{"accessLevel": "public", "bureauCode": ["010:12"], "contactPoint": {"@type": "vcard:Contact", "fn": "Isabelle M. Cozzarelli", "hasEmail": "mailto:icozzare@usgs.gov"}, "description": "In a crude-oil-contaminated sandy aquifer at the Bemidji site in northern Minnesota, biodegradation of petroleum hydrocarbons has resulted in release of naturally occurring As to groundwater under Fe-reducing conditions. This data set was collected for a study that used chemical extractions of aquifer sediments collected in 1993 and 2011-2014 to evaluate the relationship between Fe and As in different redox zones (oxic, methanogenic, Fe-reducing, anoxic-sub-oxic transition) of the contaminated aquifer over a twenty year period. The data presented showed that 1) the aquifer has the capacity to naturally attenuate the plume of dissolved As, primarily through sorption; 2) Fe and As are linearly correlated in sediment across all redox zones, and a regression analysis between Fe and As reasonably predicted As concentrations in sediment from 1993 using only Fe concentrations; 3) an As-rich \u201ciron curtain,\u201d associated with the  anoxic-sub-oxic transition zone, migrated 30 m downgradient between 1993 and 2013 as a result of the hydrocarbon plume evolution; and 4) silt lenses in the aquifer preferentially sequester dissolved As, though As is remobilized into groundwater from sediment after reducing conditions are established.", "distribution": [{"@type": "dcat:Distribution", "accessURL": "https://doi.org/10.5066/F7K35RWK", "description": "Landing page for access to the data", "format": "XML", "mediaType": "application/http", "title": "Digital Data"}, {"@type": "dcat:Distribution", "description": "The metadata original format", "downloadURL": "https://data.usgs.gov/datacatalog/metadata/USGS.5909fc1be4b0fc4e44916002.xml", "format": "XML", "mediaType": "text/xml", "title": "Original Metadata"}], "identifier": "http://datainventory.doi.gov/id/dataset/USGS_5909fc1be4b0fc4e44916002", "keyword": ["USGS:5909fc1be4b0fc4e44916002", "arsenic", "biodegradation", "biogeochemical cycling", "sediment geochemistry", "water chemistry", "water quality"], "modified": "2020-08-31T00:00:00Z", "publisher": {"@type": "org:Organization", "name": "U.S. Geological Survey"}, "spatial": "-95.646972655946, 47.28303200061, -94.02099609351, 48.169824217141", "theme": ["geospatial"], "title": "Chemical extraction results of aquifer sediments for concentrations of iron and arsenic in different redox zones at the crude-oil spill site near Bemidji, Minnesota"}