Sewage- Septic systems are failing all around the country, causing untreated waste materials to flow freely into streams, rivers, and lakes. Over 1.2 trillion gallons of untreated sewage, groundwater, and industrial waste are discharged into U.S. waters annually.
Waste Water- Detergents can have poisonous effects in all types of aquatic life if they are present in sufficient quantities, and this includes the biodegradable detergents. All detergents destroy the external mucus layers that protect the fish from bacteria and parasites; plus they can cause severe damage to the gills.
Industrial waste- Mercury is one of the most harmful pollutants faced by fish and wildlife. Toxic mercury is released from coal burning power plants across the country and accumulates in rivers, lakes, and forests.
Farm Runoff-Manure and fertilizer runoff from farms is the leading cause of phosphorous pollution in Lake Champlain. This is the sixth-largest freshwater body in the country. The phosphorus is linked to toxic summer algae blooms, which state officials now say poses a risk to fish and drinking water. Americans uses over 2.2 billion pounds of pesticides every year, which eventually washes into our rivers and lakes. Patrick Leahy, D-Vt., said Vermont is a small state with high-profile water quality issues: algae blooms, sea lamprey and the invasive spiny water flea.
Boats-The dumping of sewage, leaking fuel and oil and using toxic cleaning products can threaten water quality, especially near the shoreline.
Harmful substances that get into water are pesticides, heavy metals and hydrocarbons that are often released into the aquatic environment. When large quantities of these substances are released, there can be immediate impact to aquatic animals such as fish.