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Radium accumulation in carbonate river sediments at oil and gas produced water discharges: Implications for beneficial use as disposal management

November 30, 2018

In the western U.S., produced water from oil and gas wells discharged to surface water augments downstream supplies used for irrigation and livestock watering. Here we investigate six permitted discharges on three neighboring tributary systems in Wyoming. During 2013-16, we evaluated radium activities of the permitted discharges and the potential for radium accumulation in associated stream sediments. Radium activities of the sediments at the points of discharge ranged from approximately 200-3600 Bq/kg with elevated activities above the background of 74 Bq/kg over 30 km downstream of one permitted discharge. Sediment as deep as 30 cm near the point of discharge had radium activities elevated above background. X-ray diffraction and targeted sequential extraction of radium in sediments indicate that radium is likely coprecipitated with carbonate, and to a lesser extent sulfate minerals. PHREEQC modeling predicts radium coprecipitation with aragonite and barite, but over-estimates the latter compared to observations of downstream sediment, where carbonate predominates. Mass-balance calculations indicate over 3 billion Bq of radium activity (226Ra+228Ra) is discharged each year from five of the discharges, combined, with only 5 percent of the annual load retained in stream sediments within 100m of the effluent discharges; the remaining 95 percent of the radium is transported farther downstream as sediment-associated and aqueous species

Citation Information

Publication Year 2019
Title Radium accumulation in carbonate river sediments at oil and gas produced water discharges: Implications for beneficial use as disposal management
DOI 10.1039/C8EM00336J
Authors Bonnie McDevitt, Molly McLaughlin, Charles A. Cravotta, Moses A Ajemigbitse, Katherine J. Van Sice, Jens Blotevogel, Thomas Borch, Nathaniel R. Warner
Publication Type Article
Publication Subtype Journal Article
Series Title Environmental Science
Series Number
Index ID 70204011
Record Source USGS Publications Warehouse
USGS Organization Pennsylvania Water Science Center