Medical Hydrology and Balneology: Environmental Aspects

Water mineralization origin inferred from the
rainfall contribution. Relationship between
quality of water, soil and lithology
Vázquez I (1) , González J (2) , Moreno AM (2)
(1) Geological Survey of Spain (IGME), Tres Cantos - Madrid, Spain.
(2) Department of Geology. Pharmacy University. Complutense
University of Madrid, Madrid, Spain.
i.vazquez@igme.es
Introduction and Objectives
The composition of superficial water depends on its interaction with the rock
substrate of the hydrologic basin, the soil (non saturated zone) and its velocity of
circulation. Processes involved in soil development and soil composition in a specified
zone have a significant impact on water composition too.
The aim of this work is to infer the possible relationship between the quality of
water, the soil and the lithology.
Materials and Methods
This work is about the physical characterization (pH, conductivity, dry residue at
180º C, total hardness and oxidability) and chemical composition (main anions and
cations by High Performance Ion Chromatography, HPIC, and elements by Inductively
Coupled Plasma –Atomic Emission Spectroscopy, ICP-AES), of waters
collected in ten different points of the Jarama river basin and its tributaries.
Results
Test results show that most of the waters have calcium and/or sodium bicarbonate
composition with a very low mineralization level, together with neutral or
slightly basic pH values.
Some of the most common ion ratios, such as rNa/rK or rMg/rCa were calculated
in order to deduce some of the physicochemical reactions affecting the water.
These reactions are related to materials that are in contact with the water and/or
with modifying phenomena of water composition (organic matter decomposition,
mineral precipitation, etc).
From the concentration of a conservative element (chloride ion) in rainwater and
groundwater, we calculated the rainfall contribution (Appelo & Postma, 1993)
while water quality has been linked to the lithology of the studied zone and soil
over the water pass through.
Finally, concentrations of main elements such as As, Ba, Ca, Ce, Co, Fe, K, La,
Mg, Mn, Na, Ni, P, Pb, V and Zn in water, soil and rock have been statistically
Balnea 229
ISBN: 978-84-669-1887-0
978-84-669-3482-4
2012, núm. 6, 229-230