Collaborative Research: Phthalate Plasticizers: Temperature Dependence of Material/Air Equilibria and Consequences for Emissions, Exposure and Risk

项目负责人：John Little / Ying xu42提案编号：CBET-1066802 / 1066642机构：弗吉尼亚理工大学/德克萨斯大学奥斯汀分校标题：合作研究：邻苯二甲酸酯增塑剂：材料/空气平衡的温度依赖性以及排放，暴露和风险的后果现代室内环境包含大量制造材料，其中许多排放有毒污染物。特别值得关注的是，近几十年来，室内邻苯二甲酸酯增塑剂的含量大幅增加。这些半挥发性有机化合物（SVOCs）增强了产品的性能，并且无处不在，从其原始来源重新分布到室内空气中，然后再分布到所有室内表面。由于它们在表面上的分裂非常强烈，许多SVOCs在源被移除后仍然存在数年。生物监测（测量血液和尿液中的浓度）提供了直接证据，表明人类几乎普遍接触增塑剂，这可能导致生殖道发育发生深刻和不可逆转的变化。美国国家科学院最近的一份报告紧急建议确定邻苯二甲酸盐暴露的最重要来源。虽然仅靠生物监测无法提供这个答案，但pi已经开发并验证了一种基本方法，可用于确定最重要的塑化剂暴露源。基于这一有希望的概念飞跃，他们的研究目标是：(1)根据材料中存在的不同邻苯二甲酸盐的测量浓度（C0）选择几种室内聚氯乙烯产品（PVCPs）；(2)开发一种新的、直接的固相微萃取（SPME）方法来测量与C0平衡的气相浓度（y0），并使用所得的C0 vs y0数据来建立作为温度函数的平衡关系的性质；(3)表征所选pvcp中9种目标邻苯二甲酸酯的排放特征，并在一定温度范围内的室内实验中验证其新邻苯二甲酸酯的排放模型；(4)扩展室法，以同时测量两个邻苯二甲酸盐源的排放（每一种材料都充当另一种材料的邻苯二甲酸盐汇）；(5)在控制条件下测试温度对车辆邻苯二甲酸盐排放、吸附和冷凝的影响，并与类似室内研究结果进行比较；(6)使用测量/预测的y0值来估计所研究的整个pvcp范围的筛查水平暴露，并将暴露与ToxCast的毒性结合起来？获取风险，为快速确定对人体健康危害最大的室内污染源提供简单方法。本研究建立在首次成功阐明从高分子材料中释放邻苯二甲酸盐的基本机制的基础上。pi将首次开发一种创新的新的SPME方法来测量y0；建立C0和y0随温度的平衡关系；并测试温度对汽车和家庭中邻苯二甲酸盐排放和吸收的影响。当阳光直接照射在房间或汽车的PVCP表面时，温度效应可能具有重要意义，从而使排放率增加几个数量级。当一个人进入一辆炎热的汽车，在不打开窗户的情况下打开空调时，冷却的邻苯二甲酸盐蒸汽会凝结，在包括人体皮肤在内的内部表面涂上一层薄薄的液态邻苯二甲酸盐薄膜，这可能会对健康造成重大威胁。PIs还将开发一种强大而简单的pvcp筛选水平暴露评估方法，并大大提高我们预测所有邻苯二甲酸酯增塑剂暴露（通过吸入，皮肤吸收和口服灰尘摄入）的能力。他们预测pvcp中邻苯二甲酸盐暴露的基本方法几乎可以肯定地推广到从家庭、汽车、学校、办公室和工厂中发现的大量材料和产品中排放的其他SVOCs（多溴二苯醚、有机化合物和杀虫剂）。新的机械理解将使绿色材料的有意识设计成为可能，因为控制排放的化学和材料特性被清楚地理解了。多样性将通过他们的ACE（实验学分）计划以及与三所hbcu同事的个人关系来灌输。弗吉尼亚理工大学的ACE本科生将评估他们在自己家中接触到的一些pvcp，从而识别进入市场的新的含邻苯二甲酸酯的pvcp以及一些“遗留”的pvcp。不再生产的产品。鉴于大多数pvcp几十年来都在排放邻苯二甲酸盐，这是该项目的一个重要方面。德州大学奥斯汀分校的本科生将参与第一次汽车舱室温度控制测试。他们用于估计筛查水平健康风险的方法可用于优先考虑具有成本效益的行动，并可能彻底改变如何评估室内材料对人类健康的影响。

PIs: John Little / Ying XuProposal Numbers: CBET-1066802 / 1066642Institutions: Virginia Tech / Univ. of Texas-AustinTitle: Collaborative Research: Phthalate Plasticizers: Temperature Dependence of Material/Air Equilibria and Consequences for Emissions, Exposure and RiskModern indoor environments contain a vast array of manufactured materials, many of which emit toxic contaminants. Of special concern are indoor levels of phthalate plasticizers, which have increased substantially in recent decades. These semi-volatile organic compounds (SVOCs) enhance product performance, and are ubiquitous, redistributing from their original sources to indoor air, and subsequently to all interior surfaces. Because they partition so strongly to surfaces, many SVOCs persist for years after the source is removed. Biomonitoring (measuring concentrations in blood and urine) provides direct evidence of the virtually universal human exposure to plasticizers, which may result in profound and irreversible changes in the development of the reproductive tract. A recent report by the National Academies urgently recommends that the most important sources of phthalate exposure be identified. While biomonitoring alone cannot provide this answer, the PIs have developed and validated a fundamental approach that can be used to identify the most important sources of exposure to plasticizers. Building on this promising conceptual leap in understanding, their research objectives are to: (1) Select several indoor polyvinyl chloride products (PVCPs) based on the measured concentration of different phthalates present in the materials (C0); (2) Develop a novel, direct, solid-phase microextraction (SPME) method to measure (y0) the