Hydrogeochemical and isotopic indications of groundwater-surface water interactions at Lake Pyhajarvi, SW Finland

摘要

General water chemistry, PCE/TCE-concentrations and ~(18)O isotopic compositions are used to indicate the groundwater discharge from esker aquifers into Lake Pyhajarvi and to evaluate the proportion of groundwater in inshore water. Discharge sites were identified via measuring temperature, electrical conductivity (EC), and pH in the lake water; and measuring lake bed sediment temperatures. There are differences in EC and pH, and the main ionic as well as ~(18)O isotopic composition of surface and groundwater. The proportion of groundwater in inshore water ranged from 6 to 34% near the shoreline. PCE and TCE concentrations confirmed the discharge into the lake in a contaminated part of one aquifer.