According to the Blacksmith Institute and Green Cross Switzerland, the world's worst toxic pollution problem in terms of the people affected is mercury poisoning from small-scale gold mining, which affects about 3.5 million people. The next-worst pollution problems are lead pollution from industrial parks and pesticide use in agriculture, which affect about 3 million people and 2 million people, respectively. Other significant toxic pollution problems include lead smelting; chromium pollution, which comes from a substance used in leather tanning; and arsenic in groundwater, which is the only naturally occurring toxic pollution problem.
More facts about pollution:
- A report by the Blacksmith Institute included limited information on the effects of chemical manufacturing and uranium mining, which are thought to affect about 100 million people, as well as information about petrochemical production, which also is a major pollutant.
- Hexavalent chromium, a chemical compound that used in leather tanning, is a carcinogen and can lead to respiratory cancers, eye damage and ulcers. It also can lead to holes in the septum, which is the part of the nose that divides the left and right nostrils.
- Some of the most polluted places in the world include Linfen, China, which is continually clouded in coal dust; Dzerzhinsk, Russia, where 300,000 tons (about 273 million kg) of chemical waste were dumped; Kabwe, Zambia, where zinc and lead mining has made large amounts of metal dust and residue in the soil and in the water; and the heavy-metal mining town of La Oroya, Peru.