Trace and Rare Earth Element Geochemistry of Croatian ThermalWaters

Concentrations of 42 trace elements, including rare earths, in Croatian thermal waters were
investigated. Originating from different parts of Croatia, i.e. different types of aquifers, studied thermal waters
provide insight into the range of concentrations of broad spectrum of elements in Croatian thermal waters.
Covering a wide range of temperature (30 - 92 °C), studied thermal waters are generally classified as geothermal
springs (Hrvatsko Zagorje and Lipik) and low-temperature geothermal reservoirs (Bizovac), differing from
each other not only by temperature but also by geochemical composition. Thermal waters from Bizovac Spa,
from the eastern part of Croatia, were found significantly enriched in majority of measured elements in
comparison with waters from Hrvatsko zagorje and Lipik. Significant variability between studied waters was
also observed regarding the rare earth elements levels and fractionation patterns, substantially different
normalized REE patterns and wide range of Eu and Ce anomalies, ranging from 0.10 to 0.84 and from 3.48 to
159, respectively. Characterized by near-neutral to alkaline pH (6.8 - 8.1) and great variability with respect to
the geochemical composition, studied waters were found to primarily reflect the underlying geology.