SPATIAL AND TEMPORAL PATTERNS OF ARSENIC AND URANIUM ABUNDANCES IN PRIVATE WELL WATER ON NORTHERN MOUNT DESERT ISLAND, MAINE

Over half of people in Maine rely on privately owned wells for their drinking water. Largely due to the local geology, well owners in New England tend to consume low doses of arsenic over long periods of time, leading to long-term issues such as cancer of the lung, liver, bladder, skin, prostate, and nasal cavities (ME CDC). Moroz et al. (2018) analyzed the spatial distribution of As and other common contaminants in the groundwater of northern Mount Desert Island, Maine. They found a correlation between bedrock geochemistry and private well water chemistry. Based on anecdotal evidence, it became apparent that seasonality plays some role in well conditions as some well owners reported that their well ran dry during the summer months. During fall 2019, we conducted a reconnaissance study in the same region and with some of the same participants in order to assess potential changes in water quality through time. Initial data show changes in the abundances of some elements, including As, during the dry season. In order to better assess temporal variation in well water quality, we have initiated a contact-free monthly sampling project in the same locality in which we will resample ~30 wells, pre and post filter (when possible). We plan to sample each month for at least a year beginning in July 2020. This work will provide new high resolution temporal data, collected by and for private well owners, which bears on our understanding of water quality and public health issues in Maine. This is especially important as Maine is currently experiencing a mild drought as well as considering the uncertain future hydrologic conditions given ongoing climate change. We will present the findings of both the spatial and temporal patterns of groundwater quality from all sampling events from winter 2016 through fall 2020, a total of over 200 samples from ~80 different wells.