First reassessment results of environment state in former arsenic plant impact zone in Vershino-Darasunsky settlement (Transbaikal region)

The purpose of the research is to study the geoecological situation in the urban-type settlement of Vershino-Darasunsky (Transbaikal region, Russia), where a plant producing white arsenic for chemical warfare agents operated from the 1930s until 1973. Reclamation did not follow the shutdown of the plant, which causes a serious environmental threat not eliminated with past decades due to the low priority of this territory in the register of objects of accumulated environ mental damage. The authors consider the current facility assessment, which is based on data on the insignificant area in the boundaries of the former industrial site of the plant, to be critically underestimated. The latter is the main reason for the failure of a number of attempts made by executive authorities for years to launch the development of this site reclamation project. The conducted research is an illustrative case study from real Russian environmental practice and may be of interest to academic and professional communities. The study includes the analysis of the relevant regulatory framework for the assessment and elimination of the objects of accumulated environmental damage as well as the adopted method ology to carry out the assessment. A complex of field and laboratory studies was conducted on the area of 16.5 km 2 , more than 150 soil samples were taken. The article presents the first results of geochemical soil studies, according to which it is not only contaminated industrial site, but also the entire studied territory, which has changed its physico-chemical parameters over many decades are the sources of negative impact on environmental objects. Anomalies of arsenic and heavy metals exceeding the maximum permissible and approximate permissible concentrations by hundreds and thousands of times have been detected, and they are localized not only in the area of the known facility of accumulated environmental damage, but also in several other places without currently visible sources of man-made impacts. The results obtained made it possible to declare the need to expand the reclamation area beyond the immediate territory of the former plant. In accordance with the accepted criteria, the environmental hazard indicator has been recalculated and the need to change the reclamation prioritization of this facility has been justified. Moreover, based on the existing regulatory framework, recommendations are given for further assessment of the impact of objects of accumulated environmental damage on the lives and health of citizens.