Changes in the lower Drava River water quality parameters over 24 years

Area of Science:

• Environmental Science
• Water Quality Management
• River Ecology

Background:

• The Drava River's water quality is crucial for the region's ecosystem and human use.
• Assessing long-term water quality trends requires analyzing historical data across different periods.
• Environmental changes, including potential impacts of conflict, can affect riverine systems.

Purpose of the Study:

• To analyze physico-chemical and microbiological parameters of the Drava River water.
• To compare water quality between pre-war (1985-1992) and post-war (1993-2008) periods.
• To identify spatial and temporal variations in Drava River water quality.

Main Methods:

• Water samples collected from three sites in the lower Drava region.
• Analysis of 13 key physico-chemical and microbiological parameters.
• Comparative statistical analysis of data from two distinct timeframes.

Main Results:

• Most water quality parameters remained within tolerable limits throughout both periods.
• Elevated levels of nitrate-nitrogen (NO3-N), ammonium-nitrogen (NH4-N), and biochemical oxygen demand (BOD5) were observed.
• High concentrations of total coliforms and heterotrophic bacteria were predominantly found downstream of Osijek in the post-war period.

Conclusions:

• The lower Drava River exhibited slight organic pollution but maintained high dissolved oxygen levels.
• Localized bacterial contamination downstream of Osijek indicates specific pollution sources.
• Water quality upstream of Osijek showed a trend towards improvement over the study duration.