Combining bioavailability assays with modeling to predict PCBs in fish after reme

描述（由申请人提供）：多氯联苯等生物蓄积性污染物对生态和人类健康的影响主要表现为有毒化合物在高营养级生物（如人类和生态系统中的顶级捕食者食用的鱼类）中的积累。然而，由于补救措施的结果，鱼类的变化是缓慢显现的，人们往往要等上几年才能看到这种变化。为了及时评估补救进展，一种替代办法是进行适当的测量，以表明暴露于鱼类的关键途径的变化。虽然最近在利用被动取样技术评估孔隙水浓度方面取得了一些进展，这种技术对原位补救措施反应更快，但这种措施与鱼类积累的关系尚未得到证实。此外，在命运和生物吸收模型的开发和利用方面也存在重大差距，这些模型可以使用被动采样测量，并在数量上将这些测量与吸收途径联系起来，并预测鱼类浓度的最终变化。这个拟议的研究项目将改进采样方法，以评估多氯联苯的吸收途径，并与从业人员合作，将这些措施纳入多氯联苯的命运和生物吸收模型，以评估鱼类浓度随时间的变化，并通过受控的实验室暴露研究和实地测量来验证该方法。该项目的三个主要目标是：具体目标1：发展被动采样的基本基础。本研究将使用先进的荧光显微镜、红外微光谱学和切片技术，直接测量有机分子在常用被动取样材料（聚乙烯、聚甲醛和PDMS）中的扩散。这一努力将导致选择和使用适当的聚合物材料进行被动平衡取样，对暴露期间达到的平衡性质有更大的信心。具体目标2：使用被动采样来测量鱼类的生物利用度过程和吸收。本研究旨在通过受控的实验室中观研究，评估在野外用活性炭吸附剂改性的沉积物如何影响两种鱼类对多氯联苯的生物吸收，并与在目标1下开发的被动采样装置中的吸收进行比较。具体目标3：将被动采样输入纳入PCB命运和生物积累模型。本文将建立一个数学模型，用于解释以下结果：1)中观环境暴露实验；2)多氯联苯污染河流现场观测，探讨活性炭处理对鱼类多氯联苯积累的影响。特别感兴趣的是提高模型预测的准确性，预测活性炭原位处理的好处，旨在降低孔隙水浓度和污染物的生物利用度。

DESCRIPTION (provided by applicant): Ecological and human health impacts of bioaccumulative contaminants like PCBs are primarily manifested through accumulation of the toxic compounds in higher trophic level organisms like fish that are consumed by humans and top predators in the ecosystem. However, changes in fish are slow to manifest as a consequence of a remedial action and often one has to wait for several years to see such change. To make timely assessments of remediation progress, one alternative is to perform appropriate measurements that indicate changes in key pathways of exposure to fish. Although some advances have been made recently to assess porewater concentrations using passive sampling techniques which respond more rapidly to in-situ remedies, relationship of such measures to accumulation is fish has not been demonstrated. Also, there is a major gap in the development and utilization of fate and biouptake models that can use passive sampling measurements and quantitatively link those measurements to uptake pathways and predict eventual changes in fish concentrations. This proposed research project will refine sampling methods to assess PCB uptake pathways and work with practitioners to incorporate such measures into PCB fate and biouptake models to assess changes in fish concentration over time, and validate the approach through controlled laboratory exposure studies and measurements in the field. The three primary aims of this project are: Specific aim 1: Develop the fundamental basis of passive sampling. This research will use advanced fluorescence microscopy, IR microspectroscopy, and sectioning techniques to directly measure the diffusion of organic molecules in commonly used passive sampler materials (polyethylene, polyoxymethylene, and PDMS). This effort will lead to the selection and use of appropriate polymeric materials for passive equilibrium sampling with much greater confidence about the nature of equilibrium achieved during the exposure period. Specific aim 2: Use passive sampling to measure bioavailability processes and uptake in fish. This research aim will evaluate how sediments amended with activated carbon sorbents in the field impact PCB biouptake in two types of fish through controlled laboratory mesocosm studies and compare with uptake in passive sampling devices developed under Aim 1. Specific aim 3: Incorporate passive sampling inputs to PCB fate and bioaccumulation model. A mathematical model will be developed and used to interpret results from: 1) the mesocosm exposure experiments, and 2) field observations from a PCB-impacted river site to explore the effect of activated carbon treatments on PCB accumulation in fish. Of particular interest is improving the accuracy of model predictions of the benefits of in-situ treatment with activated carbon aimed at reducing pore water concentrations and contaminant bioavailability. PUBLIC HEALTH RELEVANCE: This research will advance the assessment of remediation effectiveness at Superfund sediment sites through a combination of improving the science of passive sampling, experimentally establishing the link between passive sampling measurement and human health risk drivers such as contaminants in fish, and developing and testing contaminant fate and bioaccumulation models that can use passive sampling measurements for decision making. The teaming of academic researchers with a leading expert and field practitioner affords this project an unique practical perspective and natural translation of the outcome to end users.