Does anyone know where I can find the values of the naturally-occurring isotopic abundances of thorium? Thanks in advance! -- Melissa Woo | University of Illinois at Urbana-Champaign Health Physicist | Environmental Health & Safety Bldg., MC225 office phone: 1.217.244.7233 | 101 S. Gregory St., Urbana, IL 61801 m-woo@uiuc.edu | http://www.cso.uiuc.edu/ph/www/m-woo