Left unmanaged, runoff flows directly into our streams, lakes, and marine ecosystems, bypassing treatment systems and introducing pollutants that can have far-reaching environmental and public health impacts.These chemical pollutants can harm not just a beach, but an entire ecosystem. Tiny microbes, such as plankton or algae, absorb pollutants in the runoff. Fish or shellfish consume the microbes or absorb the pollutants directly. Animals such as birds consume the fish, increasing the level of pollutants in their own bodies. This process in which the concentration of a substance increases as it passes up the food chain is called biomagnification. 🔗

Eutrophication, the gradual increase in the concentration of phosphorus, nitrogen, and other plant nutrients in aquatic ecosystems. Among the most concerning consequences is nutrient loading— runoff from lawn fertilizers, pet waste, and decaying organic matter—which fuels harmful algal blooms. These blooms reduce oxygen levels, create dead zones, destroy aquatic habitats, and pose risks to both wildlife and human communities by contaminating drinking water supplies. 🔗

Additionally, combined sewer overflows (CSOs)—which route stormwater, household sewage, and industrial wastewater through the same pipeline—can become overwhelmed during periods of heavy rain. When capacity is exceeded, untreated wastewater is released directly into natural waterbodies, compounding the risks to ecosystems and public health. 🔗