Search

During field studies of the vegetation in the canal network of the Hydro-System Danube-Tisa-Danube in Serbia, in 2008, 2011 and 2012, populations of Cabomba caroliniana A. Gray 1837 were recorded. Cabomba caroliniana was not previously recorded in the aquatic vegetation in Serbia. It is a popular aquarium plant native to South America (Brazil, Uruguay, Paraguay, and northeastern Argentina) and, according to some authors, to southeastern United States. It was introduced into the rest of the USA, Canada, Australia, Asia (China, Malaysia, India, Japan), and in many regions of its new range it is considered an invasive and noxious aquatic weed. In Europe, it was found in the United Kingdom (introduced to England), Belgium, the Netherlands, and Hungary. Newly recorded populations in Serbia are restricted to the canals in Bačka. Populations are established only on two localities (Mali Stapar and Odžaci). [Projekat Ministarstva nauke Republike Srbije, br. III43002]

Effluents collected from the industrial complex of Pancevo, Serbia (oil refinery, petrochemical plant, and fertilizer factory) are discharged into a wastewater canal entering the Danube River. In this study, which was focused on sediment assessment, a complex triad approach consisting of chemical analysis, sediment toxicity tests and macrozoobenthos community analysis was applied. In toxicity tests on sediment elutriates, the following responses were registered - stimulatory effect in algal bioassay, no effect in acute test with Daphnia magna, and low to moderate toxicity in the conventional Vibrio fischeri test. Moderate to high toxicities were recorded in solid phase tests on Myriophyllum aquaticum and V. fischeri. High content of Hg, certain PAHs and noncharacterised sediment contaminants accumulated over years contribute not only to the registered toxicity, but also to the complete absence of macrozoobenthos. The obtained results proved that regularly measured conventional and priority pollutants are hardly ever the only toxic contaminants present in sediments. Toxicity tests, in particular the contact test, might guide towards a better selection of parameters to be regularly or occasionally monitored. In addition, complete sediment toxicity tests proved to be an appropriate method for assessing the bioavailability of the chemically detected contaminants. The analysis of the macrozoobenthos composition and structure as inevitable part of sediment risk assessment procedures integrates the effects of multiple stressors and gives a realistic insight into not only sediment contamination by toxic pollutants, but also the sediment status in general.