Two stages of cation exchange in the geochemical evolution of seawater intrusion into the coastal aquifer of Israel

摘要

Inspection of chemical and isotopic data from saline and brackish groundwater samples at the coastal aquifer of Israel indicates that there are three main stages in the geochemical evolution of seawater intrusion toward the coastal aquifer. In the first stage (SWS water type), which is within the marine bottom sediments, anaerobic oxidation of relatively old organic carbon might occur. Later on, but still far from the fresh-saline water interface (FSI) in the aquifer, the intrusion is slightly diluted with about 15% fresh groundwater (SDS water type). During this dilution cation exchange reactions yield the sediments sites to be close to 90% from their saturation with seawater composition. At the FSI a conservative behavior or additional ion exchange were observed.