Radioactive contamination of rivers around a top-secret Russian nuclear weapons complex in Siberia has reached "staggering" levels, the worst ever monitored, and is out of "rational control", a joint team of Russian and American radiation monitors said yesterday.
Following a monitoring expedition in July and August to the closed plutonium complex at Seversk, outside Tomsk in western Siberia, the Russian and American nuclear watchdogs, Siberian Scientists for Global Responsibility and Government Accountability Project, said they had registered alarming levels of radioactivity in tributaries of the River Ob, one of the key Siberian waterways.
"We've never encountered such radiation. It's the worst contamination we've found," said Prof Sergei Pashchenko, a Novosibirsk-based expert in atmospheric pollution who headed the survey on the Russian side.
Mr Tom Carpenter, the director of the American watchdog, said: "We were shocked at the levels of contamination."
The environmentalists said they found levels of strontium-90 and caesium vastly exceeding safety levels in the rivers Tom and Romashka close to the "Siberian Chemical Complex", a sprawling top-secret facility established by the Soviet Union in the 1950s to manufacture weapons-grade plutonium for Red Army warheads.
But even more disturbingly, said Prof Pashchenko, plant life in the rivers contained high levels of phosphorus-32 which decays within a couple of weeks, meaning that the radioactive effluent was of very recent origin whereas the strontium and the caesium could date from the 1960s.
"The phosphorus-32 is a very short-lived isotope and this means they are very fresh," he said. The closed nuclear town of Seversk is effectively a suburb of Tomsk, a city of half a million in western Siberia.
Seversk was born in 1949 at the very onset of the then superpowers' nuclear arms race.
It ranked among the top three sites for the manufacturing of the weapons-grade plutonium and uranium enrichment for the Soviet Union's nuclear arsenal throughout the cold war.
The plutonium was manufactured from five nuclear reactors commissioned between 1955 and 1967.
"They are very old reactors and very unsafe," said Mr Igor Forofontov, radiation specialist with Greenpeace in Moscow.
The three oldest reactors were closed down between 1990 and 1992 and under a 1992 agreement between Moscow and Washington aimed at halting plutonium production all five reactors were to have been closed down by this year.
But two reactors are still operating, providing heating and electricity to Tomsk and there is no sign of their closure. "The authorities have no intention of closing them," said Mr Forofontov.
There was an explosion at the plant in 1993 which resulted in large amounts of radioactivity being emitted.
Mr Forofontov also said lethal amounts of radioactivity were leaching into the earth and the water in the region. "The nuclear waste is being piped straight into the environment," said Mr Norm Buske, one of the American researchers who is an oceanographer and a physicist. The monitors were unable to pinpoint the source of the pollution because they were not granted access to the top-secret plant.
Prof Pashchenko and 10 of his colleagues were detained for six hours questioning by the FSB, the successor to the KGB, while conducting research around Novosibirsk last summer.