Application of sequential extractions and X-ray absorption spectroscopy to determine the speciation of chromium in Northern New Jersey marsh soils developed in chromite ore processing residue (COPR)

Paustenbach, Dennis J., Deborah M. Meyer, Patrick J. Shee han, and Virginia Lau (1991). An assessment and quantitative uncertainty analysis of the health risks to workers exposed to chromium contaminated soils. Toxicol. Industrial Health. Millions of tons of chromite-ore processing residue have been used as fill in various locations in Northern New Jersey and else where in the United States. The primary toxicants in the residue are trivalent chromium [ Cr(III)] and hexavalent chromium [ Cr(VI)]. The hazard posed by Cr(III) is negligible due to its low acute and chronic toxicity. In contrast, Cr(VI) is considered a inhalation human carcinogen at high concentrations. Approxi mately 40 commercial and industrial properties in Northern New Jersey have been identified as containing chromite ore processing residue in the soil. One site, a partially-paved trucking terminal, was evaluated in this assessment. The arithmetic mean and geo metric mean concentrations of total chromium in soil were 977 and 359 mg/kg, respectively. The data were log-normal distrib uted. The arithmetic mean and geometric mean concentrations of Cr(VI) in surface soil were 37.6 and 3.1 mg/kg, respectively. The data could not be fit to a standard distribution, likely due to the large number of samples with concentrations below the method detection limit (65%). Dose was calculated for each exposure route using a Monte Carlo statistical simulation.

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Combining Selective Sequential Extractions, X-ray Absorption Spectroscopy, and Principal Component Analysis for Quantitative Zinc Speciation in Soil

Environmental Science & Technology ◽

10.1021/es025669f ◽

2002 ◽

Vol 36 (23) ◽

pp. 5021-5028 ◽

Cited By ~ 148

Author(s):

Andreas C. Scheinost ◽

Ruben Kretzschmar ◽

Sabina Pfister ◽

Darryl R. Roberts

Keyword(s):

Principal Component Analysis ◽

Absorption Spectroscopy ◽

Principal Component ◽

Component Analysis ◽

Sequential Extractions ◽

X Ray ◽

Zinc Speciation ◽

X Ray Absorption

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Use of micro X-ray absorption spectroscopy and diffraction to delineate Cr(VI) speciation in COPR

Global NEST Journal ◽

10.30955/gnj.000608 ◽

2013 ◽

Vol 11 (3) ◽

pp. 318-324

Keyword(s):

Light Source ◽

Absorption Spectroscopy ◽

Chromium Oxide ◽

X Ray ◽

Ore Processing ◽

Advanced Light Source ◽

The Matrix ◽

Elemental Maps ◽

X Ray Absorption

The speciation of Cr(VI) in Cromite Ore Processing Residue was investigated by means of bulk XRD, and a combination of micro-XRF, - XAS and –XRD at the Advanced Light Source (ALS), Berkeley, CA, U.S.A.. Bulk XRD yielded one group of phases that contained explicitly Cr(VI) in their structure, Calcium Aluminum Chromium Oxide Hydrates, accounting for 60% of the total Cr(VI). Micro-analyses at ALS yielded complimentary information, confirming that hydrogarnets and hydrotalcites, two mineral groups that can host Cr(VI) in their structure by substitution, were indeed Cr(VI) sinks. Chromatite (CaCrO4) was also identified by micro- XRD, which was not possible with bulk methods due to its low content. The acquisition of micro-XRF elemental maps enabled not only the identification of Cr(VI)-binding phases, but also the understanding of their location within the matrix. This information is invaluable when designing Cr(VI) treatment, to optimize release and availability for reduction.

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