engleski

The impact of industrial effluents on element concentrations in water and sediments of the karst ecosystem, Krka National Park

Industrial activities are nowadays one of the most important sources of metal contamination in the aquatic environments. Such example in Croatia is the Krka River, which lower part is protected as the national park, but upstream part is impacted by improperly purified industrial effluents from the screw factory. Industrial impact was assessed in July 2021 by comparison of element concentrations (As, Ba, Co, Cu, Fe, Hg, Mo, Mn, Na, Ni, Sr, U, Zn) in water and sediments from three sites: industrial wastewaters (IWW), the Orašnica tributary (TOR) directly affected by IWW and Krka River source (KRS) as the reference site. In addition, physicochemical parameters in water were considered. Chemical oxygen demand, ammonia and total nitrogen indicated degraded water quality at IWW and TOR, which was related to significant increases of element concentrations in sediments and water compared to KRS. The highest concentrations of all elements were evident at IWW, except higher Zn in water and Hg, Mn in sediments at TOR. The highest increase was observed for Fe, Mo, Co, Ni and Cu, elements commonly used in industry. Compared to KRS, IWW had up to three orders of magnitude higher element levels in water (Mn>Co>Fe) and even more in sediments (Zn>Co>Mo). TOR, which pose the direct threat to the Krka River, as IWW basins sometimes overflow into TOR, also had much higher concentrations of all elements than KRS. Thus, presented research indicates a deterioration of the Krka River by industrial effluents and highlights the need of adequate purification and monitoring strategies to protect the living world and tufa barriers of this sensitive karst ecosystem.

metals ; Krka River ; sediments ; wastewaters

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