Contamination and human health risk assessment of heavy metal(loid)s in topsoil and groundwater around mining and dressing factories in Chifeng,North China

Chifeng is a concentrated mining area for non-ferrous metal minerals,as well as a key prevention and control area for heavyduty enterprises.This situation necessitates an efective ecological and human health risk assessment of heavy metal(loid)s driven by the wide distribution of metal ore processing,mining,and smelting factories in Hexigten Banner and Bairin Left Banner.We conducted surveys to assess the levels of heavy metal(loid)s(Cr,As,Pb,Cd,and Hg)in the topsoil and groundwater of the areas.The results indicated that the concentrations of As,Cd,and Pb in partial soil samples exceeded the environmental quality standards of Grade II.Based on contamination assessments,such as geoaccumulation indices and pollution indices,we inferred that Cd,Pb,and As were primary pollutants in topsoil.Potential ecological risks when considered as part of the average risk indices(RI)are up to 1626.40 and 2818.76,respectively,in the two areas.Comparative analysis revealed that Cd posed a very high potential ecological risk,followed by As.Moreover,the evaluation showed that the three exposure pathways of carcinogenic and non-carcinogenic risk followed a descending order:inhalation>ingestion>dermal contact,except for Pb.Arsenic in topsoil posed a potential non-carcinogenic risk to human health,while there were no adverse efects of As in groundwater.In addition,the average total carcinogenic risk for As in the two areas,as well as the risk of Pb in the topsoil of Bairin Left Banner and all the fve heavy metal(loid)s in groundwater,exceeded human tolerance.Pb–Zn mines caused higher human health risks.In addition,the tandem contamination of heavy metal(loid)s in soil and groundwater was not obvious.This research study provides a basis for pollution remediation to control heavy industry-induced ecological and health risks of heavy metal(loid)s.

Human Health Risk Assessment Model of Organic Pollution in Groundwater:Shijiazhuang Industrial Zone

In this study, a risk-based management model is developed and applied to an industrial zone. The models proposed by the United States Environmental Protection Agency and Han Bing have been improved by adding a residual ratio of volatile organic compounds （VOC） after boiling and deleting the related parameters in half-life. Using this improved model, an integrated process was used to assess human health risk level in the study area. Compared with water quality analysis, the results highlight the importance of applying an integrated approach for decision making on risk levels and water protection. The results of this study demonstrated that： （1） Compared with these permissible level standards in China （GB 3838-2002） and National Primary Drinking Water Regulations of the United States, the residents＇ daily life had not been affected by the groundwater in this area （except for relative bad water quality of HB3-4 and HB3-6）; （2） The typical detected organic contaminants of all groundwater samples were chloroform, carbon tetrachloride, trichloroethylene and tetrachloroethene, and the pollution sources were mainly industrial sources by preliminary investigations; （3） As for groundwater, the non-carcinogenic risk values of all samples do not exceed the permissible level of 1.0 and the carcinogenic risk values are relatively lower than the permissible level of 1.00E-06 to 1.00E-04; （4） Drinking water pathway of trichloroethylene and tetrachloroethylene mainly contribute to increasing the health risk of residents＇ in study areas; （5） In terms of non-carcinogenic risk and carcinogenic risk, the health risk order for drinking water pathway and dermal contact pathway was： drinking water pathway 〉 dermal contact pathway.

Current situation and human health risk assessment of fluoride enrichment in groundwater in the Loess Plateau:A case study of Dali County,Shaanxi Province,China

