Geochemist Lex van Geen is a research professor at Lamont-Doherty Earth Observatory and is member of the Earth Institute at Columbia University. His research focuses on ways to reduce the impact of the environment on human health. For two decades, he coordinated earth-science on the origin and health effects of elevated levels of arsenic in groundwater. His other projects focus on fluoride in groundwater in India, bauxite dust in Guinea, or soil contaminated with lead from mine-tailings in Peru, and fallout of lead over Paris following the fire in Notre Dame. Dr. Van Geen is a firm believer in the more widespread use of field kits by non-specialists to reduce exposure to environmental toxicants."So the reason people drink well water in the first place is because surface water, which is more easily accessed is often contaminated with microbial pathogens, and this was true, especially in a high population density area like Bangladesh. You can boil the water, of course, but boiling takes fuel and effort. To avoid these microbial pathogens, it turns out that pumping the water through the sand underneath is very effective. There the levels of microbial pathogens in well water are orders of magnitude lower, and so this is why the number of wells in Bangladesh grew exponentially to maybe 10 million today in the past three decades. What people didn't know as these wells were being installed - they didn't know until the late nineties - is that some of these wells had high levels of arsenic. Not levels of arsenic that killed you on the spot, but chronic exposure over time can have serious health impacts."www.ldeo.columbia.edu/~avangeenwww.oneplanetpodcast.orgwww.creativeprocess.info