Surface water quality and potential health risk assessments in Changsha-Zhuzhou-Xiangtan section of Xiangjiang River, China

The Changsha-Xiangtan-Zhuzhou City Group is a heavy industrial district and accepted as the serious pollution area in the Xiangjiang River basin.In this study,7 metals(Pb,Hg,Cd,As,Zn,Cu and Se)and the river water quality parameters including pH,dissolved oxygen(DO),Escherichia coli(E.coli),potassium permanganate index(CODMn),dichromate oxidizability(CODCr),five-day biochemical oxygen demand(BOD5),ammonia nitrogen(NH4+-N),total nitrogen(TN),total phosphorus(TP)and fluoride(F)in 18 sampling sites of the Changsha-Xiangtan-Zhuzhou section are monthly monitored in 2016,which is the year to step into the second stage of the“Xiangjiang River Heavy Metal Pollution Control Implementation Plan”.It is found that E.coli,TN and TP are the main pollutants in the Changsha-Zhuzhou-Xiangtan section,and the pollution of heavy metal is not serious but As with potential risk to local people especially children should be concerned.In addition,Xiangtan city is mainly featured with heavy metal pollution,while Zhuzhou and Changsha city are both featured with other pollutants from municipal domestic sewage.

Arsenic and fluoride co-enrichment of groundwater in the loess areas and associated human health risks:A case study of Dali County in the Guanzhong Basin

This study aims to reveal the occurrence and origin of typical groundwater with high arsenic and fluoride concentrations in the loess area of the Guanzhong Basin—a Neogene faulted basin.Key findings are as follows:(1)Groundwater samples with high arsenic and fluoride concentrations collected from the loess area and the terraces of the Weihe River accounted for 26%and 30%,respectively,of the total samples,with primary hydrochemical type identified as HCO_(3)-Na.The karst and sand areas exhibit relatively high groundwater quality,serving as preferred sources for water supply.It is recommended that local governments fully harness groundwater in these areas;(2)groundwater with high arsenic and fluoride concentrations in the loess area and the alluvial plain of rivers in Dali County is primarily distributed within the Guanzhong Basin,which represents the drainage zone of groundwater;(3)arsenic and fluoride in groundwater originate principally from natural and anthropogenic sources;(4)the human health risk assessments reveal that long-term intake of groundwater with high arsenic and fluoride concentrations pose cancer or non-cancer risks,which are more serious to kids compared to adults.This study provides a theoretical basis for the prevention and treatment of groundwater with high arsenic and fluoride concentrations in loess areas.

Identifying the Hydrochemical Characteristics,Genetic Mechanisms and Potential Human Health Risks of Fluoride and Nitrate Enriched Groundwater in the Tongzhou District,Beijing,North China

Fluoride and nitrate enriched groundwater are potential threats to the safety of the groundwater supply that may cause significant effects on human health and public safety,especially in aggregated population areas and economic hubs.This study focuses on the high F^(−)and NO_(3)^(−)concentration groundwater in Tongzhou District,Beijing,North China.A total of 36 groundwater samples were collected to analyze the hydrochemical characteristics,elucidate genetic mechanisms and evaluate the potential human health risks.The results of the analysis indicate:Firstly,most of the groundwater samples are characterized by Mg-HCO_(3) and Na-HCO_(3) with the pH ranging from 7.19 to 8.28 and TDS with a large variation across the range 471-2337 mg/L.The NO_(3)^(−)concentration in 38.89%groundwater samples and the F^(−)concentration in 66.67%groundwater samples exceed the permissible limited value.Secondly,F^(−)in groundwater originates predominantly from water-rock interactions and the fluorite dissolution,which is also regulated by cation exchange,competitive adsorption of HCO_(3)−and an alkaline environment.Thirdly,the effect of sewage disposal and agricultural activities have a significant effect on high NO3-concentration,while the high F^(−)concentration is less influenced by anthropogenic activity.The alkaline environment favors nitrification,thus being conducive to the production of NO_(3)^(−).Finally,the health risk assessment is evaluated for different population groups.The results indicate that high NO_(3)^(−)and F^(−)concentration in groundwater would have the largest threat to children’s health.The findings of this study could contribute to the provision of a scientific basis for groundwater supply policy formulation relating to public health in Tongzhou District.

