In Situ Sampling Tool for Assessing Bioavailability and Toxicity of Sediments

摘要本项目介绍了一种测定沉积物污染物生物利用度的新策略，这些污染物具有广泛的化学结构、性质和物理化学行为。该项目解决了超级基金利益攸关方的迫切需要，即以方便和可靠的方式确定受污染沉积物对人类健康的风险和实施的补救战略的有效性。原位取样/生物利用度测定（IS2B）工具是一种新型的、正在申请专利的设备，能够同时测定散装水和孔隙水中的污染物水平，迄今为止无法达到的低方法检测限（mdl）。部署时，管状IS2B装置的一半埋在沉积物中，另一半暴露在大量水中。集成的多通道泵同时将散装水和沉积物孔隙水吸入主动采样装置，并分别以高和低理想流速通过一系列过滤器和吸附介质。水样既可以储存在装置中，也可以随意排出到散装水中。由于在部署过程中可以无限制地接触孔隙水和散装水，因此IS2B工具可以为广泛的污染物提供超低的mdl，范围从完全水溶性到高度吸附和疏水。该功能将器件与目前可用的被动采样策略区分开来。目前正在利用以前三个SRP项目的专门知识来测试IS2B技术可以可靠地用于(i)取样散装和孔隙水污染物进行亚微克/分范围的分析，（ii）提供关于沉积物污染物的生物利用度和生物活性的信息，（iii）提供关于人类接触和食用鱼类带来的相关健康风险的信息，以及（iv）跟踪沉积物修复活动的进展情况。实验室和实地研究将对来自阿普卡湖的污染沉积物进行研究，阿普卡湖是佛罗里达州众多超级基金的所在地之一。为了说明IS2B适用性的广度，本项目集中于两种传统的和三种新兴的沉积物污染物（p,p'-DDE，狄氏剂与氟虫腈，三氯生，三氯卡班）。由于通过采样器数据建模预测的生物积累与实际的生物积累之间可能存在差异，污染物的生物利用度和生物积累将在实验室实验中通过测定两种测试生物的身体负荷来评估，这些生物分别是新鲜加药的和长期老化的污染沉积物。还将使用DNA微阵列分析来测量鱼类对污染物暴露的生物反应，以评估可能无法仅根据母体化合物的身体负担预测的影响。将根据理论和实验室数据制定散装水、孔隙水、蠕虫和鱼类中污染物浓度之间的数学关系，并将其应用于is2b衍生的数据，以预测风险并跟踪两种修复方法的有效性，即颗粒活性炭（GAC）修正和污染沉积物的深耕。

DESCRIPTION (provided by applicant): ABSTRACT This project introduces a novel strategy for bioavailability determination of sediment-borne contaminants featuring a wide range of chemical structures, properties and physical-chemical behaviors. The project addresses the pressing need of Superfund stakeholders to determine in a convenient and reliable fashion both human health risks from contaminated sediments and the effectiveness of implemented remediation strategies. The in situ sampling/bioavailability determination (IS2B) tool is a novel, patent-pending device enabling simultaneous determination of contaminant levels in bulk water and pore water at hitherto unattainably low method detection limits (MDLs). When deployed, one half of the tubular IS2B device is buried in sediment and the other is exposed to bulk water. Integrated multi-channel pumps simultaneously draw bulk water and sediment pore water into the active sampling device and push it at, respectively, high and low desirable flow rates through an array of filters and adsorption media. Water samples either can be stored in the device or expelled into the bulk water at will. Due to unlimited access to pore and bulk water during deployment, the IS2B tool provides ultra-low MDLs for a broad spectrum of contaminants, ranging from fully water-soluble to highly sorptive and hydrophobic. This functionality distinguishes the device from presently available passive sampling strategies. Know-how from three previous SRP projects is being leveraged to test the working hypothesis that the IS2B technology can serve to reliably (i) sample bulk and pore water pollutants for analysis in the sub-ng/L range, (ii) inform on the bioavailability and bioactivity of sediment contaminants, (iii) inform on human exposures and associated health risks from fish consumption, and (iv) track the progress of sediment remediation activities. Laboratory and field studies will be conducted with contaminated sediments from Lake Apopka, home to one of Florida's various Superfund sites. To illustrate the breadth of IS2B applicability, this project concentrates on two traditional and three emerging sediment contaminants (p,p'-DDE, dieldrin versus fipronil, triclosan, triclocarban). Because there may be discrepancies between the bioaccumulation predicted via modeling from sampler data and actual bioaccumulation, bioavailability and bioaccumulation of pollutants will be assessed in lab experiments with freshly spiked and long-term aged contaminated sediments via determination of body burdens in two test organisms: Lumbriculus variegatus and Pimephales promelas. Biological responses to contaminant exposure will also be measured in fish using DNA microarray analysis to evaluate effects that may not be predicted solely based on body burden of parent compounds. Mathematical relationships between pollutant concentrations in bulk water, pore water, worms and fish will be formulated from theory and lab data, and applied to IS2B-derived data to predict risk and track the effectiveness of two remediation approaches, granular activated carbon (GAC) amendment and deep tilling of contaminated sediment. PUBLIC HEALTH RELEVANCE: Project Narrative This research project addresses the pressing need for better monitoring of toxicant bioavailability in contaminated sediments by introducing the in situ sampling/bioavailability determination (IS2B) approach. The proposed device and mathematical model will inform risk assessment for environmental management for Superfund and other hazardous waste sites.