Comprehensive transformation of industrial zones of Belgorod as a strategy for integration into the urban environment

The study focuses on the comprehensive redevelopment of industrial zones in Belgorod and the Belgorod region that have lost their production functions and now represent large depressed areas negatively affecting the urban environment. The research object includes former machine-building, construction, and metallurgical sites located both within the city and its suburbs. The methodology combines field surveys, environmental monitoring, sociological surveys, and economic-mathematical modeling, which made it possible to assess the current state of these areas and to elaborate various redevelopment scenarios. The results revealed a high level of environmental stress: nitrogen dioxide concentrations in the air reached 76–81 µg/m against the permissible 40 µg/m, soil lead content was up to 240 mg/kg with a norm of 65 mg/kg, and noise exceeded sanitary standards by 10–15 dBA. A sociological survey of 350 residents showed that 68% considered these territories unsafe, while 57% supported projects for their renovation. Economic analysis indicated that multifunctional projects, integrating residential, commercial, and public spaces with ecological improvements, provided the highest efficiency with an internal rate of return of 11.8% and a break-even point by the seventh year. Comparison with international experience confirmed similar patterns, while highlighting regional specifics such as the relatively small scale of industrial zones and higher community involvement. The scientific novelty lies in combining ecological, social, and economic evaluation into an integrated index of redevelopment efficiency and in forecasting ecological improvements under reclamation measures. The study concludes that multifunctional redevelopment strategies should be prioritized to reduce environmental risks, strengthen social cohesion, and create new growth points for sustainable urban development.