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.

Spatiotemporal variations of ozone exposure and its risks to vegetation and human health in Cyprus:an analysis across a gradient of altitudes

Ground-level ozone(O_(3)) aff ects vegetation and threatens environmental health when levels exceed critical values,above which adverse eff ects are expected.Cyprus is expected to be a hotspot for O_(3)concentrations due to its unique position in the eastern Mediterranean,receiving air masses from Europe,African,and Asian continents,and experiencing a warm Mediterranean climate.In Cyprus,the spatiotemporal features of O_(3) are poorly understood and the potential risks for forest health have not been explored.We evaluated O_(3) and nitrogen oxides(NO and NO 2)at four regional background stations at different altitudes over 2014−2016.O_(3) risks to vegetation and human health were estimated by calculating accumulated O_(3)exposure over a threshold of 40 nmol mol^(−1)(AOT40)and cumulative exposure to mixing ratios above 35 nmol mol^(−1)(SOMO35)indices.The data reveal that mean O_(3)concentrations follow a seasonal pattern,with higher levels in spring(51.8 nmol mol^(−1))and summer(53.2 nmol mol^(−1))and lower levels in autumn(46.9 nmol mol^(−1))and winter(43.3 nmol mol^(−1)).The highest mean O_(3)exposure(59.5 nmol mol^(−1)) in summer occurred at the high elevation station Mt.Troodos(1819 m a.s.l.).Increasing(decreasing)altitudinal gradients were found for O_(3)(NO x),driven by summer–winter diff erences.The diurnal patterns of O_(3) showed little variation.Only at the lowest altitude O_(3) displayed a typical O_(3) diurnal pattern,with hourly diff erences smaller than 15 nmol mol^(−1).Accumulated O_(3) exposures at all stations and in all years exceeded the European Union’s limits for the protection of vegetation,with average values of 3-month(limit:3000 nmol mol^(−1)h)and 6-month(limit:5000 nmol mol^(−1)h)AOT40 for crops and forests of 16,564 and 31,836 nmol mol^(−1)h,respectively.O_(3) exposures were considerably high for human health,with an average SOMO35 value of 7270 nmol mol^(−1) days across stations and years.The results indicate that O_(3) is a major environmental and public health issue in Cyprus,and policies must be adopted to mitigate O_(3) precursor emissions at local and regional scales.

Assessment of Risk to Human Health from Landfill Gas at Sharra Landfill, Tirana--Albania

Urban waste management and particularly dumpsites represents one of the most significant problems tot the long term protection of public health and environment in Albania. All waste management options, including landfilling, involve an element of risk to human health. This article addresses the question, if sources of emissions from Sharra landfill lead theoretically to public exposures exceeding health criteria？ This question is approached using an exposure pathway analysis framework, which link a source of one or more harmful pollutants at a site with a human receptor that inhales the pollutant. The risk posed to human health from HCHO （formaldehyde） and dioxin is estimated for on-site and off-site receptors in Sharra landfill. For on-site receptors, the average risk to get harm through the inhalation pathway from HCHO is in the range of 20 times to 300 times greater than allowed risk value, while for off-site receptors the average risk is in the range of 10 times to 180 times greater. While for dioxin the risk is in the range from 50 to 600 for on-site receptors and 10 to 35 for off-site receptors, times greater than often allowed risk.

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.

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.

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.

OVERVIEW OF ENVIRONMENTAL ASSESSMENT FOR CHINANUCLEAR POWER INDUSTRY AND COAL－FIRED POWER INDUSTRY

A quantitative environmental assessment method and the corresponding computer code are introduced in this paper. By the consideration of all fuel cycle steps,it gives that the public health risk of China nuclear power industry is 5.2 × 10-1 man /(GW.a), the occupational health risk is 2.5 man /(GW.a), and the total health risk is 3.0 man /(GW.a). After the health risk calculation for coal mining, transport, burning up and ash disposal, it gives that the public health risk of China coal-fired power industry is 3.6mall/(GW-a), the occupational health risk is 50man /(GW.a), and the total is 54man /(GW.d). Accordingly, the conclusion that China nuclear power industry is an industry with high safety and cleanness is derived at the end.

