Lead in Drinking Water: Reducing/Replacing Phosphate Dosing

饮用水中的铅：减少/替代磷酸盐剂量

• 批准号: 2907425
• 金额: --
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2907425
• 关键词: Lead; Drinking; Water; Reducing; Replacing

Lead (Pb) in drinking water is a proven threat to public health, which continues to have devastating consequences, e.g., a series of errors by authorities in Flint (USA) resulted in mass poisoning of the local population. Currently, water suppliers are legally obliged to ensure that the level of Pb in drinking water (DW) does not exceed a certain concentration. Compliance is typically pursued through a combination of pH control and phosphate dosing, which is intended to produce a surface film of a highly insoluble Pb phosphate salt that restricts the amount of dissolved Pb (i.e., plumbosolvency). Water sampling, however, indicates that this chemical treatment is far from perfect, and that the legal limit of dissolved Pb is sometimes exceeded. Moreover, there are increasing concerns that the current phosphate treatment regime will soon become economically unviable, and alternative solutions will be required; existing phosphate dosing levels are simply based on empirical knowledge, with little/no work undertaken to explore benefit/detriment of changes. Motivated by the above, the goal of the PhD project is to test the following hypothesis:Mechanistic understanding of Pb scale evolution/plumbosolvency routes in DW pipes will enable knowledge-based decisions on reducing/replacing phosphate dosing.In sharp contrast to other work undertaken in this arena, work will not be concerned with ex-service Pb-water pipes, which have complex and ambiguous histories that inherently undermine their value for gaining mechanistic insight. Instead, effort will focus initially on elucidating the temporal evolution of scale/plumbosolvency for a reference Pb/DW system, i.e., a Pb sample immersed in a well-defined DW chemistry, in the absence/presence of phosphate dosing (Phos). Such an approach will facilitate the transparency required for mechanistic understanding, including evaluating the relative importance of two potential plumbosolvency routes, i.e., Release of Pb from Pb salts/oxides versus Local corrosion of metallic Pb.To facilitate research delivery, a series of measurable research objectives have been devised, i.e.,(i) Implement experimental setups/procedures suitable for laboratory studies of plumbosolvency/scale evolution in Pb-water pipes.(ii) Identify and quantify routes for plumbosolvency in reference Pb/DW Phos system.(iii) Characterise structure and chemistry of scale formed in Pb/DW Phos system. (iv) Quantify impact of reducing phosphate dosing on plumbosolvency/scale evolution.(v) Elucidate impact of varying DW chemistry on plumbosolvency/scale evolution.(vi) Use experimental data to develop knowledge-based guidelines for phosphate dosing.(vii) Investigate possible alternatives to phosphate dosing.The student will combine electrochemical measurements/solution analysis with scale characteristaion, using advanced electron microscopy, spectroscopy and diffraction techniques, to follow plumbosolvency as a function of scale evolution. It is anticipated that this program will initiate a step-change in our understanding of the relationship between surface scale and Pb in drinking water and provide underpinning knowledge for reduction/replacement of phosphate dosing. Consequently, it will contribute to the following EPSRC priorities: the physical and mathematical sciences powerhouse, frontiers in engineering and technology, and transforming health and health care.

饮用水中的铅（PB）是对公共卫生的证明威胁，这种威胁仍带来毁灭性后果，例如，弗林特当局（美国）的一系列错误导致当地人口大规模中毒。目前，水供应商在法律上有义务确保饮用水中的PB水平（DW）不超过一定的浓度。通常通过pH控制和磷酸盐剂量的结合来实现依从性，该剂量旨在产生高度不溶性PB磷酸盐盐的表面膜，该膜限制了溶解的Pb量（即铅溶剂）。但是，水采样表明这种化学处理远非完美，并且有时超过溶解的PB的法定限制。此外，人们越来越担心当前的磷酸盐治疗制度将很快在经济上变得不可行，并且需要替代解决方案；现有的磷酸盐剂量水平仅基于经验知识，而几乎没有工作以探索对变化的利益/损害。 Motivated by the above, the goal of the PhD project is to test the following hypothesis:Mechanistic understanding of Pb scale evolution/plumbosolvency routes in DW pipes will enable knowledge-based decisions on reducing/replacing phosphate dosing.In sharp contrast to other work undertaken in this arena, work will not be concerned with ex-service Pb-water pipes, which have complex and ambiguous histories that inherently undermine their value for gaining机械洞察力。取而代之的是，努力最初将集中于参考PB/DW系统的尺度/铅溶剂的时间演变，即在不存在磷酸盐剂量（PHOS）的情况下，浸入了定义明确的DW化学中的PB样品。这种方法将促进机械理解所需的透明度，包括评估两种潜在的铅溶剂途径的相对重要性，即从PB盐/氧化物/氧化物中释放PB与金属PB的局部腐蚀，从（ii）在参考PB/DW PHOS系统中识别和量化PB/DW PHOS系统中的铅溶剂的途径。（iii）表征PB/DW PHOS系统中形成的规模结构和化学。 （iv）量化减少磷酸盐剂量对铅质剂量/尺度进化的影响。（v）阐明不同DW化学对铅质验证/尺度进化的影响。（vi）使用实验数据来开发基于知识的指南，用于使用磷酸盐量的磷酸盐量的替代方法。电子显微镜，光谱和衍射技术遵循铅溶剂作为尺度演化的函数。可以预料，该程序将在我们对饮用水中表面尺度和PB之间的关系的理解中启动逐步变化，并为减少/替代磷酸盐剂量提供基础知识。因此，它将有助于以下EPSRC优先级：物理和数学科学强国，工程和技术领域的前沿以及改变健康和卫生保健。