Development of Stable Isotope Based Methods to Predict Bioavailability of Hydroph

开发基于稳定同位素的方法来预测 Hydroph 的生物利用度

• 批准号: 8229227
• 负责人: Jay Gan
• 金额: $ 27.59万
• 依托单位: UNIVERSITY OF CALIFORNIA RIVERSIDE
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-20 至 2014-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8229227
• 关键词: Adopted; Adsorption; Affect; Aging; Amendment; Area; Bioavailable; Biological Assay; Biological Availability; Calibration; California; Carbon; Chemicals; Consumption; Dependence; Deposition; Development; Dioxins; Effectiveness; Environment; Equilibrium; Exposure to; Fiber; Fishes; Halibut; Health; Human; In Situ; Isotopes; Isotropy; Label; Link; Los Angeles; Marine Sediment; Measurement; Measures; Methods; Monitor; Performance; Phase; Polychlorinated Biphenyls; Procedures; Property; Recovery; Sampling; Schedule; Shellfish; Silicon Dioxide; Site; Solid; Stable Isotope Labeling; System; Techniques; Testing; Time; Toxic effect; Trace Elements; absorption; base; bioaccumulation; exposed human population; feeding; improved; instrument; novel; operation; organic contaminant; remediation; stable isotope; superfund site

DESCRIPTION (provided by applicant): Human exposure to sediment-borne contaminants is not directly related to chemical concentrations in the bulk sediment, but is instead controlled by the bioavailable concentration or bioavailability. Remediation practices, such as dredging, sand capping, sorbent amendment, and even monitored natural recovery (MNR) may all affect the bioavailability of sediment contaminants differently than the bulk sediment chemical concentration. In particular, bioavailability is a key to better assessing human exposure to hydrophobic organic contaminants (HOCs) such as DDT, PCBs, PAHs and dioxins through consumption of fish from contaminated areas. However, current methods for determining sediment HOC bioavailability suffer from method-specific limitations. Partial extraction techniques to estimate bioaccessibility are invariably influenced by types of extractants and extraction conditions selected. Passive samplers, including solid phase microextraction (SPME), must be used under equilibrium conditions that may take months to reach. In this project we exploit the wide availability of stable isotope labeled HOC compounds and GC-MS systems in two novel applications aiming to greatly improve the efficiency and accuracy of bioavailability measurement. The first approach uses the concept of isotope exchange (or dilution), similar to what has been done for trace elements, to derive the exchangeable concentration as an approximation of bioaccessible concentration. The fact that most HOCs are highly stable lends them the quality of being conservative and thus ideal for such an application. In the second approach, we incorporate stable isotope labeled HOCs with SPME by using the labeled HOCs as performance reference compounds so that SPME may be used under non-equilibrium conditions with short sampling time. The isotope exchange approach may be applied to ex situ assessment while the stable isotope- SPME method may be used for both ex situ and in situ measurements. We will carry out systematic studies to prove the underlying assumptions, develop and optimize the methods using spiked sediments, validate the methods through extensive bioaccumulation assays using a common fish prey (polychaete worm) and a deposit-feeding fish (California halibut), and then apply the methods for ex situ and in situ measurement of bioavailability of DDTs and PCBs at the Palos Verdes Shelf Superfund site off the coast of Los Angeles that has undergone pilot remediation trials and is scheduled for sand capping in 2012. At the end of this project, we expect to produce a range of rigorously tested methods that may be easily adopted for ex situ or in situ monitoring of sediment remediation sites to evaluate the effectiveness of remediation operations and predict changes in human exposure potential. PUBLIC HEALTH RELEVANCE: Human exposure to sediment-borne contaminants such as DDT, PCBs, PAHs and dioxins is not directly related to chemical concentrations in the bulk sediment, but is instead controlled by bioavailability. In this project we exploit the wide availability of stable isotope labeled HOC compounds and GC-MS systems in two novel applications aiming to greatly improve the efficiency and accuracy of bioavailability measurement. These methods may be easily adopted for ex situ or in situ monitoring of sediment remediation sites to evaluate the effectiveness of remediation operations and better predict changes in human exposure potential.

描述(申请人提供)：人类接触沉淀物中的污染物与沉积物中的化学浓度没有直接关系，而是由生物可利用浓度或生物利用度控制。修复措施，如疏浚、覆沙、吸附剂修正，甚至监测的自然恢复(MNR)，都可能对沉积物污染物的生物有效性产生不同于对总体沉积物化学浓度的影响。特别是，生物利用度是通过食用受污染地区的鱼更好地评估人类接触DDT、多氯联苯、多环芳烃和二恶英等疏水性有机污染物的关键。然而，目前测定沉积物HOC生物利用度的方法受到特定方法的限制。评估生物可及性的部分提取技术总是受到所选萃取剂类型和提取条件的影响。被动取样器，包括固相微萃取(SPME)，必须在可能需要几个月才能达到的平衡条件下使用。在这个项目中，我们利用稳定同位素标记的HOC化合物和GC-MS系统在两个新的应用中的广泛应用，旨在极大地提高生物利用度测量的效率和准确性。第一种方法使用同位素交换(或稀释)的概念，类似于对痕量元素所做的工作，以推导出可交换浓度作为生物可达浓度的近似值。事实上，大多数HOC是高度稳定的，这赋予了它们保守的品质，因此是此类应用的理想选择。在第二种方法中，我们将稳定同位素标记的HOCs与SPME结合，以标记的HOCs作为性能参考化合物，从而使SPME可以在非平衡条件下以较短的采样时间使用。同位素交换法可用于非原位测量，稳定同位素-固相微萃取方法可用于非原位和原位测量。我们将开展系统研究来证明基本假设，开发和优化使用添加沉积物的方法，通过使用普通鱼类(多毛虫)和以沉积物为食的鱼类(加利福尼亚大比目鱼)进行广泛的生物累积分析来验证方法，然后在洛杉矶海岸外的Palos Verdes Shelf Superfund站点应用这些方法来异地和现场测量DDT和PCbs的生物有效性，该站点已经进行了试点补救试验，计划于2012年进行沙盖。在这个项目结束时，我们预计将产生一系列经过严格测试的方法，这些方法可以很容易地用于沉积物修复地点的异地或现场监测，以评估修复操作的有效性，并预测人类暴露潜力的变化。 公共卫生相关性：人类接触沉积物中的污染物，如滴滴涕、多氯联苯、多环芳烃和二恶英，与大量沉积物中的化学浓度没有直接关系，而是由生物利用度控制。在这个项目中，我们利用稳定同位素标记的HOC化合物和GC-MS系统在两个新的应用中的广泛应用，旨在极大地提高生物利用度测量的效率和准确性。这些方法可以很容易地用于沉积物修复地点的异地或现场监测，以评估修复行动的有效性，并更好地预测人类暴露潜力的变化。