<P> In addition to the acute problems of water pollution in developing countries, developed countries also continue to struggle with pollution problems . For example, in a report on water quality in the United States in 2009, 44 percent of assessed stream miles, 64 percent of assessed lake acres, and 30 percent of assessed bays and estuarine square miles were classified as polluted . </P> <P> Surface water pollution includes pollution of rivers, lakes and oceans . A subset of surface water pollution is marine pollution . </P> <P> One common path of entry by contaminants to the sea are rivers . An example is directly discharging sewage and industrial waste into the ocean . Pollution such as this occurs particularly in developing nations . </P> <P> Large gyres (vortexes) in the oceans trap floating plastic debris . Plastic debris can absorb toxic chemicals from ocean pollution, potentially poisoning any creature that eats it . Many of these long - lasting pieces end up in the stomachs of marine birds and animals . This results in obstruction of digestive pathways, which leads to reduced appetite or even starvation . </P>

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