The behaviour of REE in Agios Nikolaos karstic aquifer, NE Crete, Greece

Abstract

Water and rock samples were collected from the karstic aquifer hosted in the Mirambello region, NW of Lasithi. In both rock and groundwater samples REE were determined. The rare earth elements’ concentrations increase according to the groundwater flow. The origin of REE in groundwater along the recharge area of the aquifer is due to the dissolution of the mineral matter of the aquifer skeleton. Afterwards, they move conservatively showing a similar character with that of the REE of the hosting rocks. The REE concentrations in the water during their transportation within the aquifer are straightly connected to the physico-chemical conditions that prevail. The variations of REEs that have been observed in the brackish and in the freshwater coastal zone of the aquifer show that their behavior alters and they adopt similar character to those of the salt water rare earths. These variations show that the brackish zone and the penetration depth of sea water can be divided into a coastal karstic aquifer among the standardized diagrams of brackish and freshwater samples of the aquifer.