Influencing Factors for Hydrochemistry and δ13CDIC of Karst Springs

To gain more knowledge on the change of karst spring and its influencing factors, the hydrochemistry and δ13CDIC of Baishuwan spring, Lanhuagou spring and Hougou spring were monitored in rainy season (from June 2014 to October 2014) and contrasted with the results obtained in dry season. The results showed that more carbonate rock was dissolved and less CO2 was consumed in rainy season. And for Lanhuagou spring and Hougou spring, the CO2 consumption was less than the production. Compared to other months in rainy season, the least carbonate rock dissolution and the most CO2 consumption were observed in July 2014. Influenced by hydrodynamic condition, carbonate rock dissolved by HNO3 and H2SO4 increased while that dissolved by H2CO3 decreased during the rainy season. The δ13CDIC increased due to the HNO3 and H2SO4 dissolution of carbonate rock and the dehydration of HCO3-. Therefore, δ13CDIC correlated negatively to HCO3- concentration and positively to NO3- + SO(4)2- concentration. It was indicated that the hydrochemistry and δ13CDIC of karst springs were affected by the HNO3, H2SO4 and hydrodynamic condition.