the health risks of OMPs and metals in groundwater of rural areas in China where groundwater is used for drinking so as to provide a benchmark for monitoring and improving groundwater quality in future developments.Methods:One hundred sixty-six groundwater samples were collected in the rural areas of China, and 1,300 OMPs and 25 metals were screened by GC-MS, LC-QTOF/MS, and ICP-MS analysis. To assess the noncarcinogenic and carcinogenic risks of the detected pollutants, missing toxicity threshold values were extrapolated from existing databases or predicted by quantitative structure–activity relationship (QSAR) models. Monte Carlo simulation was performed to account for uncertainties in the exposure parameters and toxicity thresholds.Results:Two hundred thirty-three OMPs and 25 metals were detected from the 166 samples. The concentration summation for the detected OMPs ranged from 2.9 to among the different sampling sites. Cumulative noncarcinogenic risks for the OMPs were estimated to be negligible. However, high metal risks were calculated in 23% of the sites. Forty-two carcinogens (including 38 OMPs) were identified and the cumulative carcinogenic risks in 34% of the sites were calculated to be (i.e., one excess cancer case in a population of 10 thousand people). The carcinogenic risks were estimated to be mainly associated with exposures to the metals, which were calculated to contribute 79% (0–100%) of the cumulative carcinogenic risks.Discussion:The overall status of OMPs and metals pollution in the groundwater and the corresponding health risks were determined preliminarily, which may provide a benchmark for future efforts in China to ensure the safety of drinking water for the local residents in rural areas. The joint application of QSARs and Monte Carlo simulation provided a feasible way to comprehensively assess the health risks of the large and ever-increasing number of pollutants detected in the aquatic environment. https://doi.org/10.1289/EHP6483