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.

环境基质中污染物的总浓度并不能预测潜在的不利生态或公共健康影响。引入环境中的污染物会经历各种反应，降低其活性，从而降低目标生物体的生物利用度。这些反应包括吸附到颗粒上或颗粒内、与碎屑有机物络合、或作为不溶性络合物沉淀。从决策的角度来看，需要能够确定样品中可分配到目标受体的污染物的比例。这显然对于真正估计污染物对给定生态系统的影响是必要的。目前检查生物利用度的技术涉及在实验室环境中进行严格的分析分离。这些方法可能非常耗时，并且可能会受到采样和分析过程中样品条件改变而引入的伪影的影响。该提案的目标是开发和现场测试采样装置，以确定水生沉积物中金属和有机污染物的自由活动（而不是总浓度）。采样器的基本前提是引入对感兴趣的污染物具有已知热力学亲和力的固体或液体基质。污染物分配到基质上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性和原始样品的特定环境因素。这些采样器可用于进一步检查控制环境中污染物的活性和生物利用度的特定环境因素。半透膜装置 (SPMD) 将用于在实验室和现场条件下检查沉积 PAH 的生物利用度。要测试的主要假设是，来自碳氢化合物燃烧的烟灰相碳（除了总有机碳）的存在将改变多环芳烃的分配，使得来自燃烧源的多环芳烃的热解混合物的生物利用度低于相似浓度的多环芳烃。石油泄漏产生的多环芳烃的石油混合物。对于金属污染物，将构建固定有 8-羟基喹啉的硅胶板来采样游离金属离子，以测试金属浓度的游离离子浓度来自硫化物和总有机碳浓度的假设。