Project 5 - Bioavailability as a Central Concept in Determining Remediation Goals and Strategies for PCDD/F-Contaminated Superfund Sites

项目 5 - 生物有效性作为确定 PCDD/F 污染超级基金场地修复目标和策略的核心概念

• 批准号: 10353536
• 负责人: Brian John Teppen
• 金额: $ 28.94万
• 依托单位: MICHIGAN STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-04-01 至 2027-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10353536
• 关键词: Address; Adopted; Age; Amendment; Biological; Biological Availability; Carbon; Charcoal; Chemicals; Collaborations; Complex; Computer Models; Corn Oil; Data; Decision Making; Development; Dose; Ecosystem; Environmental Impact; Equilibrium; Furans; Goals; Hazardous Substances; Hazardous Waste; Health; Human; In Situ; Individual; Kinetics; Literature; Mammals; Mass Fragmentography; Measurement; Measures; Methods; Minerals; Mus; National Institute of Environmental Health Sciences; Oral; Procedures; Process; Property; Protocols documentation; Research; Rest; Risk; Risk Assessment; Role; Sampling; Science; Series; Signal Recognition Particle; Silicon Dioxide; Site; Soil; Solid; Structure; Sum; Superfund; System; Testing; Tetrachlorodibenzodioxin; Time; Toxic effect; United States Environmental Protection Agency; Water; Work; aged; aryl hydrocarbon receptor ligand; base; clay; cost; design; dibenzo(1,4)dioxin; evidence base; experimental study; improved; landfill; microbial; mouse model; particle; prevent; remediation; response; superfund site; water solubility

Due to their exceptionally low water solubilities, polychlorinated dibenzo-p-dioxins and -furans (PCDD/Fs) are strongly and extensively bound to the solid particles of sediments and soils, especially charcoal-like pyrogenic carbonaceous matter (PCM, [1]), amorphous organic matter (AOM), and clay minerals. The United States Environmental Protection Agency (USEPA) conservatively assumes that 100% of soil-bound PCDD/Fs are bioavailable to mammals, including humans [2], while measured bioavailabilities of PCDD/Fs in real soils are far lower [3-13]. Real mammalian bioavailabilities are poorly understood, but we have recently advanced the science of PCDD/F bioavailability from soils by relating it to the properties of individual particle types: We have shown that PCDDs that are bound to AOM, clay minerals, or porous-silica particles are indeed 100% bioavailable (relative to those in corn oil) [14-18]. In contrast, we showed that PCDDs bound to a special kind of PCM called activated carbon (AC) had bioavailabilities of zero to mice [19, 20] and protected mammalian health. Our recent work provides two hypotheses to inform risk assessment and remediation strategies for PCDD/F-contaminated sites: 1) Low levels of PCM are ubiquitous in soils and sediments, so AC-like domains in PCM may be responsible for lowering the mammalian bioavailabilities of PCDD/Fs in real soils, and 2) Our understanding of soil particle types simplifies the complexity of soils enough that we can directly and mechanistically test whether AC amendment of PCDD/F-contaminated soils has potential to be protective of human and ecosystem health by minimizing mammalian bioavailability. Remediation using AC amendment was proposed long ago, because it is far cheaper and less environmentally disruptive than removing contaminated soils to hazardous-waste landfills, but regulators cannot adopt AC as a remedy because no one has shown that AC amendments are truly protective of mammalian and human health. We propose a set of experiments designed to rigorously test the hypothesis that PCDDs bound to AC amendments are no longer bioavailable to mammals, and thereby help USEPA and state regulators critically assess this promising treatment for remediation of PCDD/F-contaminated Superfund sites: We will track the full mass balance of PCDDs in soils after AC has been added, and then administer these soils orally to mice and measure PCDD bioavailability and mass balance in the mice. For the first time, we will directly measure the kinetics of PCDD accumulation in AC amendments and compare these with measured kinetics of soil-PCDD mammalian bioavailability. This work will inform risk assessment by supplying data for six practical criteria that EPA uses [21] to select Superfund remedies, including whether AC amendments are likely to protect human and ecosystem health, the kinetics of their short-term bioavailability reduction, and the longer- term stabilities of PCDD-AC complexes once they form. In sum, Project 5 will collaborate with the rest of the Center to transform the experimental basis for regulatory decision-making about AC amendment as a potential low-cost remediation treatment for PCDD/F-contaminated Superfund sites.

由于多氯二苯并二恶英和多氯二苯并呋喃（PCDD/Fs）的水溶性极低， 与沉积物和土壤中的固体颗粒强烈和广泛结合，特别是炭状热解 碳质物质（PCM，[1]），无定形有机物（AOM）和粘土矿物。美国 美国环境保护局（USEPA）保守地假设，100%的土壤中的多氯二苯并对二恶英/多氯二苯并呋喃 哺乳动物，包括人类[2]，而在真实的土壤中测得的PCDD/Fs的生物利用度远 低[3-13]。真实的哺乳动物生物利用度知之甚少，但我们最近在科学上取得了进展 土壤中PCDD/F的生物可利用性，将其与单个颗粒类型的特性相关联： 与AOM、粘土矿物或多孔二氧化硅颗粒结合的PCDDs确实是100%生物可利用的 （相对于玉米油）[14-18]。相反，我们发现PCDDs与一种特殊的PCM结合， 活性炭（AC）对小鼠的生物利用度为零[19，20]，并保护哺乳动物的健康。我们最近 工作提供了两个假设，为PCDD/F污染的风险评估和修复策略提供信息 1）低水平的PCM普遍存在于土壤和沉积物中，因此PCM中的AC样结构域可能是 负责降低哺乳动物的生物利用度的二恶英/Fs在真实的土壤，和2）我们的理解， 土壤颗粒类型简化了土壤的复杂性，我们可以直接和机械地测试， PCDD/F污染土壤的AC改良具有保护人类和生态系统健康的潜力， 最小化哺乳动物的生物利用度。很久以前就提出了使用AC修正的补救措施，因为它是 比将受污染的土壤移到危险废物填埋场便宜得多，对环境的破坏也小得多， 但监管机构不能采用AC作为补救措施，因为没有人证明AC修正案真正具有保护性 对哺乳动物和人类健康的影响。我们提出了一组实验，旨在严格检验假设 与活性炭修正物结合的多氯二苯并对二恶英不再对哺乳动物具有生物利用性，因此有助于美国环保局和 州监管机构严格评估了这种有前途的处理方法，以修复受PCDD/F污染的超级基金 我们将跟踪添加活性炭后土壤中多氯二苯并对二恶英的全面质量平衡， 小鼠口服土壤，并测量小鼠体内多氯二苯并对二恶英的生物利用度和质量平衡。这是我们第一次 直接测量AC修正物中PCDD累积的动力学，并将其与测量结果进行比较。 土壤-多氯二苯并对二恶英哺乳动物生物利用度的动力学。这项工作将通过为六个国家提供数据，为风险评估提供信息。 环保署使用[21]选择超级基金补救措施的实际标准，包括AC修正案是否可能 保护人类和生态系统健康，其短期生物利用度降低的动力学，以及长期- 多氯二苯并对二恶英-AC复合物形成后的长期稳定性。总之，项目5将与其余部分合作， 中心改造的实验基础，为监管决策关于AC修正案作为一种潜在的 对受到多氯二苯并对二恶英和多氯二苯并呋喃污染的超级基金场址进行低成本补救处理。