1 SUMQAYIT, AZERBAIJAN—This area gained the dubious distinction of landing atop the Blacksmith Institute's list of the world's most polluted sites. Yet another heir to the toxic legacy of Soviet industry, this city of 275,000 bears heavy metal, oil and chemical contamination from its days as a center of chemical production. As a result, locals suffer cancer rates 22 to 51 percent higher than their countrymen, and their children suffer from a host of genetic defects, ranging from mental retardation to bone disease.
“As much as 120,000 tons of harmful emissions were released on an annual basis, including mercury,” says Richard Fuller, founder of Blacksmith, an environmental health organization based in New York City. “There are huge untreated dumps of industrial sludge.”
2 CHERNOBYL, UKRAINE—The fallout from the world's worst nuclear power accident continues to accumulate, affecting as many as 5.5 million people and leading to a sharp rise in thyroid cancer. The incident has also blighted the economic prospects of surrounding areas and nations.
3 DZERZHINSK, RUSSIA—The 300,000 residents of this center of cold war chemical manufacturing have one of the lowest life expectancies in the world thanks to waste injected directly into the ground. “Average life expectancy is roughly 45 years,” says Stephan Robinson, a director at Green Cross Switzerland, an environmental group that collaborated on the report. “Fifteen to 20 years less than the Russian average and about half a Westerner's.”
4 KABWE, ZAMBIA—The second largest city in this southern African country was home to one of the world's largest lead smelters until 1994. As a result of that industry, the entire city is contaminated with the heavy metal, which can cause brain and nerve damage in children and fetuses.
5 LA OROYA, PERU—Although this is one of the smallest communities on the list (population 35,000), it is also one of the most heavily polluted because of extensive lead, copper and zinc mining by the U.S.–based Doe Run mining company.
6 LINFEN, CHINA—A city in the heart of China's coal region in Shanxi Province, Linfen is home to three million inhabitants, who choke on dust and air pollution and drink arsenic that leaches from the fossil fuel.
7 NORILSK, RUSSIA—This city above the Arctic Circle contains the world's largest metal-smelting complex and some of the planet's worst smog. “There is no living piece of grass or shrub within 30 kilometers of the city,” Fuller says. “Contamination [with heavy metals] has been found as much as 60 kilometers away.”
8 SUKINDA, INDIA—Home to one of the world's biggest chromite mines—chromite makes steel stainless, among other uses—and 2.6 million people. The waters of this valley contain carcinogenic hexavalent chromium compounds courtesy of 30 million tons of waste rock lining the Brahmani River.
9 TIANYING, CHINA—The center of Chinese lead production, this town of 160,000 has lead concentrations in its air and soil that are 8.5 to 10 times those of the national health standards. The concentrations of lead dusting the local crops are 24 times too high.
10 VAPI, INDIA—This town at the end of India's industrial belt in the state of Gujarat houses the dumped remnant waste of more than 1,000 manufacturers, including petrochemicals, pesticides, pharmaceuticals and other chemicals. “The companies treat wastewater and get most of the muck out,” says David Hanrahan, Blacksmith's London-based director of global operations. “But there's nowhere to put the muck, so it ends up getting dumped.”
Biello is the award-winning online associate editor for environment and energy. He joined Scientific American in November 2005 and has written on subjects ranging from astronomy to zoology for both the Web site and magazine. He has been reporting on the environment and energy since 1999--long enough to be cynical but not long enough to be depressed. He is the host of the 60-Second Earth podcast, a contributor to the Instant Egghead video series, host of PBS's "Beyond the Light Switch" and author of a children's book on bullet trains. He also happens to think Charles Darwin's The Origin of Species is a surprisingly good read.