Geoscience Reference
In-Depth Information
Fig. 17.7 Seasonal fluctuations of pH in three springs in stony sandy till, Lofsdalen, Sweden
(Knutsson
1994
)
Fig. 17.8 Decreasing pH and alkalinity in groundwater from the research catchment of Birkenes,
Norway during the years 1980-1992 (Knutsson
1994
)
well as by relatively high values of sulfate. The high SO
4
2-
/Cl
-
ratio suggests a
source of sulfur from air pollution in addition to that of marine salts. The acidified
groundwater profile in the upper region is followed by an abrupt increase in pH at
greater depth. This increase may be explained by the buffering effect of the geo-
chemical environment (Appelo and Postma
2005
). Another example of ground-
water acidification induced by acid rain is reported by Franken et al. (
2009
), in a
Quaternary sandy aquifer (Hannover, Germany). The average bulk deposition at
the study area, from atmospheric acid loads, is about 0.4 kmol/ha/year; this value
is comparable to other sites in northern Germany. The pH measured in various
locations of the studied area is shown in Fig.
17.9
. In the upper 5 m, the pH has a
value between 3.5 and 5, while the zone below 6 m is characterized by a pH
ranging from 5 to 7.
