Assessing Inhalation Exposure to Aerosolized Contaminants from Drinking Water

1605355 Dietrich该拟议项目填补了关于人类在空气-水-人界面接触超声波加湿器排放的气溶胶污染物的关键知识空白。通常，消费者购买超声波加湿器，用饮用水填充它们，并每天在卧室等密闭空间中使用它们几个小时。超声波加湿器产生的吸入暴露信息将使科学家能够合理评估与饮用水中溶解的污染物相关的人类健康风险，并随后为消费者使用提供建议。超声波加湿器气雾剂组成的基本特征，现实生活条件下的命运和运输，以及婴儿，儿童和成人吸入暴露的倾向和导致的吸入剂量，这将是第一次评估空气-水-人界面的这一方面。描述气溶胶粒径-污染物浓度与室内表面气溶胶沉积模式之间的关系，将为气溶胶的健康效应提供新的数据和视角。该项目对人类健康具有影响，因为吸入雾化饮用水的暴露具有不确定性。实验研究有四个目标和研究由四个假设指导：1）使用粒度和级联冲击仪器，结合电感耦合等离子体质谱，全面表征加湿器气溶胶的大小，分布和无机化学成分的不同水质代表的现实饮用沃茨。假设1：无机污染物浓度是相同的，在所有的气溶胶颗粒大小为一个给定的水质。2)为了检查表面上的气溶胶沉积被确定为与加湿器的距离的函数，该加湿器位于现实的室内生活场景中。采样位置在湿化器羽流内部和外部。假设2：无机污染物浓度将以相似的空气浓度沉积在房间的所有位置。3)实验数据输入校准和验证USEPA风险室内空气质量模型，其首次应用于房间大小的超声波加湿器。假设3：使用本研究的实验数据，可以校准USEPA风险模型，以符合ASTM空气模型指南（1991年）。4)所获得的数据将使用USEPA风险模型来评估涉及婴儿、儿童和成人的许多实际暴露情景中人体吸入气溶胶污染物的暴露情况。假设4：室内空气模型证实，人体吸入超声波加湿器气溶胶中的无机污染物超过健康指南。将根据吸入暴露法规、现有剂量数据和地理上不同的水质对模型结果进行评价。PI和co-PI致力于发展学生在这个项目上的专业，道德，推广和研究准备。博士生和本科生将积极从代表性不足的群体中招募，正如参与该项目的教师多年来所做的那样。该项目将招募代表性不足的学生，并为他们提供教育，研究和专业经验，包括指导6-12年级的学生。学生研究人员将通过Water INTERFACE网站（https：//blogs.lt.vt.edu/water/）上的博客在整个地球仪上交流他们的结果，该网站由弗吉尼亚理工大学研究生院为水研究领域的教师和学生维护，并通过发表科学文章。

1605355DietrichThis proposed project fills a critical knowledge gap concerning human exposure, at the air-water-human interface, to contaminants from aerosols emitted by ultrasonic humidifiers. Typically, consumers purchase ultrasonic humidifiers, fill them with drinking water, and use them in confined spaces such as bedrooms for several hours per day. The resulting inhalation exposure information, from ultrasonic humidifiers, will allow scientists to reasonably assess the human health risks associated with dissolved contaminants in drinking water and subsequently offer recommendations for consumer use.The fundamental characterization of ultrasonic humidifier aerosol composition, fate and transport under realistic living conditions, and propensity for infant, child, and adult inhalation exposure and resulting inhaled dose, will be the first of its kind for assessing this aspect of the air-water-human interface. The description of the relationships between aerosol size - contaminant concentration and aerosol deposition patterns on room surfaces will provide new data and perspective for the health effects of aerosols. This project has implications for human health because of the uncertainty surrounding inhalation exposures from aerosolized drinking water. The experimental research has four objectives and the reseach is guided by four hypotheses: 1) To use particle size and cascade impactor instruments, in conjunction with inductively coupled plasma mass spectrometry, to comprehensively characterize humidifier aerosols in size, distribution, and inorganic chemical composition for varying water qualities representative of realistic drinking waters. Hypothesis 1: Inorganic contaminant concentrations are the same in all aerosol particle sizes for a given water quality. 2) To examine aerosol deposition on surfaces is determined as a function of distance from a humidifier which is situated in realistic indoor living scenario. Sampling locations are both within and outside the humidifier plume. Hypothesis 2: Inorganic contaminant concentrations will be deposited at similar aerial concentrations in all locations of the room. 3) The experimental data are inputs to calibrate and validate the USEPA RISK Indoor Air Quality model for its first application to room-sized ultrasonic humidifiers. Hypothesis 3: The USEPA RISK model can be calibrated to meet ASTM air modeling guidelines (1991) using the experimental data from this study. 4) The data obtained will use the USEPA RISK model to assess the human inhalation exposure to aerosolized contaminants for many realistic exposure scenarios involving infants, children, and adults. Hypothesis 4: The indoor air model confirms that human inhalation exposure to inorganic contaminants in ultrasonic humidifier aerosols exceed health guidelines. The model results will be evaluated with respect to inhalation exposure regulations, existing dose data, and geographically varying water quality. The PI and co-PIs are committed to developing the professional, ethical, outreach, and research preparation of students on this project. The PhD and undergraduate students will be actively recruited from underrepresented groups, as has been done for many years by the faculty involved in this project. This project will recruit underrepresented students and provide them educational, research, and professional experiences, including mentoring grade 6-12 students. The student researchers will communicate their results throughout the globe through blogs at the Water INTERface website (https://blogs.lt.vt.edu/water/), maintained by the Virginia Tech Graduate School for faculty and students in water research and though publication of scientific articles.