Potential of Compound-Specific Isotope Analysis (CSIA) to Trace Galaxolide Reactivity and Origin

Abstract

Galaxolide, a synthetic musk widely used in commercial products, including sanitation products and personal care products, poses environmental risks. Its sources and transformation pathways in aquatic environments remain poorly understood. Compound-specific isotope analysis (CSIA) offers a promising method to trace the origin and transformation of organic micropollutants by analyzing their individual isotopic signatures in natural abundance. While CSIA has been applied to various contaminants, its use with personal care products containing persistent organic pollutants is less explored. This study investigated the potential of CSIA for galaxolide to elucidate both abiotic and biotic transformations and trace its origin in personal care products. Batch experiments simulating photodegradation under UVC light and biodegradation by the strain Priestia sp. in MM₂₀ medium revealed no significant isotopic fractionation (Δ¹³C < 0.5‰). Despite the wide variation in the concentrations of galaxolide in personal care products, with some exceeding 15 g L^–1, δ¹³C values alone did not allow discrimination between sources and origins. Further research is necessary to evaluate how various environmental processes, both abiotic and biotic, could affect the stable isotopic composition of galaxolide and other synthetic musks.