Health risk assessment of trace metal(loid)s in agricultural soils based on Monte Carlo simulation coupled with positive matrix factorization model in Chongqing, southwest China

This study aimed to investigate the pollution characteristics, source apportionment, and health risks associated with trace metal(loid)s(TMs) in the major agricultural producing areas in Chongqing, China. We analyzed the source apportionment and assessed the health risk of TMs in agricultural soils by using positive matrix factorization(PMF) model and health risk assessment(HRA) model based on Monte Carlo simulation. Meanwhile, we combined PMF and HRA models to explore the health risks of TMs in agricultural soils by different pollution sources to determine the priority control factors. Results showed that the average contents of cadmium(Cd), arsenic (As), lead(Pb), chromium(Cr), copper(Cu), nickel(Ni), and zinc(Zn) in the soil were found to be 0.26, 5.93, 27.14, 61.32, 23.81, 32.45, and 78.65 mg/kg, respectively. Spatial analysis and source apportionment analysis revealed that urban and industrial sources, agricultural sources, and natural sources accounted for 33.0%, 27.7%, and 39.3% of TM accumulation in the soil, respectively. In the HRA model based on Monte Carlo simulation, noncarcinogenic risks were deemed negligible(hazard index <1), the carcinogenic risks were at acceptable level(10^(-6)<total carcinogenic risk ≤ 10^(-4)), with higher risks observed for children compared to adults. The relationship between TMs, their sources, and health risks indicated that urban and industrial sources were primarily associated with As, contributing to 75.1% of carcinogenic risks and 55.7% of non-carcinogenic risks, making them the primary control factors. Meanwhile, agricultural sources were primarily linked to Cd and Pb, contributing to 13.1% of carcinogenic risks and 21.8% of non-carcinogenic risks, designating them as secondary control factors.

Health risk assessment of heavy metals in soils and crops in a mining area(Au-Ag-Cutrona-oil et al.) of the Nanyang Basin, Henan Province, China

Heavy metal distribution in mining areas has always been a hot research topic due to the special environment of these areas. This study aims to explore the impact of heavy metal pollution on soils and crops in the study area, ensure the safety of local crops and the health of local residents, and provide a basis for the subsequent environmental restoration and the prevention and control of environmental pollution. Based on the analysis of the heavy metal concentrations in local soils and crops, the study investigated the spatial distribution, pollution degrees, and potential ecological risks of heavy metals in the farmland of a mining area in the southeastern Nanyang Basin, Henan province, China explored the sources of heavy metals and assessed the health risks caused by crop intake. The results of this study are as follows. The root soils of crops in the study area suffered heavy metal pollution to varying degrees. The degree of heavy metal pollution in maize fields is higher than that in wheat fields, and both types of fields suffer the most severe Cd pollution. Moreover, the root soils of different crops suffer compound pollution.The root soils in the maize fields suffer severe compound pollution at some sampling positions, whose distribution is similar to that of the mining area. Cd poses the highest potential ecological risks among all heavy metals, and the study area mainly suffers low and moderate comprehensive potential ecological risks. The principal component analysis(PCA) shows that the distribution of Zn, Cd, Pb, and As in soils of the study area is mainly affected by anthropogenic factors such as local mining activities;the distribution of Cr and Ni is primarily controlled by the local geological background;the distribution of Hg is mainly affected by local vehicle exhaust emissions, and the distribution of Cu is influenced by both human activities and the geological background. Different cereal crops in the study area are polluted with heavy metals dominated by Cd and Ni to varying degrees, especially wheat. As indicated by the health risk assessment results, the intake of maize in the study area does not pose significant human health risks;however, Cu has high risks to human health, and the compound heavy metal pollution caused by the intake of wheat in the study area poses risks to the health of both adults and children. Overall, the soils and crops in the study area suffer a high degree of heavy metal pollution, for which mining activities may be the main reason.

