EPA 

December 2009 

REVIEW OF STATE SOIL CLEANUP LEVELS FOR DIOXIN 

National Center for Environmental Assessment 

Office of Research and Development 

U.S. Environmental Protection Agency 

Washington, DC 20460
 

 

 

REVIEW OF STATE SOIL CLEANUP LEVELS FOR DIOXIN 

Prepared by 

Margaret MacDonell, Andrew Davidson, Molly Finster, Marci Scofield, and Boyan Peshlov 

Environmental Science Division 

DOE-Argonne National Laboratory 

Argonne, IL 60439 

In collaboration with 

Kacee Deener 

National Center for Environmental Assessment 

Office of Research and Development 

U.S. Environmental Protection Agency 

Washington, DC 20460
 

December 2009 
DISCLAIMER 
 

This document is a review of state agency data and as such has not itself been peer reviewed. 

EPA will consider any significant technical comments it receives. Mention of trade names or 

commercial products does not constitute endorsement or recommendation for use. 

Preferred citation: 

U.S. EPA (Environmental Protection Agency). 2009. Review of State Soil Cleanup Levels for 

Dioxin. December 2009. National Center for Environmental Assessment, Washington, DC. 

Available from http://www.epa.gov/ncea. 
 

 

 

REVIEW OF STATE SOIL CLEANUP LEVELS FOR DIOXIN
 

TABLE OF CONTENTS
 

NOTATION ............................................................................................................................... iv 

EXECUTIVE SUMMARY .......................................................................................................... S-1 

1 INTRODUCTION................................................................................................................. 1 

1.1 Purpose and Scope.................................................................................................... 1 

1.2 Report Organization ................................................................................................... 1 

2 APPROACH ....................................................................................................................... 2 

2.1 Document/Literature Search ...................................................................................... 3 

2.2 Evaluation Criteria...................................................................................................... 4 

3 RESULTS ........................................................................................................................ 5 

3.1 Soil Dioxin Levels by State......................................................................................... 5 

3.2 Toxicity Values and Target Risks............................................................................... 26 

3.3 Derivation Methodology.............................................................................................. 56 

3.4 Evaluation Criteria...................................................................................................... 80 

4 SUMMARY AND DISCUSSION ....................................................................................... 80 

4.1 State Soil Cleanup Levels for Dioxin....................................................................... 80 

4.2 Factors Contributing to Similarities and Differences ............................................... 84 

4.3 Evaluation Context .................................................................................................. 85 

5 ACKNOWLEDGEMENTS ................................................................................................ 86 

6 REFERENCES................................................................................................................. 87 

APPENDIX A: Supporting Information for the Approach ..................................................... A-1 

APPENDIX B: Detailed Data Tables.................................................................................... B-1 

TABLES 

1 Scope of the Survey for Dioxin Soil Cleanup Levels by State.......................................... 3 

2 Information Resources Pursued....................................................................................... 4 

3 Selected Tables and Figures of State Values for Dioxin in Soil ....................................... 5 

4 Representative Soil Cleanup Levels for Dioxin by State: Unrestricted/Residential Use .. 7 

5 Additional State Concentrations Potentially Relevant to Soil Cleanup............................. 17 

December 2009 Page i 
 

TABLE OF CONTENTS (Cont’d.) 

TABLES (Cont’d.) 

6 States without Formal Soil Cleanup Levels for Dioxin ..................................................... 25 

7 Representative Soil Cleanup Levels for Dioxin by State: Commercial/Industrial 

 (Restricted) Use ............................................................................................................... 27 

8 Additional State Concentrations: Commercial/Industrial (Restricted) Use ...................... 37 

9 Supporting State Context: Subsurface Values................................................................. 45 

10 Dioxin Toxicity Values Underlying the State Cleanup Levels........................................... 47 

11 Supporting Context from Other Agencies ........................................................................ 50 

12 Target Risks for the State Cleanup Levels....................................................................... 53 

13 Basic Components of the Derivation Methodology .......................................................... 58 

14 Summary Comparison of State Derivations for Incidental Soil Ingestion......................... 70 

15 Main Factors Leading to Differences in Dioxin Cleanup Levels for the 

Unrestricted/Residential Scenario.................................................................................... 74 

A.1 Checklist to Support Field Review of Data Tables ........................................................... A-3 

B.1 Detailed Data for States in U.S. EPA Region 1................................................................ B-5 

B.2 Detailed Data for States in U.S. EPA Region 2................................................................ B-8 

B.3 Detailed Data for States in U.S. EPA Region 3................................................................ B-10 

B.4 Detailed Data for States in U.S. EPA Region 4................................................................ B-15 

B.5 Detailed Data for States in U.S. EPA Region 5................................................................ B-21 

B.6 Detailed Data for States in U.S. EPA Region 6................................................................ B-27 

B.7 Detailed Data for States in U.S. EPA Region 7................................................................ B-31 

B.8 Detailed Data for States in U.S. EPA Region 8................................................................ B-34 

B.9 Detailed Data for States in U.S. EPA Region 9................................................................ B-37 

B.10 Detailed Data for States in U.S. EPA Region 10.............................................................. B-50 

FIGURES 

1 Phased Approach for Identifying Soil Dioxin Cleanup Levels .......................................... 2 

2a Soil Cleanup Levels: Unrestricted/Residential Use, by State (arithmetic scale) .............. 13 

2b Soil Cleanup Levels: Unrestricted/Residential Use, by State (logarithmic scale) ............ 14 

3 Soil Cleanup Levels: Unrestricted/Residential Use, by Concentration............................. 15 

4 Soil Cleanup Levels: Unrestricted/Residential Use, by Region........................................ 16 

5 Soil Cleanup Levels and Screening Values: Unrestricted/Residential Use, by State ...... 19 

6 Soil Cleanup Levels and Screening Values: Unrestricted/Residential Use, 

 by Concentration.............................................................................................................. 20 

December 2009 Page ii 
TABLE OF CONTENTS (Cont’d.) 

FIGURES (Cont’d.) 

7 Soil Cleanup Levels and Screening Values: Unrestricted/Residential Use, by Region ... 21 

8 Supporting Context: Cleanup Levels Identified for Unrestricted/Residential Use 

from Contaminated Site Applications, by State................................................................ 22 

9 Supporting Context: Cleanup Levels Identified for Unrestricted/Residential Use 

from Contaminated Site Applications, by Concentration ................................................. 23 

10a Soil Cleanup Levels: Commercial/Industrial (Restricted) Use, by State 

(arithmetic scale).............................................................................................................. 33 

10b Soil Cleanup Levels: Commercial/Industrial (Restricted) Use, by State 

(logarithmic scale) ............................................................................................................ 34 

11 Soil Cleanup Levels: Commercial/Industrial (Restricted) Use, by Concentration............. 35 

12 Soil Cleanup Levels: Commercial/Industrial (Restricted) Use, by Region ....................... 36 

13 Soil Cleanup Levels and Screening Values: Commercial/Industrial (Restricted) Use, 

 by State .......................................................................................................................... 39 

14 Soil Cleanup Levels and Screening Values: Commercial/Industrial (Restricted) Use, 

 by Concentration.............................................................................................................. 40 

15 Soil Cleanup Levels and Screening Values: Commercial/Industrial (Restricted) Use, 

 by Region......................................................................................................................... 41 

16 Supporting Context: Cleanup Levels Identified for Restricted Use from 

Contaminated Site Applications, by State ........................................................................ 42 

17 Supporting Context: Cleanup Levels Identified for Restricted Use from 

Contaminated Site Applications, by Concentration .......................................................... 43 

18 Supporting State Context: Subsurface Values, by State.................................................. 46 

19 Dioxin Toxicity Values Underlying the State Cleanup Levels........................................... 52 

20 Distribution of States Listing Specific Risk Targets for Dioxin Cleanup Levels: 

Unrestricted/Residential Use ........................................................................................... 54 

21 Distribution of States Listing Specific Risk Targets for Dioxin Cleanup Levels: 

Commercial/Industrial Use............................................................................................... 55 

22 Distribution of Soil Cleanup Levels by Concentration: Unrestricted and Restricted Uses 82 

B.1 States in U.S. EPA Regions............................................................................................. B-3
 

December 2009 Page iii 
NOTATION 

(This list includes many of the acronyms and abbreviations used in the report. Other terms used in 

equations are defined with those equations. Note that certain state agencies use the same acronyms for 

departments or divisions, so to avoid duplication in this report, acronyms are not necessarily the standard 

agency acronyms.) 

ADEC Alaska Department of Environmental Conservation 

ADEM Alabama Department of Environmental Management 

ADHS Arizona Department of Health Services 

AFB Air Force base 

AK Alaska 

AL Alabama 

AMD amendment (to record of decision) 

APEC Arkansas Pollution Control and Ecology Commission 

AR Arkansas 

ARAR applicable or relevant and appropriate requirement 

ARBCA Alabama Risk-Based Corrective Action Guidance Manual 

ARDEQ Arkansas Department of Environmental Quality 

AS American Samoa 

ASTM American Society for Testing and Materials 

AT averaging time 

ATSDR Agency for Toxic Substances and Disease Registry (DHHS) 

AZ Arizona 

AZDEQ Arizona Department of Environmental Quality 

BHRG baseline human health potential remediation goal 

BCL basic comparison level (NV) 

BRA baseline risk assessment 

BW body weight 

c cancer 

CA California 

CAG Carcinogen Assessment Group (U.S. EPA) 

CalEPA California EPA 

CARB California Air Resources Board 

CCME Canadian Council of Ministers of the Environment 

CDC Center for Disease Control and Prevention (DHHS) 

CDHS California Department of Health Services 

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act, as 

amended 

CEHTUF Center for Environmental and Human Toxicology at the University of Florida 

CLARC cleanup levels and risk calculation (WA) 

CO Colorado 

CODPHE Colorado Department of Public Health and the Environment 

conc concentration 

CSEV Colorado soil evaluation value 

CSF cancer slope factor 

CT Connecticut 

CTL cleanup target level (FL) 

CWLP City Water, Light, and Power (Springfield, IL) 

December 2009 Page iv 
NOTATION (Cont’d.) 

d day(s) 

DAF dilution attenuation factor 

DC District of Columbia 

DCC direct contact criteria(on) (MI) 

DCV direct contact value 

DE Delaware 

DEC Department of Environmental Conservation; also Department of Ecology (WA) 

DEDNREC Delaware Department of Natural Resources and Environmental Control 

DEM Department of Environmental Management 

DEP Department of Environmental Protection 

Dept Department 

DEQ Department of Environmental Quality (AZ, AR, MI, MS, MT, OK, OR) 

DES Department of Environmental Services 

DHHS U.S. Department of Health and Human Services 

DLC dioxin-like compound(s) 

DoA U.S. Department of the Army 

DoD U.S. Department of Defense 

DOE U.S. Department of Energy 

DoN U.S. Department of the Navy 

DOT U.S. Department of Transportation 

DTSC Department of Toxic Substances Control (CalEPA) 

EAL environmental action level 

EC Ecology Center 

eco ecological 

ECOS Environmental Council of the States 

ED exposure duration 

EF exposure frequency 

EFH Exposure Factors Handbook (U.S. EPA NCEA) 

ELCR excess lifetime cancer risk 

EPA Environmental Protection Agency (U.S. unless otherwise indicated) 

ERP Environmental Restoration Program 

ESD explanation of significant difference 

ESL environmental screening level (AS, GM, HI, NMI, TT) 

ET exposure time 

EVS Environmental Science Division (DOE/Argonne) 

FDA U.S. Food and Drug Administration 

FDEP Florida Department of Environmental Protection 

FL Florida 

FS feasibility study 

GA Georgia 

GADNR Georgia Department of Natural Resources 

GCN generic cleanup number (OH) 

GEPA Guam Environmental Protection Agency 

GM Guam 

GW groundwater 

December 2009 Page v 
NOTATION (Cont’d.) 

HDOH Hawaii Department of Health 

HEAST Health Effects Assessment Summary Table 

HEER Hazard Evaluation and Emergency Response (Office) (HI) 

HHSL human health screening level (CalEPA) 

HI Hawaii 

HSRA Hazardous Site Response Act (GA) 

HWS Hazardous Waste Section (NC) 

IA Iowa 

IADNR Iowa Department of Natural Resources 

IAG interagency agreement 

ID Idaho 

IDEM Indiana Department of Environmental Management 

IL Illinois 

ILCR individual lifetime cancer risk 

IN Indiana 

IR intake rate 

IRIS Integrated Risk Information System (U.S. EPA NCEA database) 

ISL initial screening level (UT) 

KDHE Kansas Department of Health and Environment 

kg kilogram 

KS Kansas 

KY Kentucky 

LA Louisiana 

LDEQ Louisiana Department of Environmental Quality 

LOAEL lowest observed adverse effect level 

LRP Land Recycling Program (IA) 

LUST leaking underground storage tank 

MA Massachusetts
 

MADEP Massachusetts Department of Environmental Protection 

MADL maximum allowable dose level 

ME Maine 

MEDEP Maine Department of Environmental Protection 

MD Maryland 

MDHSS Missouri Department of Health and Senior Services 

MDNR Missouri Department of Natural Resources 

mg milligram)(s) 

mg/kg-d milligram(s) per kilogram (body weight) per day 

MI Michigan 

MIDEQ Michigan Department of Environmental Quality 

MLE maximum likelihood estimate 

MN Minnesota 

MNDOH Minnesota Department of Health 

MO Missouri 

MPCA Minnesota Pollution Control Agency 

December 2009 Page vi 
NOTATION (Cont’d.) 

MRBCA Missouri Risk-Based Corrective Action 

MRL minimal risk level (ATSDR) 

MS Mississippi 

MSC medium-specific concentration (PA) 

MSDEQ Mississippi Department of Environmental Quality 

MSSL medium-specific screening level (U.S. EPA Region 6) 

MT Montana 

MTCA Model Toxics Control Act 

MTDEQ Montana Department of Environmental Quality 

n noncancer 

NAS National Academy of Sciences 

NAVFAC Naval Facilities Engineering Command 

NC North Carolina 

NCDENR North Carolina Department of Environment and Natural Resources 

NCEA National Center for Environmental Assessment (U.S. EPA) 

ND North Dakota 

NDEQ Nebraska Department of Environmental Quality 

NDEP Nevada Department of Environmental Protection 

NE Nebraska 

NH New Hampshire 

NHDES New Hampshire Department of Environmental Services 

NIH National Institutes of Health 

NJ New Jersey 

NJDHSS New Jersey Department of Health and Senior Services 

NM New Mexico 

NMED New Mexico Environment Department 

NMI Northern Mariana Islands 

NOAEL no observed adverse effect level 

NSRL no significant risk level 

NTP National Toxicology Program (DHHS) 

NV Nevada 

NY New York 

NYDEC New York Department of Environmental Conservation 

OEHHA Office of Environmental Health Hazard Assessment (CalEPA) 

OH Ohio 

OK Oklahoma 

OKDEQ Oklahoma Department of Environmental Quality 

OR Oregon 

ORDEQ Oregon Department of Environmental Quality 

ORNL Oak Ridge National Laboratory 

OSWER Office of Solid Waste and Emergency Response (U.S. EPA) 

OU operable unit 

p para 

PA Pennsylvania 

PADEP Pennsylvania Department of Environmental Protection 

PBT persistent, bioaccumulative and toxic 

December 2009 Page vii 
 

 

NOTATION (Cont’d.) 

PCB polychlorinated biphenyl(s) 

PCL protective concentration level (TX)
 

PEC probable effect concentration 

PHAGM Public Health Assessment Guidance Manual 

PHG public health goal 

POTW publicly owned treatment works 

ppb part(s) per billion 

ppm part(s) per million 

PPRTV provisional peer-reviewed toxicity value (U.S. EPA) 

ppt part(s) per trillion 

PR Puerto Rico 

PRG preliminary remediation goal (U.S. EPA OSWER; Region 9) 

PWG Pathology Working Group 

RAGS Risk Assessment Guidance for Superfund 

RAIS Risk Assessment Information System (online ORNL database) 

RBC risk-based concentration (U.S. EPA Region 3, AK, OR, others) 

RBSC risk-based screening concentration 

RBSL risk-based screening level (MI) 

RCRA Resource Conservation and Recovery Act, as amended 

RG remediation goal (NE) 

RGO remedial goal objective 

RI Rhode Island
 

RIDEM Rhode Island Department of Environmental Management 

RME reasonable maximum exposure 

ROD record of decision 

RODS Record of Decision System (U.S. EPA database) 

RSL regional screening level (U.S. EPA)
 

SC South Carolina 

SCDHEC South Carolina Department of Health and Environmental Control 

SCTL soil cleanup target level (FL) 

SD South Dakota 

sed sediment 

SF slope factor
 

SFd dermal slope factor 

SFi inhalation slope factor 

SFo oral slope factor 

SPHEM Superfund Public Health Evaluation Manual 

SPS soil performance standard 

SRL soil remediation level (AZ) 

SRSNE Solvents Recovery Service of New England 

SRV soil reference value (MN) 

SSL soil screening level (MI, U.S. EPA, others) 

ST state 

TAC Toxic Air Contaminant Program (CA) 

TAGM Technical and Administrative Guidance Memorandum (NY) 

TCDD 2,3,7,8-tetrachlorodibenzo-p-dioxin 

December 2009 Page viii 
 

NOTATION (Cont’d.) 