gas-phase concentration in equilibrium with C0, and use the resulting C0 vs y0 data to establish the nature of the equilibrium relationship as a function of temperature; (3) Characterize emissions of the target phthalates from nine of the selected PVCPs and validate their emissions model for the new phthalates in chamber experiments over a range of temperatures; (4) Extend the chamber approach to simultaneously measure emissions from two sources of phthalates (with each material acting as a sink for the phthalate from the other material); (5) Test the effect of temperature on phthalate emissions, sorption and condensation in vehicles under controlled conditions, and compare the results with analogous chamber studies; and (6) Use the measured/predicted y0 values to estimate screening-level exposure for the entire range of PVCPs studied and combine exposure with toxicity from ToxCast? to get risk, providing a simple method for the rapid prioritization of indoor sources most harmful to human health. This research builds on the first successful elucidation of the fundamental mechanisms governing the release of phthalates from polymer materials. The PIs will, for the first time, develop an innovative new SPME method to measure y0; establish the equilibrium relationship between C0 and y0 as a function of temperature; and test the temperature effect on phthalate emissions and sorption in cars and homes. The temperature effect could be of great significance when sunlight shines directly on a PVCP surface in a room or car, increasing the emission rate by orders of magnitude. When a person enters a hot car and turns on the air conditioning without opening the windows, the cooling phthalate vapor will condense, coating interior surfaces, including human skin, with a thin film of liquid phthalate, imposing potentially significant health risks. The PIs also will develop a powerful yet simple screening-level exposure assessment approach for PVCPs, and substantially enhance our ability to predict exposure (via inhalation, dermal sorption and oral ingestion of dust) to all phthalate plasticizers. Their fundamental approach to predict exposure to phthalates in PVCPs can almost certainly be generalized to a wide range of other SVOCs (PBDEs, organotins, and pesticides) emitted from a host of materials and products found in homes, cars, schools, offices, and factories. The new mechanistic understanding will enable the conscious design of green materials because the chemical and material properties that govern emissions are clearly understood. Diversity will be inculcated through their ACE (Academic Credit for Experimentation) program, as well as through personal relationships with colleagues at three HBCUs. The undergraduate ACE students at Virginia Tech will estimate exposure to some of the PVCPs in their own homes, enabling identification of new phthalate-laden PVCPs entering the market as well as some of the ?legacy? products that are no longer produced. Given that most PVCPs emit phthalates for decades, this constitutes a vital aspect of the project. The undergraduate students at UT Austin will be engaged in the first temperature controlled tests of automobile cabins. Their approach for estimating screening-level health risks can be used to prioritize cost-effective action, and could revolutionize how human health effects of indoor materials are evaluated.