Seasonal variations and health risk assessment of trace elements in the Badigad River,lesser Himalayas,Nepal

The consumption of contaminated river water can have severe effects on human health.This study aims to investigate the trace elements(TEs)content and their health risk assessment in the Badigad River Basin in the lesser Himalayas of Nepal.In total,44 water samples were collected from 22 different sites during the pre-monsoon and monsoon seasons,and 25 TEs were analyzed.Correlation matrix and principal component analysis(PCA)were used to analyze the potential relationship between the measured TEs and their source tracking.Furthermore,the water quality index(WQI),metal index(MI),and cancer index(CI)were evaluated.The TEs content in all samples were found to be within the WHO recommended guideline for drinking and domestic purposes.The dominancy order of the TEs was observed as Sr>Ba>Li>Rb>Zn>Cr>Sc>Mn>Ti>Cu>As>Ni>Co>U>V>Pb>Cs>Ga>Y>Tl>Th>Zr>Bi>Cd>Nb.The PCA analysis suggested that TEs could have natural,anthropogenic,and mixed origins.The WQI indicated that the river water is safe from a human health perspective.The MI suggested that Badigad River can be considered safer for drinking purposes,and the cancer index(CI)showed that all the reported TEs are at low-risk levels.The findings of this study could be useful for government agencies in developing more sustainable water management policies in the region.However,it is suggested that further investigations should be conducted in terms of other hydrogeochemical variables,including major ions,at spatiotemporal levels for the sustainability of the river basin.

Health risk assessments of polycyclic aromatic hydrocarbons and chlorinated/brominated polycyclic aromatic hydrocarbons in urban air particles in a haze frequent area in China

The potential threats of polycyclic aromatic hydrocarbons(PAHs)and chlorinated/brominated PAHs(Cl/Br-PAHs)to human health from particulate matter in the urban ambient air were studied using human health risk assessments.The risk to human health caused by exposure to PAHs was evaluated in Shijiazhuang,China,from January to December 2018.The PAHs concentration range was 16.02e475.21 ng/m3 and the toxic equivalent was 13.605 ng/m3.For adults,the average carcinogenic risk caused by respiratory exposure was 5.163×10^-6 and the resulting loss of life expectancy was 32.10 min.The human health risks of respiratory exposure to Cl/Br-PAHs in atmospheric samples from the Haidian District,Beijing,China,were evaluated from November 2017 to July 2018.The concentration ranges for the Cl-and Br-PAHs were 60.38e482.17 pg/m3 and 1.32e25.35 pg/m3,respectively.The average carcinogenic equivalent concentrations were 0.3274 pg/m3 and 0.0061 pg/m3 for the Cl-and Br-PAHs,respectively.For adults the average carcinogenic risks caused by respiratory exposure were 1.243×10^-10 and 2.316×10^-12 for the Cl-and Br-PAHs,respectively.The resulting loss of life expectancy values were 0.001 min(Cl-PAHs)and 0.00 min(Br-PAHs).The pollution concentrations and toxic equivalents of the Cl/Br-PAHs in Beijing and of the PAHs in Shijiazhuang both showed toxicity was high in the winter.The average carcinogenic risk for exposure of adults to PAHs in Shijiazhuang was low with certain potential hazards.The concentration of Cl-PAHs in Beijing was higher than that of Br-PAHs,and the average carcinogenic risk for exposure of adults to Cl/Br-PAHs was very low with slight harm.

Assessing the concentration and potential health risk of heavy metals in China's main deciduous fruits

To assess levels of contamination and human health risk, we analyzed the concentrations of the heavy metals lead （Pb）, cadmium （Cd）, chromium （Cr）, and nickel （Ni） in China’s main deciduous fruits-apple, pear, peach, grape, and jujube. The concentration order of the heavy metals was Ni〉Cr〉Pb〉Cd. In 97.5% of the samples, heavy metal concentrations were within the maximum permissible limits. Among the fruits studied, the heavy metal concentrations in jujube and peach proved to be the highest, and those in grape proved to be the lowest. Only 2.2% of the samples were poluted by Ni, only 0.4% of the samples were poluted by Pb, and no samples were poluted by Cd or Cr. Compared with the other fruits, the combined heavy metal polution was signiifcantly higher （P〈0.05） in peach and signiifcantly lower （P〈0.05） in grape. For the combined heavy metal polution, 96.9% of the samples were at safe level, 2.32% at warning level, 0.65% at light level, and 0.13% at moderate level. In the fruits studied, the contribution of heavy metals to the daily intake rates （DIR） folowed the order of Ni〉Cr〉Pb〉Cd. The highest DIR came from apple, while the lowest DIR came from grape. For each of the heavy metals, the total DIR from ifve studied fruits corresponded to no more than 1.1% of the tolerable daily intake, indicating that no signiifcant adverse health effects are expected from the heavy metals and the fruits studied. The target hazard quotients and the total target hazard quotients demonstrated that none of the analyzed heavy metals may pose risk to consumers through the fruits studied. The highest risk was posed by apple, folowed in decreasing order by peach and pear, jujube, and grape. We suggest that the main deciduous fruits （apple, pear, peach, grape, and jujube） of China’s main producing areas are safe to eat.

