MDI Biological Laboratory
Press Release

Study Aims to Raise Awareness of Groundwater Toxins

Project sampling local well water for arsenic expanded to all of Mount Desert Island

BAR HARBOR, MAINE – College of the Atlantic (COA), in partnership with MDI Biological Laboratory and Dartmouth College, will be conducting free private well water sampling for Mt. Desert Island residents from November 29 to December 18, 2021.

The project is focused on investigating the spatial and temporal patterns of groundwater chemistry. This phase of the study aims to raise awareness of the need for regular well water testing and build upon College of the Atlantic’s spatial groundwater quality dataset, a study that was begun in 2016. The project is funded by a National Institute of Health (NIH) Science Education Partnership Award (SEPA) supplement grant.

Test results will yield concentration information for 13 different elements including arsenic and uranium, two toxins frequently found in local groundwater. Even with low, chronic exposure, arsenic is known to cause negative health outcomes such as developmental issues in children and cancer. Based on prior sampling and testing results, at least 10% of wells on Mount Desert Island have arsenic or uranium values above the federal and state recommended limit of 10 parts per billion (ppb).

This sampling round has been expanded to include the southern half of Mount Desert Island; previous testing over the last few years has focused on the northern portion of the island. Residents who abide on the southern half of MDI who have a private well and are interested in having their well tested, can contact Sarah Hall, Professor of Earth Science, College of the Atlantic, by email ( to set up an appointment.

Residents will collect their own sample, which takes about 10 minutes; drop off and collection is contact-free.

Residents in the northern part of the island who have not yet had their well tested are invited to contact Hall to be put on an interest list for future sampling events. A similar project, started in October 2021 in conjunction with the Town of Bar Harbor, aims to test 100 wells within the town limits.

You can find out more about the ongoing local study by visiting the project website: