Salts in building substrate and subsoils

From Saltwiki

Author:Hans-Jürgen
English Translation by Sandra Leithäuser

back to Origin of Salts


Abstract

Saline solutions often originate from the substrate of an object. Depending on the local conditions, ground-, surface and rainwater contain varying amounts of salt forming ions and thus transport salts into objects.

Groundwater, surface water, rainwater

The moisture that is present in all objects mainly originates from groundwater, surface water or rainwater. Groundwater and rainwater are the reservoirs for structures without horizontal damp proof course. These structures may be damaged by rising damp and moisture from the side due to adjacent soil. Table 1 and 2 show that water can carry differing kinds and amounts of potentially damaging salts. For instance, a groundwater source in Eilsum (Germany) contains lower levels of salts than the rainwater of this area, while another groundwater (probably situated close to the surface) contains unusually high level of salts.

Due to a significant drop in SOx- air pollution levels (in the last years in Germany), the rainwater pollution has become relatively low. However, coastal locations still have to take high sodium chloride (NaCl) levels into consideration.


Table 1: Rainwater and groundwater analysis

[mg/l] Rainwater[1] Groundwater[2] Groundwater residential sewage water
Pr.Nr. Idensen Id286 Id287 Id274 Id33 Lübeck (Townhall) near-surface groundwater in loose sediments (according to [Scheytt:??]The entry doesn't exist yet.) according to [Matthess:1990]Title: Lehrbuch der Hydrogeologie 2: Die Beschaffenheit des Grundwassers
Author: Mattheß, Georg
Link to Google Scholar
K+ 1.2 2.4 26.9 3.4 261 1 - 5 7 - 15
Na+ 1.2 1.4 10.1 61.7 475 10 - 50 40 - 70
Mg2+ 0.4 0.3 3.4 10.0 46 5 - 20 3 - 6
Ca2+ 5.9 3.5 66 179 568 50 - 200 6 - 16
Cl- 2.35 1.8 6.1 136 940 15 - 80 20 - 50
SO42- 10.9 3.5 23.5 179 310 20 - 150 15 - 30
HCO3- 9.0 19 217 284      
NO3- <0.1 <0.1 44.4 <0.3 600 0 - 150 20 - 40 (ΣN)
pH 6.00 7.8 8.00 7.3      
Conductivity [µS/cm] 54 48 480 1200      

Groundwater may contain large amounts of ions, e.g. mineral waters, water containing ferrous substances. Particularly anthropogenic pollution is very prominent.

Table 2: Analysis of rainwater and groundwater near Eilsum (Germany)

Eilsum[3] Groundwater Rainwater
Pr.Nr. Ei76 Ei264 Ei331 Ei294
K+ 281.4 3.6 10.8 2.6
Na+ 50.8 7.1 20.2 36.3
Mg2+ 18.3 1.3 6.7 4.4
Ca2+ 66.4 12.2 73.9 5.7
NH4+ <0.05     1.5
Cl- 74.1 13,5 36.7 60.2
SO42- 122.0 7.7 33.1 26.3
HCO3- 542.0 29.0 25.0 6.0
NO3- 25.4 6.2 3.1 3.7
H2PO4- 31.0      
pH-Wert 7.4 7.8   6.0

Weblinks

  1. Rösch, Schwarz: Interne Projektberichte. Zitat:
  2. Schwarz: Interne Projektberichte. Zitat:
  3. Rösch, Schwarz: Interne Projektberichte. Zitat:

Literature

[Matthess:1990] Mattheß, Georg (1990): Lehrbuch der Hydrogeologie 2: Die Beschaffenheit des Grundwassers, Bornträger, Berlin, StuttgartLink to Google Scholar
[Scheytt:??]The entry doesn't exist yet.