A tua

Direct discharge

Acid mine drainage in the Rio Tinto River.
See also: Sewerage, Industrial waste, and Environmental issues with mining
Pollutants enter rivers and the sea directly from urban sewerage and industrial waste discharges, sometimes in the form of hazardous and toxic wastes.
Inland mining for copper, gold. etc., is another source of marine pollution. Most of the pollution is simply soil, which ends up in rivers flowing to the sea. However, some minerals discharged in the course of the mining can cause problems, such as copper, a common industrial pollutant, which can interfere with the life history and development of coral polyps.[2] Mining has a poor environmental track record. For example, according to the United States Environmental Protection Agency, mining has contaminated portions of the headwaters of over 40% of watersheds in the western continental US.[3] Much of this pollution finishes up in the sea.
[edit]Land runoff
Main article: Surface runoff
See also: Urban runoff and Stormwater
Surface runoff from farming, as well as urban runoff and runoff from the construction of roads, buildings, ports, channels, and harbours, can carry soil and particles laden with carbon, nitrogen, phosphorus, and minerals. This nutrient-rich water can cause fleshy algae and phytoplankton to thrive in coastal areas; known as algal blooms, which have the potential to create hypoxic conditions by using all available oxygen.
Polluted runoff from roads and highways can be a significant source of water pollution in coastal areas. About 75 percent of the toxic chemicals that flow into Puget Sound are carried by stormwater that runs off paved roads and driveways, rooftops, yards and other developed land.[4]
[edit]Ship pollution
Main article: Ship pollution
See also: Ballast water discharge and the environment

A cargo ship pumps ballast water over the side.
Ships can pollute waterways and oceans in many ways. Oil spills can have devastating effects. While