The potential risk from 222radon posed to archaeologists and earth scientists: reconnaissance study of radon concentrations, excavations and archaeological shelters in the Great cave of Niah, Sarawak, Malaysia

This reconnaissance study of radon concentrations in the Great Cave of Niah in Sarawak shows that in relatively deep pits and trenches in surficial deposits largely covered by protective shelters with poor ventilation, excavators are working in microenvironment in which radon concentrations at the ground surface can exceed those of the surrounding area by factor of 4:2. Although radon concentrations in this famous cave are low by world standards (alpha track-etch results ranging from 100 to 3075 Bq m_3), they still may pose health risk to both excavators (personal dosemeter readings varied from 0.368 to 0.857 mSv for 60 daysof work) and cave occupants(1 yr exposure at 15 per day with an average radon level of 608 Bq m_3 giving dose of 26.42 mSv). The data here presented also demonstrate that there is considerable local variation in radon levels in such environments asthese.