体外胃肠模拟评估土壤和灰尘中重金属生物可给性研究进展

有效评价人体经手-口无意摄入的土壤和灰尘中重金属生物可给性是全面评价环境污染健康风险的重要组成部分。体外胃肠模拟(in vitro)实验已广泛应用于土壤和灰尘中污染物的生物可给性研究。本文综述了Pb、As人体生物可给性的几种常用体外胃肠模拟方法,如欧洲生物可给性研究组统一法(UBM)、生物原理提取法(PBET)、Rodriguez体外胃肠法(IVG)、生物可给性简化提取法(SBET),及影响其结果的因素,提出在今后的研究中应加强模拟方法的适应性和通用性研究。     

土壤重金属污染生态风险评价方法研究进展

城市化所导致的土壤环境恶化已成为影响居民健康的一个重要因素,土壤的重金属污染问题已成为研究的热点。该文综述了目前常用的土壤重金属污染生态风险评价方法 [形态分析法、TCLP(Toxicity characteristic leaching procedure)法、体外试验评估法、植物培养法、蚯蚓生态毒理法]。指出今后的研究重点是制定土壤重金属环境质量标准和建立完善的评价体系,确定植物重金属污染指示作用的重要性,利用地理信息系统(GIS)技术开展重金属污染填图及建立土壤重金属污染信息系统,这些研究可为土壤管理提供科学指导依据。     

体外消化模型在真菌毒素生物可及性研究中的应用及研究进展

在人类健康风险评估中,经口摄入是人类暴露于许多污染物的主要途径.模拟污染物经口腔、胃和小肠消化过程的体外消化模型已成为探究污染物生物可及性、肠转运和代谢的热点,并成为评估食品、土壤等基质中重金属、有机污染物、真菌毒素风险的重要技术手段.模拟机体进食、禁食条件创建体外消化模型并验证,探讨真菌毒素在体内的生物可及性及影响因素,对发展准确、灵敏、方便的膳食暴露真菌毒素风险评估工具意义非凡.本文就真菌毒素生物可及性研究的最新进展进行综述.     

基于体外模拟法的城市土壤铅的健康风险评估

目的了解广州主城区土壤的Pb生物可给性,探讨土壤Pb生物可给性的影响因素,评估广州主城区土壤Pb经口无意摄入的人体健康风险。方法选择广州主城区62个采样点的土壤为研究对象,采用体外试验法模拟人体消化系统进行消化,运用原子吸收分光光谱法测定胃、小肠消化阶段反应液中可溶态Pb和土壤Pb含量。结果广州主城区土壤Pb平均含量高于广州市、广东省和中国土壤背景值(P<0.05);广州主城区土壤在模拟胃阶段Pb平均生物可给性(33%)高于小肠阶段(7.0%);不同城区儿童、成人经口无意摄入途径的Pb平均摄入量分别为28.51、7.13μg/d,不同城区儿童、成人Pb摄入量的分布差异存在统计学意义(P<0.05),其中黄埔区儿童、成人Pb摄入量最高(129.92、32.48μg/d);不同城区的儿童在模拟胃阶段和小肠阶段中的Pb平均生物可给量分别为11.58、1.85μg/d,成人则分别为2.89、0.46μg/d,不同城区儿童、成人在模拟小肠阶段中Pb生物可给量的分布差异有统计学意义(P<0.05);胃肠消化阶段中Pb溶出量与土壤Pb总量呈正相关(P<0.05);黄埔区土壤Pb的儿童健康绝对风险系数(Ka=2.4)、模拟胃阶段健康相对风险系数(Kr1=1.38)超过WHO人体健康防线警戒线。结论广州主城区土壤Pb不同程度受到污染,黄埔区土壤铅对儿童的健康风险应引起重视。     

