Guarapari, BrazilAtlantic coasts of Brazil are covered by the sand with radioactivity which came back with the wave from the sea. The radioactivity was originated from the mountains rich in zirconites and monazites along the coast.
http://www.taishitsu.or.jp/radiation/guarapari-e.htmlRamsar, IranRamsar, a northern coastal city in Iran, has areas with some of the highest levels of natural radiation measured to date. The effective dose equivalents in very high background radiation areas (VHBRAs) of Ramsar in particular in Talesh Mahalleh, are a few times higher than the ICRP-recommended radiation dose limits for radiation workers.
http://www.taishitsu.or.jp/radiation/ramsar-e.htmlhttp://www.angelfire.com/mo/radioadaptive/ramsar.htmlKerala,Indiahttp://www.taishitsu.or.jp/radiation/kerala-e.htmlYangjiang, ChinaBrick production using the clay obtained near-by field. The brick has high radioactivity. Thus inside the buildings made of these bricks, radon concentration and γ-ray dose are very high.
http://www.taishitsu.or.jp/radiation/china-e.htmlSurfing the web I found some interesting articles.