Toxic Chemicals

Toxic chemicals—such as dangerous heavy metals and even common pesticides used around the house—are a major threat to estuaries across the country. Toxic chemicals can build up in the tissues of fish and cause more problems as they work their way up the food chain. Toxic substances can enter estuaries through “point sources” (a single place) such as hazardous waste from a factory pipe or through “nonpoint sources” (many places) such as rainwater that washes over parking lots, lawns, or farms. Towns will close shellfish beds or fisheries if they become contaminated by toxic chemicals.