This study aims to investigate the mechanisms and health risks of fluoride enrichment in groundwater in the Loess Plateau,China.By taking Dali County,Shaanxi Province,China as an example,this study obtains the following results through field investigation and the analyses of water,soil,and crop samples.(1)The groundwater can be divided into two major types,namely the Quaternary pore-fissure water and Karst water.The Karst area and sandy area have high-quality groundwater and serve as the target areas for optional water supply.The groundwater in the study area is slightly alkaline and highly saline.Meanwhile,high-fluoride groundwater is mainly distributed in the loess and river alluvial plains in the depression area of the Guanzhong Basin and the discharge areas of the groundwater,with the highest fluoride concentration exceeding seven times the national standard.(2)Fluoride in groundwater mainly originates from a natural source and human activities.The natural source refers to the fluoride-bearing minerals in rocks and soil,and the fluoride from this source is mainly controlled by natural factors such as climate,geologic setting,pH,specific hydrochemical environment,ion exchange,and mineral saturation.Human activities in modern life can be further divided into industrial and agricultural sources primarily.(3)The health risks of fluoride contamination are very high in the Loess Plateau,especially for children compared to adults.Meanwhile,the risks of fluoride exposure through food intake are higher than those through drinking water intake.The authors suggest selecting target areas to improve water supply and ensure the safety of drinking water in the study area.Besides,it is necessary to plant crops with low fluoride content or cash crops and to conduct groundwater treatment to reduce the fluoride concentration in drinking water.These results will provide a theoretical basis for safe water supply in the faulted basin areas in the Loess Plateau.

Geochemical signatures and human health risk evaluation of rare earth elements in soils and plants of the northeastern Qinghai-Tibet Plateau,China

Information on rare earth elements(REEs)in soils and plants of the Qinghai-Tibet Plateau is very limited.Therefore,in this study,we performed field sampling to explore the geochemical signatures and human health risk of REEs in soils and plants of the northeastern Qinghai-Tibet Plateau,China.A total of 127 soil samples and 127 plant samples were collected from the northeastern Qinghai-Tibet Plateau to acquire the geochemical signatures and related human health risks of REEs.The mean total concentrations of REEs in soils and plants of the study area reached 178.55 and 10.06 mg/kg,respectively.The light REEs in soils and plants accounted for 76%and 77%of the total REEs,respectively.REEs showed significantly homogenous distribution in soils but inhomogeneous distribution in plants of the study area.Characteristic parameters indicated that light REEs were enriched and fractionated significantly,while heavy REEs were moderately fractionated in soils and plants.REEs in soils and plants showed significantly negative Europium anomaly.Cerium showed slightly positive anomaly in plants and slight anomaly in soils.The normalized distribution patterns of REEs were generally similar in the analyzed soils and the corresponding plants of the study area.The average bio-concentration factor of REEs ranged from 0.0478(Scandium)to 0.0604(Europium),confirming a small accumulation of REEs by plants.Health risks caused by REEs in soils and plants were negligible,while risks for adults were lower than those for children.This study provides important information on REEs in soils and plants of the northeastern Qinghai-Tibet Plateau.

Human Health Risk through Groundwater Ingestion and Dermal Adsorption： Field Investigation and Practise Using U. S.EPA Evaluation Method

Aiming to ascertain the groundwater pollution status in a southern city of China,shallow groundwater samples were collected,and 9 heavy metals Zn,Mn,Cr,Cd,Pb,Ni,Ba,Be and Hg were tested to determine the contents and environmental controlling factors,and U. S. EPA assessment method was used to evaluate the human health risk through different exposure pathways. The results indicated that the contents of heavy metals in the groundwater of the study area were relatively low,Zn,Mn,Be,Cd and Pb were frequently detected in local groundwater and the rates of exceeding the groundwater quality standard of Mn and Be were larger than 5%,and most of the heavy metals showed negative correlation with groundwater p H. The average values of non-carcinogenic and carcinogenic risk of heavy metals were lower than the threshold values,and ingestion was the major pathway that the residents were exposed to the risk. Mn,Pb and Cd were the most important heavy metals in local groundwater that should be well concerned.

Ecological and Human Health Risk Assessment of Toxic Metals in Water, Sediment and Fish from Lower Usuma Dam, Abuja, Nigeria

