Pollution from litter and chemicals is present in all the world s oceans, from coastal areas to the open ocean. Most of the trash and pollutants produced by human activities end up in the world s oceans. Sometimes these materials are directly drained or dumped into the ocean, either on purpose or, as in the case of oil spills , by accident. A lot of marine pollution comes from rivers and streams that empty into the oceans. These rivers carry sewage, industrial waste, overflow from city streets, fertilizers and pesticides from farms, and sedimentation.
People can become seriously ill from eating contaminated shellfish or by swimming in polluted water.
Non-biodegradable plastics not only hurt fish, birds, seals , and other sea animals, but they also destroy the natural beauty of beaches. This oil dirties beaches, kills animals, and causes problems for marine organisms. Most of these are natural, but a few are caused by the testing of nuclear weapons.