Lex van GeenLex van Geen is a geochemist by training and joined Lamont-Doherty Earth Observatory in 1994, after completing his Ph.D. (1989) from the MIT/WHO Joint Program in Oceanography and post-doctoral fellowships in Civil and Environmental Engineering at Stanford University and the Water Resources Division of the US Geological Survey. His research interests span the reconstruction of past climate change from ocean sediment cores to the health effects on children of exposure to lead from mine tailings in Peru. He coordinates earth-science and mitigation efforts under Columbia's Superfund Research Program on the health effects and geochemistry of arsenic contained in US and Bangladesh groundwater. Van Geen has initiated complementary studies of behavioral constraints on arsenic mitigation in Bangladesh and the contamination of groundwater with microbial pathogens. He is a firm believer in the more widespread use of field kits by non-specialists to reduce exposure to environmental toxins, particularly in developing countries. He holds a Lamont Research Professor appointment and has published over 100 peer-reviewed papers.