In this study, the Regional Transportation District's (RTD's) light rail operations were examined for pollutant production and runoff. Conclusions from the study: Water leaving ballasted tracks carries only a small fraction of the heavy metals that are introduced into tracks from the light rail operations. Heavy metal concentrations at the most heavily traveled light rail station showed that pollutant concentrations were far below the regulatory limits....

Our drinking water supplies, fishing and recreational waters are fouled by uncontrolled pollution when rainwater and snowmelt wash over city streets, parking lots, and suburban lawns and pick up toxic chemicals, disease-causing organisms (from pet waste), and dirt and trash. This problem is called urban stormwater pollution. Recent studies have found that urban stormwater rivals and in some cases exceeds sewage plants and large factories as a source...