Post on 02-Jun-2022
Groundwater quality Baseline investigations in Estonia
Andres Marandi
November 10th, 2011, Riga
Baseline conceptThe range of concentrations of a given element, species or chemical substance present in solution, being derived from natural geological, biological or atmospheric sources.
The range of concentrations of a given element, species or chemical substance present in solution, being derived from natural geological, biological or atmospheric sources
The natural baseline concentration varies spatially in relation to many factors such as geology and temporally with residents time
Baseline concept
Baseline conceptThe range of concentrations of a given element, species or chemical substance present in solution, being derived from natural geological, biological or atmospheric sources
The natural baseline concentration varies spatially in relation to many factors such as geology and temporally with residents time
Estonian geology
Historical data versus new data
No significant differences between "old" and "new" data
Distribution of TDS in CVAS
300 mg/l in north
16 g/l in south
Groundwater chemical types in CVAS
Buried valleys act as recharge areas for CVAS in N-Estonia
Recharge of modern precipitation is marked by d18O
• Intensive abstraction
• Depressione cone
Conceptual model for V2vr in NE-Estonia
Conceptual model for V2vr in NE-Estonia
Natural background
• low in SO4
• Variation in HCO3/Cl
• High in Na
• HCO3/Cl ~1
Natural background
Seawater intrusion
• Increase of Cl content during last 10 year
Sillamäe water supply well:
• Change in water type towards seawater
• HCO3 decreasing
• TDS increasing
Seawater intrusion
• Increase in HCO3 and Ca
Recharge from buried valleys
• HCO3/Cl increasing
• TDS decreasing
Recharge from buried valleys
• Stable isotope sampling of water (34S, 13C-DIC, 18O, 2H)
• gas isotopes sampling(13C-CH4)
• Radioactive isotope sampling (14C)
• Major ion sampling
Current activities in Estonia
Thank you for your attention!
Andres Marandi
andres.marandi@gi.ee