基于土壤气挥发通量的污染场地三氯甲烷健康风险评估

我国现行技术导则在评估VOCs呼吸暴露途径健康风险时推荐Johnson-Ettinger(J&E)模型,该模型虽然简单易用,但在实际应用中存在过于保守的问题,采用双元平衡模型(dual equilibrium desorption, DED)对J&E模型进行校正后可以在一定程度上克服该问题.为准确评估实际场地中VOCs呼吸暴露风险,探索JE-DED模型在预测实际场地中VOCs呼吸暴露途径健康风险的适用性,选取苏州某污染场地面积约314 m2 的重污染区域开展三氯甲烷土壤气挥发通量研究进行精细化风险评估,并与基于土壤中三氯甲烷浓度采用J&E模型和JE-DED模型的计算结果进行比较.多手段风险评估结果显示,评价区域三氯甲烷呼吸暴露途径的人体致癌健康风险水平超过可接受水平1.00×10-6 ;就本场地而言,相对于基于土壤浓度风险评估,以基于实测土壤气挥发通量的风险评估结果来表征研究区域整体暴露风险水平更加稳定;研究区域土壤三氯甲烷浓度整体偏高,J&E和JE-DED模型计算的风险水平无明显差异;通过数据模拟发现,针对该场地,当三氯甲烷浓度＜6 mg·kg-1时,能更好地发挥JE-DED模型的优势.该场地三氯甲烷健康风险评估结果表明,基于实测土壤气挥发通量能够一定程度上避免基于土壤浓度计算带来的偶然性结果;JE-DED模型在较低浓度时,才能发挥优势.     

基于健康风险的土壤修复目标研究程序与方法——以多环芳烃污染土壤再利用工程为例

提出了基于人体健康风险的土壤修复目标的制定方法和程序,并以上海市某重大工程多环芳烃污染土壤处理后再利用工程为例,模拟了多环芳烃在处置场地上的多介质迁移途径及人体暴露场景。模拟结果显示,填埋场污染土壤苯并(a)芘(该污染物毒性因子高,毒性强,致癌风险相对较大)经口摄入和皮肤接触途径最大致癌暴露量分别为1.89×10-6和0.93×10-6mg.kg-1.d-1,人体最大致癌风险水平分别为1.38×10-5和6.79×10-6,超出了中国规定的单致癌污染物的可接受风险水平(≤10-6)。苯并(a)芘呼吸吸入途径最大致癌暴露量为7.79×10-10mg.m-3,人体最大致癌风险水平为6.86×10-10。基于场地的特征条件和参数,以保护人体健康为目的,确定了再利用作为填埋场中层覆土的土壤中5种多环芳烃污染物的修复目标限值(w,mg.kg-1)分别为:苯并(a)芘,0.994;二苯并(a,h)蒽,0.995;苯并(a)蒽,9.95;苯并(b)荧蒽,9.95;苯并(k)荧蒽,99.5。     

重金属污染场地土壤风险筛选值关键影响因子研究——以砷为例

合理确定重金属土壤筛选值是污染场地风险识别和调查评估的基础,过松或过严的标准都会增加风险评估的不确定性,甚至可能会导致风险管控措施失效或修复资金浪费,确定重金属土壤筛选值的关键影响因子是合理确定重金属土壤筛选值的前提。选择工业污染场地中检出频率高、毒性大的砷作为研究对象,通过假设工商业用地下的暴露情景,根据《污染场地风险评估技术导则》(HJ25.3—2014)得到砷筛选值计算公式,利用基于蒙特卡罗模拟的Crystal Ball模型计算公式中各参数对结果的敏感性和贡献率来确定关键影响因子,通过调研国内外砷筛选值现状,从计算模型、毒性评估及关键影响因子等方面对引起各国砷筛选值差异的原因进行了分析探讨。结果表明:工商业用地下土壤砷筛选值取值为0.84～175.7 mg·kg~(-1),均值为21.4 mg·kg~(-1),95%的置信上限为24.19 mg·kg~(-1);风险可接受水平、每日土壤摄入量(IR)、暴露频率(EF)和暴露周期(ED)对砷筛选值的贡献率依次为41.3%、-27.3%、-16.3%和-12.7%,其余因子的贡献率均小于1%;关键影响因子按贡献率绝对值从大到小分别为风险可接受水平、每日土壤摄入量(IR)、暴露频率(EF)、暴露周期(ED)。计算模型和毒性评估存在差异是国内外土壤砷筛选值差异的基础原因,当计算模型和毒性评估差异不大时,关键影响因子才是决定性因素,其影响程度与模拟计算的结果一致。建议我国完善筛选值计算模型,对砷的毒性效应和符合我国暴露人群特征的关键影响因子展开深入研究。     

