U.S. Geological Survey Professional Paper Professional Paper PP U.S. Department of the InteriorU.S. Geological Survey1044-96122330-7102 XXXX10.3133/ppXXXX Natural and Anthropogenic (Human-Made) Hexavalent Chromium, Cr(VI), in Groundwater Near a Mapped Plume, Hinkley, California Natural and anthropogenic (human-made) hexavalent chromium, Cr(VI), in groundwater near a mapped plume, Hinkley, California Natural and anthropogenic Cr(VI) in groundwater near a mapped plume, Hinkley, California Prepared in cooperation with Lahontan Regional Water Quality Control Board Edited by John A. Izbicki 2022 U.S. Geological Survey Reston, Virginia

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 Chapter A: Introduction to Study Area Hydrogeology, Chromium Sources, Site History, and Purpose of Study Chapter B: Survey of Chromium and Selected Element Concentrations in Rock, Alluvium, and Core Material Chapter C: Chromium in Minerals and Selected Aquifer Materials Chapter D: Analyses of Regulatory Water-Quality Data Chapter E: Groundwater Chemistry and Hexavalent Chromium Chapter F: Environmental Tracers of Groundwater Source, Age, and Geochemical Evolution Chapter G: Evaluation of Natural and Anthropogenic (Human-Made) Hexavalent Chromium Chapter H: Predevelopment Water Levels, Groundwater Recharge, and Selected Hydrologic Properties of Aquifer Materials, Hinkley and Water Valleys, California Chapter I: Sequestration and Reoxidation of Chromium in Experimental Microcosms Chapter J: Summary and Conclusions