Precipitation Method for Determination of Carbon and Oxygen Isotopes to Detect Groundwater Contamination Near a Municipal Landfill

Abstract

The paper emphasizes the importance of isotope studies as a unique tool for detecting groundwater contamination with the landfill leachate. The aim of the study was to present an additional and useful method for detecting groundwater contamination, based on stable isotope analysis. The proposed method relies on the interpretation of measured δ¹³C_DIC and δ¹⁸O levels (in precipitated carbonates during preparation of a water sample). According to this method, two zones with different isotope composition of groundwater were identified: the first zone with natural groundwater and with low δ¹³C_DIC levels (from −20.6 to −12.4‰) and high δ¹⁸O levels (from −13.6 to −8.0‰), and the second zone with leachate-contaminated groundwater rich in δ¹³C_DIC (from −10.9 to + 3.6‰) and high level of δ¹⁸O (from −9.8 to −7.1‰). Measuring the isotopic composition of oxygen alone, is insufficient to delimit the contaminated zone due a partial overlap of natural levels with those of the contaminated with groundwater leachates. Determination of δ¹³C_DIC and δ¹⁸O in the landfill leachate-contaminated water can provide an effective tool to detect groundwater contamination near municipal landfills, and it can help to minimize the number of samples collected for the analysis of conventional parameters. This proven method may offer an easy-to-use solution for detecting groundwater contamination.