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Assessing the surface water status in Pannonian ecoregion by the water quality index model

Tomas, Damir, Čurlin, Mirjana, Marić, Ankica Senta
Ecological indicators 2017 v.79 pp. 182-190
biochemical oxygen demand, carbon, correlation, ecoregions, linear models, monitoring, nitrates, nitrogen content, oxygen, pH, phosphorus, prediction, regression analysis, surface water, water quality
The results of a 3-year monitoring study of surface water status in the Pannonian ecoregion for three different water types (4, 5B, 5C) are presented and evaluated statistically with descriptive and multivariable analyses. A modified water quality index (WQIM) for the Pannonian ecoregion is performed based on 7 indicators of water quality (pH, dissolved oxygen, biological oxygen demand (BOD), total organic carbon (TOC), nitrate, total nitrogen and total phosphorus). The applied analysis indicates correlation between individual variables with particularly strong correlation between BOD and TOC. Two linear prediction models (multivariable linear regression model (MLR) and piecevise linear regression model (PLR)) of WQI for assesment of water status in the Pannonian ecoregion were developed. In these linear models, indicator BOD was replaced with indicator TOC. In predicting WQI for the three different water types in the Pannonian ecoregion, better results were obtained with a correlation coefficients R2(4)=0.88, R2(5B)=0.76 and R2(5C)=0.79 by piecevise linear regression model.