Study on Risk Assessment Method of Informal Landfill

At present,there are a large number of informal landfills to be treated all over the country. Under the condition of limited treatment funds,it is necessary to prioritize the treatment of informal landfills. In this paper,the pollution risk of waste dump,surrounding soil,groundwater and surface water is analyzed,and a set of comprehensive risk assessment method system of informal landfill is established,which could provide reference for decision making department deciding landfill disposal.

ArcGIS-Based Rural Drinking Water Quality Health Risk Assessment

Aiming at the unsafe of water quality which is the core problem in rural drinking water safety, the study col-lected 221 water samples of rural drinking water sources in Ya'an and detected the concentrations of the car-cinogen and the non-carcinogen. Based on the analysis of water environment characteristics and the identifi-cation of water environment health risk source of Sichuan Ya’an City, which includes seven counties and a district and is the typical region of the western margin of Sichuan Basin, this study calculated and analyzed the carcinogenic risk (R) and non-carcinogenic risk (hazard index, HI) by applying the health risk model recommended by the US National Research Council of National Academy of Science. Then, taking advan-tage of the geo-statistic spatial analysis function of ArcGIS, this study analyzed the assessment result data (R and HI), selected the proper interpolation approach and educed R and HI spatial distribution maps of the study area. R and HI of the single factor and integrate factors were evaluated and thus obtained the following conclusions: For one thing, the cancerous risk indexes of the vast majority of water sources (about 94%) is the level of 10-7 and it belong to the safety extension. The main carcinogen in the water sources are As, Cr6+ and Pb, their concentrations are in the ranges of 0.004-0.01, 0.005, 0.01mg/l respectively and such water source mainly distributed in Yucheng district and Mingshan county. For another, the non-cancerous hazard indexes of the vast majority of water sources (about 98%) is also less than the limit value 1 and will not harm the local residents. The health risk of non-carcinogen comes mainly from As and fluoride, their concentra-tions are in the ranges of 0.004-0.01 and 0.1-4.2mg/l respectively. The results of the integrate factors health risk assessment showed that the total cancerous risk were still at the level of 10-6, only 12 drinking water source investigation sites (5%) exceeded the drinking water management standard value of EPA (the limit value is 10-6);the total non-cancerous hazard indexes are still in the range of 10-2-10-1, and will not harm the local residents either, only 18 drinking water source investigation sites (8%) exceeded the drinking water management standard value of EPA(the limit value is 1).The densely populated areas such as Yucheng Dis-trict, Tianquan County, Yingjing County and Shimian County are where the four contaminating materials, i.e., As, Cr6+, Pb and fluoride should be monitored with emphasis. Study results disclosed the health risk control indexes of source water quality of the studied area and thus provided the scientific basis for the water quality control of water sources. This study had worked efficiently in practice. Compared with the same kind of methods which had been found, the paper had the outstanding results for the health risk assessment of the rural drinking water safety.

Legal response to environmental health risks in a risky society

The protection of public health is one of the legislative purposes of China’s environmental legal system.Article 39 of the Environmental Protection Law of the People’s Republic of China establishes an environmental and health risk assessment system.The health risk assessment system has biases in understanding,and it fails to face up to the functional transformation from the ex-post relief of environmental damage to the pre-prevention prevention of health risks in the environmental legal system;lack of a complete environmental and health legal system,unclear environmental and health risk assessment framework,and unclear environmental and health risk assessment frameworks.Health risk management capabilities need to be improved,there is a lack of specialized environmental and health risk assessment institutions,and there is a lack of supporting risk assessment technical standard system construction.It is necessary to combine practical experience with China’s national conditions and actual needs,construct an environmental health risk assessment system with Chinese characteristics from both the entity and the procedure,strengthen legislative support,and improve my country’s environmental and health laws on the basis of objective and scientific protection of the assessment process.Institutional system,establish a national environmental health risk assessment expert committee as soon as possible,improve my country’s environmental and health risk assessment framework,strengthen environmental and health management capacity building,improve the environmental and health risk assessment technical system,and promote the development of China’s environmental and health risk assessment system develop and give play to the institutional mission of safeguarding public health.

