Low Threat by Sulphate Particles and Ozone on Tufa at Plitvice Lakes National Park

Plitvice Lakes National Park presents one of the most beautiful karst complexes in the world. Its waters are supersaturated with dissolved calcium carbonate (calcite) which is released and deposited in the form of tiny crystals as a result of water splashing at tufa barriers. Sulphates, present in the particulate matter (PM), can be deposited on the surface of the calcite. In the air, sulphate particles are formed by the oxidation of SO 2 in a series of chemical reactions as reported by Li et al. ( Atmospheric Chemistry and Physics 6 :2453–2464, 2006 ). Fast oxidation of SO 2 in nature can also take place on the surface of the calcite in the presence of ozone and is significantly enhanced by high humidity as reported by Li et al. ( Atmospheric Chemistry and Physics 6 :2453–2464, 2006 ) and Massey ( Science of the Total Environment 227 (2–3), 109–121, 1999 ). The resulting sulphates can destroy the surface of the calcite and indirectly influence the composition and quality of water. Hourly concentrations of ozone, PM 10 and PM 2.5 at the monitoring station Plitvice Lakes in the period from 2012 to 2014 are presented. After assessing the observed values of both PM and ozone, presently there are no significant danger for Plitvice Lakes. However, this can change in the future so continuous monitoring will be necessary in the future.