Health Risk Assessment of Lead in Urban Soil by Simulation Methods in vitro

目的 了解广州主城区土壤的Pb生物可给性,探讨土壤Pb生物可给性的影响因素,评估广州主城区土壤Pb经口无意摄入的人体健康风险.方法 选择广州主城区62个采样点的土壤为研究对象,采用体外试验法模拟人体消化系统进行消化,运用原子吸收分光光谱法测定胃、小肠消化阶段反应液中可溶态Pb和土壤Pb含量.结果 广州主城区土壤Pb平均含量高于广州市、广东省和中国土壤背景值(P＜0.05);广州主城区土壤在模拟胃阶段Pb平均生物可给性(33％)高于小肠阶段(7.0％);不同城区儿童、成人经口无意摄入途径的Pb平均摄入量分别为28.51、7.13μg/d,不同城区儿童、成人Pb摄入量的分布差异存在统计学意义(P＜0.05),其中黄埔区儿童、成人Pb摄入量最高(129.92、32.48 μg/d);不同城区的儿童在模拟胃阶段和小肠阶段中的Pb平均生物可给量分别为11.58、1.85 μg/d,成人则分别为2.89、0.46 μg/d,不同城区儿童、成人在模拟小肠阶段中Pb生物可给量的分布差异有统计学意义(P＜0.05);胃肠消化阶段中Pb溶出量与土壤Pb总量呈正相关(P＜0.05);黄埔区土壤Pb的儿童健康绝对风险系数(Ka=2.4)、模拟胃阶段健康相对风险系数(Kr1=1.38)超过WHO人体健康防线警戒线.结论 广州主城区土壤Pb不同程度受到污染,黄埔区土壤铅对儿童的健康风险应引起重视.     

2018年广东省惠州市部分农村土壤卫生状况调查及风险评估

目的 初步评价广东省惠州市部分农村地区土壤卫生状况及其对人体的健康风险,为该地区土壤污染物健康风险评估提供科学依据和理论基础。方法 按照《土壤环境监测技术规范》（HJ/T 166 - 2004）进行监测,根据《土壤环境质量标准》（GB 15618 - 1995）进行评价,并应用国际机构推荐的人群健康风险模型评价本地居民土壤重金属污染经摄食途径和经皮肤接触引起的健康风险值。结果 本次调查的80份土壤中,有10个监测点土壤中检测出蛔虫卵,土壤中重金属铅、镉、铬二级及以上土壤质量标准达标率为97.92%;各县区的3种重金属通过2种途径的人群非致癌性风险和致癌性风险值均小于1.0×10 - 4/年,为可接受风险值。结论 惠州市农村土壤环境卫生状况总体良好,蛔虫卵轻度污染,尚未发现3种重金属的明显污染;根据风险模型评估3种重金属分布水平不会对人体产生明显的健康危害。     

血铅塞曼石墨炉原子吸收光谱法测定

铅是一种有毒的重金属，经多种途径进入人体，长期摄入蓄积体内，到一定浓度导致血液和神经系统等疾病。血铅是反映铅暴露的生物检测指标之一。其检测的主要方法有原子吸收光谱法和微分电位溶出法等。而石墨炉原子吸收光谱法已成为测定血铅的标准方法。本文利用塞曼背景校正技术，用基体改进剂稀释血样后直接测定全血中的铅，得到满意结果。     

基于双聚类和可视化的重金属污染领域研究热点探析

目的 探究2006-2015年间国内重金属污染领域文献的研究热点.方法 以中国知网数据库重金属污染的文献数据为研究对象,采用BICOMB软件生成70个高频关键词的词篇矩阵,将该矩阵导入gCLUTO软件中进行双聚类分析并可视化,得到重金属污染的研究热点.结果 重金属污染文献聚类结果主要集中在5个方面.包括重金属污染对农作物的影响;重金属污染造成的生态风险及评价;植物对重金属污染的防治作用;土壤重金属的生物有效性;重金属污染造成的食品安全及人体健康风险问题.结论 通过双聚类分析和可视化,可以得出当前重金属污染领域的研究热点,从而为科研人员和环保部门提供一定的参考依据.     

西南某煤矿区土壤重金属污染特征及人群健康风险评价

目的探讨西南某煤矿区土壤重金属污染特征及人群健康风险。方法于2014年4—8月采集西南某煤矿区土壤,测定其重金属元素Pb、Cd、Hg、As、Cu的含量。采用潜在生态风险指数法、地积累指数法对土壤生态环境质量进行评价,结合美国环保署人体暴露健康风险评价法对土壤重金属健康暴露风险进行评价。结果除Pb、Hg、As外,研究区土壤中Cd、Cu的平均含量均超过贵州省土壤背景值,分别是背景值的1.02、3.33倍。研究区土壤中5种重金属潜在生态风险指数(RI)平均为91.36,整体处于Ⅰ级轻微生态风险,Cd和Hg是造成土壤重金属污染的潜在生态风险因子。地积累指数评价表明,研究区土壤Cu污染最严重,Pb、Hg、As尚不构成土壤污染。健康风险评价结果表明,儿童和成人日暴露剂量均值均为CuPbAsCdHg,经口摄入是儿童和成人非致癌健康风险和致癌健康风险的主要途径。Cd对儿童的致癌风险指数(CRn)为3.06×10~(-6),可能存在致癌风险;对成人的CRn为4.94×10~(-7),不存在致癌风险。As对儿童的CRn为1.24×10~(-4),存在致癌风险;对成人的CRn为1.79×10~(-5),可能存在一定的致癌风险。As对区域非致癌健康风险(HI)和致癌健康风险(CRtotal)的贡献率最高。结论本研究区土壤重金属整体处于轻微生态风险,Cu、Cd、Hg是土壤污染治理的重点,应防范As的暴露风险,加强预防重金属经口摄入暴露途径对健康的影响。     

