engleski

Stygophilous Amphipod Synurella Ambulans As a Potential Bioindicator of Metal Pollution in the Hyporheic Zone of the Sava River, Croatia

Due to the growing impact of human activities on aquatic ecosystems, it is important to carry out biomonitoring programmes and assess the ecological status of waters in order to adequately protect aquatic ecosystems. The hyporheic zone (HZ) is a linking ecotone between surface and groundwater bodies. It is exposed to constant anthropogenic influences, which can affect the quality of surface running waters as well as aquifers. The aim of this study was to investigate the accumulation of metals in the stygophilous crustacean species Synurella ambulans (F. Müller, 1846) in order to assess its potential as a bioindicator of water quality in HZ. Amphipods were sampled by Bou-Rouch pump in the HZ of the Sava River gravel bar on the average depth of cca 50 cm once per season in winter 2018, spring, summer and autumn 2019 at two localities. First was located about 3 km upstream from the wastewater outlet of the town of Zaprešić, and second about 13 km downstream from the outlet situated in the city of Zagreb. Through the sewerage system of the town of Zaprešić treated wastewaters from the pharmaceutical industry are discharged together with treated municipal wastewaters. Measured concentrations of Cd, Cr, Cu, Co, Fe and Mn in the interstitial water of HZ, were not significantly different between two locations in most seasons, while Pb and Zn were below the detection limit of the method. Ni was significantly elevated at downstream location, and Al at upstream location in most seasons. According to the environmental quality standards, the metal concentrations in the interstitial water of the Sava River do not exceed the maximum permitted concentrations for groundwater. Concerning the bioaccumulated concentrations, it was found that Pb, Ni, Cr and Al were significantly elevated in S. ambulans at downstream location, while for Cd, Cu, Co, Zn, Mn and Fe no difference was observed between locations in most seasons. Elevated concentrations of metals in S. ambulans compared to the interstitial water of HZ indicate their high bioaccumulation in organisms. Because of their capacity to bioaccumulate metals, stygophilous amphipods may be useful in research on the long-term risk of metal discharges into subterranean habitats. In conclusion, biomonitoring of HZ is crucial for protection of this transitional ecosystem and S. ambulans can be used as potential bioindicator of metal pollution.

bioaccumulation ; subterranean ecosystem ; biomonitoring ; anthropogenic impact

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