srAr
SIS J
v	
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
G\v
*c PrO^
PLC 3 1 2012
OFFICE OF
SOLID WASTE AND
EMERGENCY RESPONSE
MEMORANDUM
OSWER Directive 9200.1-113
SUBJECT: Compilation and Review of Data on Relative Bioavailability of Arsenic in Soil
and Recommendations for Default Value for Relative Bioavailability of Arsenic
in Soil Documents
The purpose of this memorandum is to transmit the OSRTI Technical Report entitled
"Compilation and Review of Data on Relative Bioavailability of Arsenic in Soil" and
"Recommendations for Default Value for Relative Bioavailability of Arsenic in Soil". This
report identifies and evaluates published literature relevant to estimating a relative bioavailability
(RBA) value of arsenic in soil.
Based upon the analysis and external independent peer review, the following conclusions
have been determined:
1.	Currently available research information suggests that an RBA of arsenic in soils can be
expected to be less than 100%.
2.	Based upon evaluation of current data sets of arsenic RBAs in the US, the upper
percentile of the data set results in a default RBA value of 60%.
3.	The default RBA for arsenic in soils should only be used if site-specific assessments for
arsenic RBA are not feasible.
FROM: Becki Clark, Director
Assessment and Remediation Division, unice of Superfund Remediation and
Technology Innovation
TO:
Superfund National Policy Managers, Regions 1-10
Internet Address (URL)  http://www.epa.gov
Recycled/Recyclable  Printed with Vegetable Oil Based Inks on 100% Postconsumer, Process Chlorine Free Recycled Paper

-------
2
This report and other efforts related to addressing arsenic in soil can be found on the
internet at http://epa.gov/superfund/bioavailability/guidance.htm. Please contact Michele
Burgess at (703) 603-9003 if you have questions or concerns.
Attachments
1.	"Compilation and Review of Data on Relative Bioavailability of Arsenic in Soil"
2.	"Recommendations for Default Value for Relative Bioavailability of Arsenic in Soil"
cc: Mathy Stanislaus, OSWER
Lisa Feldt, OSWER
Barry Breen, OSWER
Lawrence M. Stanton, OSWER/OEM
Suzanne Rudzinski, OSWERORCR
David Lloyd, OSWER/OBLR
Reggie Cheatham, OSWER/FFRRO
Carolyn Hoskinson, OSWER/OUST
Elliott Gilberg, OECA/OSRE
Dave Kling, OECA/FFEO
John Michaud, OGC/SEWRLO
OSRTI Managers
Regional Superfund Branch Chiefs, Regions 1-10
Lisa Price, Superfund Lead Region Coordinator, Region 6
NARPM Co-Chairs
TRW Committee Members

-------