| Autor: |
Fiket Ž; Divison for Marine and Environmental Research, Ruđer Bošković Institute, Bijenička Cesta 54, HR-10000 Zagreb, Croatia., Petrović M; Divison for Marine and Environmental Research, Ruđer Bošković Institute, Bijenička Cesta 54, HR-10000 Zagreb, Croatia., Medunić G; Department of Geology, Faculty of Science, University of Zagreb, Horvatovac 95, HR-10000 Zagreb, Croatia., Ivošević T; Faculty of Maritimes Studies, University of Rijeka, Studenska 2, HR-51000 Rijeka, Croatia., Fiket T; Department of Geophysics, Faculty of Science, University of Zagreb, Horvatovac 95, HR-10000 Zagreb, Croatia., Xu LZ; Nanjing Easysensor Environmental Technology Co., Ltd., Nanjing 210018, China., Wang Y; Nanjing Easysensor Environmental Technology Co., Ltd., Nanjing 210018, China., Ding S; State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China. |
| Abstrakt: |
Assessing the environmental quality of coastal systems is important not only for the management and protection of such areas, but also for improving the quality of water resources. Since sediment itself can often be a source of certain toxic elements, in addition to information on the distribution of metals in the water column and in the sediment itself, it is useful to determine the bioavailable forms of individual elements, particularly toxic ones. In this study, water and sediment geochemical data were supplemented with oxyanion mobility in sediments estimated by diffusion gradients in thin film (DGTs). The data obtained indicate that the chemical composition of the water in the Raša River estuary primarily reflects the high input of suspended sediment from the catchment, the mixing of freshwater and seawater, and to a lesser extent the effects of anthropogenic activities. Although sediment composition is primarily determined by geological and hydrodynamic conditions in the catchment, it also indicates moderate enrichment in Co, Cr, Mo and Ni. In contrast, the distribution of oxyanions in sediment pore water indicates the influence of sediment as a source of some elements in the bottom water; e.g., sediment contributes to 40% of the arsenic bottom water budget. The obtained depth profiles of the oxyanion distribution in the sediment pore water indicate an early onset of suboxic to anoxic conditions in Raša Bay, which is prone to rapid sedimentation. All this demonstrates the need to consider the bioavailable forms of elements when assessing environmental quality, as the lack of such information can lead to an incomplete assessment, especially in dynamic coastal systems such as estuaries. |
