Assessment of Water Quality in the Ukrainian Part of the Danube Delta Based on Biotesting and Bioindication of Bottom Sediments

The study presents the results of several years of monitoring (2007 to 2013) in the Ukrainian Delta region using biotesting and bioindication methods. The sampling stations were: Kilia arm (1 station), Ochakivskyi arm (2 stations), Bystryi arm (2 stations), and Vostochnyi arm (2 stations). Animal test-organism Daphnia magna Strauss together with plant test-organisms Allium cepa L. and Lactuca sativa L. were used in the biotesting. Bioindication was performed using taxonomic diversity of the macrozoobenthos organisms. The following biotic indices were calculated: Trent Biotic Index, Belgian Biotic Index, Biological Monitoring Working Party Index, and Goodnight-Whitley Index. The findings of biotesting showed a slow decrease in the toxic impact level from 2007 to 2012. However, the biotic indices mostly revealed a Poor ecological status for all sampling stations through all years of monitoring.