Acute And Chronic Health Effects From Lead In Drinking Water Of Schools And Day Care Facilities: Detection, Bio-Availability, And Predicted Impacts On Blood Lead

0933246爱德华兹美国目前有一个自愿计划，以确定，检测和减轻学校和日托中心饮用水中的铅问题。虽然传统观点认为学校用水中的铅几乎不会对健康造成危害，但认识上的巨大差距可能导致这一问题的严重性被低估。结合“最坏情况”的管道配置和水流模式，以及非常年幼的儿童的易感人群，使得对这个问题的详细评估是可取的。研究的三个阶段旨在解决最重要的问题。第一个审查学校饮用水中铅含量的关键方面，使用密集的采样活动，旨在统计表征水中铅的自然变异性。将对选定的“问题”水龙头进行类似的分析，这些水龙头已知至少以某种频率排放危险废物水平的铅。热水中的铅含量也将首次进行系统测试。采样协议的目的是确保没有“错过”的铅在水中，经常发生在使用传统的铅在水中的分析程序和指导。然后，将使用一系列分析技术，在法医学上将水中高铅的出现与特定的管道来源联系起来。第二阶段的工作是系统地评估铅的生物利用度。据推测，水中的铅颗粒不具有生物可利用性，对健康的危害很小，但另一方面，最近发生的几起儿童铅中毒事件无疑与水中存在小颗粒的铅焊料有关。来自学校水中的颗粒铅样品将暴露于一系列具有代表性的模拟胃酸、搅拌条件和胃滞留时间。将根据存在的铅颗粒的粒度和类型跟踪样品中的铅溶解。还将进行测试，以检查在烹饪过程中，水中的颗粒铅到面食的分配，以及胃酸中微量还原剂在使颗粒铅或多或少生物可利用性方面的作用。这项基础研究以前没有进行过铅颗粒来自真实的饮用沃茨。最后，将利用生物动力学模型，其中包括前两个阶段的研究结果，以评估一系列现实的接触情景，根据这些情景，儿童在学校可能会接触到水中的铅。先前的建模工作明显偏向于低估可能因暴露于铅污染的饮用水而导致的血铅升高。这项建模工作将是第一个：1）考虑急性和慢性健康风险，2）评估使用热水制作速溶婴儿配方奶粉，汤和茶的潜在危害（据怀疑热水中的铅通常比冷水中的铅多得多），以及3）确定在受污染的水中烹饪的食物中铅的可能贡献。这项研究工作是弗吉尼亚理工大学，儿童？美国国家医疗中心（CNMC），健康家庭联盟，无毒替代品家长，以及一个由关心的家长和高中学生/教师组成的网络。研究结果将用于考虑用于控制和减轻学校和家庭饮用水中铅危害的现有方法的保护性。我们没有资金的初步努力已经产生了显著的效果，华盛顿州和加拿大采取了更严格的标准，并重新评估了2001-2007年期间华盛顿特区高铅水对儿童血铅的影响，就证明了这一点。这些初步的成功，跨学科的方法和明确的公共卫生影响支持了研究的必要性。

0933246 EdwardsThe United States currently has a voluntary program to identify, detect and mitigate problems with lead in drinking water of schools and day care centers. Although the conventional wisdom is that lead in school water poses little health risk, substantive gaps in understanding may have caused the magnitude of this problem to be underestimated. The combination of "worst case" plumbing configurations and water flow patterns, and susceptible populations of very young children, makes a detailed evaluation of this issue desirable. Three phases of research are directed at resolving the most important issues. The first examines key aspects of lead occurrence in potable water of schools using intensive sampling events designed to statistically characterize the natural variability of lead in water. A similar analysis will be conducted for selected "problem" taps that are known to dispense hazardous waste levels of lead with at least some frequency. The level of lead in hot water will also be systematically tested for the first time. Sampling protocols are designed to ensure that none of the lead in water is "missed", as often occurs when using conventional lead in water analytical procedures and guidance. The occurrence of high lead in water will then be forensically linked to specific plumbing sources using an array of analytical techniques. The second phase of work systematically evaluates the bioavailability of the lead. It has been speculated that the particulate lead in water is not bioavailable and poses little health risk, but on the other hand several recent cases of lead poisoning for children were unambiguously tied to the presence of small particles of lead solder in the water. Samples of particulate lead from water of schools will be exposed to a range of representative simulated gastric acids, churn conditions, and stomach retention times. Lead dissolution will be tracked in samples as a function of particle size and type of lead particle present. Tests will also be conducted to examine partitioning of particulate lead in water to pasta during cooking, and the role of trace reducing agents in gastric acid in rendering particulate lead more or less bioavailable. This fundamental research has not been previously conducted for lead particulates derived from real drinking waters. Finally, bio-kinetic models will be utilized that incorporate results of the first two phases of research, in order to evaluate a range of realistic exposure scenarios by which children might be exposed to lead in water while in schools. Prior modeling efforts were significantly biased towards underestimating the elevation in blood lead that might result from exposure to lead contaminated drinking water. This modeling work will be the first to: 1) consider acute as well as chronic health risks, 2) evaluate the potential hazard that arises from use of hot water for instant infant formula, soups, and tea (it is suspected that there is often much more lead in hot water than cold water), and 3) determine the possible contribution of lead in foods cooked in contaminated water. This research work is a collaborative effort between Virginia Tech, the Children?s National Medical Center (CNMC), the Alliance for Healthy Homes, Parents for Non-toxic Alternatives, and a network of concerned parents and high school students/teachers. Results will be used in considering the protectiveness of existing approaches that are used to control and mitigate lead hazards in potable water of schools and homes. Our unfunded preliminary efforts have already had a significant effect, as evidenced by tougher standards in the State of Washington and in Canada, and through a re-evaluation of effects of high lead in water on blood lead of children in Washington D.C. from 2001-2007. These initial successes, interdisciplinary approach, and clear public health implications support the need for the research.