Pollutant impacts to Cape Hatteras National Seashore from urban runoff and septic leachate

► We assessed urban runoff and septic system pollution on a nearby coastal park. ► Urban stormwater runoff polluted beach waters with high fecal bacteria counts. ► Septic system leachate loaded nutrients and fecal microbes into park water bodies. ► Nutrient loading caused algal blooms, high BOD and hypoxia in park water bodies. ► Development on barrier islands threatens the quality of nearby public trust waters.