C-RAG模型在砷污染场地中的修正及应用研究

为了解我国基于人体健康《建设用地土壤污染风险评估技术导则》 (Chinese Risk Assessment Guide, C-RAG)在矿区场地中的分析模式及应用情景,以青海某废弃矿区场地为例,在结合矿场未来规划的基础上,通过对C-RAG模型参数的修正和改进,研究了该场地的风险状况及修复目标值,为污染地块适度修复提供了借鉴依据.结果表明,以砷污染为主的矿区场地,在修正暴露途径、土壤摄入量、暴露频率和PM10 后,致癌风险水平普遍降低为原来的1/4.综合考虑污染物的可给性、风险水平与修复投入之间的平衡关系以及工程可行性后,确定以引入生物可给性的致癌风险控制值21.1 mg·kg-1为最终修复目标值.     

焦化场地典型多环芳烃类污染物精细化风险评估

为准确评估多环芳烃(PAHs)污染土壤对人体的健康风险,解决目前基于总量风险评估导致土壤PAHs修复目标值过严的问题,采用德国标准研究院颁布的生物可给性测试方式研究了石家庄某焦化厂土壤中苯并[b]荧蒽(BBF)、苯并[k]荧蒽(BKF)、苯并[a]芘(BAP)、茚并[1,2,3-cd]芘(IPY)和二苯并[a,h]蒽(DBA)共5种PAHs的生物可给性,并基于考虑和不考虑生物可给性计算了场地PAHs经口摄入途径下的人体健康致癌风险及修复目标值.结果表明,(1)调查研究区域BBF、BAP、IPY和DBA浓度超出《土壤环境质量建设用地土壤污染风险管控标准(试行)》(GB36600—2018)规定的第一类用地筛选值;(2)土壤中PAHs的生物可给性范围为14.71% ～56.42% ;(3)在考虑生物可给性后,4种超标PAHs的健康风险均有所降低,其中BBF的风险值已低于国家导则规定的人体可接受水平;(4)引入生物可给性后BAP、IPY和DBA的修复目标值(95% UCL)为2.83、34.63和1.95 mg·kg-1 ,分别提高了2.6倍、3.4倍和1.5倍.对焦化场地典型污染物PAHs进行精细化健康风险评估,可以在一定程度上克服现有技术导则计算土壤PAHs修复目标值过于严格的问题.     

苯并[a]芘污染土壤的植物根际修复研究初探

研究了黑麦草(Lolium multiflorumL.)对多环芳烃苯并[a]芘污染土壤的修复作用。研究结果表明,土壤中苯并[a]芘的可提取态wB[a]P随着时间延长而逐渐减少,黑麦草加快了土壤中可提取态苯并[a]芘的减少,提高了苯并[a]P在土壤中的降解率,在1、10、50mg·kg-1苯并[a]芘处理下,黑麦草生长土壤中苯并[a]芘的降解率分别达90.3%、87.5%、78.6%;而没有黑麦草生长土壤中苯并[a]芘的降解率则为79.3%、66.4%、55.6%。黑麦草根际增加土壤中微生物碳的含量,从而提高植物对苯并[a]芘的降解率。植物的地上部也可积累少量苯并[a]芘,但植物对苯并[a]芘的吸收不是黑麦草对其修复的主要机制。土壤自身具有修复苯并[a]芘的潜能,种植黑麦草具有强化土壤修复苯并[a]芘污染的作用。     

我国苯的环境暴露、风险评估与管控

我国苯生产量大,且用途广泛。与此同时,大量的苯系物通过化石燃料燃烧、汽车尾气排放以及生产使用过程中泄漏的方式进入环境。结合国内外对苯的毒理研究成果,探索了苯在环境中释放与转归路径,统计了我国大气、土壤、地下水、地表水、沉积物及食物链中苯的赋存现状。由于苯有致癌性,长期或频繁地暴露在苯环境中的人群存在致癌风险。环境中苯主要以气态相存在,呼吸吸入是人体苯暴露的主要途径,研究采用美国环境保护局(US EPA)吸入风险评估模型,计算人群在苯暴露下的致癌风险。根据化工区、交通干道两侧和地下车库3个区域空气苯的统计数据,开展人体健康风险评估,致癌风险分别为3.98×10-5、9.66×10-5和1.44×10-6,风险不可接受;以可接受风险水平10-6为目标,反推以上3种情景下苯的最大允许暴露浓度分别为0.0002、0.0002和0.0321 mg·m-3。上述研究结果为确定我国环境空气质量标准中苯的控制限值和保护人体健康提供了基础数据。     