TCEQ Texas Commission on Environmental Quality 

TDH Texas Department of Health 

TEC toxic equivalency concentration 

TEF toxic equivalency factor 

TEQ toxic equivalent(s) 

TMDL target method detection limit 

TN Tennessee 

TPH total petroleum hydrocarbons 

TRG target remediation goal (MS) 

TRRP Texas Risk Reduction Program 

TRW Tittabawassee River Watch 

TSG Toxic Steering Group 

TT Trust Territories 

TX Texas 

TXNRCC Texas Natural Resource Conservation Commission 

UCL upper concentration limit 

μg microgram(s) 

μg/kg-d microgram(s) per kilogram (body weight) per day 

URS uniform risk-based remediation standard (DE) 

USACE U.S. Army Corps of Engineers 

USAF U.S. Air Force 

USEPA U.S. Environmental Protection Agency 

UT Utah 

UTDEQ Utah Department of Environmental Quality 

VA Virginia 

VCP Voluntary Cleanup Program (NE) 

VDEQ Virginia Department of Environmental Quality 

VI Virgin Islands 

VRP Voluntary Remediation Program (NM, VA, WY) 

VT Vermont 

WA Washington 

WADEC Washington State Department of Ecology 

WHO World Health Organization 

WI Wisconsin 

WIDNR Wisconsin Department of Natural Resources 

WV West Virginia 

WVDEP West Virginia Department of Environmental Protection 

WY Wyoming 

WYDEQ Wyoming Department of Environmental Quality 

y year(s) 

December 2009 Page ix 
December 2009 Page x 
 

EXECUTIVE SUMMARY 

S.1 OBJECTIVE 

This report summarizes existing state cleanup levels for dioxin in soil, together with their 

scientific bases where available. It is part of the Science Plan for Activities Related to Dioxins in 

the Environment, which was announced by the U.S. Environmental Protection Agency 

(U.S. EPA) Administrator in May 2009. The objective is to inform an interim recommended 

preliminary remediation goal (PRG) for dioxin in soil, which is to be developed by the Office of 

Solid Waste and Emergency Response (OSWER). 

As context, the extant OSWER PRG or starting point for setting a cleanup level for residential 

scenarios is 1 part per billion (ppb) or 1,000 parts per trillion (ppt) as dioxin toxic equivalents 

(TEQ) in surface soil. The TEQ reflects the combined toxicity of the dioxin mixture for which 

individual toxicities are weighted relative to the most potent form, 2,3,7,8-tetrachlorodibenzo-pdioxin (hereafter referred to as TCDD) using toxic equivalency factors (TEFs). This cleanup 

level considers a reasonable maximum exposure that emphasizes a childhood pattern of 

incidental soil ingestion, and a TCDD cancer slope factor based on a scientific evaluation of 

rodent bioassay data published in 1978. The parallel recommended starting points for 

commercial/ industrial scenarios are in the range of 5 to 20 ppb, or 5,000 to 20,000 ppt. 

S.2 APPROACH 

State agency websites and other online resources were searched for all 50 states to identify soil 

cleanup levels for dioxin, as well as their scientific bases. The District of Columbia (DC), Puerto 

Rico, the Virgin Islands, and four Pacific Rim territories – American Samoa, Guam, Northern 

Mariana Islands, and the Trust Territories – were also included in this review, bringing the total 

entities checked to 57. The primary focus was levels for unrestricted/residential land use; 

values for commercial/industrial (restricted) use were also compiled where readily available. 

Because a number of states call for site-specific determinations of cleanup levels, context was 

also pursued for recent cleanup decisions where generic state values were not found. The 

combined data were tabulated and provided to technical contacts across the ten U.S. EPA 

Regions to coordinate field reviews. 

S.3 RESULTS 

Nearly half the states and territories (26) have identified a cleanup level or guideline for dioxin in 

soil. About 60 percent of these levels are as TCDD, with the rest as dioxin or TCDD TEQ. 

The concentrations identified across these states and territories, as well as the scientific bases 

in terms of the exposure calculations, target risks, and toxicity values used, are highlighted in 

the following sections. Also summarized is context for four evaluation criteria considered for 

these health-based values. (Note that to simplify this presentation, specific references are not 

cited in the summary; citations are included in the body of the report and in the appendices.) 

Some states list multiple dioxin concentrations that address different land use scenarios and 

assumptions, such as extent of exposure and target risk level. About 280 values were identified 

in this review, so to simplify comparisons the key figures and tables in this report emphasize a 

representative value per state and land use category, grouped as unrestricted/residential and 

commercial/industrial land use. More detailed data are available in Appendix B. 

December 2009 Page S-1 
 

 

 

S.3.1 Soil Cleanup Levels 

Soil cleanup levels have been identified for unrestricted/residential use by 26 states and 

territories, ranging from nearly 4 to 1,000 ppt as shown in Figure S-1. Some values are not yet 

available online, and parenthetical dates accompany those identified by the field during the 

review phase (such as internal and provisional concentrations). Frequency distributions of the 

cleanup levels for both unrestricted and restricted scenarios are presented in Figure S-2. The 

commercial/industrial cleanup levels range from 18 to 5,000 ppt, differing by a factor of about 

270, compared to 250 for the unrestricted/residential cleanup levels. 

For unrestricted/residential use, more than 75 percent of the values (20) fall at or below 120 ppt, 

and most (15) are less than 40 ppt. While values reported as TEQ may be expected to be 

somewhat higher than those based on TCDD, and several are, half of the ten TEQ-based 

cleanup levels are in the group below 120 ppt, and 30 percent of those below 36 ppt are TEQs. 

At the lowest end of the concentration range are seven states with cleanup levels documented 

in the last ten years that are the same as soil concentrations commonly used for preliminary 

screening evaluations, i.e., 3.9 to 4.5 ppt. This suggests that nearly a third of the states with 

cleanup levels have essentially adopted a value intended for screening purposes (generally 

based on a target risk of 10-6 with default residential assumptions). 

In the concentration group above 120 ppt are four cleanup levels that are 100 times higher than 

the lowest set. These four, which range from 390 to 450 ppt as dioxin TEQ, are for Hawaii and 

three Pacific Rim territories (documented in 2006 and 2008, respectively). 

Topping the range is the cleanup level of 1,000 ppt identified by two states, Alabama and Texas 

(documented in 2007 and 2009, respectively). This is the recommended OSWER concentration 

for residential soils, as TEQ. Alabama identifies the basis as TCDD, while Texas indicates 

TEQ. The five states that join Texas, Hawaii, and three Pacific island territories in reporting 

cleanup levels as TEQs are Florida, Maine, Michigan, Minnesota, and Ohio. (Wyoming adopts 

the EPA Regional screening level for TCDD and indicates TEFs may be considered for others.) 

All but 5 of the 26 states with unrestricted use levels also identify cleanup levels for commercial/ 

industrial use. (These five are: Alaska, Georgia, Michigan, Ohio, and Wyoming.) For the rest, 

levels for restricted use are higher than for residential, as expected. This reflects less extensive 

exposures and in some cases less restrictive target risks. As a group, these concentrations are 

within a factor of 5 of the residential levels and thus span a wider range. (States use various 

terms for these scenarios; for simplicity, they are grouped as “commercial/industrial” here.) 

Soil concentrations that are not formal cleanup levels but could offer related insights were found 

for nearly half the remaining states and territories (15 of 31). Most were clarified as screening 

values during field review; these values are included in the report as potential context for those 

cases where standard cleanup levels are unavailable. No generic cleanup levels for dioxin were 

identified for the remaining 15 states and the last territory. In fact, these states (including 

California and Utah) and the Trust Territories have deferred identifying generic cleanup levels, 

calling instead for risk-based determinations that can incorporate site-specific factors. This 

same approach is taken by a number of the states that identify screening values but no cleanup 

levels. For example, while Arkansas lists concentrations of 4.5 and 18 ppt as screening levels, 

and Massachusetts lists values of 20, 50, and 300 ppt (TEQ) from essentially a screening 

approach, both refer to the need for site-specific determinations of an actual cleanup level. 

December 2009 Page S-2 
AK, Jun-08 AL, Apr-08 AS, Oct-08 AZ, May-07 DE, Dec-99 FL, Feb-05 GA, 1992 GM, Oct-08 HI, Sum-08 IA, Jul-09 

IN, 2006 (Jun-09) KS, Jun-07 MD (Jul-09) ME (Jul-09) MI, Jan-06 MN, Jun-09 MS, Feb-02 NE, Oct-08 NH, May-07 NMI, Oct-08 OH, Oct-09 OR, Sep-09 PA, No

1,1001,000

900800700600500400300200100

0

1,000 

450 450 450

390

45 90 80

(60) 60 38 35.8 19 20 4.5 

4.5 4 7 4.5 10 4.26 3.9 9

Soil Dioxin Concentration (ppt) 

FIGURE S-1 Soil Cleanup Levels: Unrestricted/Residential Use, by State 

(A dark border indicates the basis is TEQ rather than TCDD; a dashed border and lighter sha

value; parenthetical dates reflect field inputs for values not yet available online.) 

December 2009 
3.9 to 11 >11 to 120 

>120 to <1,000 16 to 40 >40 to 160 >160 to <1,000 

Frequency of Value 

12 11 10 

9 8 7 6 5 4 3 2 1 0 

Unrestricted (Residential) Restricted (Commercial/In

11 

WA 

10 

ME 

9 

NH 

120 

PA 

7 

FL 

90 

MI 

80 GA 

40 

DE 

4.5 

60 

KS (IN) 

38.2 

MS 

AZ, MD, 

OR, WY 45 

IN 

35 

MN 

38 

AK 

31 

ME 

53

PA 

4.26 

MS 

35.8 

OH 

450 

AS, GM, 

NMI 

30 

FL 160 

36

IA 

4 

DE 

20 

MN 

1,000 

TX 

20 

OR 

AZ, NE 30

NH 

3.9 

NE 

19 

IA 

390 

HI 

1,000 

AL 

18 

MD 

100 

KS 

18

IN 

Soil Dioxin Concentration (ppt) 

FIGURE S-2 Distribution of Soil Cleanup Levels by Concentration: Unrestricted and Restricted Uses 

(A dark border indicates the basis is TEQ rather than TCDD; parenthetical italics indicate a draft v

December 2009 
 

 

S.3.2 Exposure Calculations 

The exposure calculation is central to the determination of health-based cleanup levels. The 

current review of soil cleanup levels for dioxin indicates that states generally follow the standard 

EPA approach for deriving such concentrations, tapping the standard equation from the EPA 

1989 risk assessment guidance for Superfund or 1996 soil screening guidance. The same 

basic equation also underlies the EPA Regional screening levels (RSLs), which have been 

adopted as cleanup levels by several states. 

