Text by Marilyn Smith / Photos by Nigel Dickinson
Six months after Chernobyl’s spring rain of radionuclides it became clear that harvests would arrive hand-in-hand with economic hardship. The fields and forests that dominate the surrounding landscape looked healthy enough, but high levels of radioactivity made it necessary to destroy 500 000 tonnes of grain, 300 000 tonnes of milk and 80 000 tonnes of potatoes.
|In Ukrainian, ‘chornobyl’ comes from the words for ‘black’ (chornyi) and ‘grass’ (byllia) – a reference to the fertile land on which the nuclear power plant was built.|
“Agriculture is the most important area for recovery and development,” says Vladimir Tsalko, Chairman of the Committee on Problems of the Consequences of the Catastrophe at the Chernobyl NPP. “We must also deal with the problem in finding new ways to use our natural resources.” For Belarus, a country in which agriculture is the mainstay of rural life and forestry is one of the most valuable natural resources, these are significant challenges. Shortly after the disaster, radiation monitoring confirmed that 25% of farmland (1.8 million hectares) and 20% of forests posed health hazards and needed to be taken ‘out of commission’. But the need to restrict access to vast tracts of land also created a unique research opportunity.
“Before Chernobyl, almost everything science knew about radiation effects on the environment was learned from small-scale tests carried out in laboratory settings,” says Juri Bondar. “Here we deal with the real thing, on a very large scale, on a day-to-day basis.”
“Here” is the State Polessje Radiation-Ecological Reservation, a science centre situated on the most contaminated land on the planet; Bondar is the Reservation’s deputy director for science. Polessje suffered Chernobyl’s worst blow. In addition to receiving large amounts of the most widespread radionuclides (caesium-137 and strontium-90), the area absorbed virtually all of the longest lasting (plutonium-238, -239, and -240). The latter means the area will remain an ‘exclusion zone’ for 25 000 years.
Guarded gates, road blocks and warning signs serve as a constant reminder that the Reservation lies in what is commonly known as ‘the dead zone’. Thus, it is somewhat surreal to drive past dense forests, carefully cultivated fields and hand-painted portraits of local wildlife – bison, wild boars, moose, etc. In fact, it is the very liveliness of the reservation that makes it such an enticing study environment.
|In the earliest days of spring, it is easy to think of the Exclusion Zone as a ‘dead’ area. But hand-painted signs attest to the abundance of wildlife in an area that has virtually no human influence.|
“Our mandate is to observe the dynamics of radionuclides in soil, water and fauna, as well as survey changes in the population of animals and plants, including rare species,” says Bondar.
Belarus recognized that the opportunity to conduct radiological research in an area that has virtually no human influence could attract scientists from around the world – and sought IAEA TC assistance to acquire expertise and equipment. On any given day, Reservation scientists and technicians measure and analyse radioactivity in every type of organic material imaginable, thereby creating and maintaining baseline data for visiting investigators.
|Testing the radiation levels of wood chips from various areas of the Reservation is one way to map both contamination levels across the region and the migration routes of radionuclides through the ecosystem.|
“Creating a modern and well-equipped laboratory in Polessje is helping to increase the quality of scientific research undertaken in the Chernobyl region,” says Andrei Chupov, TC Programme Management Officer. “In addition to monitoring the region, the centre will develop and verify models of radionuclide migration in various bio-scenarios.”
The Belarusian Research Institute for Soil Science and Agrochemistry (BRISSA) also has a keen interest in remediation – and is another institute that attributes its enhanced scientific capacity to IAEA TC support for fellowship training, expert advice and the purchase of new equipment at its own radiological laboratory in nearby Gomel.
One of BRISSA’s goals is to find ways to bring contaminated land back into active duty while minimizing the risk of radionuclides entering the food chain or migrating into waterways. The Institute has established demonstration fields in contaminated areas, on which production methods are carefully controlled and radiological parameters closely monitored.
|BRISSA scientists study the finest details of a large variety of plants to better understand how radionuclides influence their growth and suitability for food products – and to determine their capacity to be ‘put to work’ on the task of soil remediation.|
BRISSA experiments show that it is possible to reduce radionuclide uptake by plants, increase soil fertility and improve animal productivity by rotating crops, using particular ploughing techniques and applying fertilizers (e.g., lime, potassium and encapsulated slow release nitrogen fertilizers and green manures grown under low input regimens including biological nitrogen fixation). BRISSA regularly hosts demonstration days, on which they invite local farmers to learn about radionuclide migration and how to apply effective soil remediation techniques on their own land.
As time passed, BRISSA scientists became increasingly intrigued by the challenge of ‘containing’ radionuclides throughout the decay period – a task they believed could be accomplished by putting plants to work. After extensive studies of various candidates, BRISSA found a crop with the right qualifications.