Assessment of pollution levels and human health risk of heavy metals in dust deposited on Yerevan＇s tree leaves (Armenia)

The total concentrations of Cd,As,Pb,Cr,Ni,Co,Zn,Cu,Ag,Hg,and Mo were determined in the atmospheric dust of the city of Yerevan by atomic absorption spectrometry(AAnalyst PE 800).Heavy metal pollution levels were evaluated by calculating geo-accumulation(I_(geo)) and summary pollution(Z_c) indices.Potential human health risk was assessed using the United States Environmental Protection agency's human health risk assessment model.The results show that mean contents of all elements tested except Ni and Cr were substantially higher than local geochemical background values.According to the I_(geo),Yerevan territory is strongly-to-extremely polluted by As,Ag,Hg,Mo,and Cd.The Z_c assessment indicated that very high pollution was detected in 36%of samples,high in 32%,average in 12%,and low in 20%.The health risk assessment revealed a noncarcinogenic risk(HI >1) for children at 13 samplings sites and for adults at one sampling site.For children the risk was due to elevated levels of Mo,Cd,Co,and As,while for adults,only Mo.Carcinogenic risk(>1:1,000,000) of As and Cr via ingestion pathway was observed in 25 and 14 samples,respectively.This study,therefore,is the base for further detailed investigations to organize problematic site remediation and risk reduction measures.

Research Progress in Occupational Health Risk Assessment Methods in China

Traditional occupational disease control and prevention has remained prevalent in China over recent decades. There are appropriately 30,000 new case reports of occupational diseases annually. Although China has already established a series of occupational disease prevention programs, occupational health risk assessment （OHRA） strategies continue to be a limitation.

Soil Heavy Metal Pollution and Health Risk Assessment of Abandoned Land in Coal Mining Areas in Xingren County

Total contents of heavy metals （ Pb, Cr, Cd, Hg, As, Cu, Zn, and Ni） in 68 soil samples were determined to evaluate the contamination level of soil from five coal mine areas in Xingren County, Guizhou province. The pollution levels of heavy metals were characterized by anthro- pogenic influence multiple, and the pollution of heavy metal in soil was evaluated using geo-accumulation index. Based on the health risk models recommended by the U.S. Environmental Protection Agency （ US EPA）, the health risks of heavy metals in the soils were assessed. The results showed that the abandoned land in the five coal mining areas were contaminated by heavy metals, and the order of pollution levels of eight heavy metals was As 〉 Pb 〉 Cu 〉 Hg 〉 Ni 〉 Cr 〉 Cd 〉 Zn. The soils suffered moderate-heavy pollution from As and Pb, and the contents of As and Pb in the soils were 13.16 and 4.76 times higher than the background values of Guizhou Province, followed by Cu, Hg and Ni , while soil pollution from Cr, Cd and Zn was mild. The order of non-caminogenic risks of the heavy metals in the soils was As 〉 Pb 〉 Cr 〉 Ni 〉 Cu 〉 Hg 〉 Cd 〉 Zn, and the non-carcinogenic dsk value of As was higher than that its threshold value 1, which indicated that As had a high potential health risk to adults and children. The order of carcinogen risks of the four heavy metals was As 〉 Cd 〉 Cr 〉 Ni, and the carcinogenic risk value of As was higher than its threshold value, indicating that As had a high carcinogenic risk to adults and children. The carcinogenic risk values of other three heavy metals （ Cd, Cr and Ni） were lower than the threshold value, so they had no carcinogenic risk to human health. Moreover, children were more sensitively affect- ed by heavy metals from the abandoned land. Therefore, the health of children in such areas should be paid more attention to. The HI value of the eight heavy metals to children was seven times higher than that to adults. The contribution rate of HQAs to HI was about 88%, and the contribution rate of CRA, to TCR was about 98%, so As was the most crucial factor influencing non-carcinogenic and carcinogenic dsk in the abandoned soils.

