Construction projects often contribute large amounts of sediment. Certain lumbering practices affect sediments in runoff. Sediments may fill stream channels and harbors that later require dredging. Sediments suffocate fish and shellfish populations by covering fish nests and clogging the gills of bottom fish and shellfish. Petroleum Products Oil and other petroleum products like gasoline and kerosene can find their way into water from ships, oil drilling rigs, oil refineries, automobile service stations, and streets.
Birds are unable to fly when oil loads the feathers.
Shellfish and small fish are poisoned. If it is washed on the beach, the oil requires much labor to clean up. Fuel oil, gasoline and kerosene may leak into ground water through damaged storage tanks. Animal Waste Human wastes that are not properly treated at a waste treatment plant before being released to water may contain harmful bacteria and viruses. The main source of this problem is sewage getting into the water.