University of Guilan Caspian Journal of Environmental Sciences 1735-3033 21 2 2023 04 01 Transboundary river water quality as a core indicator for sustainable environmental development in Europe: A case study between republics of Bulgaria and Serbia 291 300 6491 10.22124/cjes.2023.6491 EN Kristina Gartsiyanova National Institute of Geophysics, Geodesy and Geography, Hydrology and Water Management Research Centre, Bulgarian Academy of Sciences (NIGGG-BAS), Sofia, Bulgaria & Acad. G. Bonchev Str., Bl. 3, Sofia 1113, Bulgaria Stefan Gencev National Institute of Geophysics, Geodesy and Geography, Department of Geography, Bulgarian Academy of Sciences (NIGGG-BAS), Sofia, Bulgaria & Acad. G. Bonchev Str., Bl. 3, Sofia 1113, Bulgaria Atanas Kitev National Institute of Geophysics, Geodesy and Geography, Department of Geography, Bulgarian Academy of Sciences (NIGGG-BAS), Sofia, Bulgaria & Acad. G. Bonchev Str., Bl. 3, Sofia 1113, Bulgaria Journal Article 2023 05 06 In recent years, the issue of the sustainable management and protection of water resources has gained increasing emphasis in environmental policies at the local, national and supranational levels. The goal of the present study is the analysis and assessment of water quality in the Bulgarian section of the Timok, Nishava and Erma (Jerma) rivers for the period 2015-2021. The quality status of the studied river courses was assessed by the values of ten physicochemical indicators and the concentrations of eight heavy metals. The analysis and assessment performed were based on the Water Act (WA) in accordance with the criteria by Directive 2000/60/EC or so called Water Framework Directive. The Canadian Water Quality Index (CWQI) was applied for the analysis. Achieving the goal formulated in the study could serve as a good basis for making informed management decisions. https://cjes.guilan.ac.ir/article_6491_09178078f727c893fe32a9bd4f60548a.pdf