The Massachusetts Department of Public Health (MDPH) Bureau of Environmental Health (BEH) Radiation Control Program (RCP) conducts environmental radiation monitoring within in the Emergency Planning Zones (EPZs) of operating nuclear power stations in or near the Commonwealth as part of our regulating responsibilities and to provide a system of watchfulness.

The EPZs in Massachusetts for Pilgrim, Seabrook, and Vermont Yankee Nuclear Power Stations all have environmental radiation sampling programs. Environmental media samples typically include food crops, milk, surface water, sediment, fish, and air. The samples collected are analyzed by the MDPH BEH Massachusetts Environmental Radiation Laboratory (MERL). MDPH also has a network of radiation detectors that surround Pilgrim Nuclear Power Station that detect gamma radiation in real-time. A computer server with enhanced software provides remote real-time access to the data by designated MDPH BEH staff. Emergency pager alerts are sent to senior MDPH officials if radiation is detected above typical background levels. This is to ensure that immediate actions can be taken if necessary. Real-time air monitoring is also done by the C-l 0 Research & Education Foundation, Inc., a non-profit under contract with MDPH, in the Massachusetts communities within the Seabrook EPZ. The MDPH BEH Environmental Toxicology Program (ETP) in collaboration with MDPH BEH RCP is tasked with evaluating the data and interpreting results in the context of typical background concentrations and potential public health exposure concerns.

Environmental Monitoring Report

Pilgrim, Vermont Yankee, and Seabrook Nuclear Power Station Emergency Planning Zones

Environmental Monitoring Presentations

The Tritium in Groundwater Monitoring Wells at Pilgrim Nuclear Power Station (PNPS)

The Nuclear Entergy Institute proposed in 2006 that nuclear power plants begin a voluntary groundwater protection initiative aimed at monitoring for tritium in groundwater. This was prompted by tritium found in groundwater near several operating nuclear power plants in the United States. In response to this voluntary initiative, Entergy began monitoring for tritium in groundwater in 6 monitoring wells at Pilgrim Nuclear Power Station (PNPS) in Plymouth, MA in 2007. Massachusetts Department of Public Health (MDPH) officials were provided with the monitoring results of tritium in groundwater from these wells. In response to tritium in groundwater findings at the Vermont Yankee Power Plant in VT, PNPS planned to install a few additional groundwater monitoring wells in May of 2010. Following discussions with MDPH scientists and MEMA officials, the total number of monitoring wells was increased to 12. Based on what appeared to be rising levels of tritium measured in one of these new wells (MW205), and a review of available site specific groundwater information, MDPH recommended that Entergy install additional monitoring wells and begin collecting surface water samples immediately off-shore from PNPS. In July 2010, MDPH received a report from Entergy indicating what seemed to be an unusually high level of tritium in a groundwater sample collected from MW205. That report showed 25,552 picocuries per liter (pCi/L) detected in a sample collected from MW205 on 7/7/10. At that time, MDPH representatives along with MEMA representatives asked for increased communications and a meeting with PNPS officials to discuss the need for more frequent monitoring, regular review and discussion of groundwater data collected, and a comprehensive investigation to determine the source(s) of tritium. In August 2010, Entergy installed 6 additional monitoring wells, increased the frequency of groundwater testing, and began surface water sampling. Since September 2010, MDPH has provided government officials and local representatives with regular updates on the tritium investigation, which has resulted in the installation of additional monitoring wells to evaluate specific sources of interest, bringing the current total to 22 wells.

Results of groundwater monitoring well samples collected at PNPS to date can be accessed by clicking on the link below. Groundwater samples collected at PNPS were analyzed by an Entergy contract laboratory and split samples were analyzed by MDPH/RCP Massachusetts Environmental Radiation Laboratory (MERL). All groundwater samples were collected from groundwater monitoring wells located on the PNPS property. Approximate locations of monitoring wells can be viewed by clicking on the map link below.

To improve readability, the environmental monitoring data (previously reported in one large table) have been split into smaller tables summarized by year for 2007, 2008, and 2009; data are reported quarterly for the more frequent sampling which began in 2010. A graph showing tritium concentrations in groundwater monitoring wells MW205, and MW206 over time has also been added for clarity.


Map and Graph

Summary Updates on Tritium Investigation at Pilgrim Nuclear Power Station (PNPS)






This information is provided by the Radiation Control Program within the Department of Public Health.

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