健康风险评估方法在中国重金属污染中的应用及暴露评估模型的研究进展

经济的快速发展导致中国环境质量日趋恶化.随着健康意识的增强,人们越来越重视污染物暴露人群的健康风险评估.与其他污染物相比,重金属污染区域广,重金属暴露人群多且集中.为了研究重金属暴露条件下人群的健康风险,USEPA 模型、统计模型、地理信息系统、可给性研究的方法已被中国不同学者应用.暴露评估模型作为污染物暴露人群健康风险评估的主要环节,国外的研究已经比较成熟,但相关研究在中国还处于空白阶段.对中国近年来在城市表层土壤（灰尘）、矿区土壤、膳食、地下水和饮用水、大气颗粒物进行重金属风险评估中应用的健康风险评估方法,进行了归纳和评述,并对欧美常用暴露评估模型：环境暴露评估模型、膳食暴露评估模型进行了介绍.中国健康风险评估工作起步晚,在评估的各环节均存在很大缺陷.随着新技术的发展以及人群对环境健康风险认识的深化,健康风险评估将成为中国热门研究领域之一.污染的环境行为、剂量一效应关系、模型、风险信息等方面,将是未来中国健康风险评估研究的重点.     

我国土壤环境的风险评估技术分析与展望

随着我国工业化、城镇化及农业高度集约化的快速发展,耕地和场地土壤复合污染问题日益突出,土壤污染的风险日趋显现.本文在总结国内外土壤污染健康风险评估技术发展历程的基础上,探讨我国国内建设用地健康风险评估技术导则的异同点,分析目前国内外有关土壤环境风险评估技术研究的热点与不足,重点介绍了蒸气入侵模型的发展、土壤中有机污染物和重金属健康风险评估方面的研究工作.最后,本文提出根据场地利用场景并结合考虑生物可给性的模型校正开展精细化的土壤环境人体健康风险评估,同时也要加强土壤环境的生态风险评估以及地质高背景区的风险管控.本文为未来场地土壤环境的分级分类管理提供了前瞻性建议.     

典型城镇工业污染场地环境风险评估

研究根据场地环境风险评估方法对于城镇化初始居民的适用性,提出了基于增加蔬菜摄入暴露途径的改进风险评估技术方法,并以天津市某污染场地为例,比较两种方法计算结果。结果显示利用改进方法计算得到风险结果显著高于现有导则方法,其中蔬菜摄入暴露途径对于评估结果的贡献率高达38.38%。说明导则方法忽视蔬菜摄入暴露途径将造成风险评估结果偏低,改进方法更适用于现有典型城镇的场地风险评估。     

内蒙古呼和浩特市大气TSP和PM_(10)中PAHs的健康风险评价

于2012—2013年6月和12月采集了内蒙古呼和浩特市大气颗粒物样品,用GC-MS分析测定其中16种PAHs的浓度,并用苯并(a)芘(Ba P)致癌、致突变等效浓度、终身致癌超额危险度和预期寿命损失3个指标评价了内蒙古呼和浩特市大气颗粒物TSP和PM_(10)中PAHs的人群健康风险。结果显示:内蒙古呼和浩特市大气颗粒物TSP和PM_(10)中PAHs对成人、儿童的日均暴露剂量范围分别为0.71×10~(-6)~2.01×10~(-6)、0.45×10~(-6)~1.28×10~(-6)和0.31×10~(-6)~2.41×10~(-6)、0.19×10~(-6)~1.15×10~(-6)mg·kg~(-1)·d~(-1);TSP和PM_(10)中PAHs对成人和儿童的终身致癌超额危险度范围分别为2.21×10~(-6)~6.24×10~(-6)、1.41×10~(-6)~3.97×10~(-6)和0.95×10~(-6)~7.47×10~(-6)、0.60×10~(-6)~4.75×10~(-6),终身致癌超额危险度均处于可接受水平范围内(10-4~10~(-6))。TSP和PM_(10)中PAHs对成人和儿童的预期寿命损失范围分别为13.74~38.78、8.752~24.70和5.88~46.39、3.74~29.54 min。     

Use of the ouput of a lead risk assessment model to establish soil lead cleanup levels

Three general methods to calculate soil contaminant cleanup levels are assessed: the truncated lognormal approach, Monte Carlo analysis, and the house-by-house approach. When these methods are used together with a lead risk assessment model, they yield estimated soil lead cleanup levels that may be required in an attempt to achieve specified target blood lead levels for a community. The truncated lognormal approach is exemplified by the Society for Environmental Geochemistry and Health (SEGH) model, Monte Carlo analysis is exemplified by the US EPA's LEAD Model, and the house-by-house approach is used with a structural equation model to calculate site-specific soil lead cleanup levels. The various cleanup methods can each be used with any type of lead risk assessment model. Although all examples given here are for lead, the cleanup methods can, in principle, be used as well with risk assessment models for other chemical contaminants to derive contaminant-specific soil cleanup levels.     