The study assessed the levels of some toxic metals (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) with their potential ecological and human health risks in water, African Catfish (Clarias gariepinus), Tilapia (Oreochromis spilurus niger) and sediment samples from the Lower Usuma dam FCT, Nigeria during two major seasons in a year (rainy and dry seasons). Toxic metal concentrations were determined using Atomic Absorption spectrophotometry (Cd, Cr, Cu, Ni, Pb and Zn) and Atomic Emission Spectrophotometry (for As and Hg), and the results obtained were compared with national and international standards. The ecological and human health risk indices of the toxic metals present in the samples from the Dam were evaluated and interpreted. Tilapia from the dam posed the highest but medium ecological and human health risk due to Pb concentration of up to 7.11 mg/kg;ecological risk index of 35.55 and hazard quotient of 50.78. Overall ecological and human health risks were low due to the low concentrations of other toxic metals determined. As, Cd, Cr, Cu, Hg, Ni and Zn concentrations were all below WHO limits in the LUD water;Ni and Pb were above limits in the African Catfish and Tilapia samples. The data obtained were analyzed using one-way analysis of variance (ANOVA) and significant differences accepted at p ≤ 0.05. There was no statistical difference in the concentrations of toxic metals in water but there was significant difference between the concentrations of toxic metals in the fish and sediment samples. Correlation was found to exist between toxic metals in the water, fish and sediment analyzed from the dam. The ecological and human health risks of toxic metals in Lower Usuma dam require regular checks and monitoring hence, it was recommended by the researcher, that this and similar research work be carried out annually by NESREA and also, as research work by other students of Environmental and Analytical chemistry.

Future climate change decreases multi-pathway but increases respiratory human health risks of PAHs across China

Future climate change will affect the environmental fate of hydrophobic organic contaminants(HOCs)and associated human health risks,yet the extent of these effects remains unknown.Here,we couple a high-resolution environmental multimedia model with a bioaccumulation model to study the multimedia distribution of 16 priority polycyclic aromatic hydrocarbons(PAHs),a group of HOCs,and assess future PAH-related human health risks under varying climate change scenarios over China at a continental scale.After removing the effects of PAH emission changes,we find that the total PAH concentrations would decrease in the air,freshwater,sediment,soil,and organisms,while the high-molecular-weight PAH would increase in the air with climate warming from 1.5°C to 4°C.Consequently,the multi-pathway exposure human health risks predominately influenced by dietary ingestion are expected to decrease by 1.7%–20.5%,while the respiratory risks are projected to rise by 0.2%–5.8%in the future.However,the persistently high multi-pathway human health risks underscore the need for reducing future PAH emissions by 69%compared with 2009 levels in China.Our study demonstrates the urgency of limiting PAH emissions under future climate change for public health and highlights the importance of including the contribution of dietary ingestion in human health risk assessment.

Pollution level and human health risk assessment of some pesticides and polychlorinated biphenyls in Nantong of Southeast China

Food consumption is one of the key exposure routes of humans to contaminants. This article evaluated the residue levels of 51 pesticides and 16 polychlorinated biphenyls （PCBs） in selected fish and food items which were commonly consumed in the Nantong area of Jiangsu Province, Southeast China. The 51 pesticides and 16 PCBs were analyzed by highly sensitive gas chromatography- tandem mass spectrometry （GC-MS/MS）. The results showed that organochlorine pesticides such as dichlorodiphenyltrichloroethanes （DDTs）, hexachlorocyclohexanes （I-ICHs）, hexachlorobenzene （HCB） and mirex and other pesticides including chlorpyrifos, pyrethroid pesticides, metolachlor, pyridaben and trifluralin were frequently detected in the samples, which was consistent with the accumulation level and characteristics of these toxic chemicals in human adipose tissue of people living in Nantong. Meanwhile, correlation of the residue level of toxic chemicals with their physical chemical properties and historic use pattern in Nantong area was observed. Combined with dietary survey results at the same sampling locations, human health risk assessment of ingestion through the dietary route was performed. The results suggested that the non-cancer risks of the chemicals investigated can be considered negligible in the Nantong area, however, the cancer risks from lifetime dietary exposure to DDTs and HCB have exceeded the acceptable levels.

Nitrated and parent PAHs in the surface water of Lake Taihu,China:Occurrence,distribution,source,and human health risk assessment