Spatial variation of health risk of groundwater for drinking water supply in Mingshan County,Ya'an City,China

Rural drinking water safety is a growing concern in China. This study investigated the health risk of pollution of groundwater for the drinking water supply in Mingshan County, Ya＇an City, in Sichuan Province, China, using 46 samples from the years 1991 to 2010. Carcinogenic, non-carcinogenic, and total risks were assessed by the model recommended by the United States Environmental Protection Agency （U.S. EPA）. Thematic maps of the risks caused by single and multiple factors were generated from inverse distance weighting interpolation （IDW） and the geostatistical analysis functions of ArcGIS. The results show that the carcinogenic risks caused by chemicals in groundwater for drinking water supply are low, within the acceptable interval for risk management. However, non-carcinogenic risks are high and the number of sampling sites with risk values exceeding the standards amounted to 29. Non-carcinogenic risks of Cr6＋, nitrate, fluoride, and Fe at sites 43, 46, 50, 64, 67, and 74 were the sources that caused high total health risk. This study reveals the risk level of groundwater quality and orders of treatment of pollutants, and provides a scientific basis for groundwater management in this area.

Occupational Health Risk Assessment of Benzene,Toluene,and Xylene in Shanghai

Objective This study was designed to conduct a retrospective and systematic occupational health risk assessment(OHRA)of enterprises that used benzene,toluene,and xylene(BTX)in Shanghai,China.Methods All data for the study were obtained from 1,705 occupational health examination and evaluation reports from 2013 to 2017,and a semiquantitative model following Chinese OHRA guidelines(GBZ/T 298-2017)was applied for the assessment.Results The selected enterprises using BTX were mainly involved in manufacturing of products.Using the exposure level method,health risk levels associated with exposure to BTX were classified as medium,negligible,or low.However,the risk levels associated with benzene and toluene were significantly different according to job types,with gluers and inkers exhibiting greater health risks.For the same job type,the health risk levels assessed using the comprehensive index method were higher than those using the exposure level method.Conclusion Our OHRA reveals that workers who are exposed to BTX still face excessive health risk.Additionally,the risk level varied depending on job categories and exposure to specific chemicals.Therefore,additional control measures recommended by OHRA guidelines are essential to reduce worker exposure levels.

Groundwater pollution and human health risk based on Monte Carlo simulation in a typical mining area in Northern Anhui Province,China

The main objective of this study was to evaluate eight kinds of trace element pollutants in groundwater from a typical coal mine area,and carry out a corresponding health risk assessment for the local populace.To do this,34 shallow groundwater(SG)samples and 18 mid-layer groundwater(MG)samples were collected from the Sulin mining area.To minimize the uncertainties in the health risk assessment,this paper relied on Monte Carlo simulations and sensitivity analysis.The results revealed that Sr and Mn contents exceeded their corresponding WHO(Guidelines for drinking water quality,4th edn.Geneva,2011)guidelines and Chinese groundwater standards(GB/T14848-2017),while the other analyzed trace elements remain below those threshold values.The calculated hazard quotient and hazard index values for adults from ingestion exposure to SG and MG were well below the threshold limit of 1.Probabilistic simulations further show that the total cancer risk value above the limit of 1×10^(-6) is 0%for SG and 29.39%for MG.Sensitivity analysis identified the Sr and Cr contents as the most relevant element variables affecting the probabilistic non-carcinogenic and carcinogenic risk values in the model,respectively.

