Krall, A.L., Erickson, M.L., and Berquist, E.C., 2018, Total and aqueous arsenic concentrations and physiochemical characteristics of groundwater from newly constructed drinking water wells in central, northwest, and northeast Minnesota, 2014 – 2016 (ver. 2.0, July 2018): U.S. Geological Survey data release, https://doi.org/10.5066/F7736PVK.
Summary
This data release provides total and aqueous arsenic (As) determinations and associated field readings collected from groundwater sampled from 254 newly constructed private residential wells between 2014 and 2016. The study focuses on three regions of Minnesota that differ geologically: south-central (herein called central), northwest, and northeast. These study regions were chosen due to their prevalent elevated As concentrations in drinking water. Each of the 254 wells were sampled in three rounds by the Minnesota Department of Health (MDH). The timing of the three sampling rounds was (1) immediately or shortly after well construction (round 1); (2) 3-6 months after initial sample collection (round 2); and (3) 12 months after initial [...]
Summary
This data release provides total and aqueous arsenic (As) determinations and associated field readings collected from groundwater sampled from 254 newly constructed private residential wells between 2014 and 2016. The study focuses on three regions of Minnesota that differ geologically: south-central (herein called central), northwest, and northeast. These study regions were chosen due to their prevalent elevated As concentrations in drinking water. Each of the 254 wells were sampled in three rounds by the Minnesota Department of Health (MDH). The timing of the three sampling rounds was (1) immediately or shortly after well construction (round 1); (2) 3-6 months after initial sample collection (round 2); and (3) 12 months after initial sample collection (round 3). During each round, samples were collected for both total and aqueous As. Physiochemical characteristics, including specific conductance, pH, dissolved oxygen, oxidation reduction potential, and temperature, were also measured to gage the well water stability prior to sample collection. Round 1 sampling was timed to co-occur and mimic well driller regulatory sampling. Drillers collected samples after well development from the drill rig groundwater pump or from the residential plumbing, and the MDH sampler replicated the sample location and timing used by the driller. Sampling from the drill rig’s groundwater pump occurred after the well was drilled and developed, when the water was visibly clear, with little visible sediment particles. Samples from plumbing were collected after the plumbing was flushed out and physiochemical characteristic readings stabilized. Round 2 and round 3 by MDH staff were collected only from plumbing. Samples collected from plumbing were taken from faucets, hydrants, or pressure tanks prior to filters or treatment systems.
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AsMetadata.xml “Metadata” Original FGDC Metadata
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AsData.csv “Arsenic and field parametere data”
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Related External Resources
Type: Related Primary Publication
Erickson, M. L., Malenda, H. F. and Berquist, E. C. (2018) How or when samples are collected affects measured arsenic concentration in new drinking water wells. Groundwater. Accepted Author Manuscript. doi:10.1111/gwat.12643
Arsenic is a naturally-occurring contaminant in geologically diverse aquifers throughout the world, making chronic exposure to elevated arsenic via drinking water is a human health concern. In Minnesota, USA, elevated arsenic concentrations are prevalent in drinking water aquifers in certain regions of the state where newly constructed drinking water wells exceed the U.S. Environmental Protection Agency's maximum contaminant level for arsenic, 10 micrograms per liter. In 2008, Minnesota well code requires arsenic testing of all newly constructed drinking water wells, but sampling methods are not specified in the code. This data set compares the effects of sample filtration and typical well driller arsenic sample collection protocols (no filtration and no specific time frame) on the variability of measured arsenic concentrations in newly constructed drinking water wells in three different regions of Minnesota with prevalent elevated arsenic concentrations in well water. The purpose of this data collection was to understand differences in arsenic concentrations resulting from different methods of sample collection (i.e. collection point, collection time, and filtration). Results can help regulatory agencies establish specific protocols for collection of water quality samples from newly constructed drinking water wells to ensure repeatable water quality measurements for new well owners.
