Water pollution

           Estimates suggest that nearly 1.5 billion people worldwide lack safe drinking water and that at least 5  million  deaths  per  year  can be attributed to waterborne diseases. Water pollution may come from point sources or  nonpoint  sources. Point  sources  discharge  pollutants from specific  locations,  such as factories, sewage treatment plants, and oil tankers. The technology  exists to monitor and   regulate  point  sources  of pollution,  although  in  some areas this occurs only sporadically. Pollution from nonpoint sources occurs when rainfall or snowmelt moves over and through the ground. As the runoff  moves, it picks up and carries away pollutants, such as pesticides and fertilizers, depositing  the  pollutants  into  lakes,  rivers,  wetlands, coastal  waters,  and even underground sources of drinking water. Pollution arising from nonpoint sources accounts for a majority of the contaminants in streams and lakes.

With almost 80 percent of the  planet  covered by oceans, people have long acted as  if  those  bodies  of water could serve as a limitless dumping ground  for  wastes. However,  raw sewage,  garbage,  and oil spills have begun to overwhelm the diluting capabilities of  the  oceans, and most coastal waters are now polluted,  threatening  marine wildlife. Beaches around the world close regularly, often because the surrounding waters contain high levels of bacteria from sewage disposal.