体外模拟法在土壤-人途径重金属污染的健康风险评价中的应用

目的 对某重金属污染区域的土壤经土壤-人途径的健康风险进行评估,从而为相关环境决策提供理论依据.方法 采集重金属污染区和对照区农田和路旁土壤,通过体外模拟装置模拟人体消化系统进行消化,分别取胃和小肠阶段反应液样本离心过滤后检测其Cd、Pb、Zn含量并计算其生物可给性;根据重金属生物可给量进行健康风险评价.结果 污染区土壤在模拟胃阶段的Cd、Pb、Zn的生物可给性分别为21%～33%,21%～28%,33%～43%;对照区分别为27%,23%,95%.污染区土壤在模拟小肠阶段的Cd、Pb、Zn的生物可给性分别为16%～19%,3.4%～4.9%,14%～8%;对照区分别为11%,2.6%,18%.污染区儿童在模拟胃阶段Cd、Pb、Zn的生物可给量分别为0.04～1.46、3.09～55.53、3.86～39.39 μg/d,成人分别为0.01～0.36、0.77～13.88、0.97～9.85μg/d.对照区儿童分别为0.01、0.74、5.64 μg/d,成人分别为0.00、0.19、1.41μg/d.污染区儿童在模拟小肠阶段Cd、Pb、Zn的生物可给量分别为0.03～0.71、0.50～9.92、1.26～9.55μg/d,成人分别为0.01～0.18、0.11～2.48、0.31～2.39μg/d;对照区儿童分别为0.00、0.08、1.07 μg/d,成人分别为0.00、0.02、0.27μg/d.结论 污染区V2土壤中Pb对当地儿童的健康具有较大的潜在风险,其他数据虽然在相应限量以下,但由于通过土壤-人途径的摄入会增加人体对重金属摄入的总量,从而使健康风险的总量增加.     

城市土壤重金属研究进展

基于文献计量法探究城市土壤重金属研究的热点、修复技术与关键问题。城市土壤重金属污染是能有效反映城市环境污染状况的重要指标之一,城市土壤重金属生态地球化学、环境风险和污染修复是目前研究的热点和焦点。城市土壤与重金属微界面过程及机制、城市土壤重金属生物有效性及其健康风险以及城市土壤重金属复合污染效应、作用机理及其污染控制是目前城市土壤重金属研究有待解决的关键科学问题。城市土壤重金属研究仍然是今后环境科学研究的热点方向,而我国西部地区的研究有待加强。     

Nitrogen and Phosphorus Fertilizer Increases the Uptake of Soil Heavy Metal Pollutants by Plant Community

Soil heavy metal pollution is widespread around the world. Compared with hyperaccumulation plants, non-hyperaccumulator plant communities have many advantages in the remediation of heavy metals pollution in soil. The application of nitrogen (N) and phosphorus (P) is inexpensive and convenient, which can promote the growth of plant. N and P fertilizer might increase plant community remediation of heavy metal polluted soils. In our study, the effects of N and P fertilizer on remediation of soil Cd, Cu, Pb pollution by plant community were studied through a greenhouse experiment. Our results indicated that addition of N, P and N?+?P fertilizer increased plant community aboveground biomass. Simultaneously, addition of N and P fertilizer increased the accumulation of heavy metals in aboveground of the plant community and accelerated plants absorption soil heavy metals. Among them, N fertilizer had the best effect. Our results provide an inexpensive method for remediation heavy metal pollution of contaminated farmland, abandoned land and mine tailings, etc.

