Uranium munching fungi

Fungi are notable living things with remarkable qualities. Some of them have special biogeochemical attributes which could be used to immobilize uranium, a toxic heavy metal. Certain fungi accumulate uranium upto 0.3 to 0.4 g per g of dry weight.

K.S.Parthasarathy




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Uranium munching fungi
Recently, Dundee University researchers found evidence that fungi can “lock” depleted uranium (DU) into a mineral form that may be less likely to find its way into plants, animals or water supply (Current Biology, May 6).
Depleted uranium
In a new report, they claimed that fungi may have an important role to play in the fate of potentially dangerous depleted uranium left in the environment during the war in Iraq (in 1991 and 2003) and in the Balkans (in 1995 and 1999).
DU is a by-product of uranium enrichment process. It is used to make ammunition because it is dense; also it resists deformation. When a DU round hits a target, it preserves its shape and “self- sharpens”, as it moves forward. Uranium dust generated at the time of impact can create a fierce fire, as uranium is pyrophoric.
British and US forces fired about 320 tonnes of depleted uranium munitions in the 1991 gulf war and may have used up to 2000 tonnes in the 2003 invasion of Iraq. (The British Medical Journal, November 11, 2006). DU is 40 per cent less radioactive than natural uranium. It is chemically toxic like cadmium or lead. The Royal Society studied the possible health impacts of DU.
Long term threat
“Our study … concluded that the soil around the impact site of depleted uranium penetrators may be heavily contaminated, and could be harmful if swallowed by children, for example. In addition, large numbers of corroding depleted uranium penetrators embedded in the ground might pose a long term threat if the uranium leaches into water supplies,” Professor Brian Spratt, who chaired the Royal Society Working Group, clarified.
Royal Society recommended that the fragments of depleted uranium penetrators should be removed and areas of contamination around depleted uranium penetrator impact site should be identified and, where necessary made safe.
The uranium munching fungi may be useful agents in remediation and re-vegetation techniques for soils polluted by uranium. These humble living things serve nature uniquely and incredibly. Some decompose organic matter.
Any material lying un-protected for some time in humid conditions will have hair like fungi growing on them. Some of these fungi have very useful biogeochemical properties.
All the species of fungi tested by UK researchers exhibited high DU tolerance. They could colonize uranium metal surfaces forming moisture-retaining bio-films. Fungi grew in the form of fine filaments.
Metal coupon
In the presence of air, the metal coupon corroded producing black and yellow decomposition products; they formed mixed oxides.
Fungal bio-films retained moisture on DU surfaces and facilitated corrosion. DU-colonizing fungi grew over the corrosion products.
After interacting with the DU metal, the fungi filaments developed a yellow hue in its growing part clearly demonstrating uranyl migration.
The metal coupons lost 5.5-8 per cent of weight over three months. Scientists studied the chemical species released in the micro-environment. DU- exposed fungi produced oxalic acid. Most such fungi showed greater accumulation of uranium with increasing amounts of excreted oxalate (Cell Biology, May 6, 2008)
DU-exposed fungi exhibited a notable ability to accumulate mobilized uranium in their biomass to the extent of 0.3 to 0.4 g per g of dry weight. The scientists clearly demonstrated extensive bio-mineralization by using sophisticated analytical tools.
Leaching out
Geoffrey Gadd, one of the researchers asserted that the fungal-produced minerals are capable of long term retention, so this may prevent uptake of uranium by plants, animals and microbes.
“It might also prevent the spent uranium from leaching out from the soil.” he claimed.
Cleaning up a vast uranium contaminated area is yet to be demonstrated.
K.S. PARTHASARATHY
Former Secretary, AERB (ksparth@yahoo.co.uk)
© Copyright 2000 - 2008 The Hindu

Nuclear power: Deal, discussion and debates

The article compares some of the debates in which scientists and journalists participated. Looking at the current scene, the author concludes that they may not get any support from any politician, defending the nuclear cause.

