Evaluation of Water Quality in the Danube River at km 181 Area Chiscani Based on the Water Quality Index (WQI)

Abstract

The Danube River is one of the most significant freshwater resources in Europe, serving a vital role in sustaining natural ecosystems, as well as supporting economic and social activities.

In this study, the overall water quality was assessed on the basis of physico-chemical parameters of the Danube in the area of Chiscani locality at 181 km of the river. The Water Quality Index (WQI) was calculated and according to the obtained values the water quality category of the river section investigated.

The seasonal average values, year 2024, spring, summer, autumn and winter of the essential physico-chemical parameters were analyzed: pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), organic matter, and concentrations of nitrogen compounds such as nitrites (NO₂⁻) and nitrates (NO₃⁻). The findings indicate a moderate water quality status, with nitrite and nitrate concentrations remaining within permissible limits-suggesting that the influence of agricultural and urban activities is relatively contained. However, the dissolved oxygen levels are at the lower threshold of ecological standards, reflecting a fragile equilibrium within the aquatic environment.

The analysis of the overall water quality of the Danube River in the Chiscani area (km 181) highlights the importance of maintaining a consistent monitoring program, as well as the need to implement, when necessary, proactive measures aimed at protecting aquatic biodiversity and ensuring long-term water quality.