Urban Stormwater Runoff Contamination Associated with Gutter and Pipe Material Degradation

The purpose of this research was to investigate how different pipe, gutter, and storage tank materials, time of contact, and pH affect water quality. The tests were conducted using a series of controlled laboratory experiments for a period of three months by immersing sections of the test materials in large quantities of pH buffer solutions made using locally collected roof runoff and storm drain inlet water. The tests were conducted at pH 5 and pH 8. Water samples were periodically collected and then analyzed for a broad range of metallic and nutrient constituents and toxicity utilizing Microtox procedure. Copper release from copper gutters increased with decreased pH. The highest concentrations of zinc were observed from galvanized materials. Decreasing the pH increased zinc concentration from galvanized steel materials during the first 27 hours of exposure. Galvanized steel materials were the only source of lead concentrations.