Jelena Tomović

Monitoring of DNA damage in haemocytes of freshwater mussel Sinanodonta woodiana sampled from the Velika Morava River in Serbia with the comet assay

This study was undertaken to investigate the potential of the freshwater mussel Sinanodonta woodiana for detection of genotoxic pollution of the environment. Study was performed at two sites in the Velika Morava River, from May 2010 to February 2011. The alkaline comet assay on haemocytes was used, and the olive tail moment (OTM) was chosen as a measure of DNA damage. The specimens held on acclimation under controlled laboratory conditions for 10d were used as a control. Chemical analysis revealed the presence of phosphates and increased concentrations of zinc, copper and nickel at both sites during the entire sampling period. The values of OTM in mussels collected from the environment, significantly correlated with the concentration of zinc (r=0.6248), temperature (r=0.7006) and dissolved oxygen (r=0.7738). Seasonal variations in genotoxic response were observed, with the highest OTM values obtained during summer months. Preliminary results of the in vitro study indicated the effect of water temperature on genotoxic response to zinc and cadmium in S. woodiana suggesting that the presence of genotoxic pollutants during months with lower temperature could be under-estimated. Obtained results indicate that S. woodiana could be a valuable tool for active biomonitoring of aquatic environments and emphasizes the importance of seasonal genotoxic monitoring with this organism.

Aquatic Macroinvertebrates of the Sava River

The objective of this chapter is to present the data on aquatic macroinvertebrate communities along the Sava River, based on investigation performed during 2011 and 2012 at 12 sampling sites within the sector between Vrhovo (Slovenia) and Belgrade (confluence to the Danube). During our study 227 macroinvertebrate taxa were recorded in the Sava River. Having in mind that upper stretch of the Sava River was not covered by this work (alpine and subalpine stretch), as well as based on the review of previous works on the macroinvertebrate fauna of the Sava River, more than 300 species will be confirmed for the Sava River. The data on the distribution of aquatic macroinvertebrates revealed five different stretches—alpine, subalpine, Upper Sava plain, Middle Sava and Lower Sava. Physical habitat degradation, pollution and pressure caused by biological invasions were found to be the main factors of endangerment of aquatic macroinvertebrate fauna diversity. There is an obvious need for further investigation of the Sava River in order to complete the data on aquatic macroinvertebrates and to provide the basis for accurate assessment of environmental status of the river.

Genotoxicological Studies of Lower Stretch of the Sava River

Genotoxicity monitoring of the lower stretch of the Sava River was performed by the combined approach of in situ assessment of genotoxicity and active biomonitoring of two species of mussels from the Unionidae family, Unio pictorum and Unio tumidus. Genotoxic response was studied using comet assay on hemocytes. For active biomonitoring, the mussels were acclimated to controlled laboratory conditions for 10 days and then exposed at two sites in the Sava River in the area of the city of Belgrade. Hemolymph of exposed specimens of each species was taken after 7, 14, and 30 days of exposure. For in situ assessment, the mussels were collected from five sites in the lower flow of the Sava River. The mussels were sampled immediately after the acclimation served as controls in both types of monitoring procedures. The results of our studies indicated the presence of genotoxic pollution at all studied sites at the Sava River. The level of DNA damage varied at different sites depending on the source and level of pollution. The response to genotoxic pollution was evident at the site in the urban area of Belgrade city, as well as at the sites far from the large urban settlements, suggesting that the lower flow of the Sava River is under pollution pressure.

Oligochaeta of the Danube River — a faunistical review

The aim of this work is to discuss the distribution of Oligochaeta (Annelida) in the Danube River using the collections made by the Joint Danube Survey 2007 (JDS2) on more than 2800 km of the river. The basic faunistical features of the oligochaete assemblages were analysed with regard to three main sectors of the Danube (upper, middle and lower reaches, the last with the Danube Delta). A total of 52 oligochaete taxa have been recorded. Most of the observed species are typical of the potamon-type rivers in the region, and are well adapted to moderate-to-high organic load. The highest taxa richness and frequency of occurrence were observed among the Tubificidae family. Naididae, Propappidae, Enchytraeidae and Haplotaxidae had also low frequency. The upper reach of the Danube showed the lowest species richness, while the middle reach is characterised by its highest species richness. Construction of dams and regulation of the riverbed have resulted in an increase of limno(rheo)philic taxa which prefer slow-flowing and lentic zones.

Contribution to the improvement of diatom-based assessments of the ecological status of large rivers – The Sava River Case Study

The Sava River Basin is a major drainage basin of southeastern Europe, significantly influenced by anthropogenic activities. Our study was focused on diatom communities as an indicator of the ecological status of running waters. We investigated over 937km of the Sava River at 19 sampling sites. Benthic diatom communities and 17 diatom indices were analyzed along with a large set of environmental parameters. CCA revealed that the most important elements along the spatial gradient were As and Si. Our results show that the species Navicula recens (Lange-Bert.) Lange-Bertalot and Eolimna minima (Grunow) Lange-Bertalot are very abundant at downstream localities where the highest concentrations of As were measured. The number of motile diatoms increased along the nutrient gradient, i.e. with Si availability. Correlations between diatom indices and selected environmental factors showed that temperature, As, Si and Fe are in significant negative correlation with most diatom indices. Analysis revealed the influence of As and metals in water on diatoms, although their concentrations did not exceed environmental standards. While our findings do not confirm that diatom indices reveal the intensity of pressures solely caused by nutrient and/or organic pollutants, they suggest that in moderately polluted large rivers benthic diatoms are good bioindicators of multiple pressures, and that diatom indices could serve as indicators of the level of overall degradation of an ecosystem.

Microbial Characterisation of the Sava River

Data on the microbiological quality of the freshwater systems under the anthropogenic influence, such as the Sava River, are of the major importance for the water resource management. Furthermore, analyses of the microbial quality of fish meat provide information of the fish as a valuable food resource from the investigated river basin. The health status of the fish, including dynamics of infection and biodiversity of endoparasites, is important bioindicator of changes in the ecosystem structure and function. For the ecosystem-based approach to the Sava River management, investigations of microbiological quality of the Sava River water and the meat of the European chub as the bioindicator organism, as well as dynamics of infection/biodiversity of intestinal parasites Acanthocephala, were performed. The survey comprised the data collected in periods 2005, 2006 and 2012. Microbiological investigation of water was performed in 2006 and 2012, while microbiological analyses of fish meat and ichthyo-parasitological investigation took place during 2005–2006. A high number of heterotrophic bacteria were recorded during 2006 survey, confirmed by the distinctly higher values of the three faecal indicators (total coliform, E. coli and enterococci), and indicated poor water quality downstream of the cities Zagreb and Velika Gorica, as a result of the municipal sewage outlets. The results from 2012 survey indicated the existence of moderate to critical faecal and organic pollution in all samples. Accumulation of the bacteria in the European chub meat was mainly uniform along the watercourse within standards and limitations for the human consumption. Sampling sites downstream cities of Zagreb and Velika Gorica were characterised with the lower prevalence and abundance of two common species of the chub intestinal acanthocephalan parasites, Pomphorhynchus laevis and Acanthocephalus anguillae. Poor microbiological quality of the water and lower distribution of chub intestinal parasites were related to the anthropogenic influence, downstream of the urban areas.