ALGAL INDICATION OF POLLUTION IN THE LOWER JORDAN RIVER, ISRAEL

The Lower Jordan River is one of the most polluted in Israel. We used algal bio-indicators to monitor pollution levels in the dry and rainy seasons in order to assess a self-purification capacity of the aquatic ecosystem. We used 135 species of algae and cyanobacteria as indicators of pH, salinity, and organic pollution. The indices of saprobity (S and EPI), river pollution, RPI, and toxicity, BI testify to a greater anthropogenic impact in the lower section, partly owing to influx of pollutants with rain water during the wet season. The aquatic ecosystem state index (WESI) indicates low self-purification activity of biotic communities in this part of the river flow. Multiple Regression Analysis highlighted salinity and trophic elements as the major impact factors for algal diversity. A combination of bio-indication metod, including new integral indices and statistic analysis, and bioassey were found most efficient for monitoring of river ecosystems in Israel.