William H. Orem, Ph.D. (Former Employee)

Water and sediment extracts samples were analyzed for extractable hydrocarbons by gas chromatography/mass spectrometry (GC/MS) using an Agilent (Agilent Technologies, Palo Alto, CA, USA) 7890 series GC and 5975 electron ionization (EI) mass selective detector (MSD) operated in scan mode. Agilent ChemStation software was used for data acquisition and analysis (version E.02.00.493 on GC/MS...

Competition between microbial sulfate reduction and methanogenesis drives cycling of fossil carbon and generation of CH4 in sedimentary basins. However, little is understood about the fundamental relationship between subsurface aqueous geochemistry and microbiology that drives these processes. Here we relate elemental and isotopic geochemistry of coal-associated water and gas to the...

For nearly two and a half decades following World War II, production wastes from the world's largest manufacturer of technical DDT (1-chloro-4-[2,2,2-trichloro-1-(4-chlorophenyl)ethyl]benzene) were discharged into sewers of Los Angeles County. Following treatment, the wastes were released via a submarine outfall system to nearshore coastal waters where a portion accumulated in shallow...

Sulfate inputs to the Florida Everglades stimulate sulfidic conditions in freshwater wetland sediments that affect ecological and biogeochemical processes. An unexplored implication of sulfate enrichment is alteration of the content and speciation of sulfur in dissolved organic matter (DOM), which influences the reactivity of DOM with trace metals. Here, we describe the vertical and...

The organic composition of groundwater along the Carrizo-Wilcox aquifer in East Texas (USA), sampled from rural wells in May and September 2015, was examined as part of a larger study of the potential health and environmental effects of organic compounds derived from low-rank coals. The quality of water from the low-rank coal-bearing Carrizo-Wilcox aquifer is a potential environmental...

This project was organized into separate field and laboratory studies aimed at answering “18 questions” in the original Scope of Work (cf., section 2 of this report, Background, for explanation). Because of some early results, certain questions became irrelevant and were, therefore, not pursued. In other cases, there simply was not enough time to complete the originally planned studies...

This data report provides a compilation of information developed over the last 6+ years by a multi-disciplinary, multi-institutional research team. The overall goal of this work has been to identify the biological, chemical, and physical factors that control rates of reductive dechlorination of DDE and DDMU in sediments of the Palos Verdes Shelf (PVS). More specific questions and...

Stable carbon and hydrogen isotope signatures of methane, water, and inorganic carbon are widely utilized in natural gas systems for distinguishing microbial and thermogenic methane and for delineating methanogenic pathways (acetoclastic, hydrogenotrophic, and/or methylotrophic methanogenesis). Recent studies of coal and shale gas systems have characterized in situ microbial communities...

Wastewaters from oil and gas development pose largely unknown risks to environmental resources. In January 2015, 11.4 M L (million liters) of wastewater (300 g/L TDS) from oil production in the Williston Basin was reported to have leaked from a pipeline, spilling into Blacktail Creek, North Dakota. Geochemical and biological samples were collected in February and June 2015 to identify...

Many coal beds contain microbial communities that can convert coal to natural gas (coalbed methane). Native microorganisms were obtained from Powder River Basin (PRB) coal seams with a diffusive microbial sampler placed downhole and used as an inoculum for enrichments with different nutrients to investigate microbially-enhanced coalbed methane production (MECoM). Coal-dependent...

Comprehensive sampling of peat, underlying lakebed sediments, and coexisting waters of a naturally uraniferous montane wetland are combined with hydrologic measurements to define the important controls on uranium (U) supply and uptake. The major source of U to the wetland is groundwater flowing through locally fractured and faulted granite gneiss of Proterozoic age. Dissolved U...

The development of unconventional oil and gas (UOG) resources has rapidly increased in recent years; however, the environmental impacts and risks are poorly understood. A single well can generate millions of liters of wastewater, representing a mixture of formation brine and injected hydraulic fracturing fluids. One of the most common methods for wastewater disposal is underground...