Environmentalists alarm over dredging operations in Chernobyl exclusion zone

Chernobyl plant standing on the bank of the Pripyat River. Credit: Vladislav Vorotnikov

Planned dredging operations on the Pripyat River, in the Chernobyl exclusion zone within Ukraine, could release radioactive strontium and cesium which accumulated in the sludge during the first years after the Chernobyl disaster in 1986, a group of Ukraine scientists said in a joint statement.

The huge risks associated with the dredging project are due to the river running so closely to the Chernobyl nuclear power plant and the sludge on the bottom of the river has been accumulating radioactive isotopes for several years, Vladimir Yakushin, deputy director of the Ukraine Institute of Hydrobiology, warned.

“After the Chernobyl disaster, a huge number of radionuclides settled on the bottom of the Kiev water reservoir. It became a buffer zone between the contaminated Pripyat River and the entire Dnepr River. With time, cesium and strontium were absorbed by sludge, and so now they are safely preserved under the water,” Yakushin said.

“If something happens, the water would carry the radionuclides down the current. We could have a second Chernobyl [disaster], as long as we are not able to deal with radioactive sludge yet,” Yakushin added.

The most dangerous radionuclide is strontium-90 and cesium-137. Should this reach the Dnepr, the radionuclides could make two-thirds of Ukraine’s fresh water undrinkable, commented Alexey Vasilyuk, a spokesperson for local environmental protection organisation, Environment-Right-People LLC. The water treatment facilities of Kiev, as well as other major cities in Ukraine, would not be able to cope with the contamination of that kind, and an estimated 30 million local residents could be affected, Vasilyuk added.

Strontium-90 and cesium-137 have half-lives of 29 and 30 years, respectively. This refers to the time required for a quantity to reduce to half of its initial value, hence at least half of the isotopes released during the accident have yet to disappear from the local environment.

Ukrainian Sea Ports Authority (USPA) signed an agreement with local dredging company Sobi LLC, on 31 December 2019, to increase depth on Pripyat River. The works are slated to begin in the first half of 2020. The cost of the contract is UAH9.8 million (USD370,000), and the project intends to connect some midland territories in central Ukraine with the ports on the Black Sea, USPA said.

Sobi LLC intended to remove 100,000 cubic metres of the river bottom, along an area of about 65 km. The task is to ensure an increased depth of 1.6 m to allow commercial ships to pass through, with a width of up to 30 m.

The Pripyat flows eastward through southern Belarus, including the cities of Pinsk and Mazyr, and then passes through the exclusion zone established around the site of the Chernobyl nuclear disaster.

Enhanced monitoring is in order

The main aim of the dredging project is to liquidate the sandbars formed on the Pripyat River over the past few years, with the sand coming down from Belarus, USPA commented. That sand is coming from beyond the 30 km Chernobyl exclusion zone, and scientists confirm it is free from potentially hazardous radioactive isotopes, USPA explained.

“Some preliminary studies on the radioactive contamination [of the river bottom] will be conducted before the dredging operations begin. The project should be greenlit by the Chernobyl exclusion zone administration and should take place under their constant supervision,” USPA promised.

The main types of cargo to be transported through the new Pripyat River are oil, mineral fertilisers, and wood, the Ukraine Infrastructure Ministry said in a November 2019 statement. The main customers are expected to be local mining companies, including Belaruskali, a mineral fertilisers producer and exporter. The project, should it go ahead, has the potential to cut logistics costs on transporting goods to the countries of the Black Sea basin, the ministry said.

The Chernobyl disaster was a nuclear accident that occurred on Saturday 26 April 1986; a reactor at the Chernobyl nuclear power plant exploded and burned, near the city of Pripyat in the north of the Ukrainian Soviet Socialist Republic. It is considered the worst nuclear disaster in history.