A current working hypothesis developed at MIT is that the influx of dissolved arsenic into the ground water is greatly enhanced where irrigation for rice cultivation provides the primary source of aquifer recharge.

To aid in validating this hypothesis, we accompanied a group of scientists from MIT ( check out their page) Stanford, and the Bangladesh University of Engineering and Technology, to undertake a rapid deployment of a wireless sensor network in a rice paddy in Bangladesh in January of 2006. We collected approximately 25,000 measurements over a period of 12 days. We deployed 42 ion-selective electrodes (ISEs) to monitor ammonium, calcium, carbonate, chloride, pH, oxidation-reduction potential, and nitrate, along with 8 soil temperature, moisture and pressure sensors distributed over 3 different depths and locations. We used directION ISEs purchased from Sentek ( http://www.sentek.co.uk/ ).

Check out my packing list for international deployments.

Some Pictures
  Highlights   Deploying a Pylon   Deploying a Big Pylon   Digging a well   People

  Data and Publications
In 2007, we returned to deploy sensors for 2 months. This data confirm the cycles we found in 2006, but are not available yet.

The data from our 2006 deployment are in directories separated by [node] , and by [sensor] .
See this (big) ppt for graphs of data and some of our notes. [1] contains more compact graphs of all data on p.8, and descriptions of some of the data faults. [2] contains a brief description of our deployment and a better discussion of data faults. [3] contains a discussion of the scientific implications of the data.

[1] Rapid Deployment with Confidence: Calibration and Fault Detection in Environmental Sensor Networks [pdf]
N. Ramanathan, L. Balzano, M. Burt, D. Estrin, E. Kohler, T. Harmon, C. Harvey, J. Jay, S. Rothenberg and M. Srivastava. CENS Tech Report #62, April 2006.

[2] The Final Frontier: Embedding Networked Sensors in Soil [pdf]
N. Ramanathan, T. Schoellhammer, D. Estrin, M. Hansen, T. Harmon, E. Kohler, M. Srivastava. Submitted, November, 2006

[3] Sensor-based investigation of biogeochemical controls on arsenic mobilization in rural Bangladesh [doc]
N. Ramanathan, C. Lee, T. Lin, R. Neumann, S. Rothenberg, C. Harvey, T. Harmon, E. Kohler, D. Estrin, J. Jay.
In Procs. of American Chemistry Society, General Meeting. Boston, 2007.

[4] Investigation of hydrologic and biogeochemical controls on arsenic mobilization using distributed sensing at a field site in Munshiganj, Bangladesh [abstract, poster]
N. Ramanathan, S. Rothenberg, D. Estrin, T. Harmon, C. Harvey, J. Jay, and E. Kohler. American Geophysical Union, Fall Meeting, 2006.

  Talks