K.S.Parthasarathy




Nuclear power: Deal, discussion & debates
By Dr. K S Parthasarathy
When the die appears to be cast, skeptics may wonder, how the protagonists and antagonists of the Indo-US civil nuclear cooperation agreement carry on discussions for hours at a stretch and that too on several sessions over many days! A blessing in disguise is the wholehearted participation of the media, opinion makers, policy planners and parliamentarians in the discussion and the debates on a topic such as nuclear power which interested only a handful of journalists over the past several decades!
Public learnt many facts. China which was far behind India is going ahead with an ambitious nuclear power programme. They do not mind breaking bread with nuclear vendors from any country so long as they get best deals from them. Their proletariat past does not inhibit them from securing nuclear technology from anyone.
India's hope for nuclear capacity addition in the near term will remain just a hope, without operationalising the civil nuclear agreement.
Indian nuclear power reactors are working at low capacity factors as there is a "mismatch between nuclear fuel supply and demand" (NPC Annual report 2006-07, confirmed recently in Parliament). India's uranium ore is of very low grade. Its uranium resources have been updated to 1,07,268 tonnes of U308 (DAE Annual Report, 2007-08).
During 2006, the production figures (in tonnes) for uranium reported by the World Nuclear Association were: World, 39429; Canada, 9862; Australia, 7593; USA, 1672; China 750; India, 177; Pakistan, 45; France, 5;
Scientists learnt a few lessons. Politicians will remain neutral in any nuclear debate when public is a party. They expect scientists to satisfy the public and the anti nuclear activists, though nuclear programme is a national programme. Scientists cannot depend on political leaders' support for nuclear activities such as uranium mining. Politicians may not correct wrong notions of the public, even when they know the facts; they believe that such efforts may erode their vote banks.
Right from 1947, Nehru's vision and Bhabha's mission on atomic energy coincided. After due discussions with the bureaucracy, they set up a sound administrative mechanism to respond swiftly, effectively and decisively to the demands from this nascent field. Scientists could not have asked for more!
It is instructive to look at the past discussions and debates. When Dr Bhabha organised the first National Symposium on Atomic Energy during November 26 and 27, 1954, Pandit Jawaharlal Nehru, the then Prime Minister and his entire cabinet, scientists from other institutions, industrialists and some members of Parliament attended the meeting. Nehru himself presided over the entire conference except for a short period when Mr. KD.Malaviya, a senior cabinet minister took the chair. Times have changed!
The symposium was Nehru's response to remarks in Parliament by eminent physicist Dr.Meghnad Saha and others. Nuclear scientists in India largely remained out of public gaze for long. Other than attending a few press conferences, media also paid no attention. Even mild criticism could upset scientists; they were not used to it. Occasionally, a few scientists portrayed journalists who challenged official views as trouble makers!
Very few journalists knew the intricacies of the subject. Those who knew could not get access to scientists. Scientists were reluctant to communicate. Mixing with the media was considered a risky occupation!
Many young journalists realised that they could make good copies by mixing news with "radiation and radioactivity". Newspaper headlines such as "Tarapur set to explode", "A bomb ticking somewhere in Hyderabad", were hilarious.
The Atomic Energy Regulatory Board (AERB) was set up in November 1983. As per its mandate, AERB remains open with the public. The Members of the Board addressed a few press conferences, mostly, after the meetings of the Board. There were some controversies, but by and large press coverage was objective.
From August 9 to 11, 1986 Sampoorna Kranti Vidyalaya Vedchhi, an NGO dedicated to a non nuclear India, held a seminar on "Atoms in India" at Sasmira Hall, Worli, Bombay. Five officials from AERB and a few officials from Nuclear Power Board attended the seminar.
The NGO did not see any difference between nuclear power reactors and nuclear weapons. V R. Krishna Iyer (Former Judge of the Supreme Court) inaugurated the seminar.
We described the safety features of nuclear reactors, explained how high level radioactive wastes are "vitrified" dispelling the wrong notion that waste is stored in glass containers! we answered several questions from the audience. Probably, we could not convince everyone but the dialogue was satisfying.
Initiating a desirable shift in policy, Dr.M.R.Srinivasan, the then Chairman Atomic Energy Commission, opened the doors of AEC to its critics. Senior officers of DAE and AERB participated in many meetings.
On December 5, 1987, the Bhabha Atomic Research Centre Officer's Association (BARCOA) organized a panel discussion on "Issues in Nuclear Technology". Dr M.R.Srinivasan, Prof De, Chairman, AERB, Shri S.L. Kati, Managing Director, Nuclear Power Corporation and Shri M.H.P. Rao, former Director, Nuclear Power Board spoke.
The panelists included Amalendu Das Gupta (The Statesman), Praful Bidwai (The Times of India). Ivan Fera (The Illustrated Weekly), G.S.Bhargava (formerly of Indian Express) and Professor Direndra Sharma. For first time, antagonists and protagonists of nuclear technology shared the platform to discuss a wide range of topics.
The Government of Karnataka held a national workshop on nuclear power projects with special reference to Kaiga at Bangalore on December 10 and 11, 1988. Shri S.R. Bommai, Chief Minister of Karnataka inaugurated the workshop. Speakers included planners, economists, professors, anti nuclear activists and journalists.
Emotional outbursts and occasional melodrama sustained the audience' interest. Speakers who are used to sober discussions found it harder to cope with some amount of heckling! It was something like the massacre of the innocents. Dr. Srinivasan rose to the occasion. He marshaled facts and figures to articulate eloquently the international consensus on nuclear power.
While Shri Bommai was speaking, power failed prompting him to say that we cannot live without power. A picture in the Indian Express vividly portrayed the situation!
PTI Feature