Using multi-isotopes (34S, 18O, 2H) to track local contamination of the groundwater from Hongshan-Zhaili abandoned coal mine, Zibo city, Shandong province

The Hongshan-Zhaili coal mine was extensively mined for several decades, lies in Zibo city, Shandong province. After closed in 1994, the coal strata water level raised above the Ordovician limestone water level, then led to the cross strata pollution, which greatly affected the normal use of local people. The Ordovician limestone aquifer is the important drinking water aquifer for local community which covered under the coal strata. Thirty-two domestic water wells near the former coal mine were sampled for water chemistry and stable-isotope analysis of water and dissolved SO42−. Groundwater plots close to the Global Meteoric Water Line and reveals evidence of recharging from atmospheric precipitation. The analysis of sensitive components NO3−, SO42−, 34S in groundwater shows an oxidation environment, promoting the pyrite oxidation. The result of 34S isotopes indicates that the Ordovician limestone water SO42− mainly derived from the atmospheric precipitation SO42−, and the contamination of the Ordovician limestone water from coal strata water has occurred locally in the study area, the Ordovician limestone water is enriched in SO42− and depleted 34S in sulfate.