hrvatski

87Sr/86Sr isotope ratio as a natural geochemical marker in the Krka River

Due to its local and temporal stability, the 87Sr/86Sr isotope ratio is increasingly used as a geochemical tracer in environmental science [1]. In the present study, we analyzed the 87Sr/86Sr isotope ratio and Sr/Ca elemental mass fraction ratio in water from the karst Krka River and its tributaries to assess the natural variability of these ratios for applications such as geochemical fingerprinting and migrations of fish. Although the lower part of the Krka River watercourse was proclaimed a national park, its upstream watercourse has been impacted by inappropriately treated wastewaters for decades and Sr isotopes could be used as natural tracer in future studies. Water was sampled in July 2021, at eight locations: three along the main Krka River watercourse, one at each of the four upstream tributaries, and one from the basins with industrial wastewater (Fig. 1.). After Sr/matrix separation by ion exchange chromatography, Sr isotope ratios were measured by MC-ICP-MS. The 87Sr/86Sr ratios were consistent with the expected signatures according to the geological age of the study area (0.70741 - 0.70771), while the Sr/Ca ratios ranged from 0.00151 to 0.0162 and particularly high ratio was determined in the Butišnica tributary. The sample from the Brljan Lake showed mixing of the Butišnica River with the main Krka River, indicating the influence of this tributary on the Krka River. Those results represent initial data for future studies on the Krka River, especially on its lower course, which is a unique natural phenomenon and needs strict protection.

karst ; geochemical tracer ; National Park

nije evidentirano

engleski

87Sr/86Sr isotope ratio as a natural geochemical marker in the Krka River

Due to its local and temporal stability, the 87Sr/86Sr isotope ratio is increasingly used as a geochemical tracer in environmental science [1]. In the present study, we analyzed the 87Sr/86Sr isotope ratio and Sr/Ca elemental mass fraction ratio in water from the karst Krka River and its tributaries to assess the natural variability of these ratios for applications such as geochemical fingerprinting and migrations of fish. Although the lower part of the Krka River watercourse was proclaimed a national park, its upstream watercourse has been impacted by inappropriately treated wastewaters for decades and Sr isotopes could be used as natural tracer in future studies. Water was sampled in July 2021, at eight locations: three along the main Krka River watercourse, one at each of the four upstream tributaries, and one from the basins with industrial wastewater (Fig. 1.). After Sr/matrix separation by ion exchange chromatography, Sr isotope ratios were measured by MC-ICP-MS. The 87Sr/86Sr ratios were consistent with the expected signatures according to the geological age of the study area (0.70741 - 0.70771), while the Sr/Ca ratios ranged from 0.00151 to 0.0162 and particularly high ratio was determined in the Butišnica tributary. The sample from the Brljan Lake showed mixing of the Butišnica River with the main Krka River, indicating the influence of this tributary on the Krka River. Those results represent initial data for future studies on the Krka River, especially on its lower course, which is a unique natural phenomenon and needs strict protection.

karst ; geochemical tracer ; National Park

nije evidentirano