Source: https://www.dtsc.ca.gov/InformationResources/Arsenic_Relative_Study.cfm
Timestamp: 2019-04-20 12:37:15+00:00

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The Department of Toxic Substances Control (DTSC) was awarded a Training Research and Technical Assistance Grant (TR-83415101) to conduct an Arsenic Relative Bioavailability Study (Study) by the United States Environmental Protection Agency Region IX (USEPA). Arsenic is the key chemical of concern at the majority of Brownfield projects at former gold mines in the California Mother Lode.
The main goal of the Study was to determine the range of arsenic bioavailability that may exist in contaminated soil at former abandoned mine land (AML) sites and develop better methods to improve the risk assessment of arsenic at these sites.
The USEPA grant was awarded in late 2008 with a term of 5 years. Two no-cost extensions were granted and the final report was submitted to USEPA December 2015. The final amount awarded was $850,000.
The initial Study was limited to AML sites in Nevada County but was later expanded to include former AML sites in Shasta, Sierra, Amador, Calaveras, Mono, and San Bernardino Counties.
aid in the development of scientifically-defensible cleanup goals that ensure the protection of human health.
These methods are described in DTSC Human Health Risk Assessment Note 6.
Historically, oral bioavailability has been measured in soils using animal models (in vivo studies). The juvenile swine model is the most widely accepted and used worldwide. These studies are often prohibitively expensive. While other in vitro methods to estimate bioaccessibility already exist, we have seen that these methods consistently under predict the bioavailability results from the swine in vivo studies in California. Our Co-Investigators at Ohio State University developed a new benchtop in vitro method to estimate bioaccessibility called the California Arsenic Bioaccessibility (CAB) method.
The CAB method can be used to accurately predict the in vivo Relative Bioavailability (RBA) of arsenic in soils. The CAB method is highly predictive of the swine when applied to soils with arsenic less than 1,500 mg/kg, regardless of arsenic source. A round robin inter-laboratory study was performed in conjunction with Prima Environmental to determine the reproducibility of the CAB method. Mean and median intra-laboratory relative standard deviations (RSDs) were 3.8% and 3.9%, respectively. Mean and median inter-laboratory RSDs were 8.5% and 4.5%, respectively. The reproducibility meets and exceeds the criteria for intra-laboratory RSD of < 10% and inter-laboratory RSD of <20%.
Alpers, C.N., Myers, P., Millsap, D., and Regnier, T.B., 2014, Arsenic associated with historical gold mining in the Sierra Nevada:Case study and field trip guide for Empire Mine State Historic Park, California. In: Bowell, R., Alpers, C.N., Nordstrom, D.K., Jamieson, H.E., and Majzlan, J. (eds), Arsenic –Environmental Geochemistry, Mineralogy, and Microbiology, Reviews in Mineralogy and Geochemistry v. 79, p. 553-587.
Basta, N.T., and Juhasz, A., 2014, Using in vivo bioavailability and/or in vitro gastrointestinal bioaccessibility testing to adjust human exposure to arsenic from soil ingestion. In: Bowell, R., Alpers, C.N., Nordstrom, D.K., Jamieson, H.E., and Majzlan, J. (eds), Arsenic –Environmental Geochemistry, Mineralogy, and Microbiology, Reviews in Mineralogy and Geochemistry v. 79, p. 451-472.
Bowell, R., Alpers, C.N., Nordstrom, D.K., Jamieson, H.E., and Majzlan, J., 2014, Arsenic -- Environmental Geochemistry, Mineralogy, and Microbiology, Reviews in Mineralogy and Geochemistry v. 79, 627 p.
Bowell, R., Alpers, C.N., Nordstrom, D.K., Jamieson, H.E., and Majzlan, J., 2014, The Environmental Geochemistry of Arsenic –An Overview, In: Bowell, R., Alpers, C.N., Nordstrom, D.K., Jamieson, H.E., and Majzlan, J. (eds.), Arsenic -- Environmental Geochemistry, Mineralogy, and Microbiology, Reviews in Mineralogy and Geochemistry v. 79, p. 1-16.
Foster, A.L, and Kim, C.S., 2014, Arsenic speciation in solids using X-ray absorption spectroscopy. In: Bowell, R., Alpers, C.N., Nordstrom, D.K., Jamieson, H.E., and Majzlan, J. (eds), Arsenic –Environmental Geochemistry, Mineralogy, and Microbiology, Reviews in Mineralogy and Geochemistry v. 79, p. 257-369.
Mitchell, V.L., 2014 Health risks associated with chronic exposures to arsenic in the environment. In: Bowell, R., Alpers, C.N., Nordstrom, D.K., Jamieson, H.E., and Majzlan, J. (eds), Arsenic –Environmental Geochemistry, Mineralogy, and Microbiology, Reviews in Mineralogy and Geochemistry v. 79, p. 435-449.
Burlak, T., 2012, Geochemistry of iron- and arsenic-bearing minerals in soil and bedrock associated with gold-quartz vein mineralization at Empire Mine State Historic Park, Nevada County, California. M.Sc. thesis, Department of Geology, California State University, Sacramento, CA, 142 p.
Mitchell, VL, Bioavailability of Arsenic in California Mining Soils: Geochemical Influences and the Development of a Predictive in vitro Method, Presentation at the Interstate Technology & Regulatory Council 2015 Spring Meeting, April 2015. (Invited presentation to the Bioavailability in Contaminated Soils Team).
Foster, A.L., and Kim, C.S., 2014, The environmental legacy of California's gold rush: Arsenic and mercury contamination from historic mining. Goldschmidt 2014, Sacramento, CA, June 8–13, 2014. (PLENARY TALK, presented by Foster and Kim, introduced by Alpers) View YouTube video of Goldschmidt 2014: The Environmental Legacy of California's Gold Rush: Arsenic and Mercury Contamination from Historic Mining.
Whitacre, S.D., N.T. Basta, V.L. Mitchell, and P. Myers. 2013. Bioavailability Measures for Arsenic in Gold Mine Tailings Using Agricultural Soil Tests to Estimate Total and Bioaccessible Pb in Urban Soils.Joint MERA/ICOBTE Sponsored Symposium: Trace Element Bioavailability for Human and Ecological Risk Assessment: Concepts and Recent Advances. Organizers: N. Basta, E. Van Genderen, and C. Schlekat. 12th International Conference for Trace Element Biogeochemistry (ICOBTE), Athens, GA, USA. June 16-20, 2013.
Whitacre, S.D., Basta, N.T., Mitchell, V.L., and Myers, P. 2012. Bioavailability Measures for Arsenic in Gold Mine Tailings. Presentation 412-1, ASA, CSSA, and Soil Science Society International Annual Meeting, Cincinnati, OH. Oct. 21 to 24, 2012.

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