In most cases, dioxin is one of many chemicals for which states have derived soil cleanup 

levels, so the agencies have identified generic exposure calculations for broad application. 

Although individual terms vary, the basic structure and concepts are similar across 

organizations. For dioxin, incidental ingestion is the dominant exposure route for unrestricted/ 

residential use, and four states (Delaware, Mississippi, Pennsylvania, and Washington) base 

their cleanup levels on this pathway alone. Most others incorporate inhalation and/or dermal 

exposures, but those contributions tend to be relatively small. However, under certain scenarios 

(such as for excavation workers), these additional exposure routes can contribute substantially 

to the derived cleanup level. 

Regarding the parameter values, most states apply common EPA default assumptions so the 

exposure factors are generally similar. However, relatively minor differences exist, with some 

reflecting state-specific context. For example, the Washington averaging time and the 

Minnesota exposure duration are slightly longer than the traditional EPA default residential 

values. The equations and values used by states to derive dioxin cleanup levels are presented 

in the body of the report and Appendix B. The combined exposure factors generally produce 

differences within a factor of ten. For example, values used for exposure frequency differ by 

about 2.4-fold, and those for the age-adjusted soil ingestion factor differ by less than 3-fold. 

S.3.3 Target Risks 

Target risks used to derive state cleanup levels for both unrestricted and restricted use range 

from 10-4 to 10-6 (which is also the EPA target incremental risk range for contaminated sites). 

These risks are shown in Table S-1 and Figures S-3 and S-4. Almost half the states that 

indicate a target risk for their unrestricted cleanup levels (11 of 24) use a value of 10-6. Eight 

use 10-5, and one (Iowa) uses a value halfway between the two, at 5 x 10-6. The last four 

(Hawaii, American Samoa, Guam, and the Northern Mariana Islands) use the upper-end value 

of 10-4. The same target risks are used for the commercial/industrial cleanup levels, except 2 of 

the 11 states that apply 10-6 for residential levels (Nebraska and Washington) use a value ten 

times higher for the restricted scenarios. 

S.3.4 Toxicity Values 

Nearly all states that identify dioxin cleanup levels (24 of 26) indicate the health endpoint, and 

all but one are based on cancer. This one level is the Iowa soil standard for nonresidential use, 

which applies if dioxin is the only chemical of concern. The reference dose used to derive this 

value is 10-9 mg/kg-d (which is the same as the chronic oral minimal risk level [MRL] established 

by the Agency for Toxic Substances and Disease Registry [ATSDR] in 1998). For all other state 

cleanup levels, including the standard residential level for Iowa, cancer is the limiting effect and 

the oral slope factor is the toxicity value of interest. 

(As a note, an online file for Texas indicates the cleanup levels are based on a noncancer effect 

[“n”] but no toxicity value is provided; field followup clarified that the basis is cancer.) 

December 2009 Page S-5 
 

TABLE S-1 Target Risks for the State Cleanup Levels 

State per 

Risk Level 

Soil Concentration per Land Use Scenario (ppt) 

Unrestricted/Residential Commercial/Industrial 

Terminology for Dioxin Cleanup Level 

(as TCDD or Dioxin TEQ) 

10-6 Incremental Lifetime Cancer Risk 

NE 3.9 (see entry under 10-5) Remediation goal for TCDD 

DE 4 40 Uniform risk-based remediation standard 

for TCDD 

MS 4.26 38.2 Target remediation goal for TCDD 

AZ 4.5 (see notes below) Soil remediation level for TCDD 

MD 4.5 18 Cleanup level for TCDD 

OR 4.5 20 Risk-based concentration for TCDD 

WY 4.5 - Cleanup level for TCDD 

FL 7 30 Soil cleanup target level for TCDD TEQ 

NH 9 300 Risk-based soil standard for TCDD 

ME 10 31 Generic soil cleanup level for dioxin TEQ 

WA 11 (see entry under 10-5) Cleanup level for TCDD 

5×10-6 Incremental Lifetime Cancer Risk 

IA 19 (see notes below) Cleanup level for TCDD 

10-5 Incremental Lifetime Cancer Risk 

MN 20 35 Soil reference value for TCDD or TEQ 

OH 35.8 - Generic cleanup number for TCDD TEQ 

AK 38 - Risk-based concentration for TCDD 

IN 45 (60) 180 Soil default closure level for TCDD 

KS 60 100 Risk-based standard for TCDD 

GA 80 - Notifiable concentration for TCDD 

MI 90 - Direct contact criterion; risk-based 

screening level for TCDD TEQ 

PA 120 530 Medium-specific concentration for TCDD 

NE (see entry under 10-6) 160 Remediation goal for TCDD 

WA (see entry under 10-6) 1,500 Cleanup level for TCDD 

10-4 Incremental Lifetime Cancer Risk 

HI 390 1,600 Action level for dioxin TEQ 

AS 450 1,800 Action level for dioxin TEQ 

GM 450 1,800 Action level for dioxin TEQ 

NMI 450 1,800 Action level for dioxin TEQ 

Notes: TCDD = tetrachlorodibenzo-p-dioxin; TEQ = toxicity equivalent(s). Values are for states that indicate a target 

risk. AL adopted cleanup levels from the 1998 OSWER directive; TX adopted similar values without explicitly stating 

they are from the directive. Although the AZ nonresidential remediation level of 160 ppt is not accompanied by an 

explicit target risk, but general language in the regulation indicates the cumulative excess lifetime cancer risk should 

not exceed 10-4. The IA nonresidential cleanup level for dioxin is based on the noncancer endpoint. The IN draft 

provisional value for unrestricted use is in parentheses. The OR value is for the occupational scenario, direct contact. 

December 2009 Page S-6 
500 

10-6 510-6 10-5 

Soil Dioxin Concentration (ppt) 

400300200100

0 

120 

90 

80 

60 

45 

(60) 

35.8 38

19 20 9 10 11 4.26 4.5 4.5 4.5 4.5 7 3.9 4

NE DE MS OR AZ MD WY FL NH ME WA IA MN OH AK IN KS GA MI PA 

FIGURE S-3 Distribution of States with Specific Risk Targets for Dioxin Cleanup Levels: Unrestricted/R

(A dark border indicates the basis is TEQ rather than TCDD; a dashed border and lighter shading ind

December 2009 
10-6 10-5 

2,000 1,800 1,600 1,400 1,200 1,000 

800 600 400 200 

0 

MD OR FL ME MS DE NH MN KS AZ NE IN PA WA H

18 20 30 31 38.2 40 

300 

35 

100 

1,500 

1,60

160 160 180 

530 

Soil Dioxin Concentration (ppt) 

FIGURE S-4 Distribution of States Listing Specific Risk Targets for Dioxin Cleanup Levels: Commercia

 (A dark border indicates the basis is TEQ rather than TCDD; a dashed border indicates a draft val

December 2009 
(More information is summarized for toxicity values than for the other topics in this report 

because of broad interest, considering the availability of more recent toxicological data and 

ongoing evaluations by EPA and other agencies.) 

Across the 24 states and territories (hereafter generally referred to as states), four different 

slope factors have been used to determine dioxin cleanup levels: 75,000; 130,000; 150,000; 

and 1,400,000 (mg/kg-d)-1. These toxicity values are presented in Figure S-5 and Table S-2, 

together with the states that use them. They were derived using toxicity data from one of two 

rodent bioassays published more than 25 years ago, combined with modeling conducted by 

U.S. EPA work groups, California EPA (CalEPA), and other scientific groups to estimate the 

incremental lifetime risk of cancer incidence for humans. Cited sources range from old EPA 

Health Effects Assessment Summary Tables (HEAST) to former and current U.S. EPA Regional 

screening level tables, the 2003 draft EPA dioxin reassessment, and CalEPA documents. 

All but two of the 24 states use a slope factor of either 150,000 or 130,000 (mg/kg-d)-1. 

Although very similar, each value is based on a different bioassay: the 1978 study by Kociba 

and colleagues, and the 1982 National Toxicology Program (NTP) study, respectively. These 

original toxicity studies were independently peer reviewed as part of their publication process, 

as were the evaluations conducted to derive the slope factors. Three of the four slope factors 

listed above are based on the Kociba study, and these three are summarized first below. 

The slope factor of 150,000 (mg/kg-d)-1 is used most often, underlying more than half the state 

cleanup levels that include a toxicity value (13 of 24). It is based on the two-year dietary study 

of Sprague-Dawley rats by Kociba et al., which showed a higher incidence of hepatocellular 

carcinoma and squamous cell carcinoma of lungs, hard palate, nasal turbinates, and tongue at 

the highest dose, yet a decreased incidence of other tumors. This slope factor has also been 

applied by other states to establish supporting concentrations for dioxin in soil, such as the 

Nevada basic comparison levels (which are screening values rather than cleanup levels). 

