Technical Report - An Extended Study on the Fractionation and Characterization of Lead-Enriched Lichens on Cassia Tree Bark
In 2026, ASTA collaborated with academic and industry partners in Vietnam to conduct a follow-up study expanding upon 2025 research investigating the potential role of lichen and moss present on the outermost bark layer of Vietnamese cassia in relation to heavy metal contamination. By comparing lead concentrations in bark, underlying wood, and surface-growing lichen, the study confirmed that lichen function as bioaccumulators, effectively capturing airborne dust and heavy metal particulates from the surrounding environment. These findings indicate that lead contamination is primarily a surface issue, suggesting that the issue is manageable through targeted mitigation strategies, including lichen removal prior to cassia processing. As next steps, researchers will evaluate technical approaches for lichen removal, assess seasonal variability in lead accumulation, identify potential sources of airborne lead, and support the development of enhanced pre-processing standards and best practices.
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Related Resources
Research Report on Heavy Metals in Vietnamese Cassia
In 2022, ASTA partnered with several NGOs (GREAT, IDH, CRED) to conduct a pilot study to identify the contributing factors of heavy metals in Vietnamese cassia. The study evaluated levels of heavy metals in the environment (soil, water, air) and in cassia products (fresh & dried). The study did not find a significant relationship between concentrations of heavy metals in the environment and in cassia. However, preliminary data supplied by a cinnamon exporting company demonstrated the potential to significantly reduce the concentration of heavy metals in finished cassia products by peeling the outermost layer of the bark.
2019 Regulatory Presentation: FDA's Initiative to Reduce Exposure from Toxic Elements in Foods
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