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.

Cultivars and oil extraction techniques affect Cd/Pb contents and health risks in oil of rapeseed grown on Cd/Pb-contaminated farmland

Substitute planting with rapeseed offers promise for safely using large areas of Cd/Pb-contaminated farmland.Cd/Pb distributions during rapeseed oil production were investigated and health risks posed by the oil were assessed.Tests were performed using three cultivars(Brassica rapa SYH and ZS100 and Brassica napus QY-1)and four oil extraction techniques(mechanical and low-temperature pressing and n-hexane and subcritical low-temperature butane extraction).The amounts of Cd and Pb in oil were 0.73%-8.44%and 3.14%-11.76%,respectively,of the amounts in rapeseed and were strongly affected by the cultivar and oil extraction technique.The heavy metal(HM)concentrations were lower in solvent-extracted oil(particularly subcritical low-temperature butane extracted oil,in which HMs were not detected)than mechanically pressed oil.The Cd and Pb transfer indices were lower(meaning larger proportions of HMs were retained by the rapeseed meal)for B.rapa than B.napus.This was attributed to a high HM binding protein content of B.rapa seed.Health risks to humans were assessed using a probabilistic risk assessment model.The carcinogenic risk was mainly(97.1%-99.9%)caused by Cd and poses more concern than non-carcinogenic risk.Stronger health risks are posed by mechanically pressed than solvent-extracted oil,and higher carcinogenic risks are posed to people living in rural areas than urban areas.Substitute planting with B.rapa and extracting oil with organic solvent(preferably subcritical low-temperature butane)are optimal for safely utilizing Cd/Pb-contaminated soil.Attention should be paid to the health risks posed by Cd in oil to rural populations.

A systematic review of the impacts of exposure to micro-and nano-plastics on human tissue accumulation and health

Micro-and nano-plastics(MNPs)pollution has become a pressing global environmental issue,with growing concerns regarding its impact on human health.However,evidence on the effects of MNPs on human health remains limited.This paper reviews the three routes of human exposure to MNPs,which include ingestion,inhalation,and dermal contact.It further discusses the potential routes of translocation of MNPs in human lungs,intestines,and skin,analyses the potential impact of MNPs on the homeostasis of human organ systems,and provides an outlook on future research priorities for MNPs in human health.There is growing evidence that MNPs are present in human tissues or fluids.Lab studies,including in vivo animal models and in vitro human-derived cell cultures,revealed that MNPs exposure could negatively affect human health.MNPs exposure could cause oxidative stress,cytotoxicity,disruption of internal barriers like the intestinal,the air–blood and the placental barrier,tissue damage,as well as immune homeostasis imbalance,endocrine disruption,and reproductive and developmental toxicity.Limitedly available epidemiological studies suggest that disorders like lung nodules,asthma,and blood thrombus might be caused or exacerbated by MNPs exposure.However,direct evidence for the effects of MNPs on human health is still scarce,and future research in this area is needed to provide quantitative support for assessing the risk of MNPs to human health.

