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Summary of Current Research in the Effect of Phosphates on Lead Particles in Water
Citation:
Paul, A., C. Formal, D. Lytle, C. Muhlen, Mike DeSantis, AND S. Harmon. Summary of Current Research in the Effect of Phosphates on Lead Particles in Water. 19th Annual EPA Drinking Water Workshop: Small System Challenges and Solutions, Covington, KY, August 29 - September 01, 2022.
Impact/Purpose:
The purpose of this poster is to show a summary of a background of lead particles and the current research in phosphates effect on lead particles. It will discuss the importance of lead, why lead particles are an area of focus, and the processes lead particles can be formed, released, and transported though a water system. It also discusses current research being done with orthophosphate and polyphosphate and their effect on particle properties, such as particle size, charge, and structure, and areas of future research. This poster is intended as a high level overview of the topic. The findings of the research presented in this poster for the orthophosphate experiments found that orthophosphate forms hydroxypyromorphite with lead when there was excess of phosphate, with particles smaller than 100 nm and able to go through a 0.2 um filter. Hydroxypyromorphite nanoparticle did not appear to settle out of water due to their size and high negative charge, which could pose a concern that they remain suspended in drinking water. The polyphosphate experiments are ongoing, though preliminary results show that polyphosphate increases filtered lead levels, though the methods are still currently unknown.
Description:
Lead exposure can impact the brain, kidneys, and cardiovascular system, with children being most at risk. Lead levels in drinking water can be related to higher blood lead levels and associated health effects. There are two different forms of lead in water, soluble and particulate. Soluble lead chemistry is relatively well known and can be reduced with corrosion control. However, particulate lead release and reduction is not well understood. The objective of the research is to study the effect of water chemistry (DIC, phosphate, and pH) on lead particles and how different water conditions affect the particle properties: mineralogy, solubility, and filterability.