Aquatic macrophytes are exceptional accumulations of heavy metals and they are very important in phytoremediation of the pollutants. The aim of the survey was to show according to content of heavy metals in aquatic macrophytes DTD (Danube-Tisza-Danube) canal complex, at localities under great human influence indicate the situation of chemical contamination these localities and to define test species, actually the ones that have the greatest accumulation. Plant material was prepared according to the Standard Methods for Examination of Water and Wastewater of the American Health Association. Analysis of heavy metals in the plant tissue samples was done by standard methods using atomic absorption spectrophotometry. The best accumulator of majority of heavy metals is Ceratophyllum demersum. The results show that mentioned species can be used for removal of heavy metals from water, what means that it has the ability of phytoremediation of pollutants.

Seasonal dynamics of plankton in DTD hydrosystem in Backa region (Serbia) was estimated during the period June 2002-March 2003. More irregular cycles of the phosphorus level and plankton activities in DTD canal network gradually downstream (Northern Western - Southern Eastern channel direction) was observed. The plankton group of total coliforms was developing in early spring in the period of beginning of vegetation season and in summer, when the phosphatases of pH 5 and pH 9 have the highest activities, in all DTD sectors. In the assessment of trophic condition of DTD canal network, sectors of canals were corresponded with bacteriological analyses and level of phosphatase enzyme activities.

In this study we analyzed the water quality of the Danube-Tisza-Danube (DTD) canal network (Serbia) in October of 2006. Selected number of microbiological parameters showing lowering of ecological potential was in accordance with quantitative plankton analyses and water phosphatase activity. Obviously, the high presence of coliform bacteria, diatoms indicating water high salinity (Cyclotella meneghiniana, Entomoneis paludosa) pointed to the considerable problems of canal water usage of the middle and southern irrigation/drainage DTD hydrosystem for agricultural watering purposes.

In order to investigate the effects of wastewater from the Vrbas-Kula-Crvenka industrial basin on Grand Backa canal water quality, the water quality in the canal and the lateral canals which fall into the Grand Backa canal was examined, along with industrial water quality for ten of the most important polluters of those canals. A significant deterioration of Grand Backa canal water quality downstream of the lateral canals I-61 and I-64 was detected, as a consequence of waste water emission from the Vrbas-Kula-Crvenka industrial basin polluters. Data analysis has shown that two sugar factories are the heaviest polluters in the examined industrial basin.

A monitoring program was organized with the aim of assessing the quality of sediment and water in Nadela canal regarding metal content (Cr, Cd, Cu, Ni, Pb, Zn, Hg). Water was the 1st/2nd class according to national requirements. The Canadian probable effect guideline value for sediment quality is occasionally or constantly exceeded for different metals. Mercury and zinc contents are in elevated concentrations and nickel shows a tendency for accumulation. The results obtained give a preliminary overview of watercourse imperilment.

In this paper the results of preliminary microbiological investigations of the canal Nadela water quality, done in order to determine level of pollution, are presented. Bacteriological analysis included the monitoring of quantitative composition of the organotrophs, presence of some physiological groups of bacteria and total number and fecal coliforms. Beside of that, level of water phosphatase activity and chlorophyll a concentration as important parameters of waterstate, were determined. Obtained results indicated low quality of the canal Nadela water and overload by organic matter, that cleary reflected negative influence of pollutants presents in that area.