Bugs ready to chew up toxic waste

September 10, 1999

Brewery techniques helped create a substance that can absorb 50 times more radioactive materials than other methods. Kam Patel reports British and Ukrainian scientists believe they are near a breakthrough in cleaning radioactive soil and water that resulted from the Chernobyl nuclear power station accident 13 years ago.

The method developed by Jim Watson and Derek Ellwood of Southampton University's physics department uses beer-brewing technology to produce bugs that can make a special form of iron sulphide. The material is able to absorb vast quantities of a range of radioactive materials including technetium, uranium and plutonium. It can also deal with a range of toxic materials such as mercury, PCBs, arsenic, lead and cadmium, as well as precious metals such as gold and platinum. The researchers plan to patent it.

The material is 50 times more absorbent than its conventional chemically produced counterpart - a teaspoon of the stuff makes available an active absorbent area equivalent to that of two football pitches. Researchers have also made it 14 times more magnetic than normal, which makes it cheap and easy to recover by magnets once it has done its job.

Professor Watson has estimated that the cost of recovering the material, loaded with toxic and radioactive materials, will be a few pence per tonne. "It is an amazing material and its potential is huge. It can clean to extremely low radiation and toxicity levels, and the same capability can be used to recover precious metals from things that are usually thrown away because they are too expensive to recover."

Scientists at the National Academy of Sciences in Kiev, 80km south of the Chernobyl site, have been working closely with the Southampton scientists to perfect the technique. The academy's Sergei Mikhalovsky, who has been involved in the clean-up operation, said: "It is certainly the best, cleverest and, important for us, cheapest technique to have emerged. It is close to being perfected for the many pools and ponds that are affected by radiation. We also have a big problem with contaminated soil in and around Chernobyl and have no methods that work. The technique is very flexible and we are optimistic that we can get it to work for soil as well." Dr Mikhalovsky is working with a team at Brighton University to help achieve this.

Kiev-based academy director Vladimir Strelko said the technique was "very cheap, uncomplicated and pioneering". He added: "We believe it can be applied to any disaster where toxic and radioactive contamination becomes a problem. We certainly think it will be of great help with treating contaminated water. We have just finished trialling a modification of the technology for soil and have been able to reduce contamination by between three and ten times the original level."

According to the academy, the Chernobyl disaster has resulted in radiation contamination of 9,500 square miles of Ukraine, Belarus and Russia. Nearly four million people are living on contaminated land, and 120,000 have been evacuated from 188 cities, towns and villages and cannot return. Children in Ukraine are nearly five times more likely to contract thyroid cancer than before the accident, and the country devotes 11 per cent of its budget to dealing with the consequences of the disaster.

The technology is attracting worldwide interest. At Southampton University, a research team from Venice University is evaluating the technique for use in the treatment of a Venetian lagoon heavily contaminated by toxic materials including cadmium,lead, mercury and PCBs. Lorenzo Lazzari, one of the researchers, said: "There is nothing available for the kind of problem we have with the lagoon, and we believe this pioneering method is very promising. We have already tested it for PCBs and the results are very positive."

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