农用地土壤重金属来源解析与健康风险空间分异特征研究——以重庆市巫山县笃坪乡为例

【目的】探明长江上游地区农用地土壤重金属来源及生态风险状况,进行人体健康风险空间分析,有助于提出有效的土壤重金属污染防治建议。【方法】以重庆市巫山县笃坪乡为研究对象,采集表层土壤样品(深度0~20 cm)45件,基于主成分分析/绝对主成分分数(PCA/APCS)受体模型进行土壤重金属(Cd、Hg、Pb、As和Cr)来源定量分析,通过人体健康风险评价模型进行人体健康风险评价,利用地统计法进行人体健康风险空间分析,得出不同区域的风险等级及影响因素,并针对性地提出风险管控建议。【结果】(1)研究区土壤Cd、Hg、Pb、As、Cr平均含量分别是重庆市土壤背景值的10.67、3.18、1.03、2.05、4.22倍,土壤重金属含量存在显著异常;(2)土壤综合环境质量优先保护类、安全利用类和严格管控类点位占比分别为2.23%、44.44%和53.33%,主要影响因子为Cd和Cr,土壤以酸性为主,对农产品质量安全及土壤生态环境的风险较高;(3)土壤Cd含量主要受到农业活动和成土母质的影响,贡献率分别为58.55%和30.30%,土壤Hg和Cr含量主要受到成土母质的影响,贡献率分别为71.55%和75.41%,土壤As含量主要受到农业活动的影响,贡献率为63.12%,土壤Pb含量主要受到道路交通的影响,贡献率为90.90%;(4)成人非致癌健康风险指数HI>1的点位占比为6.67%,总体健康风险较低,高风险区集中在研究区北部和中部地区,主要影响因子为Cr;农业活动与道路交通贡献率的高值区主要分布在研究区北部。【结论】建议研究区加强对农业投入品的监测,积极开展有机肥代替等化肥减量措施,推广使用电动农用车,减少由于农业活动对土壤重金属的输入。

Human health ambient water quality criteria for 13 heavy metals and health risk assessment in Taihu Lake

Heavy metals are widely concerning because of their toxicity,persistence,non-degradation and bioaccumulation ability.Iluman health ambient water quality criteria(AWQC)are specific levels of chemicals that can occur in water without harming human health.At present,most countries do not consider the effects of aquatic vegetables in deriving human health AWQC.Therefore,the intake of aquatic vegetables(Brasenia schreberi)was added to the derivation of human health AWQC and a health risk assessment for 13 heavy metals in Taihu Lake.The human health AWQC(consumption of water,fish and aquatic vegetables)values of 13 heavy metals ranged from 0.04(Cd)to 710.87μg/L(Sn),and the intake of B.schreberi had a very significant effect on the human health AWQC for Cu,with a more than 62-fold difference.The hazard quotients of As(2.8),Cd(1.6),Cr(1.4)and Cu(4.86)were higher than the safe level(HQ=1),indicating that As,Cd,Cr and Cu in Taihu Lake posed a significant health risk.Sensitivity analysis showed that the contribution rate of B.schreberi intake to the human health risk from Cu was 91.6%,and all results indicated that the risk of Cu in B.schreberi to human health should be of particular concern.This study adds the consideration of aquatic vegetable consumption to the traditional method of human health AWQC derivation and risk assessments for the first time,and this approach can promote the development of risk assessments and water quality criteria.

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.

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(μg·L-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.

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。

美国场地土壤筛选值研究及其对中国土壤环境基准研究的启示

土壤环境基准是土壤环境标准和土壤环境保护的基础。美国是世界上最早关注污染场地保护并开展土壤污染风险管控的国家之一,并形成了较为完善的体系,但我国在这方面还处于起步阶段。为此,本文以美国为例,综述其在土壤筛选值(SSLs)方面的研究,通过分析美国在土壤污染防治方面的法律法规和技术规范,系统梳理美国在SSLs方面的研究成果,从直接摄入、皮肤吸收、摄入污染地下水、吸入室外挥发物与颗粒物和蒸汽侵入5个方面阐述美国基于人体健康风险的SSLs制定的理论方法。在此基础上,为我国土壤环境基准研究提出了几点建议:进一步加强我国土壤环境基准研究工作,立足我国国情开展土壤环境基准研究,加强本土化参数研究和土壤环境基准研究规范化,以及协同开展土壤地下水环境基准研究,以期为我国土壤环境基准研究与制定提供参考。