{
  "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 “iron curtain,” 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"
}