Nitrated polycyclic aromatic hydrocarbons(NPAHs)have toxic potentials that are higher than those of their corresponding parent polycyclic aromatic hydrocarbons(PAHs)and thus have received increasing attention in recent years.In this study,the occurrence,distribution,source,and human health risk assessment of 15 NPAHs and 16 PAHs were investigated in the surface water from 20 sampling sites of Lake Taihu during the dry,normal,and flood seasons of 2018.The PAH concentrations ranged from 255 to 7298 ng/L and the NPAH concentrations ranged from not-detected(ND)to 212 ng/L.Among the target analytes,2-nitrofluorene(2-n Flu)was the predominant NPAH,with a detection frequency ranging from 85%to 90%and a maximum concentration of 56.2 ng/L.The three-ringed and four-ringed NPAHs and PAHs comprised the majority of the detected compounds.In terms of seasonal variation,the highest levels of the NPAHs and PAHs were in the dry season and flood season,respectively.Diagnostic ratio analysis indicated that the prime source of NPAHs was direct combustion,whereas in the case of PAHs the contribution was predominantly from a mixed pattern including pollution from unburned petroleum and petroleum combustion.The human health risk of NPAHs and PAHs was evaluated using a lifetime carcinogenic risk assessment model.The carcinogenic risk level of the targets ranged from 2.09×10^(-7)to 5.75×10^(-5)and some surface water samples posed a potential health risk.

A review of physicochemical and biological contaminants in drinking water and their impacts on human health

Clean drinking water is one of the United Nations Sustainable Development Goals.Despite significant progress in the water purification technology,many regions still lack access to clean water.This paper provides a review of selected water contaminants and their impacts on human health.The World Health Organization(WHO)guidelines and regional standards for key contaminants were used to characterise water quality in the European Union and UK.The concept of safe drinking water was explained based on the non-observed adverse effect level,threshold concentrations for toxic chemicals,and their total daily intake.Various techniques for monitoring water contaminants and the drinking water standards from five different countries,including the UK,USA,Canada,Pakistan and India,were compared to WHO recommended guidelines.The literature on actual water quality in these regions and its potential health impacts was also discussed.Finally,the role of public water suppliers in identifying and monitoring drinking water contaminants in selected developed countries was presented as a potential guideline for developing countries.This review emphasised the need for a comprehensive understanding of water quality and its impacts on human health to ensure access to clean drinking water worldwide.

Human health risk assessment of groundwater nitrate at a two geomorphic units transition zone in northern China

To assess groundwater nitrate contamination and its human health risks,489 unconfined groundwater samples were collected and analyzed from Zhangjiakou,northern China.The spatial distribution of principle hydrogeochemical results showed that the average concentrations of ions in descend order was HCO3-,SO42-,Na+,Ca2+,Cl-,NO3-,Mg2+and K+,among which the NO3-concentrations were between 0.25 and 536.73 mg/L with an average of 29.72 mg/L.In total,167 out of 489 samples(34%)exceeded the recommended concentration of 20 mg/L in Quality Standard for Groundwater of China.The high NO3-concentration groundwater mainly located in the northern part and near the boundary of the two geomorphic units.As revealed by statistical analysis,the groundwater chemistry was more significantly affected by anthropogenic sources than by the geogenic sources.Moreover,human health risks of groundwater nitrate through oral and dermal exposure pathways were assessed by model,the results showed that about 60%,50%,32%and 26%of the area exceeded the acceptable level(total health index>1)for infants,children,adult males and females,respectively.The health risks for different groups of people varied significantly,ranked:infants>children>adult males>adult females,suggesting that younger people are more susceptible to nitrate contamination,while females are more resistant to nitrate contamination than males.To ensure the drinking water safety in Zhangjiakou and its downstream areas,proper management and treatment of groundwater will be necessary to avoid the health risks associated with nitrate contamination.

Two-step calculation method to enable the ecological and human health risk assessment of remediated soil treated through thermal curing

The centralized utilization of heavy-metal-contaminated soil has become the main strategy to remediate brownfield-site pollution.However,few studies have evaluated the ecological and human health risks of reusing these remediated soils.Considering Zn as the target metal,systematic pHdependent leaching and the Community Bureau of Reference(BCR)extraction were conducted at six pH values(pH=2,4,6,8,10,12)for the remediated soil treated through thermal curing.The pHdependent leaching results showed that with the formation of ZnCr2O4 spinel phases,the remediated soil exhibited strong inherent resistance to acidic attack over longer leaching periods.Furthermore,the BCR extraction results showed that the leaching agent pH value mainly affected the acid-soluble fraction content.Moreover,a strong complementary relationship was noted between the leaching and acid-soluble fraction contents,indicating that the sum of these two parameters is representative of the remediated soil risk value.Therefore,we proposed a two-step calculation method to determine the sum of the two heavy metal parameters as the risk value of remediated soil.In contrast to the traditional one-step calculation method,which only uses the leaching content as the risk value,this two-step calculation method can effectively avoid underestimating the risk of remediated soil.

