TASHKENT, Uzbekistan, March 25 (UPI) -- Vast quantities of radioactive and toxic wastes stored not far from the Caspian Sea threaten a nearby city and could infiltrate into the world's largest inland body of water, Kazakh scientists said.
The environmental deterioration in Kazakhstan's Mangistau region began in the 1960s when the Soviet Union started extracting and processing uranium there. The ore was processed at a chemical hydro-metallurgical plant located not far from Aktau, the administrative center of the region. The Prikaspiiskii mining and chemical enterprise, as it was called, also included sulfuric acid and nitrogen fertilizer plants.
A uranium tailings dump was created in the drain-free settling pool at Koshkar-Ata, 3 miles north of Aktau and 4.5 miles east of the Caspian. Since 1965, liquid radioactive, toxic and industrial wastes and unpurified ordinary domestic drains have been discharged into the 42-yard deep Koshkar-Ata repository, which has an area of 52 square miles.
"Koshkar-Ata is filled with brine, containing an extended quantity of contaminants and heavy metals," said Kairat Kuterbekov, the scientific secretary of the Institute of Nuclear Physics in Almaty, Kazakhstan's capital.
Kuterbekov is the manager of the project called the "Overall Examination of Ecological Situation at the Toxic Wastes Storage 'Koshkar-Ata' and Development of Rehabilitation Actions."
The brine at Koshkar-Ata contains up to 0.18 ounces of salts per a cubic foot, Kuterbekov told United Press International.
The production process stopped in the early 1990s and Koshkar-Ata started to dry up. So far, some 13.8 square miles have dried up, creating toxic dust that is blown into the atmosphere.
In 1991, the International Commission on Radiological Protection issued recommendations that included limiting radiation dosages to members of the public to less than 0.1 rem per year.
A rem measures the amount of damage to human tissue from a dose of ionizing radiation. Across most of Koshkar-Ata, the exposure dose, as recorded by sensors, is 0.4 rems. In some of the area, the exposure is 1,500 micro-roentgens per hour -- equivalent to 13.0 rems per year.
When the dump was active, in addition to liquid wastes, the Soviets buried 115 million tons of solid wastes, including 57 million tons of radioactive wastes, Kuterbekov said. The radiation exposure on those plots of land -- 5,000 micro-roentgens per hour -- exceed the limiting dose by more than 400 times.
"The radioactive wastes are represented by a natural series of uranium-238; the most toxic among them are uranium-235, radium-226 and thorium-230," Kuterbekov explained.
Uranium and its decay products, including thorium, radium and radon -- a radioactive gas -- can be dangerous substances if not properly stored or isolated. Yet local residents have been digging out the radioactive metal trying to sell it to scrap dealers. The dealers refuse to buy it because of its radioactivity, so the frustrated sellers discard it anywhere, Kuterbekov said.
"A large quantity of heavy metals -- copper, zinc, nickel -- and rare-earth elements have been found in the bottom sediment," he added.
Heavy metals can damage living creatures at low concentrations and tend to accumulate in the food chain.
Last year, the effects of the radioactive and toxic dust were not as damaging to Aktau, a city with a population of 185,000 on the coast of the Caspian. However, 2003 was atypical because of a relatively large amount of precipitation and because the prevailing winds blew away from the city, Kuterbekov said.
Underground water is another worry because there is the potential to contaminate the Caspian, he said. About 17 square miles of the tailing dump are still covered with water, and five countries surround the Caspian -- Turkmenistan, Kazakhstan, Russia, Azerbaijan and Iran.
A specialist, who did not want to be identified, told UPI that concentrations some elements -- including iron, molybdenum, manganese, cadmium, selenium, ammonium and fluorine -- have been found to exceed maximum permissible levels within 1.8 to 2.25 miles of the tailing dump in the Caspian direction.
The repository represents "a huge and immediate threat to the Caspian ecosystem," Boris Golubov, a Russian scientist wrote in his article "The Caspian: Receptacle for Radiation" published in the quarterly "Give & Take" in 2001.
Moreover, "in addition to "man-made" sources of radiation, the Caspian ecosystem collects and stores high levels of natural radioactive nuclides," Golubov wrote. "Caspian waters, bottom sediments, and living organisms contain levels of uranium five to seven times higher than those in other seas."
"(The) situation of nuclear wastes in Kazakhstan is disastrous for the local people and the Caspian Sea in general," said Bahman Aghai Diba, a consultant on international law for the World Resources Company in McLean, Va.
The nuclear wastes are kept in substandard conditions and there is possibility of infiltration into the sea, Aghai Diba told UPI.
Scientists intend to supply soil to the former bottom to stimulate plant growth, Kuterbekov said, adding this way to solve the problem had been chosen because of it was relatively cheap.
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Marina Kozlova covers Central Asia for UPI Science News. E-mail [email protected]