     

Health risk-based assessment and management of heavy metals-contaminated soil sites in Taiwan

Risk-based assessment is a way to evaluate the potential hazards of contaminated sites and is based on considering linkages between pollution sources, pathways, and receptors. These linkages can be broken by source reduction, pathway management, and modifying exposure of the receptors. In Taiwan, the Soil and Groundwater Pollution Remediation Act (SGWPR Act) uses one target regulation to evaluate the contamination status of soil and groundwater pollution. More than 600 sites contaminated with heavy metals (HMs) have been remediated and the costs of this process are always high. Besides using soil remediation techniques to remove contaminants from these sites, the selection of possible remediation methods to obtain rapid risk reduction is permissible and of increasing interest. This paper discusses previous soil remediation techniques applied to different sites in Taiwan and also clarified the differences of risk assessment before and after soil remediation obtained by applying different risk assessment models. This paper also includes many case studies on: (1) food safety risk assessment for brown rice growing in a HMs-contaminated site; (2) a tiered approach to health risk assessment for a contaminated site; (3) risk assessment for phytoremediation techniques applied in HMs-contaminated sites; and (4) soil remediation cost analysis for contaminated sites in Taiwan.     

Impact of heavy metal toxicity and constructed wetland system as a tool in remediation

The objective of this review is to throw light upon the global concern of heavy metal–contaminated sites and their remediation through an ecofriendly approach. Accumulated heavy metals in soil and water bodies gain entry through the food chain and pose serious threat to all forms of life. This has engendered interest in phytoremediation techniques where hyperaccumulators are used. Constructed wetland has a pivotal role and is a cost-effective technique in the remediation of heavy metals. Metal availability and mobility are influenced by the addition of chelating agents, which enhance the availability of metal uptake. This review helps in identifying the critical knowledge gaps and areas to enhance research in the future to develop strategies such as genetically engineered hyperaccumulators to attain an environment devoid of heavy metal contamination.     

The bioaccessibility of low level radionuclides from two Savannah river site soils

Risk assessments for inorganic contaminated soils are often based on total concentration of a contaminant. However, strong binding of metals in soil can reduce the oral bioavailability. Since oral bioavailability of inorganics is generally less than 100% and partially dissolution-limited, human gastrointestinal dissolution models that measure bioaccessibility instead of the total extractable mass should be used to develop radionuclide source terms. For the reported study, a published bioaccessibility method was modified to allow measurements of bioaccessible radionuclides. The technique can be used to model human exposure and radionuclide dose from soil ingestion pathways. A step that included the addition of organic acids to the gastrointestinal fluids did not considerably affect the bioaccessibility of 90Sr and 137Cs. The bioaccessibility of 137Cs in the soils was significantly correlated to soil physicochemical characteristics, with a negative correlation with clay content, while 90Sr was significantly correlated to calcium bioaccessibility. These relationships can be used to prioritize remediation according to soil type.     

Phytotoxkit: a critical look at a rapid assessment tool

Terrestrial plant toxicity testing contributes critical information to many site risk assessments, but standardized tests can be labor-intensive, use large amounts of soil, and employ long test durations. The Phytotoxkit (MicroBioTests, Environmental Bio-Detection Products) minimizes the time and cost associated with terrestrial plant testing with a unique test setup, a shorter test duration, and less soil. However, the sensitivity of the test remains an open question. In this research, the Phytotoxkit and the standardized Environment Canada terrestrial plant toxicity test (definitive test) are compared using a parallel testing approach. Three different scenarios were examined: a multiconcentration test, in which an inhibiting concentration (ICp) was derived from chemically amended soils; a soil remediation test, in which plant growth in a remediated soil was compared to the original contaminated soil; and a site soil test, in which plant growth in a contaminated soil was compared to a reference soil. The contaminants tested were boric acid, Cr(VI) with cyclodextrin as a remediation agent, and petroleum hydrocarbons. Trifolium pratense (red clover) was used in the first and second scenarios, and six different plant species were used in the third scenario. In the first scenario, the Phytotoxkit results compared well with the definitive test results after 5 and 7 d of exposure. In the second scenario, the Phytotoxkit results agreed with the definitive test when evaluating the effectiveness of remediation. In the third scenario, the Phytotoxkit results were often not in agreement with the results from the definitive test. The reduced sensitivity of the Phytotoxkit in the third scenario may be driven by test unit design, as plant roots are separated from soil by filter paper.     

Risk Assessment for Oral Bioaccessibility of Lead and Cadmium in the Potato Growing in Smelter-Impacted Soil

Smelting activities are an important source of heavy metals in soil. More seriously, oral ingestion of crops growing in contaminated soil potentially cause harmful effects on human health. The main purpose of this study is to apply the in vitro model (PBET) and Monte Carlo Simulation (MSC) to the health risk assessment process in order to more accurately and realistically evaluate health risks of residents eating contaminated potato. Results indicated in the raw and cooked potato, the bioaccessibility of Pb was 65.9% and 74.5%, and that of Cd was 79.6% and 61.7%, respectively. Additionally, the bioaccessible hazard quotient (BHQ) was less than the permitted level except for the BHQ of Pb for children. This indicated there wasn’t potential non-carcinogenic risk for most potato-consumers but the dietary exposure risk for local children cannot be neglected. Sensitivity analysis showed that the bioaccessibility and ingestion rate appeared decisive with respect to potentially deleterious health effects.

