As you may have seen in the news this weekend, low levels of I-131 were found in a rainwater sample in Boston. MassDEP and MassDPH had a press release to communicate information and let people know that there is no public health risk. There were no detectable levels of I-131 found in samples taken at the Quabbin and Wachusett Reservoirs.
At the request of the Governor, MassDEP initiated sampling at 12 reservoirs yesterday. The list of reservoirs in the Boston Globe were: McLean Reservoir; Cleveland Reservoir; Cobble Mountain; Holden Reservoir; Notown Reservoir; Southbridge Reservoir; Merrimack River; Concord River; Wenham Lake; Assawompset Pond Complex; Brockton Reservoir; and Long Pond.
Results should be in today. We will keep you updated as we learn more.
DPH has put together a fact sheet that can be downloaded here.
STATE HEALTH OFFICIALS FIND LOW CONCENTRATIONS OF RADIOIODINE (I-131) IN RAINWATER SAMPLE COLLECTED; NO PUBLIC HEALTH CONCERN EXPECTED
No impact on state drinking water supplies
“The Massachusetts Department of Public Health (DPH) today announced that very low concentrations of radioiodine-131 (I-131), likely associated with the Japan nuclear power plant event, have been detected in a precipitation (i.e. rainwater) sample. The sample location is one of more than 100 locations around the country that are part of the U.S. Environmental Protection Agency (USEPA) Radiation Network (RadNet) monitoring system that routinely monitors for radioactivity in environmental media. Air samples at the same location have shown no detectable radiation. There is no health impact to state drinking water supplies as a result of these findings, and state and federal health officials emphasized that there are no anticipated public health concerns.
The concentration of I-131 was 79 pCi/L (picocuries per liter). The precipitation sample was taken during the past week, with results available today following analysis and confirmatory testing by the DPH Radiation Control Program. Similar testing in other states, including California, Pennsylvania and Washington, has shown comparable levels of I-131 in precipitation samples. Federal officials have indicated that such findings would likely be found in multiple locations across the country, with some variation due to weather patterns.
DPH Commissioner John Auerbach emphasized that the sampling results show no risk to state drinking water supplies. "The drinking water supply in Massachusetts is unaffected by this short-term, slight elevation in radiation. However, we will carefully monitor the drinking water as we exercise an abundance of caution." he said.
I-131 has a short half-life (the time that it takes for half of the radionuclide to break down) of eight days. Detecting a concentration of approximately 79 pCi/L in precipitation would mean that the element becomes undetectable in a relative short time, assuming no continuing source.
It is important to note that any I-131 concentrations detected in rainwater samples are significantly higher than might be detected in a surface water body, such as a lake or pond, because anything falling with precipitation would be greatly diluted once in the water body. In addition, standards that are established for the group of radionuclides, including I-131, are based on a lifetime of daily exposure. Given the short half-life of I-131 and the likely significant dilution of any precipitation that may contain I-131 once falling into a water body, health officials do not expect health concerns associated with levels currently being reported. Nonetheless DPH has worked with the Massachusetts Water Resource Authority (MWRA) to collect raw drinking water samples from the Quabbin and Wachusett Reservoirs last week as part of
an expanded monitoring system. Results of this testing showed no detectable levels of I-131 in either body of water.
Energy and Environmental Affairs Secretary Richard K. Sullivan Jr. directed the Department of Environmental Protection (MassDEP) to collect additional samples for testing for radioiodine from several water bodies across the state today (Sunday), and results will be available on a rolling basis over the next several days.
"The initial result of DPH tests on water samples from the Quabbin and Wachusetts Reservoirs - the source of drinking water for 2.5 million Massachusetts residents - is good news," said Secretary Sullivan, who chairs the board of the MWRA. "In an abundance of caution, however, MassDEP is sampling additional areas today so that we can be confident that water bodies across the Commonwealth have not been impacted by the nuclear incident in Japan."
USEPA also reported this week that four RadNet sites on the West Coast (Riverside. CA; San Francisco, CA; Anaheim, CA; Seattle, WA) had levels of I-131 in ambient air ranging from 0.003 to 0.01 pCi/m3. USEPA characterized these results as hundreds of thousands to millions of times below levels of concern. In a typical day, Americans receive doses of radiation from natural sources like rocks, bricks, and sun that are about 100,000 times higher than what has been detected coming from Japan. In Massachusetts, all measured air samples have had undetectable radiation levels.
DPH will continue to monitor precipitation and ambient air samples for the presence of radionuclides that may be associated with the Japan event and to assess trends, whether increasing or decreasing. As an added precaution, DPH will also work with the state Department of Environmental Protection to collect and analyze additional drinking water samples (where the drinking water source is a surface water body) for the presence of I-131.”