太原市土壤六六六和滴滴涕的暴露格局及健康风险

为研究六六六(HCHs)和滴滴涕(DDTs)在太原市不同功能区土壤中的暴露格局、来源以及对周围人群的健康风险,在太原市化工区、灌区、矿区、生态区周边荒地土壤中进行采样,分析测定了土壤中HCHs和DDTs含量,根据太原市人群实际情况的暴露参数和USEPA的部分参数,对土壤HCHs和DDTs的健康风险进行评价。结果表明:1)太原市表层土壤中HCHs的平均含量大小依次为化工区>灌区>矿区>生态区;DDTs平均含量的大小依次为化工区>灌区>矿区>生态区,仅6%的HCHs和3%的DDTs和的平均残留水平均高于我国土壤质量标准一级标准,但均不超过二级标准值;2)土壤中HCHs残留主要源于历史上林丹的使用,DDTs残留则来源于历史和新污染源的共同影响;3)太原市表层土壤HCHs和DDTs致癌风险大小为化工园区>矿区>灌区>生态区。非致癌风险大小为化工区>矿区>灌区>生态区。3种暴露途径的在不同功能区的健康风险贡献率大小均为经口摄入>呼吸吸入>皮肤接触;综合来看太原市表层土壤中的HCHs和DDTs并未对人类造成非致癌风险,但有一定的致癌风险。本文的研究结果可为太原市土壤质量评价和环境污染防治提供科学指导,并对太原市人群的健康风险防治提供依据。     

Regional human health risk assessment of cadmium and hexachlorocyclohexane for agricultural land in China

Widespread pollution of agricultural soil is posing great risks to food safety and human health. The absence of human health-based Generic Assessment Criteria (GAC) for agricultural land means Chinese farmers struggle to manage these risks efficiently and effectively. Cadmium (Cd) and hexachlorocyclohexane (HCH), two of the most concerned contaminants, demonstrate threshold toxicity meaning that background exposure (MDI_oral) is considered when deriving soil Generic Assessment Criteria (GAC). The CLEA (Contaminated Land Exposure Assessment) model was used to derive GAC for Cd and HCH that reflect differences in diet and soil characteristics across 19 provinces/cities. For both cadmium and alpha-HCH, Sichuan had the lowest GAC of 0.379 mg kg^?1 and 0.0136 mg kg^?1, respectively, resulting from its significant high MDI_oral values, which are approximately six to nine times larger than the average MDI_oral for all the 19 provinces/cities. Jiangxi province had the highest GAC of 1.230 mg kg^?1 and 0.0866 mg kg^?1, respectively, for cadmium and alpha-HCH, caused by its notable low MDI_oral values and low vegetable consumption rate. Human health risk assessment based on regional GAC for Cd revealed that agricultural land with very high to high risks is located in southern China, while very low-risk land is located in northern China. For HCH, alpha- and gamma-HCH pose negligible health risks, but beta-HCH poses some health risk in some of the provinces/cities. When applying the regional GAC for beta-HCH, agricultural land in Beijing and Sichuan posed the highest risk, and those in Heilongjiang and Jiangxi had the lowest risk. This reflects the significant influence of background and vegetable consumption pathway on the GAC. Regional GACs could simplify and speed up risk assessment of agricultural land in different regions of China, by avoiding the need to calculate site-specific assessment criteria, thus saving time and money by avoiding over or under remediation.