     

Remediation of heavy metal-contaminated soils using phosphorus: evaluation of bioavailability using an earthworm bioassay

This study investigated the effectiveness of phosphorus (P) as an in situ remediation technique in site soils collected from the Tri-State mining area. The site soils were treated with two different types (KH₂PO₄ and Super Triple Phosphate fertilizer) and levels (600 and 5,000 mg/kg) of phosphorus. A toxicokinetic approach was used to determine whether phosphorus amendments reduced heavy metal bioavailability to the earthworm Eisenia fetida. Bioaccumulation factors were used as a measure of bioavailability. Depuration patterns of lead, zinc, and cadmium also were studied after removing earthworms from contaminated soils and then placing them in noncontaminated artificial soil. Results showed that the high phosphorus treatments significantly reduced lead, zinc, and cadmium bioavailability to the earthworms, probably due to formation of metal-phosphate complexes in the soils. Results also indicated that other soil characteristics in addition to amended phosphorus have an affect on bioavailability. Depuration experiments showed a biphasic elimination pattern for each metal. The current results indicate that phosphorus soil amendments may reduce ecological risk to soil-inhabiting invertebrates exposed to heavy metal-contaminated soils. Received: 19 November 2001/Accepted: 13 April 2002     

Human health risk assessment in relation to environmental pollution of two artificial freshwater lakes in The Netherlands.

A human health risk assessment has been performed in relation to recreational activities on two artificial freshwater lakes along the river Meuse in The Netherlands. Although the discharges of contaminants into the river Meuse have been reduced in the last decades, which is reflected in decreasing concentrations of pollutants in surface water and suspended matter, the levels in sediments are more persistent. Sediments of the two freshwater lakes appear highly polluted and may pose a health risk in relation to recreational activities. To quantify health risks for carcinogenic (e.g., polycyclic aromatic hydrocarbons) as well as noncarcinogenic compounds (e.g., heavy metals), an exposure assessment model was used. First, we used a standard model that solely uses data on sediment pollution as the input parameter, which is the standard procedure in sediment quality assessments in The Netherlands. The highest intake appeared to be associated with the consumption of contaminated fish and resulted in a health risk for Pb and Zn (hazard index exceeded 1). For the other heavy metals and for benzo(a)pyrene, the total averaged exposure levels were below levels of concern. Secondly, input data for a more location-specific calculation procedure were provided via analyses of samples from sediment, surface water, and suspended matter. When these data (concentrations in surface water) were taken into account, the risk due to consumption of contaminated fish decreased by more than two orders of magnitude and appeared to be negligible. In both exposure assessments, many assumptions were made that contribute to a major degree to the uncertainty of this risk assessment. However, this health risk evaluation is useful as a screening methodology for assessing the urgency of sediment remediation actions.     

Effect of soil properties on lead bioavailability and toxicity to earthworms

Soil properties are important factors modifying metal bioavailability to ecological receptors. Twenty-one soils with a wide range of soil properties (USA; http://soils.usda.gov/technical/classification/taxonomy/) were amended with a single concentration of Pb (2,000 mg/kg) to determine the effects of soil properties on Pb bioavailability and toxicity to earthworms. Earthworm mortality ranged from 0 to 100% acute mortality following exposure to the same total concentration of Pb (2,000 mg/kg) in amended field soils. Internal Pb concentrations in earthworms ranged from 28.7 to 782 mg/kg, with a mean of 271 mg/kg. Path analysis was used to partition correlations in an attempt to discern the relative contribution of each soil property. Results of path analysis indicated that pH was the most important soil property affecting earthworm mortality (p < 0.01) and internal Pb (p < 0.05). Soil pH was related inversely to mortality and internal Pb, soil solution Pb, and Pb bioavailability. The most important soil property modifying reproduction was amorphous iron and aluminum oxides (FEAL). Because FEAL is rich in pH-dependent cation-exchange sites, several soil properties, including pH, FEAL, and cation-exchange capacity, have a causal effect on Pb adsorption and soluble Pb. Path analysis is useful for assessing contaminated soils with a wide range of soil properties and can assist in ecological risk assessment and remediation decisions for contaminated sites. Soil properties are important factors modifying metal bioavailability and toxicity and should be considered during the ecological risk assessment of metals in contaminated soils.