Groundwater monitoring to assess the influence of injection of liquid radioactive waste on the Tomsk public groundwater supply, Western Siberia, Russia

Abstract

This paper considers the potential impact of the deep injection of liquid radioactive waste (LRW) on the continued operation of the Tomsk public groundwater supply. The close proximity of the LRW injection polygons to the wellfield creates a geoenvironmental conflict, due to the possibility of migration of radionuclides and other toxic components of LRW from the Cretaceous aquifer system used for LRW injection to the Palaeogene aquifer complex used for water supply. Although a significant argillaceous aquitard and a non-utilized buffer aquifer horizon lie between the aquifer systems, there are indications that such inter-aquifer migration may take place, either due to sandy windows in the aquitard or to inadequately sealed well annuli. A major groundwater monitoring network, based on the co-operative use of automated information systems and GIS technologies, has been established. In order to simulate contaminant migration scenarios, the use of variably scaled numerical hydrogeomigrational models is recommended. These would allow prognostic estimations and form a basis for administrative decision-making to minimize damage to the geological environment.

Radioisotope contaminations from releases of the Tomsk–Seversk nuclear facility (Siberia, Russia)

“…However, since 1963, LRW has been disposed of by borehole injection into Cretaceous strata at a depth of 280e400 m at a distance of about 10e20 km east of the Tom River. Around 4 Â 10 19 Bq of long-lived nuclides is reported to have been disposed of by these means (Lgotin and Makushin, 1998) and a total volume of disposed wastes may reach 8 of millions of cubic meters (Bradley et al, 1996).…”

Recycling of iron-containing deposits – the main way to increase the efficiency of water-protective measures on the territory of the Tom lower course

“…It is caused by the change of water exchange conditions from active flushing to relatively delayed one. According to the data [6], the waters of the Palogene horizon used for water supply change in their chemical composition from South to North from hydrocarbonate calciferous-magnesium with the mineralization of 0.13-0.34 g/dm 3 to chloride sodium with the mineralization of 1.85-4.58 g/dm 3 , pH and Eh are within the limits of 6.8…7.6 and +90…+120 mV, respectively. Under the conditions of relatively delayed water exchange, iron is easily decomposed from the rocks, forming Fe 2+ ions.…”

“…Currently, it consists of 198 operating wells arranged in three of its lines. The water supply intake gets out ground waters from the aquifer system in Paleogene sediments of «Tomskoye» deposit in the volume of 149.32 thousand m 3 /day [5,6]. The same aquifer system is exploited by 2 water supply intakes of Seversk located on the bank of the Tom.…”

The present and future use of ‘land’ below ground

“…The Waste Isolation Pilot Plant (WIPP) in Carlsbad, New Mexico is one of the few operational sites (Swift and Corbet, 2000). Liquid ILW has, however, been injected directly into aquifers in Siberia for over 20 years (Lgotin and Makushin, 1998;Stewart, 2002).…”