Striebel, T.: Investigations on the aquatic chemistry of the
Blautopf Spring, Blaubeuren, Swabian Alb, Germany
Some water samples from the Blautopf Spring were analysed on macro
ions and heavy metals. Based on the data measured, calculations on
solubilities of carbonate and heavy metals were performed.
The ions which dominate in the samples are Ca2+ and HCO3-. The
concentrations of these ions are almost constant, differences are
depending on the delivery of the spring, not on the season.
Chloride and nitrate show distinct maxima in winter times caused
by salting of roads and leaching of soils.
In the most cases the saturation index of calcite is near zero,
meaning saturation. Only in a flood elevation a lower pH was
measured, which causes undersaturation of calcite. The saturation
index of dolomite is clear below zero, meaning distinct
undersaturation. Dissolved carbon dioxide is oversaturated
regarding its concentration in the atmosphere; this is common at
The heavy metal concentrations measured are of low environmental
significance. With the exception of Fe3+ regarding amorphous FeOOH
the heavy metals are undersaturated regarding different important
solid phases. The (apparent) oversaturation of Fe3+ is common at
many different types of water and indicates the presence of
colloidal forms of iron or organic iron complexes, both species
which are passing the membrane filter. Inorganic complexation is
mentionable for iron, copper, nickel and aluminium.
The calculations on the amount of removal of limestone in the
drainage area of the Blautopf show that a limestone layer of 63 cm
could be removed in a time of 10,000 years. The quantity of
limestone removed in one year would be enough to create a cave
with a length of 50 km and a diameter of 49 cm. After 10,000 years
this cave would have a diameter of 49 m.