The Volatilization of Pollutants from Soil and Groundwater: Its Importance in Assessing Risk for Human Health for a Real Contaminated Site

Pollution of different elements (air, water, soil and subsoil) resulting both from accidental events and from ordinary industrial and civil activities causes negative effects on the human health and on the environment. The present paper examines the analysis of a contaminated site, focusing the attention on the negative effects for receptors exposed to soil and groundwater contamination caused by industrial activities. The case study investigated is a contaminated area located in the industrial district of Trento North once occupied by the Italian Carbochimica plant. Pollution in that area is mainly due to contamination of soil and groundwater with polycyclic aromatic hydrocarbons. The methodology applied is the risk evaluation for human health, in terms of individual cancer risk and hazard index. In particular the attention has been focused on a specific migration way: if pollutants in the soil or in the groundwater undergo a phase change, they spread and get to the soil surface, causing a dispersion of vapors in the atmosphere. In this case risk assessment calls for the evaluation of volatilization factor. Among the different models dealing with the estimation of volatilization factor, those mostly known and used in the national and international field of Human Health Risk Assessment were chosen: Jury’s and Farmer’s models. A sensitivity analysis of models was performed, in order to identify the most significant parameters to estimate the volatilization factors among the wide range of input parameters for the application of models. Performing an accurate selection and data processing of the contaminated site, models for the volatilization factors calculation are applied, thus evaluating air concentrations and Human Health Risk. The analysis of the resulting estimates is an excellent aid to draw interesting conclusions and to verify if the soil and groundwater pollutants volatilization affects the human health considerably.

Evaluation of groundwater quality using pollution index of groundwater(PIG) and non-carcinogenic health risk assessment in part of the Gangetic Basin

The aim of this study was to evaluate groundwater fitness for domestic and irrigational use in Unnao district of Uttar Pradesh,India.For this study,block wise(n=16)groundwater samples were collected,and measured parameters were analyzed using the pollution index of groundwater(PIG),various irrigational indices,and graphical techniques.The results of this study suggested that most of the parameters were within the prescribed limits of WHO and BIS,excluding F-(0.4 to 2.6 mg L^(-1))and Fe^(2+)(0.1 to 1.7 mg L^(-1)).Concentrations of total dissolved solids(TDS)were exceeded the desirable limit(>500 mg L^(-1))in 43.75%of samples at some sites.The Gibbs plot revealed that groundwater chemistry was governed by rock-water interaction in the region,especially silicate weathering.The Piper plot suggested that Ca^(2+)-HCO3-is dominant hydrochemical facies in the area followed by mixed Ca^(2+)-Na^(+)-HCO_(3)^(-)type,Na^(+)-Cl^(-)type,and Na^(+)-HCO_(3)^(-)type.PIG evaluation revealed that the contribution of F-and Fe2+in groundwater degradation is high in comparison to other elements in the region,about 18.75%samples showed low pollution,while about 6.25%samples shows moderate pollution,and 6.25%samples reflected high pollution.The human health risk(HHR)assessment finding suggested that children(mean:1.36)are more vulnerable than adults(mean:1.01).Sodium absorption ration(SAR),Residual sodium carbonate(RSC),and Permeability index(PI)indicated that most of the groundwater was suitable for irrigation,whereas,Magnesium hazard ration(MHR)and Potential salinity(PS)indices suggested that only 37.5%and 56.25%of the samples were suitable for irrigational use,respectively.This regional study would help in decision making for stakeholders and relevant authorities in the execution of groundwater management and remediation plans in the area.