“We demonstrated that spring rapeseed has an uptake rate that is up to three times more efficient than other grains,” says Yuri Putyatin, Group Leader in BRISSA Laboratory of Radioecology. “But we also demonstrated that only 3% to 6% of radionuclides from this overall uptake make their way into the parts of the plant that could potentially enter the food chain (i.e. could travel from soil to plant to foraging animal to human). The vast majority are concentrated in other parts of the plant – the straw, the roots, the seed pods, etc.”
With these characteristics, Putyatin recognized spring rapeseed as a plant that could ‘contain’ radionuclides during the growing season yet still held potential for commercial products after harvest. He went on to prove the theoretical idea that one could produce ‘clean’ oil from contaminated rapeseed.
“Oil repels radionuclides,” says Putyatin. “During the pressing process, they become concentrated in the by-products such as straw, which we could then plough back into the soil, effectively creating a recycling process – uptake, extraction and redeposit – that ensures contamination is not transferred into agricultural products.”
The Institute has since refined techniques for producing industrial and edible rapeseed oils, thereby creating a new product line with growth potential and generating demand for a new agricultural crop. Recognizing that it may not be feasible for many farmers to switch from wheat and/or rye crops to rapeseed, BRISSA also kept looking for new ways to use traditional crops. The Institute found that, as with rapeseed, radionuclides tend to concentrate in the bran of wheat and other grains. The next logical step was to develop other means of removing the contaminated exterior and utilizing the clean core.
|The combination of basic science and technology creates new opportunities in a village near the Exclusion Zone. Once scientists had proven that radionuclides concentrate in the bran of wheat, technologists developed a new milling technique that separates the inner core to produce ‘clean’ flour.|
One of their ideas is now the centrepiece of a demonstration plant in nearby Khoiniki, which processes 500 kg/hour of ‘clean’ high-grade flour from locally grown wheat. A customized mill takes the idea of ‘separating the wheat from the chaff’ one step further by automatically shaving the husk off of each kernel of wheat.
In accordance with government regulations, all industrially processed crop products undergo double safety checks for radiation levels. In the first step, sample seeds are collected and tested before harvest; the results determine whether the grain is suitable for food or fodder. Using equipment supplied by the TC programme of the IAEA, the flour mill itself performs the second safety check after processing.
BRISSA continues to explore new directions and recently demonstrated that distillation is also an effective means of extracting radionuclides. They are now in the process of reopening a rectified alcohol factory.
It could be said that nature and basic science are contributing to a brighter economic future for farmers in the Chernobyl region. Lands that were affected most by caesium-137 and strontium-90 are beginning to recover and will be usable again in the next 10 to 20 years, and BRISSA’s efforts are having a positive impact. But true recovery of the agriculture sector is partly a question of economics.
“Belarus is export-oriented in the agricultural sector, with Russia being the largest market,” says Putyatin. “But in reality Russian soil is more fertile and Russian labour is cheaper. In 10 or 20 years, we may have cleaner soil, but we may not be able to compete.”
This factor reinforces the need to address a broad range of environmental issues and highlights another of the Reservation’s strengths: its ability to facilitate transfer of knowledge across disciplines and sectors. For example, it has been demonstrated that what’s true of grains is true of trees – i.e., that radionuclides concentrate in the bark and external wood. This has led to new methods for harvesting and cutting timber, some of which is once again being used for construction and other purposes. In fact, it is quite common to see tree-length piles of bark along the roadside in rural villages – evidence that residents have learned to reduce radiation exposure risks by using only core wood for cooking and heating.
As reporters prepare to drive out of the Exclusion Zone, Andrei Chupov emphasizes that the Reservation will substantially increase knowledge on how to deal with future accidental releases, to both minimize and eliminate the radioecological consequences, and to plan preventive measures against the spread of radionuclides through waterways and wildlife vectors.
|Watchtowers and fire cabins dot the landscape inside the Reservation, a constant reminder that preventing fire is a top priority in the bid to contain radionuclides in soil and plants.|
Nonetheless, the biggest risk comes neither from waterways, nor from wildlife. Bondar directs all eyes towards wide swaths of ploughed land between wooded areas, high water levels amongst trees, watchtowers dotting the horizon and wooden cabins with fire fighting gear at the ready. “Scientists on the Reservation investigate ways to contain radionuclides,” he says. “But the reality is that if a fire broke out, we would have another Chernobyl on our hands – all of the contaminants contained in organic matter here would be released and redistributed.”
Minutes later, Chupov points out that voices filtering in over the walkie-talkie mounted below the dashboard belong to forest rangers who report in hourly. Almost as an afterthought, he adds that the Agency TC programme helped purchase the radios and other special facilities aiming to enhance the fire prevention service in the Reservation.
“Technical cooperation isn’t always about high-tech equipment in laboratories,” says Chupov. “It doesn’t do much good to monitor radioactivity in soil if no one can communicate that a fire has broken out on the far side of the Reservation.”