A map of
the data from pore-water lances allowed us to define the main seepage
area and the salinity gradients caused by the advective mixing of
brackish waters with upwardly migrating fresh groundwater. At
the impacted site with groundwater seepage, the salinity clearly
decreased with depth from 7 to 0.1 PSU, whereas at the site without
seepage, only a slight decrease of salinity in the deeper sediment
layers was noted (Fig. 2a).