According to the NURP study, what is identified as a major pollutant in urban runoff?

The NURP (National Urban Runoff Program) study identifies heavy metals as a major pollutant in urban runoff due to several key factors associated with urban environments. Urban runoff typically collects various pollutants from impervious surfaces, such as roads and parking lots, where industrial activities and vehicle traffic are prevalent.

Heavy metals, including lead, copper, zinc, and cadmium, can originate from vehicle emissions, brake linings, tire wear, and industrial processes. During rain events, these metals are washed off these surfaces and can enter stormwater systems, impacting the quality of receiving waters. They are particularly concerning because they can accumulate in the environment and harm aquatic life, potentially entering the food chain through sedimentation in water bodies.

The study highlights how the concentration of these contaminants often exceeds the levels found in rural runoff, making heavy metals a critical focus for stormwater management practices. Addressing heavy metals in urban runoff is vital for reducing their environmental impact and ensuring compliance with water quality standards.