Groundwater chloride content

The chloride content of groundwater may be a sensitive indicator of either the distance between the intake area of the aquifer and coast or the amount of evapotranspiration prior to groundwater recharge. Because chloride is not normally derived from dissolution of solid aquifer materials and it does not enter into ion exchange reactions to any great extent, the chloride content in shallow aquifers and aquifers isolated from sources of connate water should reflect some of the original environmental factors of the outcrop area [19,86]. 

Figure 10 values versus chloride content in the Vienne, France groundwaters compared to those of... 

The chloride content of groundwater may be due to the presence of soluble chlorides from rocks, saline intrusion, connate and juvenile waters or contamination by industrial effluent or domestic sewage. In the zone of circulation, the chloride ion concentration normally is relatively small. Chloride is a minor constituent in the Earth s crust sodalite and apatite are... 

All water supplies to the Cambridge area are from groundwater abstractions, the majority being from a chalk aquifer, with a small amount abstracted from greensand. These waters have an alkalinity of 200 to 300 mg/1 (as CaCOs) and a pH of 7.0 to 7.5. Sulphate and chloride contents are low but nitrate approaches 50 mg/1 (NO3) at some abstractions. 

Biotransformation was also strongly indicated as a factor in the degradation of trichloroethylene in a case of soil and groundwater pollution (Milde et al. 1988). The only ethylenes at the point source of pollution were tetrachloroethylene and trichloroethylene however, substantial amounts of known metabolites of these two compounds (dichloroethylene, vinyl chloride, and ethylene) were found at points far from the source. Data from laboratory studies by the same group supported the study authors contention that degradation was due... 

The conductivity of a soil depends primarily on the degree of saturation, the particle size distribution, and the presence of pollutants. The dry subsoils are practically nonconductive, while the conductivity of the soil increases exponentially with the increase in water content up to saturation, and then it keeps constant. The conductivity of a saturated soil is much higher the more extended is the surface area, and therefore, it has the following rank clays slimes > sands > gravels. If the water content increases, the conductivity of the clay soil can go from 100 to 10000 pS/cm and that of a sandy soil from 1 to 100 pS/cm. The conductivity may be increased by the presence of chlorides 200 mg/L of chloride in the groundwater can increase 10 times the conductivity of the soil. 

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