     

城市回用水中多环芳烃致癌风险评价

为评价人群暴露于城市回用水中16种多环芳烃(polycyclic aromatic hydrocarbons,PAHs)对于人体健康的潜在风险,采用气相色谱-质谱(GC-MS)联用的分析化学方法对不同季节回用水中16种PAHs进行定量分析;在此基础上采用美国国家科学院和国家研究委员会提出的环境健康风险评价方法,分析不同回用条件下具有中国水体基质特色的城市回用水中PAHs健康风险.结果显示,回用水样中16种PAHs的总浓度为1 422.85 ng·L-1,污水处理厂二级出水水样16种PAHs的总浓度为1 791.77 ng ·L-1,经过处理后回用水中PAHs含量有所降低.风险评价分析结果显示,回用水在城市绿化、农业灌溉和景观娱乐3种不同回用途径下多环芳烃的致癌风险分别为788×10-8、2.77×10-6、3.04×10-6,总致癌风险为5.89×10-6.以上结果可以得出,回用水在城市绿化、农田灌溉和景观娱乐接触过程中多环芳烃所增加的致癌风险很低,回用水中多环芳烃的健康风险处于可接受水平.     

跳虫在土壤污染生态风险评价中的应用

随着土壤污染生态风险评价研究的逐步深入,选择适宜的生物作为风险评价的指示物成为研究热点.跳虫是一种分布极为广泛的土壤无脊椎动物,对土壤污染十分敏感,具有成为土壤环境质量指示生物的良好潜力.目前跳虫在土壤生态风险评价中的应用研究尚处于起步阶段.论文综述了跳虫在土壤生态系统中的作用,通过对当前跳虫生态毒性测试技术及其影响因素的综合分析,结合跳虫的分子生态效应的研究进展,详细阐述了跳虫在土壤生态风险评价中的应用.论文最后提出了跳虫应用于土壤污染生态风险评价所面临的技术障碍以及亟待解决的问题,并对该领域的前景进行了展望。     

Pollution of hazardous substances in industrial construction and demolition wastes and their multi-path risk within an abandoned pesticide manufacturing plant

Exploration of heavy metals and organic pollutants, their leaching capacity along with health and environmental risks in contaminated industrial construction and demolition waste (ICDW) within a pesticide manufacturing plant were investigated. A maximum content of 90.8 mg?kg^–1 Cd was found present in the wastes, which might originate from phosphorus rocks and industrial sulfuric acid used in pesticide production processes. An average concentration of 979.8 mg?kg^–1 dichlorovos and other 11 organophosphorus pesticide were also detected. Relatively high leaching rates of around 4.14‰were obtained from laboratory simulated ICDW using both glacial acetic acid-sodium hydroxide and deionized water. Pesticide pollutants had the strongest tendency to retaining on dry bricks (leaching rate 1.68‰) compared to mortar-coatings, etc. due to their different physical characteristics and octanol-water partioning coefficient. Mobility of pesticide from on-site ICDW by water was spatially correlated to waste types, process sections and human activities, with a flux of leaching rate between 5.9‰ to 27.4%. Risk-based corrective action (RBCA) model was used to simulate the risk of contaminated ICDW debris randomly scattered. Oral and dermal ingestion amount by local workers was 9.8 × 10^–3 and 1.9 × 10^–2 mg?(kg?d)^–1, respectively. Potential leaching risk to aquatic systems exceeded the limit for nearly 75% waste. Environmental and health risk exceedance was found in most ICDW, while the risk value of the most severely contaminated brick waste was 660 times beyond critical level. Implications for waste management involving construction and deconstruction work, waste transferring and regulation supplying were also provided.

Open image in new window

     

Concentrations,input prediction and probabilistic biological risk assessment of polycyclic aromatic hydrocarbons (PAHs) along Gujarat coastline

A comprehensive investigation was conducted in order to assess the levels of PAHs, their input prediction and potential risks to bacterial abundance and human health along Gujarat coastline. A total of 40 sediment samples were collected at quarterly intervals within a year from two contaminated sites—Alang-Sosiya Shipbreaking Yard (ASSBRY) and Navlakhi Port (NAV), situated at Gulf of Khambhat and Gulf of Kutch, respectively. The concentration of ΣPAHs ranged from 408.00 to 54240.45 ng g^?1 dw, indicating heavy pollution of PAHs at both the contaminated sites. Furthermore, isomeric ratios and principal component analysis have revealed that inputs of PAHs at both contaminated sites were mixed-pyrogenic and petrogenic. Pearson co-relation test and regression analysis have disclosed Nap, Acel and Phe as major predictors for bacterial abundance at both contaminated sites. Significantly, cancer risk assessment of the PAHs has been exercised based on incremental lifetime cancer risks. Overall, index of cancer risk of PAHs for ASSBRY and NAV ranged from 4.11 × 10^?6–2.11 × 10^?5 and 9.08 × 10^?6–4.50 × 10^?3 indicating higher cancer risk at NAV compared to ASSBRY. The present findings provide baseline information that may help in developing advanced bioremediation and bioleaching strategies to minimize biological risk.