CERAD has performed a successful sampling expedition within the so-called security zone, a 30-kilometer zone around Chernobyl. Expedition was organized in cooperation with National University of Life and Environmental Sciences of Ukraine (NUBiP).
Took samples from the most contaminated lake
From 18th to 24th of May, scientists took samples of water, fish, clams and sediments from the two most polluted “lakes” in the zone: cooling pond, which was the reservoir for cooling water and Lake Globoka, a lake without an outlet. Water was fractionated on site, using ultrafiltration to get information about the transport of colloids.
Still high levels of radioactivity in fish
Pike, perch and roach were dissected and analyzes will provide information on radionuclide distribution in various organs of fish.
- The fish are still very radioactive, and a fundamental issue is whether fish is able to adapt to the highly radioactive environment after several generations, says CERAD leader Brit Salbu.
"Hot" particles were found in the sediments, and dissection of the filtering organisms, like clams, should show whether such highly active particles could be taken up.
Some species are more sensitive to radiation
Samples of plants, especially pine and birch, soil and soil organisms (earthworms) were collected in the Red forest, a contaminated forest area near the reactor.
After the accident occurred, many trees dies of exposure in this area. Extensive countermeasures were implemented here; trees and other debris were buried and covered with clean soil. The uptake in trees shows that radioactive substance strontium (Sr-90) is very mobile and is absorbed into the overlying vegetation, particularly trees with adequate depth of roots.
Leaves of birch and needles of pine contain up to 1 million Bq/kg dry weight. A fundamental question is why some species, especially pine, are more sensitive to radiation than others.
Lichens were also collected from the trees, and there is no knowledge about the uptake of radioactivity in these lichens so far. Earthworms were also collected in different areas.
Human footprint has greater effect than radiation
Additionally, the groundwater was fractionated to obtain information on colloid transport, especially of plutonium, as we have seen in other highly polluted areas.
- Today, the safety zone around Chernobyl, including Red forest, is a lush green area, where biodiversity is far greater than for 30 years ago - with red foxes at close range. This is because 340,000 people have been evacuated, and that the human footprint poses a greater pressure on the environment than radiation, tells Salbu.
The expedition was led by Professor and CERAD leader Brit Salbu and Professor Valeryi Kasparov from Ukraine and consisted of 15 participants.
Salbu visited the area for the first time in 1990. At that times, it was part of the Soviet Union.
Participants from Norway were Lindis Skipperud, Ole Christian Lind, Hans-Christian Teien, Marit Nandrup Pettersen, Emmanuel Lapied from IMV, Line Nybakken from INA and Nina Bratteteig from the NRPA.