Potentially toxic metal concentration,spatial distribution,and health risk assessment in drinking groundwater resources of southeast Iran

In this study, the concentration and spatial distribution of potentially toxic metals(PTMs), including arsenic(As), cadmium(Cd), chromium(Cr), lead(Pb), copper(Cu), iron(Fe), manganese(Mn), and magnesium(Mg) in 23 wells and drinking groundwater distribution networks of Rafsanjan, located in southeast Iran were evaluated. Moreover, the assessment of carcinogenic and non-carcinogenic risks was estimated by Monte Carlo simulation(MCS). The results showed that the concentrations of As and Pb in more than 99% and 23.46% of the study area, respectively, were higher than the maximum concentration level(10 μg/L). The mean concentration of other metals, including Cd, Cr, Cu, Fe, Mg, and Mn in all drinking water resources was within the WHO standard level. The mean hazard quotient(HQ) for As in the age group of children was 9.246 and adults 2.972, indicating high non-carcinogenic risk of As in the study area. The lifetime cancer risk(LTCR) of As was 1.36 E-3 for adults and 1.52 E-2 for children, indicating high non-carcinogenic risk of As. The level of HQ and LTCR for Pb in both age groups was in the acceptable range. The results of sensitivity analysis showed that the most effective variables were pollutant concentration and body weight(BW), respectively. Finally, it can be concluded that exposure to PTMs, especially As through drinking water in the study area can have significant effects on people’s health living in the area;therefore, it is necessary to treat and remove As from groundwater resources before drinking or using for domestic purpose.

Multimedia health risk assessment:A case study of scenario-uncertainty

Assisted by framework of multimedia total exposure model for hazard waste sites(CalTOX),potential influences of scenario-uncertainty on multimedia health risk assessment(MHRA) and decision-making were quantitatively analyzed in a primary extent under the Chinese scenario case by deliberately varying the two key scenario-elements,namely conceptual exposure pathways combination and aim receptor cohorts choice.Results show that the independent change of one exposure pathway or receptor cohort could lead variation of MHRA results in the range of 3.6×10-6-1.4×10-5 or 6.7×10-6-2.3×10-5.And randomly simultaneous change of those two elements could lead variation of MHRA results at the range of 7.7×10-8-2.3×10-5.On the basis of the corresponding sensitivity analysis,pathways which made a valid contribution to the final modeling risk value occupied only 16.7% of all considered pathways.Afterwards,comparative analysis between influence of parameter-uncertainty and influence of scenario-uncertainty was made.In consideration of interrelationship among all types of uncertainties and financial reasonability during MHRA procedures,the integrated method how to optimize the entire procedures of MHRA was presented innovatively based on sensitivity analysis,scenario-discussion and nest Monte Carlo simulation or fuzzy mathematics.

Impact of artificial waterfall using reclaimed water to VOCs and its health risk assessment

To study the impact of an artificial waterfall using reclaimed water on volatile organic compounds （VOCs） in air, air samples around the waterfall sight and over the CASS pond of a wastewater treatment plant were collected and VOCs were analyzed by MC-MS with USEPA Method TO-14. The total volatile organic compounds （TOVCs） concentration of a background sample is 2112 μg/m^3, and the sample over the CASS pond has a TVOC concentration of 1858μg/m^3. The TVOC concentrations of air samples within 10 m of the artificial waterfall are between 3216 μg/m^3 and 6362 μg/m^3, which are 1.52 - 3.0 times that of the background sample. The VOCs in air sample impacted by reclaimed water or waste water exhibit a relatively high proportion of toluene but low proportion of benzene. B/T/E/X （ Benzene/Toluene/Ethylbenzene/Xylene ） ratio of the air sample around the artificial water fall is（O. 36/11.78/1/1.10）. Health risk assessment （HRA） was done with the USEPA four-step approach. The result indicates that the artificial waterfall using reclaimed water indeed leads to the increase of human risk value. The total risk value of the sample around the waterfall is 2. 8 - 1.6 times that of the background sample. However, the total risk value of the air sample around the waterfall （2. 8 × 10^-6 ） for common people is still lower,compared to the acceptable public risk level（ 10^-5 ）. For occupational workers of the wastewater treatment plant, the sum of lifetime non-carcinogenic and carcinogenic risk values （ 1.26 × 10^ -5 ） is higher than that of the acceptable public risk level.

