Potentially toxic elements in water and sediments of the Sava River under extreme flow events

Abstract

River ecosystems are exposed to various stressors. Among them, elements may contribute to overall pollution of riverine environments, in particular during the extreme flow events. To evaluate the influence of variable river flow conditions on the mobilization of potentially toxic elements (PTE) (Cr, Ni, Cd, Zn, Pb, As and Cu) from sediments into the overlaying waters of the Sava River, samples were collected in September 2014, during extremely high water discharges and in September 2015, under low water discharge conditions. In water samples the total element concentrations and the dissolved element contents (<0.45μm) were determined. Sediment pollution was estimated by determination of the total element concentrations and mobile element fraction (0.11molL acetic acid). Anthropogenic inputs of elements to sediments were evaluated by normalizing elemental against Al concentration. The results showed that concentrations of PTE in water were in general higher during high water discharges, while the soluble concentrations were higher during low water level conditions. Concentrations of PTE in the Sava sediments collected in 2015 were lower than those collected in 2014, mainly because during the extreme floods a mixture of bank sediment material and contaminated soil was sampled. Partitioning coefficients between suspended particulate matter (SPM) and soluble content of elements in the water under high and low flow conditions, indicated on different affinity of elements to SPM in relation to different flow regimes. The potential ecological risk posed by the simultaneous presence of PET in sediments was evaluated by Probable Effect Concentration Coefficient (PEC-Q) approach. Under high water level conditions, PEC-Qs were all above critical value 0.34 and derived mostly from anthropogenic inputs of Cr and Ni. Overall sediment toxicity was much lower under low water discharges. The data from this study importantly contribute to the knowledge regarding the behaviour of PTE under extreme flow events.

Potentially toxic elements in the riparian soils of the Sava River

“…PTE enter these zones as a result of the weathering of parent rocks and anthropogenic activities, as well as floods, and are incorporated into sediments and soils as pollutants (Xie et al 2014;Milačič et al 2017). With PTE concentrations in rivers increasing markedly in Europe during the nineteenth and twentieth centuries (Schulz-Zunkel et al 2013), determining their levels in natural waters and sediments is of great importance, so as to investigate the geochemical migration of chemical species and also substantiate environmental pollution in aquatic systems due to human activities (Vertačnik and Bišćan 1993).…”

“…Due to the persistence of many pollutants and their bioaccumulation potential, sediments represent a serious threat to riverine ecosystems (Vuković et al 2011). Studies on heavy metals and other pollutants in river water and sediments have multiplied in recent years, especially for large rivers such as the Danube (Woitke et al 2003;Crnković et al 2008;Pavlović et al 2016), the Sava and their tributaries the Drava and the Kolubara (Orescanin et al 2004;Crnković et al 2008;Vuković et al 2011;Vidmar et al 2017;Milačič et al 2017;Čakmak et al 2018), the Tisza (Sakan and Đorđević 2010), and the Po (Vignati et al 2003). Other researchers have studied contamination of riparian soil along the Danube (Pavlović et al 2016), the Sava and their tributaries the Drava and the Kolubara (Vertačnik et al 1995;Halamić et al 2003;Šajn et al 2011;Šajn and Gosar 2014;Čakmak et al 2018), and the Odra (Ciesielczuk et al 2014), but such studies are documented much scarcely.…”

Performance of Avocado Seed Activated Carbon as Adsorbent for Highly Sensitive Determination of Cd Using a Flow Injection System Online Coupled to TS-FF-AAS

“…1,2 Among these metals, cadmium is considered a potentially toxic element (PTE) and classified as a human carcinogen according to the International Agency for Research on Cancer (IARC). [3][4][5] For this reason, in order to perform a continuous monitoring, even at trace level, international and national legislation [United States Environmental Protection Agency (USEPA), World Health Organization (WHO), Brazilian Health Regulatory Agency (ANVISA), National Environment Council (CONAMA)] establishes allowed maximum limits of cadmium for different kinds of water. For drinking water were established maximum limits of 5.0 µg L -1 by USEPA 6 and 3.0 µg L -1 by ANVISA and WHO, 7,8 while for freshwater the established maximum limit by CONAMA 9 is 10.0 µg L -1 .…”

Quality Assessment of Some Freshwater Resources Located in Bucharest and Surrounding Areas II. Water quality assessment of Arges and Dambovita rivers

“…Freshwater is the most important natural resource for life and the environment, nevertheless it is a vulnerable and limited resource, especially due to its irrational exploitation [2][3][4]. The availability of water in sufficient quantities and of good quality will become even more challenging for Europe in the future due to climate change, the growing needs of the urban population, as well as, industry and agriculture expansion [5][6][7][8].…”

“…Pollutants and potentially toxic elements (like heavy metals) can accumulate in quantities exceeding the maximum admissible limits in both surface and underground waters and soil. The negative effects of pollutants can be expressed both directly on the organisms that populate the respective aquatic basin and indirectly by diminishing oxygenation, changing the pH and other physical and chemical properties of the water [4]. Among the harmful consequences of these substances we can mention the carcinogenic and mutagenic effects, accumulation in the food chain links, high toxicity etc., all of which contributing to the serious disturbance of the natural equilibrium [14][15][16][17].…”