About DTSC

We are determined to safeguard California from the harmful effects of chemicals

Arsenic Relative Bioavailability Study

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.

Key goals of the study included the development of methods to:

  1. better characterize the bioavailability of arsenic at former AML sites, and other arsenic-contaminated sites, throughout the state;
  2. refine human health risk assessments by reducing the uncertainty associated with the default bioavailability assumptions; and
  3. 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%.

Grant-Related Documents

  • Final Technical Report, EPA Brownfields Training, Research and Technical Assistance Grant, Arsenic Characterization/ Bioavailability on Mine-Scarred Lands, December 2015
  • Quality Assurance Project Plan for The California Department of Toxic Substances Control Arsenic Relative Bioavailability Study, August 3, 2009 (QAPP) , Appendix A (Standard Operating Procedures)
  • Field Sampling Plan for the Department of Toxic Substances Control Arsenic Relative Bioavailability Study, Empire Mine State Historic Park Grass Valley, California July 31, 2009 (Field Sampling Plan Appendices)

Publication List

Peer-reviewed publications

  • 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.

Master’s Thesis

Abstracts and Presentations

2015

  • Alpers, C.N., 2015, Environmental geochemistry and mineralogy of arsenic in the Sierra Nevada foothills gold belt, California. 27th International Applied Geochemistry Symposium (IAGS) hosted by the Association of Applied Geochemists (AAG), Tucson, Arizona, April 20-24, 2015 (INVITED KEYNOTE TALK, presented by Alpers)
  • Foster, A. L., 2015, Spectroscopic Methods for Arsenic Characterization. Reclaiming the Sierra Conference, Sacramento, CA, April 2015 (ORAL, presented by Foster)
  • Mitchell, V.M., Whitacre, S., Casteel S.W., Myers, P.A., Basta, N.T., 2015 (planned) New In Vitro Gastrointestinal Model Accurately Predicts Arsenic Bioavailability in Soils, Society of Toxicology, 54th Annual Meeting, March, 2015. (POSTER, presented by Mitchell)
  • 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).
  • Hanley, VM, Bioavailability of Arsenic in California Mining Soils: Development of a Predictive in vitro Method, Presentation to the Sacramento Professional Environmental Marketers Association, November 2015. (Invited Speaker)

2014

2013

  • 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.

2012

  • Alpers, C.N., Burlak, T.L., Foster, A.L., Basta, N.T., and Mitchell, V.L., 2012, Arsenic and old gold mines: mineralogy, speciation, and bioaccessibility. 2012 Goldschmidt Meeting, Montreal, Canada, June 24-29, 2012. (INVITED TALK, KEYNOTE ADDRESS, presented by Alpers) 
  • Alpers, C.N., Mitchell, V.L., Basta, N.T., Casteel, S.W., Foster, A.L., Blum, A.E., Kim, C.S., Myers, P., Burlak, T.L., and Hammersley, L., 2012, Evaluating the bioavailability, bioaccessibility, mineralogy, and speciation of arsenic in mine waste and soils: Empire Mine low-sulfide gold-quartz vein deposit, Nevada County, California. U.S. Environmental Protection Agency Hardrock Mining Conference, Denver, CO, April 3–5, 2012. (TALK, presented by Alpers)
  • Foster, A., 2012, Identification and quantification of arsenic species in gold mine wastes using synchrotron-based x-ray techniques. U.S. Environmental Protection Agency Hardrock Mining Conference, Denver, CO, April 3–5, 2012. (TALK, presented by Foster)
  • Mitchell, V.L., Alpers, C.N., Basta, N.T., Casteel, S.W., Foster, A.L., Kim, C.S., Naught, L., and Myers P.A., 2012, Alternative methods for the prediction of bioavailability of arsenic in mining soils. Society of Toxicology, 51st Annual Meeting, March, 2012. Toxicologist, v. 126, p. 321. (POSTER, presented by Mitchell)
  • Mitchell, V.L., Myers P.A., 2012, Alternative Methods for the Evaluation of Arsenic Bioavailability: Reclaiming Mine-Scarred Lands While Protecting Human Health. Reclaiming the Sierra, Green Solutions to Abandoned Mines Conference, Nevada City, CA, May 3-5, 2012.(TALK, presented by Mitchell)
  • Mitchell, V.L., 2012, Alternative Methods for the Evaluation of Bioavailability of Arsenic in Mining Soils, Risk Assessment Specialty Section, Society of Toxicology (WEBINAR, presented by Mitchell)
  • 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.

2011

  • Alpers, C.N., Burlak, T., Foster, A., Hammersley, L., and Petersen, E., 2011, Mineralogy and speciation of arsenic in weathered waste rock from the Empire mine low-sulfide gold-quartz vein deposit, California. Annual Meeting of the National Association of Abandoned Mine Land Programs, Squaw Valley, CA, October 10–12, 2011. (TALK, presented by Alpers)
  • Foster, A., and Alpers, C.N., 2011, Synchrotron x-ray studies of arsenic species in sediments from the Empire Mine, CA. Annual Meeting of the National Association of Abandoned Mine Land Programs, Squaw Valley, CA, October 10–12, 2011. (TALK, presented by Foster)
  • Mitchell, V., Alpers, C., Basta, N., Burlak, T., Casteel, S.W., Fears, R.L., Foster, A.L., Kim, C.S., Myers, P.A., and Petersen, E., 2011, The role of iron in the reduced bioavailability of arsenic in soil. Society of Toxicology, 50th Annual Meeting, March, 2011. Toxicologist, v. 120 (Supp 2), p. 415 (POSTER, presented by Mitchell)
  • Myers, P.A., Mitchell, V.L., Alpers, C.N., Basta, N.T., Casteel, S.W., Foster, A.L., and Kim, C.S., 2011, Methods and tools for the evaluation of bioavailability of arsenic at abandoned mine lands: the search for a more cost-effective approach to site clean-up. Annual Meeting of the National Association of Abandoned Mine Land Programs, Squaw Valley, CA, October 10–12, 2011. (TALK, presented by Myers and Mitchell)

2010

  • Burlak, T., Alpers, C.N., Foster, A.L., Brown, A., Hammersley, L., and Petersen, E., 2010, Tracking the mineralogical fate of arsenic in weathered sulfides from the Empire Mine gold-quartz vein deposit using X-ray analytical techniques: Potential implications for arsenic bioavailability in mine waste. 2010 Fall Meeting, American Geophysical Union, December 17–20, San Francisco, CA. (POSTER, presented by Burlak)
  • Mitchell, V., Alpers, C., Basta, N., Berry, D., Christopher, J., Eberl, D., Fears, R., Foster, A., Kim, C.S., Myers, P., and Parsons, B., 2010, Identifying predictors for bioavailability of arsenic in arsenic in soil at mining sites. Society of Toxicology, 49th Annual Meeting, Salt Lake City, UT, March 7–11, 2010. Toxicologist, v. 114, p. 412. (POSTER, presented by Mitchell)
  • Brown, A., Foster, A., Alpers, C.N., Dale, J. G., Hansel, C., Lentini, C., Kim, C. S., Stegemeier, J.P., Factors Affecting Principal Component Analysis (PCA) of X-ray Absorption Fine Structure Spectral Datasets of Arsenic and Iron Compounds. Fall Annual Meeting of Geological Society of America, Oct.2010 (POSTER, presented by Foster)

Contact Information:

About DTSC Links

About DTSC Related Links