Updated evaluations of these same data were used by Michigan and Minnesota, the two states 

with different slope factors than the rest. In 1986, the NTP revised its tumor classification 

scheme, and scientists (including Kociba and his colleague Squire, as well as EPA work groups) 

used the new method to reevaluate the incidence of female rat liver tumors and other tumors 

from the 1978 data. This reevaluation identified a lower tumor incidence, which produced a 

lower toxicity value. A slope factor of 52,000 (mg/kg-d)-1 was determined based on liver tumors 

alone, and a slope factor of 75,000 (mg/kg-d)-1 was determined based on total significant 

tumors. Michigan used the latter (half the older slope factor) to determine its soil cleanup level. 

In 2003, the Minnesota Department of Health (MNDOH) selected the draft slope factor of 

1,400,000 (mg/kg-d)-1 from the range of values presented in the EPA 2003 draft dioxin 

reassessment. This value, derived from the Kociba study, was identified as the upper bound for 

animal bioassays. At roughly 10 times the two most commonly applied values (and nearly 

20 times the Michigan value), this slope factor was also used in a supporting role by the Pacific 

island group (American Samoa, Guam, Hawaii, and the Northern Mariana Islands). That is, it 

was used to estimate a concentration that could be applied for the lower bound of an 

operational cleanup range, as a companion to the standard cleanup levels above which 

remedial action should be considered. Those main cleanup levels (which are the representative 

concentrations shown in key figures and tables of this report) were derived using the toxicity 

value of either 150,000 (mg/kg-d)-1 (for Hawaii) or 130,000 (mg/kg-d)-1 (for the three Pacific 

island territories). 

December 2009 Page S-9 
FIGURE S-5 Dioxin Toxicity Values Underlying the State Cleanup Levels 

 (Italics indicate the value is used for a draft or supporting level; see Notation and body for acronym

December 2009 
TABLE S-2 Dioxin Toxicity Values Underlying the State Cleanup Levelsa 

Cancer 

Toxicity Value 

(mg/kg-d)-1 

Number 

of States 

Specific 

States Scientific Basis 

150,000 13 AK, DE, 

FL, HI, 

IA, IN, 

KS, MS, NE, NH, OH, PA, 

WA 

The source of this value is commonly given as EPA HEAST from 1997, which lists several citations including the 1985 EPA Health Assessment Document 

for Polychlorinated Dibenzo-p-dioxin. This slope factor is based on the female rat bioassay by Kociba et al. from 1978. The two-year dietary study of TCDD in female Sprague-Dawley rats indicated the highest dose (0.1 μg/kg-d, or estimated dietary amount 2,200 ppt) produced multiple toxicological effects, with lesser effects reported at 0.01 μg/kg-d (210 ppt). (This was considered to support a previous study indicating chronic ingestion of 5,000 ppt caused 

many toxicological effects.) No adverse effects were reported at 0.001 μg/kg-d (22 ppt), and no carcinogenic effects reported at 0.01 or 0.001 μg (210 or 22 ppt). 

This older toxicity value reflects earlier methodology for classifying liver tumors, which was updated by the National Toxicology Program (NTP) in 1986. Many states cite the (outdated, indirect) EPA HEAST as the source. 

(Note this earlier EPA value from HEAST was also listed in the previous 

Region 9 PRG table – which preceded the 2008 harmonization of regional screening levels, or RSLs.) 

HEAprovas bSpecwas EPA docusourrevieHEAon ththat 156,HEA(Fro“The listinprovinforentriundeconcProgsuppreferenouas hconsHEAwhenatunote

December 2009 
TABLE S-2 Dioxin Toxicity Values Underlying the State Cleanup Levelsa 

Cancer 

Toxicity Value 

(mg/kg-d)-1 

Number 

of States 

Specific 

States Scientific Basis 

75,000 1 MI This value is based on a reevalution of tumor data from the 1978 rat study by 

Kociba et al. (see above), using the 1986 NTP update of the liver tumor classification scheme. This reevaluation indicated lower tumor incidence rates, which resulted in a slope factor of 52,000 (mg/kg-d)-1 based on liver 

tumors alone, and a slope factor of 75,000 (mg/kg-d)-1 based on total 

significant tumors – which updated the factor of 150,000 (mg/kg-d)-1 that had 

been based on the older methodology. 

Severeasthe KanalconsAsse

1,400,000 1 

(+4, 

to derive a supporting 

lower 

bound for 

a cleanup 

range) 

MN 

(AS, GM, 

HI, NMI) 

MN adopted this draft value, the upper bound slope factor based on animal data that was included in the EPA (2003) draft reassessment, which was derived from the Kociba et al. (1978) bioassay described above. (This value is 40 percent higher than the draft upper bound slope factor in the reassessment based on epidemiological data.) The MNDOH documentation notes: driving pathway-oral; endpoints-immune, repro, cancer; cancer target organ-liver; class-human carcinogen. Per the MNDOH overview, concerns about the quality of exposure estimates in human epidemiological studies preclude quantitative use of these data in developing a slope factor, but results from modeling the human studies are consistent with the cancer slope derived by modeling data from animal studies. MNDOH also notes this slope factor was derived from the same study as the previous value of 156,000 (mg/kg-d)-1, and 

that its development utilized current methods of analysis, including use of body burden as the dose metric for animal-to-human dose equivalence calculations (i.e., adjustments to account for the differences in half-life of dioxins in the bodies of laboratory animals and humans), and a re-evaluation of liver tumors in the Kociba study using the latest pathology criteria. 

These four entries are shown in parenthetical italics because this value only underlies supporting soil concentrations, not the basic cleanup levels for this Pacific island set. That is, this draft toxicity value was used to generate a lower bound as a companion to the standard cleanup levels based on 150,000 (mg/kg-d)-1 for HI, and on 130,000 (mg/kg-d)-1 for the other three 

islands. This toxicity value supports the lower end of the cleanup range, while the main cleanup level above which remedial action is to be considered is based on these two other slope factors applied by nearly all other states. 

The undeextesubsinde2004 basiupdarecobut arecoguidcarcinclulife apote

December 2009 
TABLE S-2 Dioxin Toxicity Values Underlying the State Cleanup Levelsa 

Cancer 

Toxicity Value 

(mg/kg-d)-1 

Number 

of States 

Specific 

States Scientific Basis 

130,000 8 AS, AZ, 

GM, MD, 

ME, NMI, 

OR, WY 

This slope factor is listed in the current EPA Regional screening level table for residential soil, with the source given as CalEPA; its derivation is documented by California EPA (CalEPA). (As a note, the CalEPA soil screening level for 2,3,7,8-TCDD is 4.6 ppt.) The asterisk * in the RSL table for the cancer basis indicates that a screening level based on the noncancer endpoint is <1% of that based on the cancer endpoint (indicated as "[n SL < 100X c SL]"). This toxicity value is based on the NTP rat gavage studies from 1982. Summarizing from the CalEPA derivation document: A linearized multistage model was used with the NTP male mouse hepatocellular adenoma/carcinoma tumor data for TCDD, providing point estimates of extra risk for both maximum likelihood estimate (MLE) and linearized 95% upper confidence value (UCL); the UCL was calculated by maximizing the linear term, or forcing a best fit (method consistent both with expected low-dose linearity and linear nonthreshold theory). The slope of 95% UCL (q1*) was taken as the plausible upper bound cancer potency of TCDD at low doses. Rodent exposure data were converted to equivalent human exposures with scaling factors. Assumptions include: oral and inhalation routes are equivalent, air concentration is assumed to be daily oral dose, route of exposure does not affect absorption, and no difference exists in metabolism/ pharmacokinetics between animals and humans. Total weekly dose levels were averaged for a daily dose level; this assumes daily dosing in the NTP studies would give the same results as the actual twice weekly dosing schedule (as described, the TCDD half-life is relatively long so both schedules should give similar tissue concentrations). A significant increase in hepatocellular hyperplastic nodules was observed in female rats exposed to 0.1 or 0.01 μg/kg-d, while the next lower dose (0.001 μg/kg-d) 

showed no effect. (Note CalEPA is currently evaluating more recent toxicity data, notably the 2004 NTP study. Implications for an updated oral toxicity value are anticipated to be available later in 2009 or early 2010, following completion of the external review process.) 

This CalifServin thfor thConundeby thBoapanewheincluSpotExtepanewas that 1983toxic1980CalEcomstudevalToxiprogdocuand 

(+1) (IN) This entry is in parenthetical italics because 130,000 (mg/kg-d)-1 underlies the 

internal draft cleanup level being considered by Indiana (60 ppt), based on field input during the review phase of this data compilation effort. The slope factor of 150,000 (mg/kg-d)-1 underlies the current provisional level of 45 ppt. 

a See the Notation section and report body for acronyms; see the body and references for the documentation indicated in t

December 2009 
 

The slope factor of 130,000 (mg/kg-d)-1 is used by one-third of the states and is being 

considered by an additional state. This value was derived from the 1982 chronic NTP study of 

rats and mice (Osborne-Mendel, dosed by gavage 3 times/week and B6C3F1, gavaged 

2 days/week, respectively). This toxicity value underlies the cleanup levels identified for Arizona 

and Oregon, as well as the three Pacific island territories as noted above. This value also 

underlies the current EPA Regional screening levels (RSLs) for dioxin, which have been 

adopted by Maryland and Wyoming. In addition, it underlies the draft cleanup level recently 

identified by Maine and the internal draft provisional value developed by Indiana – bringing the 

total number (including draft values) considering this slope factor to nine. 

