Arsenic in groundwater has lead to a massive poisoning in Bangladesh. Tens of millions of people are currently drinking dangerously high levels of naturally occurring arsenic in groundwater, resulting in adverse health effects. However, we lack a full understanding of the factors controlling arsenic (a naturally occurring element) mobilization to groundwater. A current working hypothesis is that influx of dissolved arsenic to groundwater is greatly enhanced where rice cultivation provides the primary source of aquifer recharge because anoxic irrigation-return flow mobilizes arsenic (As) as it passes through an As-enriched iron oxide band in the sediment. We plan to deploy a wireless sensor network to monitor oxidation-reduction potential (ORP), moisture, soil temperature, calcium, ammonium, pH, oxidation, and nitrate at three depths in pylons located at three different locations.