[Federal Register Volume 75, Number 4 (Thursday, January 7, 2010)]
[Pages 984-986]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-16]



[EPA-HQ-SFUND-2009-0907; FRL-9100-8]
RIN 2050-ZA05

Draft Recommended Interim Preliminary Remediation Goals for 
Dioxin in Soil at CERCLA and RCRA Sites

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of availability and announcement of public comment 


SUMMARY: The Environmental Protection Agency (EPA or the Agency) is 
announcing a 50-day public comment period for draft recommended interim 
preliminary remediation goals (PRGs) developed in the Draft Recommended 
Interim Preliminary Remediation Goals for Dioxin in Soil at 
Comprehensive Environmental Response, Compensation, and Liability Act 
(CERCLA) and Resource Conservation and Recovery Act (RCRA) Sites. EPA's 
Office of Solid Waste and Emergency and Emergency Response (OSWER) has 
developed the draft recommended interim PRGs for dioxin in soil. These 
draft recommended interim PRGs were calculated using existing, peer-
reviewed toxicity values and current EPA equations and default exposure 
    This Federal Register notice is intended to provide an opportunity 
for public comment on the draft recommended interim PRGs. EPA will 
consider any public comments submitted in accordance with this notice 
and may revise the draft recommended interim PRGs thereafter.

DATES: Comments may be submitted in writing by February 26, 2010.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
SFUND-2009-0907, by one of the following methods:
     http://www.regulations.gov. Follow the on-line 
instructions for submitting comments.
     E-mail: [email protected].
     Mail: EPA Docket Center, Environmental Protection Agency, 
Mail Code: 5305T, 1200 Pennsylvania Ave., NW., Washington, DC 20460.
     Hand Delivery: EPA Docket Center (EPA/DC), Room 3334, EPA 
West Building, 1301 Constitution Avenue NW., Washington, DC 20460, 
Attention Docket ID No. EPA-HQ-SFUND-2009-0907. Deliveries are only 
accepted from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding 
legal holidays. Special arrangements should be made for deliveries of 
boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-SFUND-
2009-0907. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available online at 
http://www.regulations.gov, including any personal information 
provided, unless the comment includes information claimed to be 
Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute. Do not submit information that you 
consider to be CBI or otherwise protected by statute through http://www.regulations.gov or e-mail. The http://www.regulations.gov Web site 
is an ``anonymous access'' system, which means EPA will not know your 
identity or contact information unless you provide it in the body of 
your comment. If you send an e-mail comment directly to EPA, without 
going through http://www.regulations.gov, your e-mail address will be 
automatically captured and included as part of the comment that is 
placed in the public docket and made available on the Internet. If you 
submit an electronic comment, EPA recommends that you include your name 
and other contact information in the body of your comment and with any 
disk or CD-ROM you submit. If EPA cannot read your comment due to 
technical difficulties and cannot contact you for clarification, EPA 
may not be able to consider your comment. Electronic files should avoid 
the use of special characters, any form of encryption, and be free of 
any defects or viruses.
    Docket: This Federal Register notice and supporting documentation 
are available in a docket EPA has established under Docket ID No. EPA-
HQ-SFUND-2009-0907. All documents in the docket are listed in the 
http://www.regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard

[[Page 985]]

copy. Publicly available docket materials are available either 
electronically in http://www.regulations.gov or in hard copy at the 
OSWER Docket, EPA West, Room 3334, 1301 Constitution Avenue,. NW., 
Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 
p.m., Monday through Friday, excluding legal holidays. The telephone 
number for the Public Reading Room is (202) 566-1744, and the telephone 
number for the OSWER docket is (202) 566-0270.

FOR FURTHER INFORMATION CONTACT: Marlene Berg, Office of Superfund 
Remediation and Technology Innovation, 1200 Pennsylvania Avenue, NW., 
Mail Code: 5204P, Washington, DC 20460; by telephone/voicemail at (703) 
603-8701; Fax: (703) 603-9112; or via e-mail at [email protected].

