While it is difficult to class rivers and lakes across the world when it comes to THE worst, there are several that stand out in the crowd. Pollutants including industrial waste, sewage runoff, overpopulation and farming discharges all make for a serious toxic brew. When you consider the fact that many of these important rivers and lakes provide food to nearby big population centers then they are having an even greater effect than as simply some polluted body of water in the middle of nowhere. Below are a few of the worst offenders that you should watch out for. Image via: Getty Images – ChinaFoto Press Lake Victoria borders several countries in East Africa, which makes it extra hard negotiate clean-up and pollution prevention. As there are very few enforced regulations, residents clean vehicles within the same lake water that sewage water is regularly released in and that they also end up bathing in. Even more difficult, people that come in contact with the water are susceptible to coming away with several diseases including, schistosomiasis, bilharzia, cholera, pneumonia, diarrhea, and several skin diseases. Image via: Smuchai on Flickr.com 500 factories are polluting Citarum River in Indonesia along its banks and it’s quite possibly the most polluted river in the world. There is so much trash covering the surface that in many areas you can’t see the water, and it is more profitable to forage for garbage than making a living fishing the river, though you do risk catching a nasty disease by spending any time in it. Image via: Sea-way.org The Great Lakes (US/Canada) took a beating through the years because of pollution from the car industry, oil refineries, steel plants, agricultural runoff and pollution, chemical plants and transportation runoff. Whilst not the worst on this list, the lakes have accumulated a toxic soup that we have yet to deal with. Image via: Getty Images – Dennis Flaherty 3,400 mile long Yellow River in China is often toxified by chemical spills, and regular diversions and damming, that causes the Yellow to often run dry and sometimes even turn red. One third of the river is useless, yet this doesn’t seem to be slowing things down since the river is used to provide water for millions of people in China, whose expanding cities are another reason the river is contaminated. Despite the fact that is small when compared to others on this list (only 65 miles), the Matanza-Riachuela River, running through the heart of Buenos Aires, is called the largest open pit toilet in the world, absorbing over 325,000 tons of sewage each day. Lead, mercury, cadmium, nitrates and copper all pollute this river and affect drinking water supplies for the over 5 million people living in the area. Image via: FJTU on Flickr.com Lake Onondaga (US) is so contaminated it was designated a hazardous waste site by the US Environmental Protection Agency. Phosphorous, ammonia, nitrite, mercury, bacterial contaminants, from a long history of industrial activity in the area, along with non-point source pollutants, combine to make this lake one toxic soup. Image via: Chromatophobe on Flickr.com Believe it or not, Lake Karachay (Russia) is totally polluted with radioactive (and other types of) waste, which was got rid of into the lake from the Mayak Nuclear Waste Storage Facility, starting in the 1950’s. The waste is currently seeping out into area soils and rockbeds, threatening other rivers and even the Arctic. Scientists predict that if it makes it to the Arctic, it could spread around the world. Image via: UNP The Yumana River could be the location of historic and holy rituals, nevertheless it’s also got its share of crap, literally. Over 3.5 billion litres of sewage pass through the river daily (making it over 100,000 times higher than limits safe for bathing), and the city removes another 1.1 billion litres of river water each day. No fish or plants can live in the river and holy leaders have threatened to boycott annual pilgrimages to the area due to the high contamination levels. Around 2,800 factories line the shores of Lake Tai, the 3rd biggest lake in China, adding to its title among the largest and most polluted in the country. Representatives have estimated a big $14.4 billion cost to clean up all the industrial dumping and sewage that contaminates these waters. Currently the waters have a green tint from all of the algae flourishing thanks to their ample source of industrial pollution in the lake. Image via: Pacific Environment The King River (Australia) is considered the most polluted river in all of Australia, primarily because of mining activities along the river dating back to the 1880’s. 1.5 million tons of mining tailings entered the river every year until 1995, while the fumes from the smelter created acid rain in the area. Today the mining operations continue to make the river highly toxic to marine life thanks to the leftover dissolved metals and tailings still in the river. Image via: Adrienne Bartl – Flickr.com The Mississippi River (US). How can we forget this mammoth river that passes across 10 states and carries millions of metric tons of pollutants with it to its mouth in the Gulf of Mexico each year, creating a the notorious “deadzone.” During the 1990s, this river discharged over 100 million pounds of toxics downriver each year. The Dead Zone is aptly named due to the low levels of oxygen, causing no aquatic life to survive in this area. kevin I actually live a few miles from Onondaga lake. People are cleaning it, but not that much.