Global radionuclide contamination resulting from the Chernobyl accident (which occurred on 26 April 1986 at the Chernobyl nuclear power plant, Ukraine) was estimated at 34 million hectares. Due to the accident, the environment was contaminated with radioactive materials with a total activity of around 12.5 EBq (one EBq is equal to 1018 Bq or one billion billion Bq). Of the total contaminated area, 20 million hectares of highly polluted radioactive soils were in Europe, 70 percent of which were in Eastern European countries: Belarus, Ukraine and the Russian Federation (Boubriak et al., 2016). The map presented in
Figure 5 illustrates the radioactive pollution of European territory in 1986 (Chernobyl Forum Expert Group on Environment, 2006). The zones with the level above 40 kBq/m2 were considered as zones with enhanced contamination, and zones with the levels above 1 480 kBq/m2 were considered as highest contaminated zones (Karaoglou et al., 1996).
In the aftermath of the accident, the main source of soil pollution was radionuclide fallout and the transfer of radionuclides to the soil from surface and groundwater. After measures were taken to limit exposure to the Chernobyl reactor #4 breach (Yablokov et al., 2016), direct exposure of radionuclides stopped. However, the enormous volume of radionuclides released has polluted soil, water and air throughout the northern hemisphere, and can be detected in all natural resources, including flora and fauna (Boubriak et al., 2016; Yablokov et al., 2016). A sarcophagus was erected in 1986 over the destroyed reactor #4 in order to reduce the emissions of radiation (IAEA, 2006). However, the construction had partially collapsed and the reactor continued to pose a danger (Yablokov et al., 2016; Yablokov, Nesterenko and Nesterenko, 2009). There was a risk of collapse of the sarcophagus (IAEA, 2006). A USD 2.5 billion project to construct a “New Safe Confinement” over the old sarcophagus was completed in 2019 with funding from the European Bank for Reconstruction and Development (EBRD) and other donors. The New Safe Confinement is designed to prevent the release of radioactive contaminants, protect the reactor from external influence, facilitate the disassembly and decommissioning of the reactor, and prevent water intrusion (EBRD, 2020). The New Safe Confinement will effectively prevent further emissions of contaminated materials from the old reactor. Obviously, the contaminants that have already been released will continue to pollute the soils onto which they deposited.
Radioactive dust occurs quite often and contaminates neighbouring territories, including Kyiv, the capital of Ukraine. In 1986-1988, large quantities of radioactive waste and extremely polluted soils were buried in the ground within 10-15 km of the old reactor. In 2006 there was concern that these burial sites might have been constructed to inappropriate appropriate standards to meet the safety regulations for hazardous waste (IAEA, 2006). In 1986, immediately after the accident, an area of 400 000 ha in Ukraine surrounding the reactor was evacuated (known as the 30-km exclusion zone) and, as of 2020, there is still no activity there besides the tour to Chernobyl station: the number of tourists increased to 108 000 people in 2019. There are two main motivators: the impact of the movie “Chernobyl” issued in 2019, which was at the top of the world’s rating and the simplification of entrance to the zone by on-line registration. The Decree of the President of Ukraine was issued in July 2019 which supported building of infrastructure, ensuring security for attendance of the Chernobyl Zone and creating a selected rivers’ route for biodiversity observation (Presidency of Ukraine, 2019).
Further away from the reactor agricultural activities were prevented on large areas that were extremely polluted by radionuclides in Ukraine (20 4000 ha), Belarus (210 000 ha), and the Russian Federation (17 000 ha) (Aleksakhin et al., 2006). During the explosion at the reactor, the following radioactive elements were emitted from the Chernobyl reactor: ruthenium-103/106; iodine-131; caesium-134/137; strontium-90; plutonium-238, plutonium-239; plutonium-240; and americium-241. At a later stage, following radioactive decay, the main soil contaminants were caesium-137, strontium-90, plutonium-241 and americium-241.
Maps of soil pollution by these radionuclides in Ukraine are presented in Figure 6 (a to c) (Vidavnitstvo, 2000). It should be noted that over the subsequent years, pollution from americium-241 will have increased mainly due to the transformation of other radioactive isotopes into americium (Figure 6d), which is predicted to be the main source of radioactive soil pollution in 2050 (Vidavnitstvo, 2000). Given the absence of anthropogenic activity in this area for decades, biodiversity has been recovered and enriched.
Radioactive pollution in 1995 by 137Cs in a) Belarus and b) the Russian Federation is presented in Figure 7.
Over the years, the level of air and water pollution has decreased, however, secondary pollution appeared due to the transfer from “soil to plant”, where radionuclides have moved to the flora and fauna from polluted soil and water (Gudkov, 2006). Humans are affected by the consumption of contaminated agricultural products, which exceed the permitted levels of radionuclides, especially long-rooted crops such as potatoes, beets or carrots, berries and mushrooms. The radioactive contamination that leached from the soil surface to deeper layers is remobilized to the surface through transfer through the plant’s roots and shoots. In addition, fish, meat and dairy products have become sources of secondary radioactive pollution (Yablokov, Nesterenko and Nesterenko, 2009), due to the consumption of contaminated grass by animals.
Since 2010, a third additional source became apparent with the migration of radionuclide pollution as a result of frequent fires in the area around the Chernobyl reactor and dust storms that carry contaminated particles over long distances by wind and precipitation (Yablokov et al., 2016).
Due to the total absence of measurements of radioactive fallout in the first month after the accident and the very limited and fragmented measurements in the following years (1986-1989), there are large inaccuracies in the data on levels of soil pollution by radioactive elements. The intensity of radioactive fallout was extremely diverse (Yablokov et al., 2016). The existence of numerous previously unknown “hot particles” and different combinations of radionuclides posed specific problems. The lack of data, in particular in the former USSR in 1986-1989, and after 2000 in Belarus, continues to limit the availability of information on the pollution. The data on soil pollution by radionuclides reported after the accident by governmental organizations, international agencies, NGOs and scientific communities varies by more than three orders of magnitude (Bubryak et al., 1992).
Radiological monitoring has been carried out continuously in Ukraine in accordance with the “Law of the Lands polluted by the Chernobyl accident” (1991) and the “Regulation of the control of radioactivity in the Exclusion Zone”. Belarus and the Russian Federation enacted similar laws, respectively “On social protection of citizens affected by the Chernobyl disaster” (1991) and “On social protection of the citizens impacted by radiation after the accident at Chernobyl nuclear station” (1991). However, since 2010, monitoring activities have decreased in all three countries. The State service for Emergency Situation in Ukraine is responsible for monitoring radiation pollution; that agency also carries out monitoring in the event of accidents, including those with hazardous wastes and chemicals release. The Department of liquidation of the consequences of the catastrophe at the Chernobyl atomic station within Ministry of the Emergency of the Republic of Belarus and Ministry of the Russian Federation for civil defence, emergencies and elimination of consequences of natural disasters perform similar functions. Roshydromet (the Russian Federation) is the main owner of the electronic archive related to environmental pollution, administrative and organization decisions done by government of the former USSR in 1986-1991 and further by the Russian Federation government for the elimination the consequences of the Chernobyl catastrophe. This archive includes the catalogue of maps illustrated the radioactive contamination mainly during first three years after the accident.
Belarus, Ukraine, the Russian Federation, the Republic of Moldova, Kazakhstan, Kyrgyzstan, Armenia, Azerbaijan, Georgia and Turkmenistan all have state registries of pesticides and agrochemicals, while Uzbekistan and Tajikistan operate with simpler state list of pesticides and agrochemicals.
The Ukrainian Institute of Agricultural Radiology is a leading unit in Ukraine for the establishment of standards for agricultural activities and products in the radionuclide-polluted zone following the Chernobyl accident. Ukraine approved the document “Recommendations of agricultural production in conditions of radioactive pollution” (Lyaschenko, Loschinov and Prister, 2016). However, in practice, the implementation of these standards is very limited. Since 2017, the National University of Life and the Environment (Kyiv, Ukraine) provides training in “Experimental Radioecology and Radiobiology” and participants learn how to assess whether soils and agricultural products are contaminated with radionuclides and their impact on human health.
Belarus has been continuously developing and implementing programmes on the mitigation of the consequences of the Chernobyl accident. Under the 5th programme (2011-2020), the country reported the existence of 201 053 ha of radioactively polluted soil in the Gomel region and 43 450 ha in the Mogilev region (Podolyak and Karpenko, 2016). In Belarus, the main unit responsible for monitoring soil pollution by radionuclides is the Institute of Radiology of the Belarusian Academy of Sciences. This organization also develops recommendations for the cultivation of agricultural products in radioactive soils.
The main sources of soil pollution caused by agricultural activities are due to the use of fertilizers (trace elements), veterinary products, and plant protection products. Nutrient pollution, for example excessive nitrogen & phosphorus, is a source of pollution of surface water and groundwater, leading to eutrophication. There are two main causes of the widespread of soil pollution by pesticides in Eurasian countries. The first cause is the continued intensive use of modern pesticides by the large-scale agro-holdings and in less extent by small-scale farmers. The second cause is use of banned and obsolete pesticides including some unidentified chemicals left by “collective farms” after the intensive use of agrochemicals during the Soviet era. There is currently an increase in agricultural production in Ukraine and Belarus, after a long period of stagnation, when only limited amounts of fertilizers and pesticides were applied between 1990 and 2000. As a result the amount of pesticides currently used in Ukraine has increased, where the contribution of agriculture to GDP has reached 60 percent from 2013 to 2017, mainly through crop production inputs (Kravchuk, 2018).
There are further concerns for soil pollution relating to the use of illegal and counterfeit pesticides in the region (Economic Truth, 2005) (UNICRI, 2016). The issue has been particularly highlighted in Ukraine due to:
For example, in 2015, a factory illegally producing pesticides from raw materials smuggled from China was closed in the Kyiv region of Ukraine (Security Service of Ukraine, 2015).
In Belarus, the proportion of GDP related of agriculture increased by 6 percent between 2015 and 2019 (The Global Economy, 2019). This was accompanied by an increase in the consumption of fertilizers and pesticides, produced locally by “Belarus Potassium” and “Grodno Nitrogen” (Doleba Antonina, 2012). Belarusian agriculture has been boosted by increased exports of agricultural products to the Russian Federation. Before the international sanctions were applied in 2006, products were supplied by the nearest European Union countries, Poland and the Baltic States.
The upward trend in agricultural production in Ukraine and Belarus could lead to diffuse soil pollution in the near future. In other countries such as Georgia, agricultural production has not increased much. The contribution of agriculture to GDP was about 10 percent in 2012 and was estimated at 8.2 percent in 2019. For the Republic of Moldova and Kazakhstan, the decline in agricultural production started in 1990 and continued to 2019 (Trading Economics, 2019a, 2019b, 2019c). For example, the contribution of agriculture to Moldovan GDP decreased from 30 percent in 1995 to 8 percent in 2018 (The Global Economy, 2018), while that for Kazakhstan decreased from 5.66 percent in 2007 to 4.36 percent in 2017 (Plecher, 2019).
The second concern about soil pollution is connected with the use of obsolete pesticides (banned, unused and unidentified) that remained in the countries after the Soviet era. These old chemicals, which have been banned since the 1990s (such as DDT), were often stored inappropriately in uncontrolled conditions. In addition to stockpiles, there are OPs burial sites that have been abandoned. OPs were occasionally excavated by local citizens, repackaged and sold illegally, sometimes stolen and applied on local farms. According to Vijgen and Egenhofer (2009), the quantity of OPs in Eurasian countries in 2009 was about 200 000 tonnes. Subsequent inventories carried out in 9 countries of the Eurasian region (Table 2) estimated the quantity of OPs to be approximately 131 950 tonnes (IHPA, 2016).
The first assessment of OPs in Armenia was done in 2002-2005 in the framework of the GEF/UNIDO project “Enabling activities to facilitate early action in the implementation of the Stockholm Convention on POPs”. This assessment identified 650 tonnes of POPs (IHPA, 2017a). A further inventory was undertaken in 2012 within the EC-funded FAO project “Improving capacities to eliminate and prevent recurrence of obsolete pesticides as a model for tackling unused hazardous chemicals in the former Soviet Union”. This inventory identified 26 dumping sites and 35.7 tonnes of OPs (IHPA, 2017a). According to data from the Armenian Ministries of Commerce, Industry and the Environment, in 2017 there were 605 tonnes of OPs in burial sites and 150 tonnes of OPs in storage in the country. There were also 100 tonnes of expired medicines and 1 720 tonnes of PCB. Around the Nurarashen burial site there were approximately 8 578 tonnes of POPs, leading to about 3 000 m3 of polluted topsoil.
The various inventories undertaken in the Eurasian region have argued that statistical data on OPs and POPs have not been collected in a systematic way. The pre-existing data are insufficiently defined and unreliable, leading to uncertainty in the stocks and use plans (IHPA, 2017b, 2017c, 2017d, 2017e, 2017f, 2017g). For example, in Ukraine in 2005, the number of OPs was assessed at 22 000 tonnes in 5 000 deposits, while, according to the inventories carried out in 2007, larger quantities were reported, with 25 000 tonnes in 4 000 depots (Gurzhiy, 2007). The 2015 inventory again reported about 24 500 tonnes, despite some 35 000 tonnes being exported for destruction in the period 2007-2015 (Ministry of Ecology and Natural Resources of Ukraine, 2016).
At the beginning of 2000, various programmes, with the support of international organizations, began to safeguard and eliminate OPs throughout the Eurasian region. Thus, under the Arctic Council Action Plan to Eliminate Pollution of the Arctic (ACAP), approximately 2 000 tonnes of OPs were repackaged in the north west of the Russian Federation (Vijgen and Egenhofer, 2009). In 2006-2007 with the support of the World Bank, 1 150 tonnes of POPs and 1 060 tonnes of PCB and PCB-polluted soils in the Republic of Moldova were safeguarded and exported for incineration (Plesca et al., 2007). The Dutch Ministry of Foreign Affairs, in cooperation with the DOEN Foundation from the Netherlands and PSO (non-governmental organization for capacity-building in developing countries), financed the risk mitigation of OPs in Georgia, Kyrgyzstan and the Republic of Moldova during 2005-2008, when approximately 400 tonnes of OPs were repacked and safely stored. In 2015, at the Nubarashen pesticides landfill (Armenia), a drainage system was installed and the landfill was fenced (IHPA, 2017a). In 2012, Belarus, with support of the GEF safeguarded and repacked 2 103 tonnes of OPs in Slonim. One thousand eight hundred tonnes of the repacked materials were exported and eliminated in Germany (IHPA, 2017b).
During 2010-2019, awareness throughout the region of the risks of soil pollution by OPs had increased significantly from that in 2000. With support from international organizations, several thousand tonnes of OPs and PCB were collected, repacked and exported for elimination by high temperature incineration, primarily in Germany, Poland and France. Many internationally funded projects included the training of local government officials in the safe management of OPs and POPs. Belarus has directly invested USD 25 million of its own funds in a hazardous waste storage in the Gomel region (IHPA, 2017b). Significant awareness-raising and financial support from GEF, FAO, EC, and the World Bank have contributed to the mitigation of risks from of OPs and POPs and a reduction of their total quantity across the Eurasian region. Some projects have also excavated and incinerated highly polluted soils.
A further concern is the level of pesticides and their degradation products that remain in the soil from the intensive use of pesticides in the 1980s on the Soviet “collective farms”. The farms were obligated to use the quantities of pesticides that were supplied annually under the centralized state economy (Pryde, 1971). Barron and his collaborators carried out a four-year study on inherited organochlorine pesticides in topsoil and raw food on the sites of two collective farms in Tajikistan. They observed that there were still organochlorine pesticides in the soil up to 1.3 mg/kg and a limited upward transfer in the food chain with 0.2 mg/kg found in dairy products (Barron et al., 2017).
Sharov and co-workers reported 424 toxic hotspots areas in eight countries of the Eurasian region (Armenia, Azerbaijan, Kazakhstan, Kyrgyzstan, Russian Federation, Tajikistan, Ukraine and Uzbekistan) in the framework of data collection by Pure Earth (Sharov et al., 2016). This non-profit organization launched the Toxic Sites Identification Program (TSIP) in 2005, which aims to identify and assess polluted sites in low- and middle-income countries. The most commonly identified contaminants in the region are radioactive elements, the trace elements lead, arsenic, mercury, chromium, cadmium, and pesticides (Table 3). These sites pose risks to the health of about 6.2 million people.
By 2020, the area of polluted soils in the Russian Federation was estimated at 3.6 million ha, of which 1.4 million ha was agricultural land. The areas polluted by trace elements and oil-products was estimated at 730 000 ha and 100 000 ha respectively.
In Azerbaijan, polluted soils are estimated at 33 300 ha, of which 11 143 ha are polluted by petroleum products, 11 000 ha impacted by mining products, and 5 000 ha by construction waste (Krasilnikov et al., 2019).
For Armenia, Azerbaijan and Georgia information on the distribution of the main polluted areas was reported by UNDP, UNEP and OSCE (2004), and several maps were produced, identifying the main sources of soil pollution such as mining and industrial activities, pesticides and the use of low-quality irrigation water.
An analysis of the major pollution sources in Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan (Central Asia) was carried out by the Zoï Environment Network (2013). The report covers current and past polluting activities, such as oil and gas extraction industries, mining (including uranium), chemical production activities, waste disposal, and military test ranges. Several maps were produced to illustrate the spatial distribution of these polluted sites and the populations in these countries that they are likely to impact.
Soil pollution monitoring in Ukraine is based on the Law on Environmental Protection (1990), and several national laws, such as the Decree of the Cabinet of Ministry on Soil Monitoring (1993), and the Decree of the Cabinet of Ministry on State Socio-Hygienic Monitoring (2006). Hydro-meteorological stations monitor soil pollution by pesticides, trace elements and other chemicals in industrial regions and cities. Soil sampling is carried out every five years. In Mariupol and Kostantinivka, in the Donetsk industrial region, soil sampling is undertaken annually. The State Ecological Inspectorate monitors air, water, soil and waste in industrial zones. Samples are tested for 27 indicators at 125 sites in 42 localities of Ukraine, and among the substances monitored are: phenol, benzene, oil-products, and the trace elements cadmium, copper, iron, lead, and manganese (Ministry of Ecology and Natural Resources, 2017). The number of indicators, localities and sites monitored has decreased since 1999, when 33 indicators were monitored in 162 sites in 53 localities (Vidavnitstvo, 2000). The monitoring data are available to professionals and the general public through the portal of the Ministry of Energy and Environmental Protection (Ministry of Ecology and Natural Resources of Ukraine, 2017). Based on the monitoring undertaken in 2017, the State Ecological Inspection has created a list of the top 100 enterprises that pollute the air, soil and water largely. The classification of polluted regions also showed that 66.4 percent of all waste accumulated in Ukraine was in the Dnipropetrovsk region (Ministry of Ecology and Natural Resources, 2017).
In Georgia, the National Environmental Agency of the Ministry of Environmental Protection and Agriculture monitors soil, water and air pollution. The Department of Ecological Expertise and Inspection of the Ministry of Environmental Protection has a function of controlling the impact of pollution on the environment, including the soil. The Ministry also carries out various geo-monitoring assessments in the event of natural or anthropogenic disasters (UNDP, 2010). In 2015, the country launched an interactive soil map, which is part of the “Atlas of forests and land use in Georgia” (Ministry of Environment and Agriculture, 2015) and enables data to be analysed at the national and regional levels including those about soil pollution. The map is managed by the Ministry of Environmental Protection and Agriculture with the support of the Institute of Global Resources.
In Kazakhstan, the State Cadastre of Natural Resources collects data on soil pollution. However, the public does not have access to these data and research institutes can receive data only on request. Soil monitoring is carried out annually to assess the concentrations of trace elements; concentrations of petroleum substances or pesticides are analysed occasionally upon requests. The country has the State Cadastre of Waste Collection operated by the Ministry of Ecology, Geology and Natural Resources. However, the data presented in the Cadastre are rather general with very limited data on soil pollution (Ministry of Ecology, 2018). The Consolidated Analytical Report on the State and Use of the Land is issued by the Ministry of Agriculture (2019) on a yearly basis. It includes the monitoring of soil data, which is organized by the State Committee on Soil Resources and carried out by the Department of the Soil Cadastre - a branch of the State Corporation “Government for citizens”. Monitoring is carried out at 630 sites in all regions of Kazakhstan, with the exception of the Mangistausskaya region. Each monitored site has an official record, which contains a table of the measured parameters and recommendations. In 2018, 9.35 million ha of agricultural soils were monitored. Soil pollution in industrial areas is monitored by the industrial enterprises themselves and the data are not presented in the Consolidated Analytical Report and are not available to the public.