Distribucija teških metala u zemljištima riparijalne zone reke Save

Abstract

Imajući u vidu da su riparijalne zone reke Save često izložene antropogenim pritiscima i kontaminaciji različitim polutantima, istraživanja u ovoj doktorskoj disertaciji bila su usmerena na proučavanje sedimenta/nanosa i zemljišta od izvora do ušća, u periodu visokog (2014. god.) i niskog (2015. god.) vodostaja, njihovih fizičkih i hemijskih karakteristika; stepena zagađenja teškim metalima i metaloidima (Ag, Al, As, Ba, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Pb, Se, Sr, Tl, Zn) sa fokusom na prioritetne polutante (As, Cd, Cr, Cu, Ni, Pb i Zn); određivanje njihovih „background“ vrednosti; ispitivanje njihovog porekla, sadržaja, distribucije, mobilnosti, biodostupnosti i međuzavisnosti u sistemu zemljište–sediment/nanos; i definisanja stepena ekološkog rizika po životnu sredinu na istraživanom prostoru. Ukupan sadržaj većine analiziranih elemenata u zemljištu i sedimentu/nanosu se povećavao od izvora ka ušću kao rezultat transporta i deponovanja na donjem delu toka i promena u oksido-redukcionim uslovima koji su povećavali njihovu rastvorljivost. Visok vodostaj (poplava) je bio dominantan faktor koji je zajedno sa teksturom zemljišta, pH i sadržajem humusa uticao na biodostupnost, raspodelu i način vezivanja teških metala i metaloida u frakcionom profilu. Na poreklo teških metala u zemljištu i sedimentu u gornjem delu toka najveći uticaj je imala geološka podloga i jednim delom antropogene aktivnosti, dok su na poreklo teških metala u donjem delu toka imale presudan uticaj antropogene aktivnosti. Na osnovu sadržaja teških metala i metaloida u zemljištu i sedimentu, kao i na osnovu analize ukupnog ekološkog rizika (RI), i analize potencijalno opasnih zona („hot spots“), zaključeno je da su lokaliteti donjeg dela toka reke Save najugroženiji i pod najvećim antropogenim pritiskom.

The riparian zones of the River Sava are continuously exposed to anthropogenic pressures and contamination by various pollutants. Therefore, research in this doctoral thesis focussed on studying sediment and soil from the river’s source to its confluence with the Danube during a period of high water levels (2014) and low water levels (2015). It aimed to determine the physical and chemical characteristics of the sediment and soil; to establish heavy metal and metalloid contamination levels (Ag, Al, As, Ba, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Pb, Se, Sr, Tl, Zn) with a focus on priority pollutants (As, Cd, Cr, Cu, Ni, Pb and Zn); to determine the elements’ background levels; to investigate their origin, content, distribution, mobility, bioavailability and interdependence in the soil-sediment system; and to define the ecological risk in the study area. The total content of most of the analysed elements in both soil and sediment increased from the source towards the confluence due to transport and deposition in the lower course of the river and to changes in redox conditions, which increased their solubility. Flooding was a dominant factor, which, together with soil texture, pH and humus content, affected the bioavailability, distribution and binding forms of heavy metals and metalloids in the fraction profile. The origin of heavy metals in soil and sediment in the upper course was most impacted by the geological substrate and, to some degree, by anthropogenic activity, while anthropogenic activities were the predominant influence on origin in the lower course. On the basis of the heavy metal and metalloid content in soil and sediment, and also the analysis of the total ecological risk (RI) and of potential ‘hot spots’, it was concluded that localities in the lower course of the River Sava are most at risk and under the greatest anthropogenic pressure.