Arsenic and the Human Microbiome
Arsenic (As) contamination of soils and water occurs worldwide-including in the U.S.-originating from both environmental and anthropogenic sources. Naturally-occurring alluvial As contaminates groundwater in South and Southeast Asia, and has caused wide-scale poisoning of a susceptible and malnourished populace. Chronic As exposure affects over 25 million people in Bangladesh alone. Industrial sources of arsenic-e.g., arsenic-containing pesticides in agriculture-also contribute to global exposure. In the United States, As tops the hazardous substance priority list of the Agency for Toxic Substances and Disease Registries, and 13 million Americans are exposed to levels exceeding the US Water Quality Standards.
Chronic exposure leads to arsenicosis, which includes melanosis, keratosis, and cardiovascular effects, as well as lung, bladder, kidney, and skin cancer. Chronic As exposure can also affect childhood intellectual function and development. There is no effective therapy for arsenicosis, emphasizing the importance of prevention and/or novel therapeutic approaches. Prevention requires effective risk-assessment, which also lays the groundwork for intervention design and treatment.
The central hypothesis of this work is that As ingestion alters the structure and function of the human gut microbiota and that differences in the human gut microbiota contribute to the observed variation in the presence/absence of arsenicosis, given equal levels of As environmental exposure.