Danube Watch 2/2019 - Cooperation and Testing: A Faecal Matter

All along the Danube, as part of the fourth Joint Danube Survey and in cooperation with the Medical University of Vienna (MedUni Wien), the Medical University of Graz (MedUni Graz), the Technical University of Vienna (TU Wien) and the Karl Landsteiner Private University for Health Sciences in Krems, researchers have taken samples and conducted tests to determine the levels of contamination by faecal matter in the river and its main tributaries.

A  general goal of JDS4 is to determine the chemical and biological standing of the entire river from its headwaters in Germany to its mouth at the Black Sea. This means systematic testing at predetermined sites along the roughly 2,600km of waterways within the Danube River Basin. To achieve this daunting task, scientific experts from the above-mentioned universities worked together to take samples and test these for faecal bacteria contamination.

Testing the levels of faecal contaminants within the Danube River Basin allows experts to determine the existence of dangerous bacteria such as E.coli and whether these bacteria are present in amounts that could potentially be a detriment to the health of the people who use the river as a source of drinking water or even as a place for recreation. These tests also enable specific problem zones along the flow of the Danube to be identified and addressed via concerted efforts.

The results, as released so far, look positive and underline a trend toward better water quality that has been progressing forward for years now. Relative improvements in faecal contamination were detected in the waters of Serbia, Hungary and Romania. “Happily, the situation in Hungary has improved immediately downstream from Budapest”. Says Professor Alexander Kirschner from the Institute for Hygiene and Applied Immunology at the Medical University of Vienna, where the Inter-university Centre for Water and Health is located.

Kirschner further clarified that “the main goal of the microbiological examination this time lies with the first linkage of the analysis of proportions and origin of faecal contaminants along the entire Danube with the emergence of antibiotic-resistant, clinically highly-important bacteria as well as their resistance genes”. To this end, an entirely new concept was developed for the first time also making possible quantitative statements about the expansion of antibiotic resistance among the main water pollutants in such a large river. Water and microfilm tests (of stones and branches) were taken along the Danube and eight of its most important tributaries, and then processed and analysed in six partner laboratories in Germany, Austria, Hungary, Serbia and Romania. Testing took place at these river locations in the centre as well as along the right and left banks of the river in cooperation with external fish experts.

The most important results concerning the levels of faecal-germs (E.coli) are already available and further analysis is underway. As was the case with the previous surveys, the highest levels within the Danube were in Serbia, Romania and Bulgaria. “In Serbia, levels of faecal contamination in the Danube ranged from critical to strong, especially downstream from large cities like Novi Sad and Belgrade”, clarified Project Partner Gernot Zarfel from the Diagnostic and Research Institute for Hygiene, Microbiology and Environmental Medicine at Med Uni Graz.

Strong faecal matter contamination was also found in the Rusenski Lom (Bulgaria) and Arges (Romania) tributaries, though levels in the Arges (an outlet channel for sewage from the capital Bucharest) showed a marked improvement compared to previous years. “That is likely due to the building of the main water treatment plant in this city of over a million inhabitants”, explained Zarfel. The strong contamination within the Danube as a result of sewage that was diagnosed in previous years in Hungary downstream from Budapest could not be found this time, a positive result likely due to the building of a central water treatment plant in the Hungarian capital, according to the experts.

From the beginning, there was the assumption that there could be high levels of contaminants in Austria due to riverborne freight and navigation on the Danube. However, this was not found to be the case in the investigation. As the results of a measurement programme implemented by Lower Austria since March 2019 already showed, the faecal contamination levels at the testing locations along the Austrian Danube sections – with one exception – were all within the low to moderate scale. The single case that was slightly over the highest value allowed for moderate levels (1000 E.coli/100ml) was in a sample taken directly downstream from the water treatment plant Abwinden/Asten (1050 E.coli/100ml). According to Kirschner, “This is absolutely at a level that is to be expected for a river of this size in areas near sewage treatment plants following current standards”. Aside from the expansion of fundamental scientific knowledge, this work will also provide national and regional authorities with some important decision-making tools. This will lead to better Danube management, and enable an improved focus on microbiological water quality. The data collected will also deliver important information that can be put to use in activities defined by the World Health Organisation within the framework of the Global Action Plan on Antimicrobial Resistance as well as the EU Action Plan Against Antimicrobial Resistance, in which special surveys of antibiotic resistance in water will be called for.