investigation of the efficacy of damp-proof montmorillonite nanoclay for radon reduction strategies in radon prone areas of ramsar

background:  ramsar, a northern city in iran, lies on the coast of the caspian sea. this city has areas with some of the highest levels of natural radiation measured to date. the radon concentration in some areas of ramsar is up to 3700 bq m–3. on the other hand, due to high level of humidity, damp-proof barriers should be used in construction of new buildings in radon prone areas of this city. montmorillonite clays can be used as both moisture-proof and radon-proof agents. this study was an attempt to investigate the radon-proof properties of montmorillonite nanoclay in construction of new buildings in radon prone areas. methods and results: although soaked nanoclay samples could not reduce the radon level, when wet nano-montmorillonite was used, mean radon level inside the house was 1082.4 ± 5.9 bq/m3 (ranged 826.3 – 11.40.5 bq/m3) while removing nano-montmorillonite sheet increased the radon level to 1146.5 ± 6.2 bq/m3. the high moisture in the soil of these areas, makes the nano-montmorillonite wet and converts it to a good radon-proof sheet. conclusion: it is worth mentioning that the nano-montmorillonite clay used in this study is not supposed to replace radon-barrier (membrane) sheets but when used with proper membranes can enhance the efficiency of radon mitigation systems.