| Industrial solid waste is one of the world’s top ten environmental issues, it not only occupy the land, but also contaminated soil and groundwater. The harmful substances of solid waste have an ill effect on human health through the food chain. In karst areas, due to the special hydrogeological structure created a fragile natural environment, the consequence become more serious and prominent from industrial solid waste. On the one hand, the harmful substances of solid waste may contaminate soil and groundwater in the process of harmful substances downward penetration into the soil and aquifer. On the other hand, the strong acid formed by oxidation of solid waste would react with carbonate rocks and interfered karst carbon sinks.In this study, Baishuwan spring and Hougou spring of Nanchuan Chongqing were chosen due to the different of external environment. To investigate the effect of industrial solid waste (slag pile) in soil and hydrological systems in karst areas, through compared the two sites’physicochemical properties of (soil) soil water and chemical characteristics of epikarst spring. Further investigate the impact of industrial solid waste (slag pile) on karst carbon sinks by analyze of the variations of DIC and△DIC. The following conclusions are obtained through this research.(])Simulation experiment showed that the slag pile contains a large number of sulfides. The sulfate cause soil acidification, and raises carbonate minerals dissolution rate and leaching the exchangeable base cations, but decrease the content of HCO3-. Although have variety and high levels of heavy metals in slag pile, however, due to the adsorption of soil to heavy metals, the heavy metals may lead to soil pollution, but will not necessarily result in groundwater contamination. (2)Slag pile direct effect on soil and influence the physicochemical properties of soil and soil water. In the absence of effects by slag pile, the soil of Baishuwan is a typical limestone soil, the contents of Ca, Mg showed A<AB<B in soil profile, and the hydrochemistry type of soil water isHCO3-Ca. The soil in Hougou which effect by slag pile was getting loose due to a large number of slag piles mixed in soil. The contents of Mg in Hougou soil still showed A＜AB＜B, however, the Ca content was showed B>A>AB, and the hydrochemistry type of soil water is SO4-Ca. Slag pile not only affects the physicochemical properties of soil, but also caused soil contamination which contains heavy metals of slag piles. Many kinds of heavy metals were detected from soil, the contents of Zn and Cu are higher than national secondary reference, it is showed that the Zn and Cu has already caused the pollution of soil in Hougou. The contents of Cr and Pb are lower than national secondary reference, but higher than national standard reference, it is showed that Cr and Pb have a potential threat to Hougou soil, in other words, the soil will be polluted depend on the degree of weathering and changing in external environment.(3)On the one hand, the chemical characteristics of karst groundwater will be affected when carbonate rocks dissolved by sulfate from oxide slag pile. Baishuwan spring which have not affected by slag pile, Ca2+and HCO3-are the main ions, and the hydrochemistry type of is HCO3-Ca. Hougou spring which have affected by slag pile, Ca2+, HCO3-and SO42-are the main ions, and the hydrochemistry type of is HCO3·SO4-Ca. Rainy season, the EC, TDS and Ca2+have significantly reduced tendency because the dilution effect of rainfall. However, the EC, TDS and Ca2+have the tendency of increased initially and then decreased that under the influence of slag pile. On the other hand, sulfate from oxide slag pile will interfere with the karst carbon sinks:Baishuwan spring with high DIC and low△DIC which have not affected by slag pile, Hougou with low DIC and high△DIC which affected by sulfate that from slag pile. |
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