The following summary of the toxicity basis for this slope factor is taken from the 1998/2008 

ATSDR toxicological profile for chlorinated dibenzo-p-dioxins. About 0.007 μg/kg-d significantly 

increased the incidence of thyroid follicular cell adenoma, and a dose 10 times higher increased 

the incidence of neoplastic nodules in the liver and hepatocellular carcinoma in females. Doses 

of 0.1 and 0.01 μg/kg-d resulted in a significant increase in hepatocellular hyperplastic nodules 

for females, while the next lower dose (0.001 μg/kg-d) did not. Total weekly doses were 

averaged to estimate a daily dose, which assumes daily dosing would give the same results. 

(The TCDD half-life is relatively long so both schedules were expected to give similar tissue 

concentrations.) These rodent data were converted to equivalent human exposures using basic 

scaling factors; assumptions included: oral and inhalation routes are equivalent, the air 

concentration is assumed to be the daily oral dose, the route of exposure does not affect 

absorption, and TCDD metabolism/pharmacokinetics do not differ between animals and 

humans. CalEPA has documented the application of the linearized multistage model to these 

rodent hepatocellular adenoma/carcinoma tumor data to derive the cancer slope factor. 

S.3.4 Key Differences 

Differences among state values used to calculate exposures from incidental ingestion are 

illustrated in Table S-3, together with the slope factors and target risks applied. While the 

averaging time is generally the same (Washington uses a slightly higher value), the exposure 

frequency can differ by about 2.4-fold, the soil ingestion factor by nearly 3-fold, the slope factor 

by about 20-fold, and the target risk by 100-fold. The input from inhalation and/or dermal 

exposures also contributes somewhat to the range of cleanup levels across states. Additional 

factors include the chemical basis (TCDD only, or dioxin TEQ), as well as whether the state has 

derived a soil concentration or adopted an existing (e.g., screening) value as the cleanup level. 

S.3.5 Evaluation Criteria 

The information compiled for state cleanup levels was considered in terms of four evaluation 

criteria commonly used to assess health-based values (including by OSWER). These criteria 

are: (1) nature of peer review, (2) transparency-public availability, (3) scientific basis, and 

(4) incorporation of most recent science. 

In many cases, only limited information was found during the online searches to address these 

criteria , and little more was obtained from field review inputs. This was particularly an issue for 

transparency and the nature of peer review, but in several cases it also extended to 

documentation of the scientific basis, notably for derivation of the underlying toxicity value. The 

CalEPA toxicity values tend to address these criteria fairly well because of the extensive peer 

review by external experts in accordance with a long-standing process, public availability, and 

typical scientific rigor. 

December 2009 Page S-14 
TABLE S-3 Summary Comparison of State Derivations for Incidental Soil Ingestion (main route for reside

Generic equation for residential/unrestricted scenario,(incidental ingestion: 

Cres_ing = TR×AT / SFo×EF×IFSadj×10-6 kg/mg 

State Conc 

(ppt) 

Oral Cancer Slope Factor. 

SFo (mg/kg-d)-1 Target Cancer Risk, TR Averaging Time (d) Exposure Frequency, EF (d/y) Soil Ing

or (IR×

NE 3.9 150,000 10-6 25,550 350 

DE 4 150,000 10-6 25,550 350 

MS 4.26 150,000 10-6 25,550 350 

AZ 4.5 130,000 10-6 25,550 350 

MD 4.5 130,000 10-6 25,550 350 

OR 4.5 130,000 10-6 25,550 350 

WY 4.5 130,000 10-6 25,550 350 

FL 7 150,000 10-6 25,550 350 

NH 9 150,000 10-6 25,550 160 

ME 10 130,000 10-6 25,550 150 

WA 11 150,000 10-6 27,375 365 

IA 19 150,000 5×10-6 25,550 350 

MN 20 1,400,000 10-5 25,550 350 

OH 35.8 150,000 10-5 25,550 350 

AK 38 150,000 10-5 25,550 330 

IN 45 150,000 10-5 25,550 250 

KS 60 150,000 10-5 25,550 350 

GA 80 (not specified) 10-5 25,550 350 

MI 90 75,000 10-5 25,550 350 

PA 120 150,000 10-5 25,550 250 

HI 390 150,000 10-4 25,550 350 

AS 450 130,000 10-4 25,550 350 

GM 450 130,000 10-4 25,550 350 

NMI 450 130,000 10-4 25,550 350 

a Shading highlights variations within related entries. Note the internal draft provisional value of 60 ppt for Indiana uses a 

AL and TX identify a cleanup level of 1,000 ppt, which is the concentration recommended in the OSWER directive for a residential sce

December 2009 
 

For dioxin, the CalEPA slope factor of 130,000 (mg/kg-d)-1 used by eight states (and being 

considered by a ninth) is well documented in terms of scientific basis, methodology, and peer 

review. This value was derived using the linearized multistage model with slightly more recent 

bioassay data (1982 NTP study) than used for the other slope factors (which are based on the 

1978 Kociba data), and its derivation and review process are publicly available online. 

In contrast, documentation for the slope factor of 150,000 (mg/kg-d)-1 used by more than half 

the states is limited. It is based on an outdated methodology, and the common citation is an 

outdated EPA HEAST source. That HEAST cancer slope factor was indicated as being a 

provisional value and was qualified as being under further evaluation. The HEAST tables were 

described in the 1997 EPA document as containing “provisional risk assessment information” 

that “have not had enough review to be recognized as high quality, Agency-wide consensus 

information.” Specific peer review information for this earlier slope factor is not readily available; 

however, the 1985 EPA Health Assessment Document (which is listed as one of the sources for 

the HEAST value) underwent external peer review. Note it is not clear that the HEAST value 

was based solely on this document, since the 1985 EPA health assessment document lists a 

cancer slope factor of 156,000 (mg/kg-d)-1, while the HEAST value is 150,000 (mg/kg-d)-1. Thus, 

this value is considered relatively weak in terms of the evaluation criteria. 

The third slope factor, 1,400,000 (mg/kg-d)-1 used by Minnesota, was taken from the draft EPA 

dioxin reassessment, which remains under review. The lack of a final peer-reviewed publication 

basis for this value limits its broader strength. 

The fourth slope factor, 75,000 (mg/kg-d)-1 used by Michigan, is a final published value based 

on an updated, peer-reviewed evaluation of the Kociba data using the updated NTP tumor 

classification. However, documentation of its derivation, independent peer review, and public 

availability of supporting information were not found to be as extensive as for the CalEPA value. 

S.4 SUMMARY 

Information on soil dioxin cleanup levels was pursued for all 50 states, DC, Puerto Rico, the 

Virgin Islands, and four Pacific island territories. Nearly half (26 of 57) have established cleanup 

levels, and another quarter have identified screening levels. The rest call for site-specific 

determinations (which incorporate relevant conditions) rather than identifying generic values. 

For those states, additional insights were pursued from site records of decision. 

The state cleanup levels for dioxin span three orders of magnitude, reflecting differences in: 

(1) target risk; (2) cancer slope factor; (3) exposure assumptions; (4) reporting basis (TCDD or 

TEQ); and (5) whether a value was adopted or derived. More than half the derived cleanup 

levels reflect an older slope factor of 150,000 (mg/kg-d)-1, which was qualified as provisional and 

under review. For unrestricted use, two states use the OSWER value of 1,000 ppt. About half 

the site-specific cleanup decisions also reflect this concentration. 

Several state cleanup levels fall in the middle range of around 400 ppt, but most are at or below 

120 ppt. More than a quarter (7 of 26) are roughly 4 ppt, which indicates a number of states 

have essentially adopted values developed for screening purposes (rather than cleanup 

decisions) as their cleanup level. These low levels match the U.S. EPA Regional screening 

level for unrestricted use. The scientific basis, external peer review, and transparency of these 

adopted values do not appear to be well documented for such an application, i.e., for other than 

the screening purpose for which they were designed. 

December 2009 Page S-16 
 

 

1 INTRODUCTION 

The purpose and scope of this report by the U.S. Environmental Protection Agency (U.S. EPA) 

National Center for Environmental Assessment (NCEA) is identified in Section 1.1, and the 

report organization is given in Section 1.2. 

1.1 PURPOSE AND SCOPE 

The purpose of this report is to provide information on soil cleanup levels for dioxin across the 

United States. In late May 2009, the U.S. EPA Administrator released the Science Plan for 

Activities Related to Dioxins in the Environment (U.S. EPA, 2009), which includes the following 

commitments: 

“EPA will evaluate information about the basis for dioxin soil clean-up levels. 

 NCEA will review information about the basis for state dioxin soil clean-up 

levels. 

 NCEA will prepare a report for OSWER that includes a survey and evaluation 

of the clean-up levels in the states. 

 The report will characterize the science that these values are based on, as 

well as the degree of peer review, if any that was done. 

