Impact of Acid Rain toδ13 CDIC of Karst Groundwater and Carbon Sink in Dry Season in Guilin
Huang Qibo
Qin Xiaoqun
Liu Pengyu
Tang Pingping
Abstract：Quantitative evaluation of the impact of sulfuric acid to karst carbon sink not only improves the estimation accuracy of karst carbon sinks,but also facilitates research on global climate change.In this paper,Guilin karst area affected by acid rain is selected for studying.The results of testing and analysis of the chemical composition and inorganic carbon isotope in 14 karst spring and 1 5 subterraneans show that in both karst spring and subterranean,Mg2+ and Ca2+ are the main negative ions,and HCO 3 - is the main positive ion ,which were accounted for more than 90% of negative ion and positive ion respectively,and SO 4 2- has a lower content,which content range was 0.004 -0.213 mmol/L and the composition ratio was 0.12% - 6.1 1%;Theδ1 3 CDIC ,[Ca2+ +Mg2+ ]/[HCO 3 - ]are more inclined to carbonate dissolution endmember,and the longer distance from sulfuric acid dissolution endmember indicates the limited impact of sulfuric acid dissolution of carbonate rocks involved in groundwater inorganic carbon (DIC)andδ1 3 CDIC .Same as the situation of Sr2+/Ca2+ values,δ1 3 CDIC could reflect the run-off condition of groundwater to some degree.Using the stoichiometry method calculate, the average proportion of DIC (HCO 3 - H2 SO4 )produced by sulfuric acid gained by stoichiometric relationship is 22.64%,accounts for 13.04%,while that produced by carbonic acid accounts for 86.96%,of which 43.48% comes from the soil atmosphere.Deducting DIC contribution of sulfuric acid to the groundwater,13.04% karst carbon sink will be reduced.
Keywords：karst carbon sinksulfuric acidC isotope of dissolved inorganic carbonSr2+/Ca2+ Guilin karst areagroundwater
Publication Date：2015-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：11( 1237-1247 )