Soil degradation is an unavoidable phenomenon that poses a real threat, as it limits soil utility and reduces its resources. Early assessment of soil degradation can prevent its further deterioration. Various parameters of soil microbial activity may be helpful in this evaluation. Therefore, the purpose of the study was to assess the usefulness of microbiological (total abundance of oligotrophic bacteria and filamentous fungi), biochemical (soil respiration) and enzymatic (dehydrogenase, protease, acid and alkaline phosphatase activity and fluorescein hydrolytic activity) indicators, as well as phytotoxicity, in monitoring the condition of chemically degraded soils due to severe alkalization. The experimental material was soil collected in three sites located at different distances from the reservoir with liquid post-production waste. The analyzed indicators were correlated with the physical and chemical properties of the soil in three variants at the level of sampling sites, soil profile and seasonal variability. All analyzed parameters showed significant changes in the level of their activity at individual sampling sites. The location closest to the waste reservoir was characterized by the lowest values of the discussed activities and the highest phytotoxicity. Individual activities also showed changes depending on the season and soil layer. Considering the usefulness in monitoring changes in soils exposed to chemical degradation, total bacterial and fungal counts, as well as acid and alkaline phosphatase activities and fluorescein hydrolytic activity proved to be the most sensitive indicators.