Exposure Level, Toxicity Effects and Health Risk Assessment of Organophosphorus Flame Retardants in Water Environment

Organophosphorus flame retardants(OPFRs) are gradually replacing brominated flame retardants(BFRs), which are widely used in the world. The increasing output of OPFRs and the increasing detection of OPFRs in environmental media have attracted wide attention of scholars at home and abroad. OPFRs are generally semi-volatile, easy to enter the environment and accumulate in organisms,causing potential hazards to the environment and human health. In this paper, the pollution status and toxic effects of OPFRs in aquatic environment were introduced,and the research progress of human health risk caused by them was summarized.The existing problems were pointed out, and the future research was prospected. In the future, the analytical methods of various environmental and biological media should be improved, and comprehensive and in-depth environmental investigation and ecological and health risk assessment should be carried out. Attention should be paid to the effects of combined pollution on organisms and the study of biological acceptability.

Migration of Heavy Metal Elements in Reclaimed Irrigation Water-Soil-Plant System and Potential Risk to Human Health

[Objectives]To study the impact of heavy metal pollution of soil and plants during the process of reclaimed water for irrigation of green land in arid areas and the potential health risks to humans during use.[Methods]Taking Zhongwei City in Ningxia,a typical arid area,as the research area,the irrigation water,soil and green grass in the reclaimed water irrigation region and the original green water irrigation region were sampled,the heavy elements Hg,As,Zn,Pb,Cd,Cr were detected,and the Nemerow method,biological absorption coefficient,and health risk assessment were employed to evaluate the degree of soil pollution,plant absorption capacity,and human health risks.[Results]Compared with the original green water,the Hg,Cd,and Cr pollution of the reclaimed water irrigated green land was higher,the As,Zn,Pb pollution was lower,and the content of Hg and Cd was higher than the environmental background values of soil in Ningxia;the Cr content exceeded the risk intervention values of the first type of land in the Soil Environmental Quality—Risk Control Standard for Soil Contamination of Development Land(GB 36600-2018).Compared with the original green water irrigation region,it is found that the reclaimed water irrigation reduced the heavy metal pollution of the soil to a certain extent.The heavy metal content of tall fescue grass(Festuca arundinacea)in the reclaimed water irrigation region was Zn,Cr,Pb,As,Cd,and Hg from high to low;the order of the biological absorption coefficient was Cd>As>Zn>Pb>Hg>Cr;irrigation water exerted a certain effect on the content of heavy metals in plants and the biological absorption coefficient through the soil.Using the health risk assessment method recommended by Environmental Protection Agency of the United States of America(USEPA),it was found that the reclaimed water has the highest risk through the inhalation route,and the occupational population has a higher risk of skin contact with soil and plants.[Conclusions]This study is intended to provide data support and theoretical basis for the environmental safety risk research of the application of reclaimed water in arid areas to urban greening.

Atmospheric deposition fluxes and health risk assessment of potentially toxic elements in Caohai Lake(Guizhou Province,China)

In this study,the sources of potentially toxic elements(PTEs)from atmospheric deposition in the waters of Guizhou’s Caohai Lake were investigated in addition to the potential risks to human health.Moss bags were used to enrich PTEs from atmospheric deposition,and eight monitoring sites that best represented geographic variation were established around Caohai Lake.Moss bags were collected and examined at every 3 months to identify spatiotemporal patterns of dry and wet atmospheric deposition of PTEs.Zn was the most abundant metal identified from deposition in Caohai(72.07%–95.94%),followed by Pb and Cd,while Hg was the least abundant(0.008%–0.354%).The contributions of wet deposition of PTEs were greater than those of dry deposition,and deposition during the heating season from December to April was greater than that between April to July.Hg was mainly derived from atmospheric dry deposition(65.38%–84.44%).Spatial distribution analysis indicated that atmospheric deposition was associated with the intensity of human activities and heating emissions.Exposure via hand-to-mouth contact accounted for over 99%of the total exposure risk although overall exposure was lower than threshold acceptable levels for carcinogenic and non-carcinogenic metals,indicating an overall lack of risk towards human health.Nevertheless,the health risk from atmospheric deposition of PTEs in Caohai Lake may be reduced by focusing on Zn,Pb,and Cd deposition in rainfall and minimizing the hazards associated with hand-to-mouth exposure to PTEs.