Evaluation of sampling and sample preparation methodologies for determination of mercury concentrations and stable mercury isotopes in foliage samples

A critical evaluation of sampling and preparation methodologies for mercury (Hg) analysis in foliage reveals significant biases that can distort our understanding of Hg cycling. The study found that rinsing samples removes 24–60% of Hg, particularly particulate-bound Hg enriched in heavier isotopes, underscoring its role in internal plant Hg dynamics but not total foliar Hg content. Vertical crown stratification also significantly influences Hg concentrations, with inner canopy foliage showing up to 50% higher Hg levels due to reduced solar exposure and enhanced throughfall deposition. The research validates the comparability of drying methods for low-Hg environments while highlighting the need for consistent rinsing protocols when studying surface-bound Hg fractions. These findings emphasize the importance of methodological rigor in foliar Hg studies, urging further investigation into inter-species differences, seasonal variability, and isotopic fractionation effects.

Ali, S. W., Božič, D., Vijayakumaran Nair, S., Živković, I., Andron, T.-D., Marković, S., Jagodic Hudobivnik, M., Horvat, M., & Kocman, D. (2025). Evaluation of sampling and sample preparation methodologies for determination of mercury concentrations and stable mercury isotopes in foliage samples. Environmental Monitoring and Assessment, 197(8). https://doi.org/10.1007/s10661-025-14318-6