Application of Stable Isotopes in an Alternative Source Demonstration

Stable isotope analysis is commonly used in age dating, provenance studies and to differentiate between sources of groundwater. Multiple studies have shown that strontium and boron isotopic ratios can be successfully used in identifying CCR impacts to groundwater. This talk presents an applied case study using boron and strontium isotopes in conjunction with additional geochemical approaches in an alternative source demonstration. Boron and strontium isotopes were measured in both groundwater and CCR leachate over sampling events from 2019 to 2025. The data revealed that strontium and boron isotopic signatures in groundwater near the CCR unit differed significantly from both site-specific leachate and literature-derived CCR values. Additionally, combined isotopic signatures provided stronger evidence for discerning source variability. This work underscores the utility of stable isotope analysis in building compelling lines of evidence that support alternative source identification.