Occurrence and sources of radium in groundwater associated with oil fields in the southern San Joaquin Valley, California

Author Posting. © American Chemical Society, 2019. This is an open access article published under an ACS AuthorChoice License. The definitive version was published in Environmental Science and Technology 53(16), (2019): 9398-9406, doi:10.1021/acs.est.9b02395.Geochemical data from 40 water wells were used to examine the occurrence and sources of radium (Ra) in groundwater associated with three oil fields in California (Fruitvale, Lost Hills, South Belridge). 226Ra+228Ra activities (range = 0.010–0.51 Bq/L) exceeded the 0.185 Bq/L drinking-water standard in 18% of the wells (not drinking-water wells). Radium activities were correlated with TDS concentrations (p < 0.001, ρ = 0.90, range = 145–15,900 mg/L), Mn + Fe concentrations (p < 0.001, ρ = 0.82, range = <0.005–18.5 mg/L), and pH (p < 0.001, ρ = −0.67, range = 6.2–9.2), indicating Ra in groundwater was influenced by salinity, redox, and pH. Ra-rich groundwater was mixed with up to 45% oil-field water at some locations, primarily infiltrating through unlined disposal ponds, based on Cl, Li, noble-gas, and other data. Yet 228Ra/226Ra ratios in pond-impacted groundwater (median = 3.1) differed from those in oil-field water (median = 0.51). PHREEQC mixing calculations and spatial geochemical variations suggest that the Ra in the oil-field water was removed by coprecipitation with secondary barite and adsorption on Mn–Fe precipitates in the near-pond environment. The saline, organic-rich oil-field water subsequently mobilized Ra from downgradient aquifer sediments via Ra-desorption and Mn/Fe-reduction processes. This study demonstrates that infiltration of oil-field water may leach Ra into groundwater by changing salinity and redox conditions in the subsurface rather than by mixing with a high-Ra source.This article was improved by the reviews of John Izbicki and anonymous reviewers for the journal. This work was funded by the California State Water Resources Control Board’s Regional Groundwater Monitoring in Areas of Oil and Gas Production Program and the USGS Cooperative Water Program. A.V., A.J.K., and Z.W were supported by USDA-NIFA grant (#2017-68007-26308). Any use of trade, firm, or product names is for description purposes only and does not imply endorsement by the U.S. Government

Radium and barium removal through blending hydraulic fracturing fluids with acid mine drainage.

Wastewaters generated during hydraulic fracturing of the Marcellus Shale typically contain high concentrations of salts, naturally occurring radioactive material (NORM), and metals, such as barium, that pose environmental and public health risks upon inadequate treatment and disposal. In addition, fresh water scarcity in dry regions or during periods of drought could limit shale gas development. This paper explores the possibility of using alternative water sources and their impact on NORM levels through blending acid mine drainage (AMD) effluent with recycled hydraulic fracturing flowback fluids (HFFFs). We conducted a series of laboratory experiments in which the chemistry and NORM of different mix proportions of AMD and HFFF were examined after reacting for 48 h. The experimental data combined with geochemical modeling and X-ray diffraction analysis suggest that several ions, including sulfate, iron, barium, strontium, and a large portion of radium (60-100%), precipitated into newly formed solids composed mainly of Sr barite within the first ∼ 10 h of mixing. The results imply that blending AMD and HFFF could be an effective management practice for both remediation of the high NORM in the Marcellus HFFF wastewater and beneficial utilization of AMD that is currently contaminating waterways in northeastern U.S.A

Origin of Hexavalent Chromium in Drinking Water Wells from the Piedmont Aquifers of North Carolina

Hexavalent chromium [Cr(VI)] is a known pulmonary carcinogen. Recent detection of Cr(VI) in drinking water wells in North Carolina has raised public concern about contamination of drinking water wells by nearby coal ash ponds. Here we report, for the first time, the prevalence of Cr and Cr(VI) in drinking water wells from the Piedmont region of central North Carolina, combined with a geochemical analysis to determine the source of the elevated Cr(VI) levels. We show that Cr(VI) is the predominant species of dissolved Cr in groundwater and elevated levels of Cr and Cr(VI) are found in wells located both near and far ( > 30 km) from coal ash ponds. The geochemical characteristics, including the overall chemistry, boron to chromium ratios, and strontium isotope ( 87 Sr/ 86 Sr) variations in groundwater with elevated Cr(IV) levels, are different from those of coal ash leachates. Alternatively, the groundwater chemistry and Sr isotope variations are consistent with water-rock interactions as the major source for Cr(VI) in groundwater. Our results indicate that Cr(VI) is most likely naturally occurring and ubiquitous in groundwater from the Piedmont region in the eastern United States, which could pose health risks to residents in the region who consume well water as a major drinking water source

Efficient transdifferentiation of human dermal fibroblasts into skeletal muscle

Skeletal muscle holds significant regenerative potential but is incapable of restoring tissue loss caused by severe injury, congenital defects or tumour ablation. Consequently, skeletal muscle models are being developed to study human pathophysiology and regeneration. Their physiological accuracy, however, is hampered by the lack of an easily accessible human cell source that is readily expandable and capable of efficient differentiation. MYOD1, a master gene regulator, induces transdifferentiation of a variety of cell types into skeletal muscle, although inefficiently in human cells. Here we used MYOD1 to establish its capacity to induce skeletal muscle transdifferentiation of human dermal fibroblasts under baseline conditions. We found significant transdifferentiation improvement via transforming growth factor-/activin signalling inhibition, canonical WNT signalling activation, receptor tyrosine kinase binding and collagen type I utilization. Mechanistically, manipulation of individual signalling pathways modulated the transdifferentiation process via myoblast proliferation, lowering the transdifferentiation threshold and inducing cell fusion. Overall, we used transdifferentiation to achieve the robust derivation of human skeletal myotubes and have described the signalling pathways and mechanisms regulating this process. Copyright (c) 2017 John Wiley & Sons, Ltd