TY JOUR TI Assessment of the state of reservoirs of the Volga-Akhtuba interfluve Re-gional significance natural park by hydrochemical indicators KW hydrochemical indicators KW hydroecological conditions KW Volga-Akhtuba interfluve KW chemical pollution index CJ KW water quality JO Oil and gas technologies and environmental safety AU Karapun, M.. AU Krivokolyasko, E.. PY 2026 IS 2026 PB Astrakhan State Technical University