Application of the Water Pollution Index in the Assessment of the Ecological Status of Rivers: a Case Study of the Sava River, Serbia

Abstract

Water quality and status assessment of water bodies could be based on a large number of various parameters, including physical, chemical, hydromorphological, microbiological and biological. Often it is difficult to interpret the results of water status assessment when numerous quality elements are analysed, since each may indicate different quality class. The Water Pollution Index (WPI) overcomes this problem by providing a single assessment score. Previously, WPI was calculated using physical and chemical parameters combined with microbiological parameters. Biological quality elements are recommended by the EU Water Framework Directive (WFD) as obligatory for the assessment of ecological status of water bodies.For the fist time in this study, the index was modifid to include also biological parameters. Sampling and fild measurements were done in 2007–2011, at three sites on the Sava River in the Belgrade region. According to the obtained WPI values, the river was assessed as polluted in 2007, moderately polluted for the period 2008–2010 and slightly polluted (“pure”) in 2011. This result shows an overall improvement of the water quality during the period of examinations. Our study demonstrates that the WPI could be effectively used as a metric for ecological assessment according to the requirements of the WFD. It should be further elaborated to provide type- and stressor-specific assessment system.