Groundwater arsenic poisoning in a primary educational institution:health risks to school-going children

This study aimed to estimate arsenic(As)and iron(Fe)content in tubewell water(n=58)in primary educational institutions and subsequently assess the health risks to school-going children.Results described that the As concentration ranged between 0.002 and 0.994 mg L^(-1)with an average value of 0.044 mg L^(-1);which exceeded the World Health Organization(WHO)provisional guideline value of 0.01 mg L^(-1).Similarly,the Fe content varied from 0.05 to 10 mg L^(-1)averaging to 2.84 mg L^(-1).Samples of 55.17%contained a greater As concentration than0.01 mg L^(-1)and 18.97%greater than Bangladesh drinking water quality(BDWQ)standard of 0.05 mg L^(-1),respectively.Meanwhile,75.86%of samples contained a higher Fe concentration than the maximum Bangladesh permissible limit of 1 mg L^(-1).Health risk assessment indicated that girls are more vulnerable than boys are.The average hazard quotients(HQs)for As intake through drinking water were 6.01±17.85 and 7.41±22.03 for boys and girls,respectively,implying non-carcinogenic health risks to both genders.The HQs for Fe intake were less than threshold value of 1 indicating no health issues may arise from Fe intake alone.However,consumption of As and Fe may trigger health risks to students as indicated by the hazard index(HI),which was higher than 1.The average cancer risk(CR)values for both boys(0.0027±0.008)and girls(0.0033±0.0099)exceeded the threshold limit of 10-6-10-4,suggesting a possibility of lifetime cancer risks to the school-going children.Consequently,school authorities should find alternative ways to ensure safe drinking water for school-going children to avoid possible cancer and non-cancer health risks through consumption of As-poisoning water.

Spatial Investigation of Nilüfer Stream Arsenic Pollution in Previous and Post COVID-19 Pandemic and Evaluation of Health Risks for Adult People

This study was carried out in Nilüfer Stream in Bursa City,where intensive industrial,agricultural and mining activities are existed.The temporal and spatial variation of arsenic was evaluated by examining its concentrations between March 2015 and December 2021.Values between March 2015 and December 2019 were evaluated as pre-pandemic,and values between March 2020 and December 2021 were evaluated as post-pandemic.The results were compared with national and international standards and the chronic and cancer risks were calculated for adults.When the 7-year general averages were examined,it was seen that the highest concentration was 0.0256 mg/L at the 8th Station,and the lowest concentration was 0.0182 mg/L at the 1st Station.The reason why the highest value is at the 8th station was that the wastewater of Nilüfer and Bursa Organized Industrial Zones was discharged to Bursa West Wastewater Treatment Plant before this station.After the pandemic the raises in concentrations were observed at all stations,except for the 3rd Station.This shows that the pollution load had increased in general during the pandemic.However,it was estimated that there was a decrease in the pollution load of the industrial wastewater coming to the 3rd Station,which was located after the Eastern Wastewater Treatment Plant of the City.It was observed that all stations examined were higher than drinking water standards and lower than irrigation water standards according to WHO and Turkish National Standards.All measuring stations were greater than 1 of the hazard quotient(HQ)values.In terms of human consumption risk,all stations had a chronic and carcinogenic risk according to the values before and after the pandemic.After the pandemic conditions,the HQ order of the stations was 8>10>7>9>2>6>4>1>3.In general,post-pandemic HQ values had generally increased and the risk of cancer had increased.

Health Risk Assessment of Some Heavy Metals in Water and Sediment at Marsa-Matrouh, Mediterranean Sea, Egypt

In an attempt to evaluate the environmental quality of Marsa-Matrouh city which covered the most famous beaches in Egypt, an environmental risk assessment was performed, including a screening level ecological risk assessment. The aim of this work was to determine which metals could possibly pose toxic adverse ecological effects to marine organisms and to determine whether hot spots exist or not. To fulfill the goals of study, surfacial sediment and water samples were collected from ten different locations covering Marsa-Matrouh city during four seasons (2010-2011). The average concentrations of Cd, Cu, Fe, Ni, Pb and Zn were 2.381 ± 3.389, 9.307 ± 14.159, 68.969 ± 9.397, 2.642 ± 1.004, 16.712 ± 8.469, 31.168 ± 15.322 μg/l in water and 0.755 ± 0.240, 5.363 ± 1.581, 962.131 ± 975.084, 3.972 ± 2.180, 15.210 ± 4.434 and 24.608 ± 7.706 μg/g dry weight in sediment respectively. The concentrations of the investigated six metals in water were within the acceptable limits except for two stations (Cleopatra and El-Obayed) which exhibited higher values than the permissible level of Cd during autumn 2010. Metal pollution assessment for both water and sediment was studied. Heavy metal pollution index indicates that water is not critically polluted with respect to the investigated metals. For sediment samples, threshold effect concentrations (TEC HQ) were lower than 1 except for Cd which showed higher value than 1, indicating the possibility of occurrence of toxic adverse ecological effects to benthic organisms for Cd, while rare adverse ecological effects are expected to occur with respect to Cu, Ni, Pb and Zn.

