Exploring Coupled Physical, Biological and Chemical Processes that Control Lead Fate and Transport through Plastic Plumbing Materials

在美国，饮用水中的铅污染是一个严重的公共卫生问题。由于即使是低水平的铅暴露也会导致儿童的神经损伤和学习障碍，美国环保局将饮用水中铅的最高污染物水平目标定为零。饮用水中的铅主要来自含铅管道和管道装置的腐蚀。塑料管越来越多地被用来取代老化的水管，以最大限度地减少和消除铅污染。尽管人们普遍认为塑料供水管道是惰性的，但最近的研究证实，塑料管道可以与水中的铅发生反应。然而，铅在塑料管上的吸附和释放机制却知之甚少。本研究的目的是加深我们对塑料给水管道对铅的吸附和释放的了解。为了实现这一目标，研究小组将表征铅从高密度聚乙烯(HDPE)和交联型聚乙烯(PEX)管道中吸附和释放到饮用水中的程度、速度和机制。这个项目的成功完成将加深我们对铅构成的风险的了解，并有助于将饮用水中铅的释放降至最低。将通过在大学一级进行STEM教育和培训以及通过向K-12学生推广STEM来进一步造福社会，从而提高国家的科学素养。饮用水分配系统中细菌生物膜的形成和生长是一个主要的健康问题。虽然生物膜对金属水管腐蚀释放铅的影响已被大量研究，但生物膜对塑料水管吸附和释放铅的影响在很大程度上被忽视。这个问题之所以令人担忧，是因为塑料管可能比金属管更容易形成生物膜。本研究的目的是研究HDPE和PEX塑料给水系统对铅的吸附和释放的物理、化学和生物机制。为了实现这一目标，研究小组将：i)调查生物膜结构和水流对HDPE和PEX管道上铅的吸附程度和动力学的影响；ii)检测不同水化学成分和流动条件下生物膜结构对塑料管道中铅的解吸和释放的作用；iii)将基因组分析与生物信息学和机器学习相结合，通过评估供水管道生物膜中的微生物基因表达谱，确定可用于检测铅污染特征的生物标志物基因。这项研究的成功完成将填补我们对塑料管在铅吸收中所起作用的认识上的重大空白。这一新知识将有助于为控制铅沉积到饮用水分配管道和从饮用水分配管道释放铅的努力提供信息。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Lead contamination in drinking water is a serious public health concern in the United States. Because even low levels of lead exposure can cause neurological damage and learning disabilities in children, the U.S. EPA has set the maximum contaminant level goal for lead in drinking water at zero. Lead in drinking water originates predominantly from the corrosion of lead-bearing pipes and plumbing fixtures. Plastic pipes are increasingly being utilized to replace aging water pipes to minimize and eliminate lead contamination. Despite the commonly held assumption that plastic water distribution pipes are inert, recent research has established that plastic pipes can react with lead in water. However, the mechanisms of lead sorption onto and release from plastic pipes are poorly understood. The goal of this research is to advance our understanding of the sorption and release of lead by plastic water distribution pipes. To achieve this goal, the research team will characterize the extent, rate, and mechanisms of lead sorption and release from high-density polyethylene (HDPE) and crosslinked polyethylene (PEX) pipes into drinking water. Successful completion of this project will further our understanding of the risk posed by lead and help minimize the release of lead in drinking water. Further benefits to society will be achieved through STEM education and training at the college level and through outreach to K-12 students, thus increasing the scientific literacy of the nation.The formation and growth of bacterial biofilms in drinking water distribution systems is a major health concern. While significant research has been devoted to the effect of biofilms on the release of lead via corrosion of metallic water pipes, the impact of biofilms on lead sorption and release by plastic water pipes has largely been overlooked. This issue is concerning in light of the fact that plastic pipes may be more susceptible to biofilm development than metallic pipes. The goal of this research is to investigate the physical, chemical, and biological mechanisms of lead sorption and release by HDPE and PEX plastic water distribution systems. To achieve this goal, the research team will: i) investigate the role of biofilm structure and water flow on lead sorption extent and kinetics onto HDPE and PEX pipes; ii) examine the role of biofilm structure on lead desorption and release from plastic pipes under varying water chemical composition and flow conditions; and iii) combine genomic assays with bioinformatics and machine learning to identify biomarker genes that could be used to detect lead contamination signatures via the evaluation of microbial gene expression profiles in water pipe biofilms. Successful completion of this research will address significant gaps in our knowledge on the role plastic pipes play in lead sorption. This new knowledge will help inform efforts to control lead deposition onto and release from drinking water distribution pipes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.