CAREER: The Role of Microorganisms in Arsenic Contamination of Groundwater

ABSTRACT: Arsenic at elevated concentrations in drinking water affects the health of millions of people worldwide from Bangladesh to New Zealand to the USA. Keratosis, skin cancer, lung and bladder cancers, and diseases of the vascular system have all been linked to arsenic exposure through drinking water (Hopenhayn, 2006). To understand the factors that contribute to high arsenic in groundwater, a multidisciplinary and international effort is required. We have found that iron- and arsenate-reducing bacteria contribute to arsenic contamination. Researchers at the University of Manchester have similarly implicated iron reducing bacteria in arsenic contamination of groundwater in West Bengal and Cambodia, and found close relatives of our groundwater isolate, Sulfurospirillum species NP4, in enrichment cultures using Cambodian sediments (Islam et al., 2004; Lear et al, 2007). Collaboration with Professor Jon Lloyd and others and the Williamson Research Centre at the University of Manchester, UK has allowed us to investigate the effects of iron reducing bacteria at surfaces and probe the ability of Geobacter uraniumreducens to cause the release of sorbed arsenic. We have also applied molecular techniques to characterize the microbial communities of groundwater samples of varying arsenic concentrations. The collaboration and techniques learned have enabled UMaine researchers to use techniques employed by geologist and molecular biologists in pursuit of new research directions and have broadened the research networks of both the PI and her graduate student