 This report will be completed before December 31, 2009, and provided to 

OSWER. 

 OSWER will announce an updated interim dioxin soil clean-up level to the 

public by December 31, 2009.” 

The extant directive from the Office of Solid Waste and Emergency Response (OSWER) for 

dioxin in soil identifies a cleanup level of 1,000 parts per trillion (ppt) for unrestricted land use 

(U.S. EPA, 1998). In the time since this directive was released, several states have developed 

their own values to guide the cleanup of contaminated sites, which are lower than the OSWER 

value. Many in the broader community are interested in updated U.S. EPA guidance to support 

cleanup activities that are under way or being planned. The Agency is responding to this need 

through the commitments outlined above. 

The scope of this evaluation focuses on 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or total 

dioxins as toxic equivalents (TEQ). It does not include dioxin-like compounds, such as 

polychlorinated biphenyls. Further details on the scope are given in Chapter 2. 

1.2 REPORT ORGANIZATION 

This report is organized as follows: 

	 Chapter 2 outlines the approach for identifying soil cleanup levels across states. 

	 Chapter 3 presents the results, including the scientific basis where available. 

	 Chapter 4 provides a brief discussion of the results. 

	 Chapter 5 acknowledges contributors, and Chapter 6 lists references for the main report. 

	 Appendices present supporting information on the approach (Appendix A) and detailed 

data for individual states, organized by U.S. EPA Region (Appendix B). 

December 2009 Page 1 
 

 

 

 

2 APPROACH 

The identification of state soil cleanup levels for dioxin involved three main phases: 

	 Survey existing information sources including the scientific literature to identify 

state cleanup levels for dioxin-contaminated soil, and supporting documentation, 

including for the toxicity value applied. 

	 Compile the state levels and their scientific bases, and provide to applied 

experts across states and U.S. EPA Regions for review and input; include in this 

compilation information for several criteria used to evaluate health-based levels. 

	 Integrate the information into a summary technical report. 

These phases are illustrated in Figure 1. Information for Phases I and II is highlighted in 

Sections 2.1 and 2.2, respectively. Supporting details for the approach are provided in 

Appendix A. 

FIGURE 1 Phased Approach for Identifying Soil Dioxin Cleanup Levels 

Note that “state” is used as a broad term to include entities such as U.S. territories for which 

information on soil cleanup levels was also pursued. That is, the scope extends beyond the 

50 states, DC, and Puerto Rico to the Virgin Islands, American Samoa, Guam, Northern 

Mariana Islands, and the Trust Territories (the last four are in EPA Region 9; see Table B.9). 

December 2009 Page 2 
 

 

 

2.1 DOCUMENT/LITERATURE SEARCH 

The scope of the literature survey to identify state soil cleanup levels for dioxin is summarized in 

Table 1. The information resources pursued in this search are highlighted in Table 2. 

TABLE 1 Scope of the Survey for Dioxin Soil Cleanup Levels by State 

Component Focus Note 

Benchmark type Cleanup level, not screening value While many states identify screening 

values, this effort focuses on soil 

cleanup levels. 

Contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin 

(TCDD) or toxic equivalents (TEQ), 

total dioxins 

Dioxin-like compounds (DLCs) such as 

polychlorinated biphenyls are not 

included. 

Environmental medium Soil When soil data are limited for a given 

state, other data are collected for 

potential insight (e.g., values for related 

use such as amendments for surface 

soil). 

Scenario (land use) Primary focus: 

Unrestricted, residential use 

Also considered: 

Commercial/industrial use 

Where a data source includes other 

scenarios (e.g., combined ecologicalhealth protection), those are also 

collected for potential insight. 

Receptor Primary focus: 

Most exposed human 

(e.g., resident/child) 

Also considered: 

Other human receptors for other 

scenarios 

A key interest is on the receptor 

assumed to be most exposed, to 

represent a level considered protective 

for others. 

Exposure route Primary focus: 

Soil direct contact, oral (incidental 

ingestion) 

Also considered: 

Other routes (e.g., inhalation, dermal) 

that contribute but to a lesser extent to 

unrestricted/residential and other land 

use scenarios 

The dominant exposure route for 

unrestricted use (residential) is oral/ 

incidental ingestion. The equations 

and parameter values highlighted in 

the data tables focus on this route to 

simplify presentation and field review. 

Toxicity value Slope factor or similar term (cancer) 

Reference dose or similar term 

(noncancer) 

Oral toxicity values are the main focus. 

Where not found online, field input was 

requested for the scientific study and 

derivation methodology underlying the 

toxicity value used. 

The primary searches for state cleanup levels for dioxin were conducted through June 2009, to 

allow state agencies an opportunity to review the data compiled during the summer and provide 

feedback by early fall, as coordinated by EPA regional counterparts. The intent was to present 

information current through summer 2009. However, in finalizing this report, a number of 

weblinks were rechecked during October and November 2009, and several recent updates were 

discovered. These updates have been added to the report where identified (including one from 

early December 2009). 

December 2009 Page 3 
December 2009 Page 4

TABLE 2 Information Resources Pursued 

Information Resource Search Note 

Primary 

State websites Multiple divisions and departments. 

Supporting 

U.S. EPA Region websites Links to information for specific cleanup sites (including voluntary 

cleanups), as well as regional values that have been adopted by 

various states and cleanup sites. 

Other agency websites Includes the Agency for Toxic Substances and Disease Registry 

(ATSDR) website, which contains soil dioxin values (and supporting 

context) that have been adopted by various states and cleanup sites. 

Scientific literature Peer-reviewed journal articles that include information on state cleanup 

levels and supporting context, where available. 

OSWER RODS database 

(Record of Decision System) 

Database of decision documents and links to related technical reports 

that identify dioxin cleanup levels established for contaminated sites on 

the National Priorities List. (These checks were conducted to help 

address gaps where state policy or guideline values were not found 

online, and as general supporting insight.) 

Other organizational websites Summaries or extracts of soil dioxin cleanup levels from various groups. 

Other online sources Data via open google searches using selected key words and 

combinations (including [state], dioxin, TCDD, TEQ, soil, cleanup, 

remediation, site, concentration, level, limit, guideline, guidance, risk, 

RBC, CERCLA, RCRA, voluntary, brownfield, record of decision, fiveyear review, toxicity value, reference dose, slope factor, potency). 

2.2 EVALUATION CRITERIA 

Four criteria were considered to evaluate the state soil cleanup levels: 

 Nature of peer review. 

 Transparency-public availability. 

 Scientific basis. 

 Incorporation of most recent science. 

These criteria are indicated in OSWER Directive 9285.7-53, Human Health Toxicity Values in 

Superfund Risk Assessments (U.S. EPA, 2003b), for toxicity values in Tier 3. That tier is tapped 

when no values are available from Tier 1 (U.S. EPA Integrated Risk Information System, IRIS) 

or Tier 2 (U.S. EPA provisional peer reviewed toxicity values, PPRTVs). Such is the case for 

dioxin. 

Similar criteria have been applied across other programs, including as reflected in a joint work 

group of the Environmental Council of States (ECOS) and U.S. Department of Defense (DoD), 

which included technical input from OSWER (ECOS, 2007). 
December 2009 Page 5

3 RESULTS 

Results of the data collection and evaluation effort are organized as follows. Soil concentrations 

identified across states are summarized in Section 3.1, and the toxicity reference values 

underlying these concentrations are presented in Section 3.2. The derivation methodologies 

used to establish the state cleanup levels and associated toxicity values are described in 

Section 3.3, and the evaluation criteria are discussed in Section 3.4. 

3.1 SOIL DIOXIN LEVELS BY STATE 

State data relevant to dioxin cleanup levels in soil are organized in groups based on land use. 

The first set addresses unrestricted/residential use, and the second addresses restricted use, 

notably for commercial and industrial settings. Key tables and figures for each group are listed 

in Table 3 and described in the sections that follow. 

TABLE 3 Selected Tables and Figures of State Values for Dioxin in Soila 

Tables and Figures 

per Land Use Category 

Data Ordered by: 

State Concentration

(alphabetical) (decreasing)

EPA 

Region 

Scale 

Basic Log 

Unrestricted/Residential 

Table 4: State cleanup levels  

Figure 2a: Representative level per state  

Figure 2b: As for 2a but log scale  

Figure 3: As for 2b, by concentration  

Figure 4: As for 2b, by Region  

Table 5: Additional values, by state  

Table 6: States with no soil cleanup level  

Figure 5: As for 2b, plus screening values  

Figure 6: As for 5, by concentration  

Figure 7: As for 5, by Region  

Figure 8: Site-specific levels, by state  

Figure 9: As for 8, by concentration  

Restricted Commercial/Industrial 

Table 7: State cleanup levels  

Figure 10a: Representative level per state  

Figure 10b: As for 10a but log scale  

Figure 11: As for 10b, by concentration  

Figure 12: As for 10b, by Region  

Table 8: Additional values, by state  

Figure 13: As for 10b, plus screening values  

Figure 14: As for 10b, by concentration  

Figure 15: As for 10b, by Region  

Figure 16: Site-specific levels, by state  

Figure 17: As for 16, by concentration  

a Additional supporting tables and figures, including for toxicity values, follow this set. 
 

