The results of works on reconstruction and development of the hydrogeological monitoring system at the Prydniprovsky Chemical Plant site, Kamyanske (PChP) and on the groundwater survey using the ...improved observation wells network are presented (first such survey since 2016). During the works, geology structure of the site was précised, hydraulic testing was carried out, and groundwater was sampled at a number of uranium production legacy objects that have not been previously covered by observations. Automated monitoring of groundwater levels (GWL) has been started. As a result, new information on the seasonal dynamics of GWL was obtained. New sources of serious chemical and radioactive contamination of the geological environment are identified at the Southern PChP site, in particular in the area of settling basins № 220 and 230. Radioactive contamination of groundwater with excess of background levels is also observed also in the zone of “historic” settling pond situated below the “Central Yar” uranium tailings. In addition to previously known chemical toxicants (Mn, Ni, Pb), the monitoring study revealed groundwater contamination by arsenic and mercury in the areas affected by the PChP facilities. Thus, groundwater contamination at the PChP industrial site is formed under the influence of more man-made legacy sources than previously thought. The identified new sources of pollution deserve additional characterization and consideration when predicting the long-term impacts of the PChP site on the surface water system of the Konoplyanka River—Dnieper River.