珠江三角洲铊在水稻籽实-根系土间迁移及人体健康风险评价

铊(Tl)是一种典型的剧毒重金属元素,其环境行为及人体健康效应日益得到广泛关注,土壤Tl富集会对土壤环境、农作物生长及人体健康造成严重的危害性。珠江三角洲作为土壤重金属富集的典型区域,当前研究主要聚集于Cu、Cd、Pb和As等元素,而对土壤Tl的地球化学特征及其影响因素、生物富集能力及人体健康效应评价的研究较少。本文以珠江三角洲3种成土母质分布区的243套水稻籽实及其根系土样品为研究对象,揭示了水稻根系土Tl含量、生物富集特征及其影响因素,并采用美国环保署(US EPA)推荐的人体健康风险评价模型对研究区土壤Tl的人体非致癌健康风险进行评价。结果表明:水稻根系土Tl含量显著高于我国和广东省土壤Tl含量背景值,18.1%的水稻根系土Tl含量超过加拿大Tl环境质量标准值及瑞士农业土壤Tl标准值(1×10^(-6))。酸性岩浆岩与第四纪沉积物分布区水稻根系土Tl超标率明显高于陆源碎屑岩。水稻根系土Tl含量表现出与K_(2)O、Al_(2)O_(3)、Pb和Zn含量显著相关。综合分析认为珠江流域硫化物矿床风化剥蚀及开采活动是导致下游平原区土壤Tl等重金属元素富集的主要原因。全区20件水稻籽实Tl含量的平均值为0.35×10^(-3),均远低于德国食品安全规定的Tl可食用标准值,水稻籽实Tl生物富集系数主要与根系土Na_(2)O、Zn和Pb含量显著相关。每个样点的HQ值分级结果显示,研究区68%的儿童有中等健康风险,46%的成人有中等健康风险,儿童健康风险显著高于成人。

若尔盖湿地土壤及水体重金属分布特征及健康风险评价

若尔盖湿地属典型的高寒湿地生态系统,是我国青藏高原生态屏障的重要组成部分.青藏高原地区重金属监测多集中在青藏高原西南部,针对若尔盖湿地重金属分布特征、污染来源及潜在人体健康风险尚未完全清楚.于2022年7月采集湿地土壤(退化湿地和未退化湿地)及地表水水样,分别对4种重金属(Cr、As、Cd和Pd)进行分析,阐述其浓度分布特征,并进行人体健康风险评估.结果表明:Cr、As、Cd和Pd在未退化湿地和退化湿地的浓度(mgkg-1)分别为6.23~26.19、2.06~45.00、0.01~0.63和1.32~10.87,7.56~23.56、5.10~21.87、0.01~0.43和2.16~11.13.参照«土壤环境质量———农用地土壤污染风险管控标准»,Cr、Pd、Cd和As达标率为100%、88%、94.4%、80%;地表水中Cd未检出,Cr、As和Pd浓度(μgL-1)分别为0.04~1.14、0.15~23.77和0.01~0.94,符合国家地表水质量Ⅰ类标准.参照美国环保署(USEPA)和国际辐射防护委员(ICRP)标准,若尔盖湿地土壤总非致癌风险指数(HI)均小于1;总致癌风险(TCR)范围为2.53×10^(-6)~1.20×10^(-4),均在可接受致癌健康风险水平10-6~10-4数量级范围内;地表水中总健康风险指数(R)为1.97×10^(-6)~2.01×10^(-4),人体最大可接受风险水平为5.0×10^(-5),其中,21.4%地表水样品超过健康风险水平.As是导致健康风险的主导因子.研究结果可补充若尔盖地区环境背景值的基础数据库,为该地污染防治及环境质量改善提供一定的数据支撑.