Navigation Links
Green sludge can protect groundwater from radioactive contamination

Radioactive waste decaying down at the dump needs millions of years to stabilize. The element Neptunium, a waste product from uranium reactors, could pose an especially serious health risk should it ever seep its way into groundwater even 5 million years after its deposition. Now, researchers at the University of Copenhagen have shown the hazardous waste can be captured and contained. The means? A particular kind of green goop that occurs naturally in oxygen-poor water.

Bo C. Christiansen is a geochemist at the University of Copenhagen who specializes in "green rust". In a recent article published in the prestigious journal Geochimica et Cosmochimica Acta, Christiansen describes how green rust is able to, so to say, encapsulate and contain neptunium. It's an insight that can greatly influence how and where to dispose of radioactive waste.

"Our study shows that even the safest encapsulation of radioactive waste could be made safer if radioactive waste canisters are buried in a place where green rust will form," explains Christiansen.

For years green rust was perceived as a problem. The substance was investigated primarily by material scientists who wanted to know how to avoid green rust formation in reinforced concrete. In recent years however, a group of chemists, physicists and geologists at the Department of Chemistry's Nano-Geoscience Research Group have been studying the substance's beneficial properties. The results have exceeded all expectations.

"Neptunium is a relatively exotic problem. Not a lot of people need to safeguard a radioactive waste depot. But green rust appears to be effective against nearly any kind of pollution," says Bo Christiansen.

Green rust is a type of clay referred to as an anionic clay. Because it consists of iron which has not entirely rusted, green rust has an electron deficit. This makes it react very readily with other pollutants, some of which are quite prevalent.

"A while ago we showed how green rust can react with the carcinogenic chromium (6) and convert it to chromium (3). "Besides being non-toxic, chromium (3) is one of the trace elements that the human body needs," says Christiansen.

Large quantities of green rust are rarely present at any given moment due to it's very high level of reactivity. On the other hand, it's easy to make. Green rust will form if iron sulphate and caustic soda are present in water. But it won't last long. As soon as oxygen is added to the mix, the rust will become ordinary red rust, known by its ochre characteristics.

Experiments demonstrating green rust's ability to immobilize neptunium have been conducted partly at SKB Swedish Nuclear Fuel and Waste Management's full scale pilot research facility at Okskarshamn on the Swedish east coast and also in part at the Karlsruhe Institute of Technology in Germany.

Typically, radioactive waste is disposed of in iron-lined copper canisters. This is suitable as long as the canisters are surrounded by water. However, any future ice-age will draw water levels downwards. Should the copper dry, it will begin to decay. And as the copper disappears, it will only take a short time for the iron to begin rusting away. Ultimately, the radioactive waste gains entry to the groundwater. Therefore, to ensure the security of radioactive waste, green rust could be established to surround the canisters.

"Green rust is no quick-fix to clean up after pollution that suddenly presents itself. But our experiments have shown the surprising result that nature can help to clean itself. Even when the pollution is with a substance as serious as neptunium," says Bo Christiansen who expects the results to inform and be applied to the design and modeling of future radioactive storage.


Contact: Jes Andersen
University of Copenhagen

Related biology news :

1. MU scientists go green with gold, distribute environmentally friendly nanoparticles
2. Carbon dioxide scrubber captures greenhouse gases
3. Green coffee-growing practices buffer climate-change impacts
4. Greenhouse gas auction revenues can help cut Md. electric use significantly, says study
5. Green tea may delay onset of type 1 diabetes
6. Potent greenhouse gas more prevalent in atmosphere than previously assumed
7. What is really happening to the Greenland icecap?
8. A green future for scrap iron
9. Expert recommends town councils to design low-allergy impact green spaces
10. Parasite-resistant peppers green alternatives to chemical pesticides
11. MIT analysis shows how cap-and-trade plans can cut greenhouse emissions
Post Your Comments:
Related Image:
Green sludge can protect groundwater from radioactive contamination
(Date:11/17/2015)... , November 17, 2015 ... au 19 novembre  2015.  --> Paris ... --> DERMALOG, le leader de l,innovation biométrique, ... la fois passeports et empreintes sur la même surface ... les passeports et l,autre pour les empreintes digitales. Désormais, ...
(Date:11/12/2015)... CAMBRIDGE, Mass. , Nov. 12, 2015 /PRNewswire/ ... Broad Institute of MIT and Harvard for use ... chemical discovery information management tools. The partnership will ... share both biological and chemical research information internally ... tools will be used for managing the Institute,s ...
(Date:11/9/2015)... , Nov. 09, 2015 ... addition of the "Global Law Enforcement ... offering. --> ) has ... Law Enforcement Biometrics Market 2015-2019" report ... and Markets ( ) has announced ...
Breaking Biology News(10 mins):
(Date:11/30/2015)... Md. , Nov. 30, 2015 ... development company committed to the fostering and monetization ... the current and prospective initiatives designed to create ... Chief Executive Officer of Spherix. "Based on published ... future licensees exceeds $50 billion and Spherix will ...
(Date:11/30/2015)... , Nov. 30, 2015  Champions Oncology, Inc. (CSBR), ... services to personalize the development and use of oncology ... Executive Officer, will be presenting at the LD MICRO ... Pacific Standard Time (PST).  The conference, held at the ... Angeles, CA , will feature 200 small/micro-cap companies ...
(Date:11/30/2015)... 30, 2015 TapImmune, Inc. ... of innovative peptide and gene-based immunotherapeutics and vaccines for ... it will be presenting at the 8 th ... at 2.30 PM PT. Dr. John N. Bonfiglio ... be giving the presentation and will join TapImmune management ...
(Date:11/30/2015)... , Nov. 30, 2015  Aytu BioScience, Inc. (OTCQB: ... and related conditions, will present at two upcoming investor ... an interactive real-time virtual conference, to be held December ... Conference, to be held December 2 nd & ... and streamed live via webcast. ...
Breaking Biology Technology: