Despite the similarities inherited from the former USSR, the three sub-regions currently differ significantly in terms of the strength of their economies and their development priorities. Each countries’ approach and capacity to address environmental impacts, including soil contamination, varies significantly. On this basis, the main causes of soil pollution have been grouped and presented for each sub-region separately.
Waste management is one of the main sources of soil pollution in the region, although the activities that generate it vary between the three sub-regions. As for 2008 the annual quantities of hazardous waste (in kg per USD 1 000 of the GDP) generated by the sub-regions vary significantly, specifically: Central Asia (3 500 kg), Caucasus (350 kg) and Eastern Europe (40 kg) (FAO, 2018; Zoï Environment Network, 2013).
For Eastern European countries, an important source of soil pollution was the radionuclide pollution after the meltdown and fire at the Chernobyl nuclear power station in 1986. Common sources also include past and present military activities, industrial and mining activities, and to a lesser extent, agricultural activities.
In Belarus, the main source of soil pollution is radioactive pollution as the fallout from the Chernobyl accident, which affected about 37 million people (Krasilnikov et al., 2019). Other main sources of soil pollution include industry (machine building, petrochemical and construction activities), urbanization (78 000 ha polluted soil), transport (119 000 ha polluted soil) and agriculture (10 000 ha polluted soil). The impact of agricultural activities is also related to obsolete pesticides (OPs). The estimated inventory of OPs stockpiles within Belarus’ National Implementation Plan for the Stockholm Convention (NIP) in 2007 identified 7 280 tonnes. Of this amount, 2 006 tonnes were repacked from the Slonim landfill and destroyed in Germany in 2012. As of 2017, the remaining OPs amounted to 5 660 tonnes which were located in 146 storehouses of varying quality and security (2 876 tonnes), seven landfills (2 482 tonnes) and one hazardous waste facility (302 tonnes) (GEF, 2017).
Belarus also has problems with soil pollution by liquid PCB. The inventory carried out in 2003-2004 in the framework of the State Scientific Technical programme “Environmental Safety” detected about 5 000 tonnes of PCBs. The hot-spot was found in the city of Lida, Grodno region, where the PCB product “Sovol” was used for the production of paint and varnish over a 30 year period (5 000 tonnes) and the territory became heavily polluted (Kukharchuk and Kazyrenka, 2018). As of 2013, the amount of liquid PCBs decreased by 17 percent following the implementation of the project “Persistent Organic Pollutants (POPs) Stockpile Management” supported in 2011-2012 by the World Bank (POPs Belarus, 2013).
In the Republic of Moldova, agriculture plays an important role in the country’s economy, with approximately 75 percent of the land used for crop and livestock production, and is the main source of soil pollution. The substantial amount of pesticides and fertilizers continues to be used (FAO, 2014; IHPA, 2016; Kravchuk, 2018)) and causes related environmental problems. However, the serious problem of OPs that the country faced in the 1990s and 2000s has almost been solved. The 2003 inventory identified approximately 3 500 tonnes of OPs. Since 2005 the country has been working to safeguard and eliminate stocks using its own resources and with support from the EC, FAO, and other intergovernmental organizations. For example, under the GEF/World Bank Project on “Persistent Organic Pollutants: Stockpiles Management and Destruction” (2006-2010): 3 350 tonnes of OPs have been repackaged, of which 1 292 tonnes were incinerated in France. In 2011-2012 an additional 200 tonnes were repackaged with the Czech Development Foundation. The Republic of Moldova is a leading country in the Eurasian region in terms of OPs developing its national capacity to implement clean-up programmes, the country developed and implemented its own methodology for identifying and characterizing polluted sites and prioritizing risk mitigation activities.
Also in the Republic of Moldova soil pollution from transport is a source of soil pollution by trace elements and petroleum products that is recently attracting the attention of researchers and legislators because of its impact on the local population. It is especially relevant in the capital city, Chişinău.
In the Russian Federation, according to the latest data (Ministry of Natural Resources and Ecology of the Russian Federation, 2018), the principal sources of soil pollution and their main pollutants are:
Urban expansion should also be considered as one of the main drivers of soil pollution, with approximately 74 percent of the population of the Russian Federation living in cities in 2018. Urban sprawl leads to increased volumes of municipal waste and the potential to overload waste management capacity. Increases in vehicle traffic and the expansion of the transport network, with more service stations, airports, and railway and bus stations, all lead to greater emissions and further soil pollution. This is particularly the case for metropolitan cities such as Moscow, St. Petersburg, Novosibirsk, Yekaterinburg, and Nizhny Novgorod (Aleksandrov, 2018). Data for the period 2008-2017 on soil pollution with trace elements identified the main contaminants to be aluminium, arsenic, cadmium, chromium, cobalt, copper, iron, lead, magnesium, manganese, mercury, nickel, and zinc. The mechanical engineering industry has polluted soils the most, often with concentrations more than threefold the permitted level. Conversely, pollution from metallurgical, chemical and construction industries has decreased during the period and is now close to safe reference values (Ministry of Natural Resources and Ecology of the Russian Federation, 2018). In 1.7 percent of the cities of the Russian Federation, the level of industrial pollution by trace elements is classified as potentially dangerous, and in 9.1 percent of the cities of the Russian Federation, it is moderately dangerous. Dangerous levels were reported for the following cities: Svirsk, Irkutsk region (cadmium, copper, lead, and nickel), Revda (cadmium, copper, lead, and zinc), Kirovsk (cadmium, copper, lead, and zinc), and Sverdlovsk region. The arsenic concentration measured in Balakovo, Sverdlovsk region was fivefold the limit set by the Russian standards.
Leakages due to pipeline system breakdowns and discharges during transportation and storage led to frequent soil, water and air pollution in the Russian Federation. The accidental oil pollution is currently growing: according to the data of the Ministry of Natural Resources and Ecology of the Russian Federation, the impact increased five times from 2017 until 2018, due to deterioration of pipelines and equipment, violation of the operation rules and equipment maintenance, and illegal tie-ins into the oil pipelines. The biggest number of accidents happened in Southern, Siberian and Ural Federal regions. Soil pollution by oil-products has been reported to exceed the permitted levels in Saransk (740 mg/kg), Podbelsk (4 677 mg/kg) and Nizhniy Tagil (2 118 mg/kg). In 1993 near the village of Elovka, Irkutsk region as a results of the construction work at the pipeline “ Krasnoyarsk-Irkutsk” about 7 955 tonnes of oil was released and oil layer was some 15 cm in a territory of 2.5 ha of soil; the polluted territory was estimated as 35.0 ha (Afonina et al., 2015). In order to liquidate the consequences the released oil was partly pumped, then the topsoil was removed and stored for incineration (Ministry of Natural Resources and Environment Irkutsk Region, 2015). While the initial mean oil concentration in the soil was approximately 5 200 mg/kg, it has decreased over time to 2 250 mg/kg in 2014 and 207 mg/kg in 2017 (Ministry of Natural Resources and Ecology of the Russian Federation, 2018). Stockpiles of pesticides and other chemicals are still a potential source of soil pollution in rural areas, however, mitigation measures have been undertaken to reduce the risks. The Arctic Council Action Plan to Eliminate Pollution of the Arctic, adopted in 1999 (U.S. State Department, 1999), supported the repackaging of 2 000 tonnes of POPs in the north-west of the Russian Federation (de Lurdes Dinis and Fiúza, 2013).
In 2000, electrical equipment containing PCBs and other PCB containing wastes were inventoried in 600 Russian enterprises (AMAP, 2000). The sectors covered by the inventory included: chemical and petrochemical manufacture, ferrous and non-ferrous metallurgical industries, mechanical engineering, timber and the military. The inventory identified approximately 27 000 tonnes of equipment, transformer oils and other materials that are estimated to contain 1 250 tonnes of pure PCBs wastes. It also identified that approximately 3 160 tonnes of PCBs had leaked into soil. This is in addition to the Sovtol spill, which polluted the soil with about 140 tonnes of PCBs.
Large organochlorine chemical manufacturing facilities, such as Ufa and Chapaevsk, have operated in the Russian Federation. Such industries have polluted large areas with POPs including PCCD/Fs (Amirova and Weber, 2015; Revich and Shelepchikov, 2008).
The Ministry of Ecology and Natural Resources of Ukraine (2016) reported that the main sources of soil pollution were:
The main industrial complexes are located in the east of the country, which has been subject to an armed conflict during the 2010s. This has disrupted the country’s industrial output, with annual reductions of 10 percent in 2014 and 17 percent in 2015. Despite the reduction in output, Ukrainian industries have continued to pollute soils due to their aged infrastructure, inefficient operations and lack of investment in environmentally sound manufacturing techniques.
Urban activities, such as municipal waste disposal and traffic emissions, have become increasingly serious sources of soil pollution in Ukraine, especially in big cities with more than one million inhabitants, such as Kyiv, Dnipro, L’viv and Odessa (Department of Ecology and Natural Resources, 2018a, 2018b). The annual quantities of municipal waste have been increasing (IFC, 2015), despite the decreasing population which fell from 52 million in 1991 (at independence) to 36-38 million in 2019. Annual quantity of municipal waste generated per head of population was 220-350 kg in 2014, which is less than in the European Union (510 kg) but more than in the Asian countries (160-200 kg). Almost all municipal waste was disposed of into 4 157 landfills (96.5 percent) and only 3.5 percent was incinerated (IFC, 2015) (Figure 2). Landfilling represents about 34 percent of all environmental expenditure in Ukraine (Degoduk and Degoduk, 2006; Ministry of Ecology and Natural Resources of Ukraine, 2016). Approximately 350 000 tonnes of medical waste were generated annually and directly disposed of in landfills without treatment, which is likely to have caused an increase in antimicrobial resistance (Ministry of Ecology and Natural Resources of Ukraine, 2016).
Approximately 22 000 tonnes of OPs were reported in Ukraine in 2005, located in about 5 000 sites. The most representative store sites are presented in Table 1.
In 2009-2010, about 1 000 tonnes of these OPs were eliminated in Germany, and in 2013 about 800 tonnes were repackaged and transported to Poland. In 2010, a single mining site was identified in Ukraine, that contained about 20 000 tonnes of hexachlorobenzene (HCB) waste from the production of organochlorine solvent. This has been excavated, repacked and sent for elimination in Poland (10 000 tonnes) and in the United Kingdom (8 500 tonnes) (Lysychenko et al., 2015; Weber et al., 2011).
Military activities are another important source of soil pollution in Ukraine. During the Soviet era, the country was actively exploited by the Soviet army as a test site, with ranges, missile and munitions storage, and parking areas for tanks and aircraft. After independence in 1991, some 4 500 military sites were reported to have occupied 600 000 ha of agricultural land, with only a very few sites subject to monitoring. Subsequently, these sites were found to be severely polluted with various trace elements, petroleum products, and other chemicals (Analitical report, 2003; Pidlisnyuk et al., 2019).
Since the start of the armed conflict in eastern Ukraine in 2014, many mining sites in the Donbass region have been abandoned and destroyed, representing a risk to the environment. In abandoned mines, groundwater is no longer pumped out and fills mine cavities, leading to subsidence and water and soil pollution. In 2018, approximately 35 mines were already flooded and a further 70 were predicted to flood in subsequent years. The estimated annual runoff of contaminated water from these flooded mines is about 760 million m3, which contains nearly 2.5 million tonnes of salts and trace elements (arsenic, lead and mercury) that are transferred to water bodies and soil (Hamilton, 2019). Another long-term environmental challenge in Donbass is associated with the use of landmines in the armed conflict. In 2018, Donbass had world’s largest and densest landmine area. Demining efforts on only 3.7 percent of the landmine area had resulted in the clearing of approximately 340 000 mines and pieces of unexploded ordnance (Ostanina, 2018). However, there is only fragmentary data on the baseline environmental conditions of the area before the start of the armed conflict, so it will be difficult to determine the exact impact of the conflict on soil pollution (EPL, 2015). Bagaeen and Clark (2016) identified that these areas would require risk reduction inventions and intensive remediation in the future in order to reclaim the land.
In the Caucasus sub-region, former mining sites and industrial complexes abandoned after the Soviet era remain the main contributors to soil pollution, along with abandoned military weapons and chemicals sites.
In Azerbaijan, the major source of soil pollution is the petroleum industry, in particular the severe petroleum pollution that occurred in the past when oil from the Caspian Sea was supplied intensively throughout the USSR. In 2019, the historic oil extraction and processing activities in the Absheron Peninsula was considered to have contaminated an area of more than 33 000 ha, of which 15 000 ha was heavily polluted and was a major environmental concern (Abbasov et al., 2019). By 2005, the environmental performance of the oil extraction sector had improved and the risk of soil pollution from newly exploited oil-facilities was considered to be limited (Asian Development Bank, 2005). The country had developed the manufacture of chemicals (acids, organics, base chemicals), the manufacture of pharmaceuticals, and the production of POPs (DDT, HCH, aldrin, dieldrin, etc.), the production of the latter was located in the Sumgait region (Aliyeva et al., 2013). As a result, by-products and residues of petrochemical industry, metallurgy waste and various chemicals pollute these areas. According to the inventory carried out within the Toxic Site Identification Program (Abbasov et al., 2018), the 136 detected polluted sites were caused by petroleum production (17), chemical production (25) and agriculture (51 that were mainly associated with pesticides). In the Soviet era, Azerbaijan intensively used its own manufactured pesticides and those supplied by the USSR in local agriculture. Between 1958 and 1988, Azerbaijani agriculture intensively used its own manufactured pesticides and some 500 000 tonnes of DDT was applied on about 1 000 m2 of agricultural area (Abbasov et al., 2019). In 2004, uncontrolled disposal of municipal waste in rural areas was also identified as a source of soil pollution, as the country had no treatment system for such a waste. The disposal of untreated and sometimes illegal waste was also part of the pollution problem (UNDP, UNEP and OSCE, 2004).
In Armenia, the major sources of soil pollution are wastes from chemical and mining industries that were intensively exploited during the Soviet era (Mach et al., 2019). In particular, areas affected by waste from the Nairi synthetic rubber plant, copper mining in Alaverdi, and molybdenum mining in Kajaran and Megri are of great concern in the country (UNDP, UNEP and OSCE, 2004). Kapan’s copper mines continue to operate and there is uncertainty about the adequacy of their environmental safeguards (World Bank, 2016b). There are also concerns about the Medzamer nuclear power plant, located 18 km from Yerevan, as it could lead to radionuclide pollution of soils. POPs are also causing soil pollution in Armenia. It is estimated that the country’s soils are highly polluted with approximately 7 100 tonnes of POPs. In 2015-2021 under the framework of GEF and UNDP project “Elimination of obsolete pesticide stockpiles and addressing pops contaminated sites”: 1 050 tonnes of POPs pesticides will be destroyed; and 12 700 tonnes of soil with low levels of POPs pesticide contamination will be disposed of in an engineered landfill.
In Georgia, agriculture is one of the main sources of the soil pollution, mainly caused by pesticides, fertilizers and trace elements (Bakradze et al., 2018; Gambashidze et al., 2014). However, the industrial sector is also a significant source. The main industrial facilities are located in Tbilisi, Kvemo, Kartli, Imereti, Shida, Kartli and Kakheti. Soil pollution has been identified in these areas. An extensive inventory of solid waste was conducted in 2007, with the assistance of UNDP. The inventory identified that hazardous waste was not being disposed of appropriately and was accumulating near industrial complexes. In 2007, these accumulations of hazardous waste were estimated to approximately 909 000 tonnes. There was no information on the toxicity of the accumulated waste, its physical state or chemical composition (Jincharadze, Javakhishvili and Tsakadze, 2011). There is a lack of comprehensive data on the quantities and types of household solid waste. Based on the data provided in 2005 by the National Statistics Service, there were 4 632 registered industrial and manufacturing facilities in Georgia. Since 2005, it is thought that their numbers have increased but updated data are not available.
Soil pollution by radionuclides and trace elements from former military activities has been identified as the cause of the pollution of the military sites of Akhakalaki and Javakheti (UNDP, UNEP and OSCE, 2004). In Abkhazia and South Ossetia, there is little or no information available on where radioactive materials were buried in the past.
In Central Asia, the common sources of soil pollution are the mining, oil and metal sectors, which were active or abandoned after the fall of the USSR. The active mining and metallurgical industries generate most of the country’s hazardous wastes. Military activities during the Soviet era left a legacy of soil polluted with radionuclides, trace elements and petroleum products in the vast desert areas where nuclear, biological and chemical weapons and missiles were tested. Agricultural activities have also led to soil pollution, mainly caused by the release of trace elements from fertilizer use, the accumulation of pesticide stockpiles and the illegal burial of domestic waste in rural areas. In addition, excessive nutrients loss from agricultural fields has led to contamination of ground and surface waters, which resulted in eutrophication.
Uranium mining and processing activities have been carried out in Central Asia since the 1940s, particularly in the mountainous areas above the Syr Darya River and the Ferghana Valley, where the borders of Kyrgyzstan, Kazakhstan, Tajikistan and Uzbekistan meet. Some mining sites closed down in the 1990s due to declining demand. Historically, uranium was produced at the request of the central government of the USSR and used in military activities. Abandoned sites still contain uranium and other hazardous wastes from radioactive processing and continue to pose a threat to the environment and human health. This is particularly the case in densely populated areas such as the Ferghana Valley (Blacksmith Institute, 2014). The risks have been recognized by United Nations Resolution 68/218 of 2013, which calls for assistance to Central Asia in the remediation of these sites (UNGA, 2019). According to the IAEA (2018), some tailing ponds are located in seismically active areas near major rivers, making them vulnerable to the threat of natural disasters such as landslides or floods. In 2003, 1 500 tonnes of obsolete pesticides were reported for Kazakhstan during an international inventory (Zoï Environment Network, 2013), which were relocated to specialized hazardous waste storage sites, but their destruction still remained an unresolved issue.
The improvements in industrial and agricultural practices, the ban of military testing and the closure of some industrial plants in 2010 improved the situation. However, ongoing legal and illegal mining activities undermine the state of the environment, including the soil.
In Kyrgyzstan, the main cause of soil pollution is past and present mining activities, in particular uranium mining. In 2012, the Kumtor gold mine in Issyk-Kul Province generated 5 million tonnes of waste per year. In the same period, the country was generating a total of 95 million tonnes of waste per year, of which 85 million tonnes was hazardous (Zoï Environment Network, 2013). There were also 145 million tonnes of waste from past mining activities. The waste generated by companies specializing in radioactive materials occupied about 300 ha of land (Zoï Environment Network, 2013). Pesticide contaminated sites are another important source of soil pollution. There were 183 former pesticide storage and disposal sites and aerial-spraying landing strips at the end of 1990 in southern Kyrgyzstan. In total, at least 1 876 tonnes of pesticides were buried, including 1 033 tonnes of POPs in two major dumpsites. Soil pollution still exists in the areas of pesticide disposal, former pesticides storehouses, agro-airstrips and cotton fields, the production of which required the application of large quantities of pesticides (Toichuev et al., 2018a). Since 2015, emphasis has been also placed on the impact of municipal solid waste on soil contamination, which has almost doubled in five years.
The most critical waste in Kazakhstan is radioactive waste (Figure 3). However, the country has made some progress in terms of safety and clean-up (Zoï Environment Network, 2013). Historically insufficient radioactive waste management is reported for Koshkar-Ata in the Caspian Sea, Zhairem and Akshatau in the central part of the country, but the worst situation is in Stepnogorsk in the north of the country. The most polluted former military nuclear test sites are Kapustin Yar and Azgir, located in northeast Kazakhstan close to the city of Kurchatov and the border with the Russian Federation.
The current waste recycling rate is low for municipal solid waste (5 percent) but higher for industrial waste (25 percent).
Of Eurasian countries, Kazakhstan ranks second, behind the Russian Federation, in terms of the extent of its soils polluted by PCB (FAO, 2012). A programme for the control, management and monitoring of POPs has been developed in accordance with the “Concept of environmental protection of the Republic of Kazakhstan for 2004-2015”. After 2015, 80 tonnes of PCB transformers and 169 tonnes of PCB capacitors have been incinerated in France, and 10 052 PCB capacitors have been disposed of in Germany. Approximately 50 000 PCB capacitors are still located in different areas, 15 000 of which were buried in the Semipalatinsk nuclear facility (Zoï Environment Network, 2013).
In Uzbekistan, the main contributor to soil pollution is agriculture, with the accumulation of agrochemicals, including POPs, in the Fergana valley (Weber et al., 2008). The second source is the industrial sector around the cities of Tashkent, Almalyk, Chirchik and Navoji. Abandoned uranium mining sites have also caused soil pollution. The industrial and agricultural sectors are the largest generators of waste (Figure 3) and the total amount of waste is estimated at 2 billion tonnes (Zoï Environment Network, 2013).
