PNNL

Abstract

Strontium isotope ratios (87Sr/86Sr) can be used to determine the geographic origin of agricultural products. In this study we measured the 87Sr/86Sr of honey samples from Richland, WA, USA, Latvia, and India, and compared the results to published 87Sr/86Sr from surrounding areas and values predicted based upon a random forest isoscape model (Bataille et al., 2020). While the 87Sr/86Sr of the honey samples compared well with previously published data, the model did not accurately predict the 87Sr/86Sr of the honey samples, demonstrating that further refinement of the model would be beneficial. Because Sr cycling in terrestrial ecosystems is complex, the 87Sr/86Sr of honey is likely to reflect several sources (e.g., nectar, surface water, dust) and may change over time. In order to accurately predict the 87Sr/86Sr of honey, models must consider local geology, ecology, and bee behavior. Additional research examining how Sr is incorporated into honey is needed to inform models.