Elucidating drinking water quality deterioration in premise plumbing

住宅管道是与私人或公共建筑(如家庭、学校)相关的供水系统的一部分。与主配水系统相比，住宅管道系统具有独特的特点，使其更容易受到水质恶化的影响，例如停滞期更长，表面积与体积比更高，以及温度升高。房屋自来水的水质也不受大多数监管制度的监督。由于优先考虑用水和提高管道装置的效率，水龄的增加增加了因氯衰变而导致水质退化的风险，以及由此导致的表面附着微生物群落(生物膜)的繁盛。有明确的证据表明，与传统建筑相比，节水型建筑可以支持10-10000倍的机会性病原体。此外，美国估计有8%的水源性疫情(不包括军团菌)与场所管道缺陷有关，基于场所管道的疫情所占比例正在增加。除了微生物风险，前提管道也被暗示为化学或生物膜介导的沉积物中无机污染物积累的场所。累积的无机物，如砷(致癌物质)、铅(铅)和锰(神经毒素)，构成了对公众健康的威胁，因为这些毒素一旦积累在表面，就会释放到水中。尽管前提管道在控制无机水质恶化方面具有重要作用，但它并不是受控实验室研究的重点。目前尚不清楚管道材料、延长的滞留时间和节水配置如何影响无机污染物的积累和释放。这一独特的研究计划将识别、表征和探索控制室内卫浴中无机污染物(如As、Pb、Mn)积累和释放的潜在生物和化学机制。TEN HQP将在一个跨学科的环境中进行培训，并通过三个相互关联的目标来探索这些机制，这三个目标将检查i)管道材料的影响；ii)停滞/水龄的作用，包括模拟节水建筑的低流量条件；以及iii)上游水质和平衡变化的影响。这项研究计划将提供对无机物积累和释放的特定生物和化学机制(例如，金属结合的关键官能团；金属表面沉积结构和特征)的基本机械见解。这项研究产生的新知识将解释控制室内管道中无机污染物积累/释放的潜在机制和环境条件，为加拿大和全球的监管机构和公用事业公司提供新的装备，以做出合理的循证决策，将暴露风险降至最低，并保护公众健康。

Premise plumbing is the portion of the water distribution system associated with private or public buildings (e.g. homes, schools). Compared to the main distribution system, premise plumbing has unique features that make it more vulnerable to water quality deterioration, such as longer stagnation periods, higher surface area to volume ratios, and elevated temperatures. Premise plumbing water quality is also unmonitored by most regulatory regimes. Increased water age, a result of water conservation priorities and improved plumbing fixture efficiency, heightens the risk of water quality degradation due to chlorine decays and the resultant flourishing of surface attached microbial communities (biofilm). There is clear evidence that water-efficient buildings can support 10-10000 times more opportunistic pathogens relative to conventional buildings. Further, an estimated 8% of waterborne outbreaks (excluding Legionella) in the USA are associated with premise plumbing deficiencies, and the proportion of premise plumbing based outbreaks is increasing. Beyond the microbiological risk, premise plumbing has also been implied as a site for inorganic contaminant accumulation in both chemically or biofilm mediated deposits. Accumulated inorganics, such as arsenic (As) (carcinogen), lead (Pb) and manganese (Mn) (neurotoxins), represent a public health threat given that once accumulated on a surface, these toxins can be released into the water. Although premise plumbing is implied to have a significant role in governing inorganic water quality deterioration, it has not been the focus of controlled laboratory study. It is unclear how pipe materials, extended stagnation times, and water efficient configurations influence the accumulation and release of inorganic contaminants. This unique research program will identify, characterize, and explore the underlying biological and chemical mechanisms that govern the accumulation and release of inorganic contaminants (e.g. As, Pb, Mn) in premise plumbing. Ten HQP will train in an interdisciplinary environment and explore these mechanisms through three interrelated objectives that will examine i) the influence of pipe materials; ii) the role of stagnation/water age, including mimicking low flow conditions of water-efficient buildings; and, iii) the impact of upstream water quality and equilibrium shifts. This research program will grant fundamental mechanistic insights into the specific biological and chemical mechanisms (e.g. key functional groups for metal binding; metals surface deposit structure and characteristics) through which inorganics can accumulate and release. The new knowledge generated by this research will explain the underlying mechanisms and environmental conditions that govern inorganic contaminant accumulation/release in premise plumbing, newly equipping Regulators and Utilities in Canada, and globally, to make sound evidence-based decisions to minimize exposure risk and protect public health.