This story was updated 4/19/13 to add more information about state approved water testing labs.
Some wells in Weston are free of arsenic, while others have higher levels than the federal limit.
Those were the results of a recent well water study conducted by Mark Cooper, health director of The Westport Weston Health District.
Mr. Cooper presented his results at a public discussion held April 11 at the library. He was joined by Brian Toal, epidemiologist with the Connecticut Department of Health (DPH).
The discussion was held in response to reports that some wells in Weston had tested high for arsenic.
Farrell Road resident Jessica Penna brought the arsenic issue to light after her well water tested high for arsenic — double the acceptable limit.
Based on reports of high arsenic levels in well water in Weston, Somers, and Pomfret, the DPH issued a statement on March 18, recommending that all private well owners in Connecticut have their water tested for arsenic and uranium.
At the meeting, Mr. Cooper displayed a map showing arsenic test results for 195 wells in Weston.
He compiled the data primarily from residents who had their wells tested on their own and called him with the results.
In addition, the district tested 12 wells in the Farrell Road area.
Mr. Cooper emphasized that the map was a work in progress, and each day he was receiving more calls with more results. He said the map information was only current up to April 10.
Of the 195 wells on the map, 77.3%, represented by green dots, were within the federal standard for arsenic, which is 10 parts per billion.
But 22.7%, represented by red dots, were above the standard.
While there were some red dots in all areas of town, there was an especially heavy concentration in the southern portion of Weston near the Westport border. There was one particularly heavy cluster in the Farrell Road and Goodhill Road area, where there were 16 red dots.
A total of 114 of the 195 wells (58.4%) had no arsenic present. With zero parts per billion, those wells were well below the 10 parts per billion standard.
37 wells (18.9%) had very low levels of arsenic. They were also under the 10 parts per billion standard, with levels between 0.005 and 0.010 (5 to 10 parts per billion).
The remaining 44 wells exceeded the 10 parts per billion standard.
32 wells had levels between 0.011 and 0.020 (11 to 20 parts per billion).
10 wells had levels between 0.021 and 0.030 (21 to 30 parts per billion)
Two wells had levels between 0.041 and 0.050 (41 to 50 parts per billion)
One well tested at 0.115 (115 parts per billion), which Mr. Cooper said was very high.
Mr. Toal explained that arsenic is a metal that occurs naturally in bedrock all over the world.
When groundwater comes in contact with the bedrock, the metals may leach out and contaminate private wells.
Arsenic is odorless and tasteless and is found in organic and inorganic forms. It is often used in industry, farming, and pressure-treated wood.
Arsenic is classified as a human cancer-causing agent, which has been associated with increased risk of lung, bladder and skin cancers.
Arsenic can also have a variety of adverse health effects if people are exposed at high enough levels and for a long period of time.
One of the single-most characteristic effect of long-term oral exposure to inorganic arsenic is a pattern of skin changes, Mr. Toal said. These include patches of darkened skin and the appearance of small “corns” or “warts” on the palms, soles, and torso, and are often associated with changes in the blood vessels of the skin. Skin cancer may also develop.
Fortunately, there is treatment available to eliminate arsenic from well water.
While the state requires testing of public water supplies every three years, there is no mandatory testing for private wells. Water testing is up to individual homeowners on a voluntary basis.
Heating or boiling water will not remove arsenic. Because some of the water evaporates during the boiling process, the arsenic concentrations can actually increase as the water is boiled. Chlorine (bleach) disinfection will not remove arsenic either.
The only way to know if arsenic is present in a private well is to have the water tested by an approved environmental water testing lab. Since tests for arsenic are not usually part of a “standard well analysis,” homeowners need to specifically ask labs to analyze for it.
While there have not been any reports about high uranium levels in Weston, Mr. Toal said it is a good idea to test for uranium too, and labs will usually do a combined arsenic/uranium test for a reasonable fee. He said the cost for testing for both metals can range between $65 and $100.
Special filtration systems can effectively remove arsenic. Carbon filters can be effective, and in some cases reverse osmosis systems will work. But each well and situation is different, so reverse osmosis does not work in all cases. Mr. Toal said to ask the testing lab for advice if a treatment is needed.
During public comment, Jessica Penna also recommended people get their wells tested. After feeling sick for years, she said she had medical tests done that revealed she had a high level of arsenic in her body. She said it wasn’t until she had her well tested for arsenic that she discovered that her water was double the federal standard at 20 parts per billion. She would like to see a state regulation that requires arsenic testing in order to prevent others from getting sick.