Delta Chromium-53/52 isotopic composition of native and contaminated groundwater, Mojave Desert, USA

Izbicki, John A.; Bullen, Thomas D.; Martin, Peter M.; Schroth, Brian

doi:10.1016/j.apgeochem.2011.12.019

Cited by 65 publications

(46 citation statements)

References 26 publications

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“…Groundwaters have δ 53 Cr-values ranging from 0.3 to 5.9 ‰ (Ellis et al 2002(Ellis et al , 2004Berna et al 2010 andZink et al 2010;Izbicki et al 2012). These authors observed an increase up to 6 ‰ in 53 Cr/ 52 Cr ratios during the reduction of chromate.…”

Section: Anthropogenic Cr In the Environmentmentioning

confidence: 84%

Isotope Fractionation Processes of Selected Elements

Hoefs

2015

Stable Isotope Geochemistry

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Section: Anthropogenic Cr In the Environmentmentioning

confidence: 84%

Isotope Fractionation Processes of Selected Elements

Hoefs

2015

Stable Isotope Geochemistry

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“…Field data (Kendall and Aravena 2000) show that apparent fractionation factors ( app ) commonly differ from laboratory-derived fractionation factors ( ) (Mariotti et al 1981). The reasons for these differences are poorly understood but have been known to occur for nitrogen isotope fractionation during denitrification (Mariotti et al 1981;Smith et al 1991), and for a number of other isotopic systems including: carbon isotope fractionation during methyl tert-butyl ether degradation (Lesser et al 2008), oxygen isotope fractionation during O 2 reduction (Revesz et al 1999), Cl and O isotope fractionation during perchlorate degradation (Hatzinger et al 2009), selenium isotope reduction during selenium reduction (Clark and Johnson 2008), and chromium isotope fractionation during chromium reduction (Berna et al 2009;and Izbicki et al 2012b).…”

Section: Quantification Of Isotopic Fractionation Processesmentioning

confidence: 99%

Fate of Nutrients in Shallow Groundwater Receiving Treated Septage, Malibu, CA

Izbicki

2014

Groundwater

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Treated wastewater discharged from more than 400 onsite wastewater treatment systems (OWTS) near the Civic Center area of Malibu, California, 40 km west of downtown Los Angeles, composes 28% of the recharge to a 3.4 km2 alluvial aquifer. On the basis of δ18O and δD data, the fraction of wastewater in some samples was >70%. Ammonium and nitrate concentrations in water from 15 water-table wells sampled in July 2009 and April 2010 ranged from <0.01 to 12 milligrams per liter as nitrogen (mg/L as N), and from <0.01 to 11 mg/L as N, respectively. Chemical and isotopic data (δ15N of ammonium and nitrate, and δ18O of nitrate) show two processes remove nitrogen discharged from OWTS. Where groundwater was reducing, sorption of ammonium resulted in 30 to 50% nitrogen removal. Where groundwater was initially oxic, nitrification with subsequent denitrification as reducing conditions developed, resulted in up to 60% nitrogen removal. Nitrogen removal through sorption dominated during the cooler April sample period, and denitrification dominated during the warmer July sample period. The combination of mixing and nitrogen removal due to denitrification, sorption, and volatilization produces a δ15N apparent fractionation factor (εapp = −5), that can be explained using laboratory-derived fractionation factors (ε) for the individual processes. Phosphate concentrations ranged from < 0.04 to 2 mg/L as phosphorous. Sorption to iron oxides on the surfaces of mineral grains at near-neutral pH's removed some phosphate; however, little removal occurred at more alkaline pH's (>7.3).

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“…Because Cr(VI) reduction consumes lighter isotopes at a greater rate than heavier isotopes, elevated d 53 Cr values in groundwater Cr(VI) can provide evidence for the occurrence of Cr(VI) reduction. Izbicki et al (2008Izbicki et al ( , 2012 traced Cr sources and Cr(VI) reduction in groundwater of the Mojave desert, USA. Berna et al (2010), Raddatz et al (2010), Gao et al (2010), andWanner et al (2012) used d 53 Cr data to provide evidence for Cr(VI) reduction in anthropogenic contaminant plumes.…”

Section: Introductionmentioning

confidence: 99%