Occurrence and environmental pathways of erionite in soil: a review

Erionite, a fibrous zeolite mineral, is recognised for its potential health risks when inhaled, particularly its association with malignant mesothelioma, a type of lung cancer that is commonly linked to asbestos exposure. While erionite is commonly found in volcanic and volcanic-derived rocks, its occurrence and character in soil environments remains significantly underexplored. This literature review highlights the need for further research into erionite in soil. Current methodologies for detecting erionite in soil show considerable inconsistency, particularly concerning sample preparation procedures such as drying temperature and sieve sizes. The lack of standardisation complicates the comparison between studies and may hinder accurate risk assessments related to human exposure. Understanding the pathways that facilitate the transfer of erionite fibres from rock to soil and subsequently into the air is crucial, but is also understudied. Erionite may transfer into residual soils through weathering of the parent rock, or via slope processes and human activities. Human activities, including mining, construction and agriculture, may exacerbate erionite mobilisation and increase human exposure risk. Future research should prioritise the establishment of uniform methodologies for erionite detection and quantification in soil, as well as comprehensive soil surveys around erionite deposits, especially in populous areas, to assess the pathways from soil to air. Investigating the engineering characteristics of soil may further contribute to elucidating the potential of erionite fibres to be liberated into the air. Overall, advancing our understanding of erionite in soil environments is needed to address public health concerns and develop effective mitigation strategies.