GROUNDWATER QUALITY OF THE AG. PARASKEVI/TEMPI VALLEY KARSTIC SPRINGS - APPLICATION OF A TRACING TEST FOR RESEARCH OF THE MICROBIAL POLLUTIO (KATO OLYMPOS/NE THESSALY)

Résumé 0

The study of the Kato Olympos karst system, based on the implementation of tracer tests and hydrochemical analyses, is aimed at the investigation of surface-groundwater interaction, the delineation of the catchment area and the detection of the surface microbial source contamination of the Tempi karst springs. The study area is formed by intensively karstified carbonate rocks, metamorphic formations, Neogene sediments and Quaternary deposits. The significant karst aquifer discharges through karst springs in Tempi valley and in Pinios riverbed. The karst springs present important seasonal fluctuations in discharge rate, moderate mineralization with TDS between 562 to 630 mg/l and they belong to Ca-HCO3 water type. The inorganic pollution indicators, such as Na+, K+, Cl- , NO3 - , NH4 +, PO4 3 , show low concentrations and do not reveal any surface influences. On the other hand, the presence of microbial parameters in karst springs proclaims the high rate of microbial contamination of karst aquifer. Tracer tests reveal hydraulic connection between the surface waters of Xirorema – Rapsani basin and the karst aquifer. The high values of groundwater flow velocity upwards of 200 m/h, show the good karstification rate of the carbonate formations and the cavy structure dominated in the study area, as well as the low self purification capability of the karst aquifer.