Healthy Drinking Waters for M A S S A C H U S E T T S S a f e a n d h e a l t h y l i v e s i n s a f e a n d h e a l t h y c o m m u n i t i e s Radon in Private Drinking Water Wells rivate well owners are responsible for the Pquality of their drinking water. !e U.S. En- vironmental Protection Agency (EPA) does not regulate private wells. Homeowners with pri- vate wells are generally not required to test their drinking water, although local Boards of Health or mortgage lenders may require well water testing. While there is also no state requirement to have your well water tested, the Massachu- setts Department of Environmental Protection (MassDEP) recommends that all homeowners ate health effects. Its effects on the human with private wells do so, and use a state certified body are chronic in that they take time to testing laboratory. !ere is currently no federal develop. !e long-term health effect of expo- drinking water standard for radon. sure to elevated radon levels in indoor air is the increased risk of lung cancer. Radon gas in Summary indoor air is the second leading cause of lung Radon occurs naturally in Massachusetts. It is cancer. Drinking water that contains radon can a radioactive colorless, odorless, and tasteless present a risk for developing internal organ gas. !e major health concern for radon is from cancers, the leading one being stomach cancer. breathing elevated amounts in the air, which However, the risk of developing cancer from can cause lung cancer. Although, there is a radon dissolved in water is smaller than the slight risk associated with ingesting water with risk of developing cancer from radon released elevated levels of radon, the primary concern is into the air. release of radon from normal water use into in- door air. !e first step is to arrange to test your Sources of Radon in Air and Water indoor air for radon. !e treatment options Radon is a radioactive, colorless, odorless, and for radon in water are aeration and the use of tasteless gas that is formed through the break- granular activated carbon filters. down of uranium in soil and rocks. Uranium is present as a trace element in granite rock. Potential Health Effects !ere are several ways for radon to enter the Exposure to radon gas does not yield immedi- home’s air: 1 Healthy Drinking Waters for Massachusetts R a d o n i n P r i v a t e D r i n k i n g W a t e r W e l l s • !e most common way is radon moving from the soil into the basement through cracks and other openings in the foundation and being released into the air. Homes that are built over bedrock containing radioac- tive materials are most susceptible to this. Sump pumps can also be a pathway for radon gas to enter the home. • Radon may be present in groundwater. !erefore homes that are served by bedrock wells are at a further risk for elevated radon levels in the air. Radon gas dissolved in water can be released to indoor air through normal household activities such as shower- ing, dishwashing, and laundry. In this sense, radon is acting like carbon dioxide in a soda bottle that is released once the soda bottle is opened. Some radon may remain in the water. • Radon may potentially be released into the air from building materials such as granite block foundations, some fireplace materials, another. On average, this transfer ratio predicts and floor or wall tiles. that 10,000 pCi/L (picocuries per liter of air) of o an radon in water can be expected to increase the anz e M ik Although there are some exceptions, in gen- overall annual average radon concentration of m/M eral, the migration of radon up from the soil the air in a conventional single family home by o .c o t o contributes the largest percent of radon found approximately 1 pCi/L. To illustrate this conver- h p k c o in the average home. Radon from a groundwa- sion assume the following example: if the radon ©ist ter water supply source, particularly a bedrock in water concentration was 5,000 pCi/L, and well, contributes the next largest percentage the radon in the air measure was 3 pCi/L, then ut o enh of radon in the home. !e radon contributed 0.5 pCi/L of the airborne radon would likely a y M from building materials is typically very small. be attributed to the water and the remaining mm o 2.5 pCi/L would be attributed to radon gas m/T o .c Testing for Radon in Private Drinking o migration up from the soil through the home’s t o h p k Water Wells foundation. It is important to note that this c o It is recommended that both the interior air of ©ist ratio is an approximation and may vary widely a home and the private well water be tested for from home to home. radon. As radon escapes from water it raises Testing the home for radon in air is simple the radon level of the air within a building. !e and inexpensive. If detected, the problem can “radon transfer ratio” predicts the increased be fixed. Radon air test kits that meet EPA radon level of indoor air in a home due to the guidelines are available at some retail outlets, off-gassing of radon from the water. !e trans- laboratories, or through a certified radon mea- fer ratio can vary widely from one home to surement consultant. 2 Healthy Drinking Waters for Massachusetts R a d o n i n P r i v a t e D r i n k i n g W a t e r W e l l s If indoor air levels of radon are 4 picoCuries • Dissolved analytical gross alpha radioactivity. or higher, EPA suggests that you arrange to • Radium 228 testing. have your well water tested for radon at a state • Radium 226 testing - the need for radium certified laboratory. Water testing can be done 226 testing can be partially evaluated by a at any time of the year. If the well/water sys- review of the analytical gross alpha data. n n a m tem has not been in regular use, the entire sys- s s o r G tem should be flushed for at least 20 minutes If you have a bedrock well, radon gas and o k i e H to ensure that fresh water is captured in the dissolved analytical gross alpha are the / m o c . o sample container. “Old” water will have a lower testing priorities. t o h p k radon concentration due to radon’s half-life of c o t s i approximately 3.6 days. A review of well water Interpreting Test Results © data shows that radon concentrations in water Radon in Indoor Air may vary substantially from one test to an- !e U.S. Environmental Protection Agency other due to many reasons including the level (EPA) has set an advisory “action level” of 4 of saturated soil above the rock, atmospheric pCi/L for radon gas in indoor air. While not pressure, prior well pumping and other factors. a mandated health standard, this level is a It is recommended that at least two radon tests guideline for people to use in assessing the se- ell w am (at least one month apart when possible) be riousness of their exposure to airborne radon. r x B e processed before determining the average ra- Concentrations noticeably lower than 4 pCi/L l m/A o don concentration in water. Follow laboratory are desirable. 4,000 picoCuries of radon in wa- .c o t o h instructions carefully to avoid contamination ter contribute roughly 0.4 picoCuries of radon p k c and to obtain a good sample. If your well water to the air for a 1,000 square foot, single story o ©ist contains elevated levels of radon, the levels home. !e radon concentration in water will that may be considered safe or unsafe depends determine the type of water treatment option on the levels detected in indoor air and if you best suited for your situation. reduce indoor air levels. !e design of a treat- ment system for radon in air should consider Development of the Radon in Drinking radon levels in water, where applicable. Water Standard At present there is no federal standard for Testing For Other Radionuclides In Water radon in drinking water. Such a standard is In addition to radon gas, other radioactive min- known as a maximum contaminant level (MCL). erals such as radium and uranium may be dis- However, the MassDEP Office of Research solved in drinking water. A test of drinking wa- and Standards has developed a guideline of ter for radon gas does not provide meaningful 10,000pCi/L for radon in drinking water. knowledge concerning the presence or absence of any other mineral radionuclides, nor does Reducing Your Exposure to Radon an elevated level for these dissolved minerals Whole house treatment, also known as point- imply the presence of an excessive amount of of-entry treatment, is the most effective way to radon gas. In other words, a minimum of three remove radon from your water. Aeration and different laboratory tests are necessary to granular activated carbon filters are the two make an initial assessment of the radioactivity types of treatment options for radon removal level of a particular well.