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

PIS：John Little/Ying Xu Proposal编号：CBET-1066802/1066642院校：弗吉尼亚理工大学得克萨斯大学奥斯汀分校：合作研究：邻苯二甲酸酯增塑剂：材料/空气平衡的温度依赖关系以及排放、暴露和风险的后果现代室内环境包含大量的人造材料，其中许多会释放有毒污染物。特别令人关注的是邻苯二甲酸酯增塑剂的室内水平，近几十年来大幅增加。这些半挥发性有机化合物(SVOC)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，然后再分布到所有室内表面。由于它们对表面的分割非常强烈，许多SVOC在源被移除后会持续数年。生物监测(测量血液和尿液中的浓度)提供了几乎普遍的人类接触增塑剂的直接证据，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接触的最重要来源。虽然生物监测本身不能提供这个答案，但私人投资机构已经开发和验证了一种基本方法，可以用来确定最重要的塑化剂暴露来源。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(C0)中不同邻苯二甲酸酯的测量浓度，选择几种室内聚氯乙烯产品(PVCP)；(2)开发一种新的、直接的固相微萃取(SPME)方法，测量(Y0)与C0平衡的气相浓度，并使用得到的C0与Y0的数据来建立作为温度函数的平衡关系的性质；(3)表征九种选定聚氯乙烯的目标邻苯二甲酸酯的排放，并在室内实验中验证它们在一定温度范围内的新型邻苯二甲酸酯的排放模型；(4)扩展小室方法以同时测量两种来源的邻苯二甲酸盐的排放(每种材料充当来自另一种材料的邻苯二甲酸盐的水槽)；(5)在受控条件下测试车辆中温度对邻苯二甲酸盐排放、吸附和冷凝的影响，并将结果与类似的室内研究进行比较；以及(6)使用测量/预测的Y0值来估计所研究的整个范围的聚氯乙烯的筛查水平暴露量，并结合ToxCast的毒性暴露量？以获得风险，为快速确定对人类健康最有害的室内来源的优先顺序提供了一种简单的方法。这项研究建立在首次成功阐明控制邻苯二甲酸酯从聚合物材料中释放的基本机制的基础上。PIS将首次开发一种创新的SPME方法来测量Y0；建立作为温度函数的C0和Y0之间的平衡关系；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。当阳光直接照射到房间或汽车中的PVCP表面时，温度效应可能会非常重要，从而使发射率增加数量级。当一个人进入一辆炎热的汽车，在没有打开车窗的情况下打开空调时，降温的邻苯二甲酸盐蒸气会凝结，在包括人体皮肤在内的内部表面覆盖一层薄薄的液体邻苯二甲酸盐，可能会带来重大的健康风险。PIS还将为PVCP开发一种强大而简单的筛查级暴露评估方法，并极大地提高我们预测所有邻苯二甲酸酯增塑剂的暴露(通过吸入、皮肤吸收和口服粉尘)的能力。他们预测PVCP中邻苯二甲酸盐暴露的基本方法几乎肯定可以推广到家庭、汽车、学校、办公室和工厂中发现的大量材料和产品排放的广泛其他SVOCs(多溴二苯醚、有机锡和杀虫剂)。新的机械论理解将使绿色材料的有意识的设计成为可能，因为控制排放的化学和材料属性被清楚地理解了。多样性将通过他们的ACE(实验学术学分)计划以及通过与三个HBCU的同事的个人关系来灌输。弗吉尼亚理工大学的ACE本科生将估计自己家中接触到的一些聚氯乙烯，从而能够识别进入市场的新的邻苯二甲酸盐聚氯乙烯以及一些遗留下来的？不再生产的产品。鉴于大多数聚氯乙烯排放邻苯二甲酸盐长达数十年，这构成了该项目的一个重要方面。德克萨斯大学奥斯汀分校的本科生将进行汽车驾驶室的第一次温度控制测试。他们估计筛查水平健康风险的方法可以用来确定成本效益行动的优先顺序，并可能彻底改变室内材料对人类健康影响的评估方式。

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.