『Abstract
The chemical compositions of the surface/ground water of Guiyang,
the capital city of Guizhou Province, China are dominated by Ca2+,
Mg2+, HCO3-and SO42-, which have been derived largely
from chemical weathering of carbonate rocks (limestone and dolomite).
The production of SO42- has multiple
origins, mainly from dissolution of sulfate evaporites, oxidation
of sulfide minerals and organic S in the strata, and anthropogenic
sources. Most ground water is exposed to soil CO2
and, therefore, the H2CO3
which attacks minerals contains much soil C. In addition, the
H2SO4 produced as a
result of the oxidation of sulfides in S-rich coal seams and/or
organic S, is believed to be associated with the chemical weathering
of rocks. The major anthropogenic components in the surface and
ground water include K+, Na+, Cl-,
SO42- and NO3-,
with Cl- and NO3- being
the main contributors to ground water pollution in Guiyang and
its adjacent areas. The seasonal variations in concentrations
of anthropogenic components demonstrate that the karst ground
water system is liable to pollution by human activities. The higher
content of NO3- in ground water
compared to surface water during the summer and winter seasons,
indicates that the karstic ground water system is not capable
of denitrification and therefore does not easily recover once
contaminated with nitrates.』
1. Introduction
2. Geography and hydrogeological background of Guiyang
3. Samples and analytical procedure
3.1. Sample description
3.2. Analytical procedure
4. Results
4.1. Seasonal variation in ground and surface water
4.2. Variation in chemical composition
4.3. Strontium and Sr isotopes
4.4. Isotopic composition of DIC
5. Discussion
5.1. Surface/ground water interaction
5.2. Anthropogenic inputs into the surface/ground water system
5.3. Control of water/rock interaction on solute source: constraints
from Sr isotope data
5.4. Carbonate mineral dissolution by soil CO2:
constraints from C isotope data
5.5. Carbonate dissolution by sulfuric acid
5.6. The roles of gypsum dissolution and sulfide oxidation
6. Summary
Acknowledgements
References