The Carlisle Mosquito Online

Friday, April 17, 2009

Board of Health to investigate Carlisle geology

Tony Mariano, a mineral exploration geologist and resident of Page Brook Road, spoke on April 7 to the Board of Health (BOH) about arsenic and uranium, which the United States Geological Survey (USGS) is studying in rocks throughout New England. Mariano said uranium and arsenic are present here and there in “very low quantities.” While he is not aware of any health risks at the levels observed, he suggested the BOH sample rocks in town in order to learn more.

Uranium and thorium, another radioactive element, can be found in rocks in this area. Mariano does not think the uranium leaches into the water. Regarding arsenic, he said, “There’s nowhere that I know of in Massachusetts where you have extensive amounts of arsenic minerals. You have them in small amounts.”

The BOH has learned through voluntary water testing that some wells scattered across town contain arsenic at levels somewhat above the EPA standards. However, BOH Agent Linda Fantasia says, “There’s never been any indication that Carlisle has any serious water quality issues.”

Local study proposed

In response to the USGS study, Mariano suggested the BOH might want to study the correlation between well water and the bedrock around the wells. Mariano recommended using a lab in Toronto where water and rocks can be analyzed quantitatively in detail. He said that for $100, the firm would test for major elements and 60 trace elements. “For a couple thousand dollars, we could get a lot of information about arsenic and various other elements in the rocks and in the water.” BOH Agent Linda Fantasia had told Mariano the Water Quality Subcommittee has a little bit of money and he suggested it could be used for this purpose.

Water can come from sand and soil planes and water from the surface can “eventually be assimilated into the bedrock at depth.” Mariano noted that there used to be orchards in parts of Carlisle where herbicides may have been used and he noted that it may be possible to figure out if any detected arsenic originated from bedrock or herbicides.

Mariano suggested drilling in ten areas in town with differing rock types, with the samples then sent to the lab for analysis of the relative abundances of various minerals. Mariano then offered his services for free, and estimated lab and other project expenses at roughly $3,000. Mariano wants to talk it over with the Water Quality Subcommittee to get their ideas and recommendations. He will also study geological maps of the town and make recommendations for drilling sites.

Mariano said it would be best to get bedrock samples at depth. He hopes that homeowners who drill new wells will consider giving the BOH drill core samples from the depth at which the water pump will sit. He wondered if there might be owners of older homes who kept rock chips from the drilling of their wells, which they might be willing to share with the BOH.

BOH Chair Jeffrey Brem asked Mariano to see if the USGS would subsidize this effort, analyzing ten bedrock specimens in Carlisle, with matching funds since Carlisle would be providing specific information to them. Mariano said he was doubtful a grant would be forthcoming, but would ask.

Brem asked Mariano to write up a plan with a time frame so this effort could be discussed further and put into action.

Water filters

Mark St. Hilaire, of Atlas Watersystems, spoke about filtering systems. He said his company is getting many calls about arsenic; testing for it is often required now before a house can be sold. St. Hilaire said, “It’s fairly easy to get arsenic out.” His company typically recommends an ion-exchange using a lead-lag system, with system monitoring every six months.

When asked about uranium, St. Hilaire said this testing is new and “only a handful of these tests are being done.” He said a lead-lag system, similar to the one used for arsenic, is used to filter uranium, although different equipment must be installed because the ion-exchange is different. Uranium gets back-washed and should go into a dry well, not into the septic system. ∆

© 2009 The Carlisle Mosquito