In Tajikistan, the main sources of soil pollution are industrial and mining entities located in the western part of the country, while in other parts of the country, the soil is almost uncontaminated. Waste deposits from uranium mining and processing are also a source of soil pollution. The total amount of waste is estimated at 200 million tonnes, located in 120 dumping sites covering an area of 1 400 ha. The country has about 10 000 tonnes of OPs, from those 7000 tones are accumulated in Vakhsh located in the southern Tajikistan, and 3000 tones including more than 500 tonnes of DDT are in Kanibadam site (Zoï Environment Network, 2013). There are PCBs-polluted sites near the city of Tursunzade (former title Regar) and the capital, Dushanbe (UNECE, 2012). Emissions from industry are polluting soils over wide areas, even across national borders. For example, the Tursunzade aluminium plant, one of the largest smelters in the region, is continuously polluting the soil at the border with Uzbekistan (Krasilnikov et al., 2019) in the north of Surkhandar’inkaya province. The annual atmospheric emissions of hydrogen fluoride are estimated at 120 tonnes and have led to a major accumulation of fluorine in the soil (Fergana news, 2011).
In Turkmenistan, the main sources of soil pollution are the oil and chemical industries located in the western part of the country on the coast of the Caspian Sea. The process of extraction of iodine and bromine from groundwater in Khazar and Balkanabat generates a radioactive by-product that pollutes surrounding soils. In Khazar, some 420 tоnnes of radioactive waste have been stored in wooden containers and in open-air storage over an area of 300 ha (Eurasianet, 2009). This radioactive waste was generated during the years 1940-1990, when the method of adsorption with activated carbon was used (250 tonnes of activated carbon concentrate were used annually) for the production of iodine and bromine from the mineral groundwater of these two cities. The wastes contained naturally occurring radionuclides: radium-226 in the uranium-238 decay series and radium-224,228 in the thorium-232 decay series.
In 2009-2012, Turkmenistan implemented the project “Safe transportation and disposal of the radioactive wastes of Khazar Chemical and Balkanabat Iodine plants” in which 4.7 ha of the factory sites were remediated. The radioactive wastes from the most polluted sites were collected, repackaged, and transported to the storage site that was built in 2004 in the desert 7 km from the Caspian Sea. In 2010, the storage site was reinforced with concrete walls, equipped by monitoring wells and a leachate collection and treatment system. The containers were packed into the storage using sand, gravel and bentonite screen layers. As reported by Gelbutovsky et al. (2014), 60 355 m3 of wastes containing radium-226 and radium-224,228 were stored there.
Annually, the country generates about 500 000 tonnes of municipal solid waste that is deposited without any pre-treatment in landfills. The annual rate of generation of hazardous waste is 30 000 tonnes. No information is available on the annual quantities of medical waste produced. Nevertheless, the country has a national programme for the management of medical waste in health care facilities (United Nations Economic Commission for Europe, 2012). There are two controlled storage sites for OPs in Zerger and Takhta. The available information on actual soil pollution in the country is limited.
When comparing the quantities of accumulated OPs in Central Asia, the highest amount is found in Uzbekistan, followed by Tajikistan, Kazakhstan and Turkmenistan.
The most critical soil pollution in Uzbekistan and Kazakhstan was caused by the Aral Sea disaster (Environmental Justice Foundation, 2012). In addition, during the 1960s, Uzbekistan experienced a new wave of massive expansion of cotton triggered by a specially designed irrigation program: cotton area increased from 1 022 000 ha in 1940th to 1 427 900 ha in 1960th and reached almost 2 000 000 ha in the early 1980th (Djanibekov et al., 2010). After 1960, the land used for cotton production constituted about 61 percent of arable land in Uzbekistan. In 1960th - 1970th with intensive usage of pesticides and fertilizers yields increased rapidly, and by the mid-1970s, raw cotton output in Uzbekistan was 3 tonnes per hectare — the highest yield among all major producers at that time. Output reached 4.6 million tons of raw cotton in 1970 and more than 5 million tonnes in 1980. However, simultaneously the pollution of the area by chemicals increased dramatically. An irrigation network canals established in 1960th used the residual resources of the Amu Darya and Syr Darya rivers. Excessive water abstraction carried out over decades has led to the shrinkage of the Aral Sea (Figure 4). In the 1980s, the lake was reduced by 75-80 percent in volume and 50-60 percent in area. In 1990, as water levels dropped, it separated into the small Aral Sea in the north and the large Aral Sea in the south. In 2019, only 10 percent of the original area of the Aral Sea is covered by water, the rest having been transformed into desert. The former seabed has become a constant source of pollution by trace elements through the mobilization of sand polluted by pesticides and trace elements. Every year wind erosion mobilizes from 40 to 150 million tonnes of polluted sediments (Micklin, 2007), which eventually settle on soils sometimes thousands of kilometres from their origin.