Development & application of methods to determine bioavailability

发展

• 批准号: 6443910
• 负责人: James P Shine
• 金额: $ 19.7万
• 依托单位: HARVARD SCHOOL OF PUBLIC HEALTH
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至 2002-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6443910
• 关键词: carbopolycyclic compound; chemical kinetics; environmental contamination; environmental exposure; environmental health; environmental toxicology; environmental transport; hazardous substances; metal metabolism; method development; toxin metabolism; water sampling /testing

The total concentration of contaminants in an environmental matrix is not predictive of the potential for adverse ecological or public health effects. Contaminants introduced in the environment undergo a variety of reactions that reduce their activity and thus their bioavailability to target organisms. These reactions include sorption onto or into particles, complexation with detrital organic matter, or precipitation as insoluble complexes. What is needed from a decision making standpoint is an ability to determine the fraction of contaminants in a sample available for partitioning into target receptors. This is obviously necessary to truly estimate the effects contaminants will have a given ecosystem. Current techniques to examine bioavailability involve rigorous analytical separations in a laboratory setting. These methods can be time consuming, and potentially suffer from artifacts introduced through alteration of sample conditions during sampling and analysis. The goal of this proposal is to develop and field test sampling devices that determine the free activity (as opposed to the total concentration) of metal and organic contaminants in the aquatic sediments. The basis premise of the samplers is to introduce a solid or liquid substrate with a known thermodynamic affinity for a contaminant of interest. The extent of contaminant partitioning to the substrate can be used to determine the contaminant's activity in the original sample. These samplers can be used to further examine specific environmental factors that control the activity and original sample. These samplers an be used to further examine specific environmental factors that control the activity and bioavailability of contaminants in the environment. Semipermeable membrane devices (SPMDs) will be used to examine the bioavailability of sedimentary PAHs under both laboratory and field conditions. The primary hypothesis to be tested is that the presence of soot phase carbon (in addition to total organic carbon) from hydrocarbon combustion will alter the partitioning of PAHs such that a pyrogenic mixture of PAH's from combustion sources will be less bioavailable than a similar concentration of a petrogenic mixture of PAH's arising from oil spills. For metal contaminants, a silica plate with immobilized 8-Hydroxyquinoline that samples free metal ions will be constructed to test the hypothesis that the free ion concentration of metal concentrations from the sulfide and total organic carbon concentrations.

环境矩阵中污染物的总浓度不能预测不利生态或公共卫生影响的潜力。在环境中引入的污染物经历了各种反应，以减少其活性，从而降低其对靶向生物的生物利用度。这些反应包括吸附或进入颗粒中，与碎屑有机物的络合或作为不溶性复合物的沉淀。从决策的角度来看，需要确定可用于分配到目标受体的样品中污染物的比例。显然，这是真正估计污染物具有给定生态系统的效果的必要条件。当前检查生物利用度的技术涉及实验室环境中的严格分析分离。这些方法可能很耗时，并可能遭受通过在抽样和分析过程中样本条件改变引入的伪影。该提案的目的是开发和现场测试采样设备，这些设备确定水生沉积物中金属和有机污染物的游离活性（与总浓度相反）。采样器的基础前提是引入具有已知热力学亲和力的固体或液体底物，以造成感兴趣的污染物。污染分配给基材的程度可用于确定原始样品中污染物的活性。这些采样器可用于进一步检查控制活动和原始样本的特定环境因素。这些采样器可用于进一步检查控制环境中污染物活性和生物利用度的特定环境因素。可半透明的膜设备（SPMD）将用于检查实验室和野外条件下沉积PAH的生物利用度。要测试的主要假设是，碳氢化合物燃烧的烟灰相碳（除总有机碳之外）的存在将改变PAH的分配，从而使PAH的充气混合物从燃烧来源中的生物利用较少，而不是类似的生物利用，而不是类似的浓度。对于金属污染物，将构建带有固定的8-羟基喹啉的二氧化硅板，将构建游离金属离子的样品，以检验以下假设：硫化物和总有机碳浓度的金属浓度的自由离子浓度。