SUPPLEMENTARY INFORMATION: Preliminary remediation goals (PRGs) 
generally are chemical-specific concentration goals for specific media 
(e.g., soil, sediment, water and air) and land use combinations at 
CERCLA sites. They are intended to serve as a point of departure in the 
remedy selection process and generally are used as a target in 
conjunction with site-specific information (e.g., exposure frequency) 
during the initial development, analysis, and selection of cleanup 
alternatives. As discussed in the National Oil and Hazardous Substances 
Pollution Contingency Plan (NCP) (40 CFR 300.430(e)(2)(i)) preliminary 
remediation goals are typically developed from readily available 
information. Preliminary remediation goals should be modified, as 
necessary, when more site-specific information becomes available (e.g., 
exposure frequency).
    In May 2009, EPA Administrator Lisa P. Jackson committed to 
accelerating the Agency's work currently underway to reassess the human 
health risks from exposures to dioxin. EPA's Science Plan for 
Activities Related to Dioxins in the Environment (http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=209690) details a plan, with interim 
milestones, for completion of the Agency's dioxin reassessment. By the 
end of 2010, EPA expects to complete the dioxin reassessment and 
release it to the public, subject to further consideration of the 
science and the scope and complexity of the revisions.
    Several site-specific investigations and decisions involving dioxin 
may need to be made before the dioxin reassessment is finalized. 
Therefore, Administrator Jackson directed the Office of Solid Waste and 
Emergency Response (OSWER) to develop draft recommended interim PRGs by 
the end of 2009 that are informed by the best available peer-reviewed 
science. The recommended interim PRGs, when finalized, will allow EPA 
to continue to make progress on key site-specific investigations and 
decisions while the dioxin reassessment is on-going. Also, development 
of the recommended interim PRGs at this juncture allows EPA to include 
the dermal absorption pathway of dioxin. The information to estimate 
the dermal pathway was not available when EPA last recommended PRGs for 
dioxin in soil in 1998.
    OSWER reviewed the Agency's current dioxin cleanup guidance and 
related work by other entities, including the states, other countries, 
and other federal agencies with the goal of developing guidance 
containing recommended interim PRGs informed by the best available 
peer-reviewed science. Once the recommended interim PRGs are finalized, 
they are intended to be considered by EPA regions until the Agency 
issues its final dioxin reassessment; at that time, OSWER may issue 
updated recommended PRGs based on the final dioxin reassessment. After 
publication of the final dioxin reassessment and any subsequent updated 
PRG guidance, EPA regions would then re-evaluate, as appropriate, 
cleanup decisions at CERCLA sites to ensure that cleanups are still 
protective. States which apply the final recommended interim PRGs to 
RCRA sites may choose to re-evaluate, as appropriate, cleanup decisions 
based on the recommended interim PRGs as well.
    The draft guidance presents current OSWER technical and policy 
recommendations regarding PRGs for soil contaminated with dioxin. While 
OSWER developed the draft guidance for facility response actions under 
CERCLA and RCRA corrective action, other regulators, including the 
States, may find it useful in their programs, although they may choose 
to use alternative assessments consistent with their own programs and 
policies. In addition, EPA may use and accept other technically sound 
approaches after appropriate review, either at its own initiative or at 
the suggestion of other interested parties. The draft guidance does not 
impose any requirements or obligations on EPA, the States, other 
Federal agencies, or the regulated community. It is important to 
understand that the draft guidance does not substitute for statutes 
that EPA administers or their implementing regulations, nor is it a 
regulation itself. Thus, the draft guidance does not impose legally 
binding requirements on EPA, the States, or the regulated community, 
and may not apply to a particular situation based upon the specific 
circumstances. Rather, the draft guidance suggests approaches that may 
be used at particular sites as appropriate, given site-specific 
    In developing these draft recommended interim PRGs, OSWER, EPA's 
Office of Research and Development and other EPA offices reviewed 
current soil cleanup levels and dioxin toxicity values used by the 
states, the U.S. Department of Health and Human Services' Agency for 
Toxic Substances and Disease Registry and other countries (see docket 
EPA-HQ-SFUND-2009-0907 for State Soil Cleanup Levels for 
Dioxin and Review of International Soil Levels for Dioxin). Based on 
this evaluation, OSWER considered EPA's currently recommended PRGs for 
CERCLA and RCRA sites (http://www.epa.gov/superfund/resources/remedy/pdf/92-00426-s.pdf), which are 1 ppb (parts per billion) (or 1,000 ppt 
(parts per trillion)) for dioxin toxicity equivalents (TEQs) \1\ in 
residential soil, and a level within the range of 5 ppb (or 5,000 ppt) 
and 20 ppb (or 20,000 ppt) in commercial/industrial soil, where 
exposure is due to direct contact. Three key components of EPA's 
current recommended PRGs were re-evaluated: available toxicity values, 
generic exposure assumptions and the cancer risk level.

    \1\ Toxicity equivalents consider the toxicity of the less toxic 
dioxin-like compounds as fractions of the toxicity of the most toxic 
compound (2,3,7,8-TCDD). Each compound is attributed a specific 
``Toxic Equivalency Factor'' (TEF). This factor indicates the degree 
of toxicity compared to 2,3,7,8-TCDD, which is given a reference 
value of 1.

    These draft recommended interim PRGs are informed by the best 
available peer-reviewed science, as well as the work of states and 
other agencies. Based on a consideration of oral and dermal exposures 
to dioxin, EPA has developed the following draft recommended interim 
PRGs for dioxin in soil: 72 ppt for residential soil and 950 ppt for 
commercial/industrial soil. EPA believes that these draft recommended 
interim PRGs would generally provide adequate protection against non-
cancer effects, and generally should protect against cancer effects at 
approximately the 1E-05 risk level (1 in 100,000). These recommended 
interim PRGs are within EPA's protective risk range of 1E-04 to 1E-06 
(see 40 CFR 300.430(e)(2)(i)(A)), and are more protective than the 1998 
    In addition, consistent with the NCP (40 CFR 300.430(e)(2)(i)(A)), 
EPA is considering (and requesting comment

[[Page 986]]

on) an alternative concentration of 3.7 ppt TEQ in residential soil and 
17 ppt TEQ in commercial/industrial soil as draft interim PRGs. These 
alternative draft interim PRGs would be protective for cancer and non-
cancer effects and are consistent with the NCP provision for PRGs 
reflecting a 1E-06 risk level as a point of departure for determining 
remediation goals. OSWER notes that PRGs based on a 1E-06 cancer risk 
level would likely be within or possibly below the average 
concentration of dioxins in rural U.S. soils. Generally, it is OSWER's 
policy not to clean below background (for more information about this 
policy visit http://cfpub.epa.gov/ncea/CFM/recordisplay.cfm?deid=150944).

    Dated: December 30, 2009.
Mathy Stanislaus,
Assistant Administrator, Office of Solid Waste and Emergency Response.
[FR Doc. 2010-16 Filed 1-6-10; 8:45 am]