Technical Papers

Based on analysis of NURP data from four sites in Fresno, California, several preliminary conclusions can be drawn about dissolved metals in urban runoff. The percent dissolved Cu, Pb, and Zn in stormwater runoff are relatively consistent, from one site to another, and are approximately 20% for Pb, 30% for Cu, and 50% for Zn. The key process controlling percent dissolved metals is adsorption. Key factors controlling percent dissolved metals incudes: total suspended solids, total metals, and alkalinity. Further analysis will be required to provide more definitive relationships between the percent dissolved metals and controlling factors. More detailed analysis will require that additional data, including total and dissolved metals and hardness, be collected in future stormwater runoff monitoring programs.