By Joe Shortsleeve, WBZ-TV

BOSTON (CBS) -The first rounds of tests are back on the safety of the water in Sherborn.

Earlier this month, the I-Team reported that the State Department of Environmental Protection was testing to see if any ground water contamination from the General Chemical hazardous waste facility in Framingham had made its way into Sherborn’s drinking water wells.

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Twelve homes were tested and two showed trace levels of “PCE” which is a chemical solvent used at the facility.

The DEP says the levels are so low that the water is still safe to drink. The DEP also says it is possible the “PCE” came from household cleaning products flushed down the septic system.

The state will test another 20 homes sometime next week.

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More info from DEP on samples:

Site: Meadowbrook Road (house #1) – Trace levels of tetrachloroethylene (PCE), below the 0.5 part per billion (ppb) Lab Reporting Limit (which means that the lab can ensure a detection down to 0.5 ppb, but can only estimate at a level below that limit). The lab estimate for PCE for his home was 0.24 ppb. The Mass. Drinking Water Standard for PCE is 5.0 ppb, which is more than 10 times higher than the trace amounts found in this well.

Site: Meadowbrook Road (house #2) – Trace levels of PCE, below the 0.5 ppb Lab Reporting Limit, estimated by the lab at 0.44 ppb. Again, the Mass. standard for PCE is 5.0 ppb. The sample for this home also detected chloroform, again at trace levels below the 0.5 ppb Lab Reporting Limit, estimated by the lab at 0.2 ppb. The Mass. Drinking Water Standard for chloroform is 70.0 ppb.

Chloroform has no connection to any activities at the General Chemical Corp. PCE has been handled at GCC, but there is no way to connect this trace amount to GCC as PCE is also used in many household cleaning products that could have been flushed down and into the septic system of the home, later leaching out into the groundwater. Also, PCE was once contained in products that were used to clean out septic systems.

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Site: Prospect Street – No PCE there. Trace levels of Methyl tertiary butyl ether (MtBE), which was once an additive in gasoline. The MtBE was reported at 0.63 ppb, slightly above the Lab Reporting Limit of 0.1 ppb. The Mass. Drinking Water Standard for MtBE is 70.0 ppb. There is no connection of MtBE to chemicals handled by GCC; it is possible that MtBE got into the groundwater due to a spill at a nearby gasoline station, or if gasoline was spilled while filling up the lawnmower or snowblower.