 

3.1.1 Unrestricted/Residential Use 

Soil Cleanup Levels 

	 About half the states have established a standard cleanup level or guideline for dioxin in 

soil, with some identifying multiple concentrations. Variations reflect differences in input 

assumptions such as extent of child exposures, target risk level, and type of carcinogen. 

To simplify comparisons, Figure 2a and Table 4 emphasize one cleanup level per state. 

(Other values identified for individual states are presented in supporting tables and 

figures.) These concentrations are shown by state in alphabetical order on a standard 

arithmetic scale. Note for Indiana, the current provisional value (45 ppt) is shown 

together with the draft proposed value (60 ppt) identified by the state during field review. 

Similarly, while no published level was found for Maine, the value identified by the state 

during field review is shown in the figures. Dark borders indicate a TEQ basis. 

	 The range of cleanup levels across states is considerable. Several concentrations at the 

lower end reflect the fact that some states have adopted values established for 

screening purposes to serve as cleanup levels. The wide distribution of cleanup levels 

makes it difficult to distinguish the smaller values when graphed on an arithmetic scale. 

To facilitate readability and comparisons across all levels, Figure 2b presents the same 

information as Figure 2a but on a logarithmic scale. 

	 Figure 3 presents these same cleanup concentrations shown in Figure 2 but in 

decreasing order rather than by state, for potential insights into concentration groupings. 

	 Figure 4 presents the same cleanup levels as Figures 2 and 3 but organized by EPA 

Region, for potential insights into regional patterns (similarities and differences), if any. 

Supporting Context: Screening Values and Illustrative Site-Specific Cleanup Levels 

	 The survey of existing state limits for dioxin in soil uncovered a variety of data that 

extend beyond the cleanup levels shown in Figures 2 through 4. Table 5 identifies these 

additional values (see lower portion), and Figure 5 presents the fuller set of 

concentrations, which includes screening values for dioxin in soil for these scenarios. 

Given that certain states have adopted screening values as cleanup levels, these data 

are considered useful as supporting context. This complement of concentration data is 

presented together with the cleanup levels, alphabetized by state, to offer potential 

insights into similarities and differences within and across these sets. 

	 Figure 6 presents the same data as Figure 5 but in decreasing numerical order rather 

than by state, to offer potential insights into concentration groupings. 

	 Figure 7 presents the same data as Figure 5, organized by EPA Region. 

	 Many states have not established a standard concentration for dioxin (see Table 6), 

invoking instead a site-specific determination of soil cleanup levels. In light of this basis, 

Figure 8 presents illustrative cleanup levels identified in documents prepared for 

contaminated sites, organized by state, for practical application insights. 

	 Figure 9 presents the same site-specific values as Figure 8, organized by concentration. 

December 2009 Page 6 
TABLE 4 Representative Soil Cleanup Level for Dioxin by State: Unrestricted/Residential Usea 

State 

Soil 

Conc 

(ppt) 

Date 

Toxicity 

Value 

(mg/kg-d)-1 

Term and Scenario 

Context 

Scientific Basis 

Exposure Toxicity Risk 

Peer Review and 

Availability 

AK 38 Jun-08 150,000 Risk-based 

concentration for TCDD, residential use, direct contact. 

General equation for direct contact, incidental ingestion and dermal exposure considered. 

Slope factor source is given as HEAST. 

10-5 Equations are give

in ADEC documents, available online. 

AL 1,000 Apr-08 Not found; 

see note at 

right for the 

toxicity 

basis. 

Preliminary screening or cleanup value for TCDD, residential use, direct contact. 

(Adopted value from OSWER directive.) 

Reflects the OSWER value; derivation basis is the evaluation by Kimbrough et al. (1984) of data from Kociba et al. (1978). 

Cleanup value and toxicological context are available online. 

AS 450 Oct-08 130,000 Tier 2 action level for 

dioxin TEQ, residential use, direct contact. (Tier 1 is a screening level; see right-most column for Tier 2 context.) 

General equation for direct contact; considers ingestion, inhalation, and dermal routes of exposure. 

Slope factor reflects the value listed in the 2008 EPA RSL table (U.S. EPA, 2009b). 

10-4 Information is 

available online. 

AZ 4.5 May-07 

(Jul-09) 

130,000 Soil remediation level 

for TCDD, residential use, direct contact. (Field review input of July 2009 indicates AZ has adopted the EPA RSL and toxicity value.) 

General equation for direct contact; considers ingestion, inhalation, and dermal routes of exposure. 

Slope factor is from CalEPA, as reflected in the EPA RSL table. 

10-6 Adopted equations 

and toxicity information from Regional EPA RSLs, for which documents are available online. 

December 2009 
TABLE 4 Representative Soil Cleanup Level for Dioxin by State: Unrestricted/Residential Usea 

State 

Soil 

Conc 

(ppt) 

Date 

Toxicity 

Value 

(mg/kg-d)-1 

Term and Scenario 

Context 

Scientific Basis 

Exposure Toxicity Risk 

Peer Review and 

Availability 

DE 4 Dec-99 150,000 Uniform risk-based 

remediation standard for TCDD, unrestricted use, protection of human health. 

General equation for direct contact; incidental ingestion is primary contributor. 

Slope factor source is given as HEAST. 

10-6 Calculations and 

risk-based tables are available onlin

FL 7 Feb-05 150,000 Soil cleanup target 

level for TCDD TEQ, residential use, direct contact. 

General equation for direct contact; considers incidental ingestion, inhalation, and dermal exposure routes. 

Slope factor source is given as HEAST. 

10-6 Derivation basis 

and equations are available online. (Default and chemical-specific parameter values are in the FDEP 2005 technical report.) 

GA 80 1992 Not found. Notifiable concentration for TCDD, 

unrestricted use scenario. (This is a default starting point for the cleanup level that is determined on a site-specific basis, which in some cases may be this same concentration.) 

General equation for direct contact; considers ingestion and inhalation exposure pathways 

Not found. 10-5 Soil values 

available online, bspecific derivation basis is unclear; toxicity value and some chemicalspecific parameter values are not provided. 

GM 450 Oct-08 130,000 Tier 2 action level for 

dioxin TEQ, residential use, direct contact. 

General equation for direct contact; considers incidental ingestion, inhalation, and dermal exposure routes. 

Slope factors and toxicological information are from CalEPA, as reflected in 2008 EPA RSL table. 

10-4 Information is 

available online. 

December 2009 
TABLE 4 Representative Soil Cleanup Level for Dioxin by State: Unrestricted/Residential Usea 

State 

Soil 

Conc 

(ppt) 

Date 

Toxicity 

Value 

(mg/kg-d)-1 

Term and Scenario 

Context 

Scientific Basis 

Exposure Toxicity Risk 

Peer Review and 

Availability 

HI 390 Sum-08 150,000 Tier 2 action level for 

dioxin TEQ, residential use, direct contact. 

General equation for direct contact; considers incidental ingestion, inhalation, and dermal exposure routes. 

Slope factor source is given as HEAST. 

10-4 Information is 

available online. 

IA 19 (Jul-09) 150,000 Cleanup level for 

residential land use. 

Exposure equation takes into account ingestion and dermal contact. 

Slope factor source is given as HEAST. 

5 

×10-6 

Formula used for risk calculations is available online. 

IN 45 

(60) 

2006 

(Jun-09) 

150,000 

130,000 

TCDD, residential soil default closure level, direct contact. Internal draft value for TCDD, residential soil default closure level, direct contact. 

Exposure equation considers ingestion, inhalation, and dermal exposure routes. 

Slope factor source is given as HEAST. 

Exposure equation considers ingestion, inhalation, and dermal exposure routes. 

Slope factor source is given as CalEPA. 

10-5 

10-5 

Current technical guide is available online. Internal draft valuepending possible changes in algorithms or toxicological data. 

KS 60 Jun-07 150,000 Tier 2 risk-based 

standard for TCDD, residential scenario. “Chemical-specific and media-specific risk-based cleanup goals ...” (see Tier 2 context in right-most column). 

Exposure equation considers ingestion, inhalation, and dermal exposure routes. 

Slope factor source is given as HEAST. 

10-5 Cleanup levels an

equations with soiexposure factors are available onlin

December 2009 
TABLE 4 Representative Soil Cleanup Level for Dioxin by State: Unrestricted/Residential Usea 

State 

Soil 

Conc 

(ppt) 

Date 

Toxicity 

Value 

(mg/kg-d)-1 

Term and Scenario 

Context 

Scientific Basis 

Exposure Toxicity Risk 

Peer Review and 

Availability 

MD 4.5 (Jul-09) 130,000 Cleanup level for 

TCDD, residential scenario. 

Exposure equation considers ingestion, inhalation, and dermal exposure routes. 

Slope factor source is given as CalEPA. 

10-6 EPA RSL equation

are available onlin

ME 10 Jul-09 130,000 Draft generic soil 

cleanup level for dioxin TEQ, residential scenario. 

Value considers incidental ingestion, dermal contact, and inhalation of fugitive dust. 

Slope factor source is given as CalEPA. 

10-6 Equations and a 

summary of calculations are available online. (Not known if this pending final publication.) 

MI 90 Jan-06 75,000 Direct contact 

criterion (DCC) and risk-based screening level (RBSL) for TCDD TEQ. 

Exposure equation considers ingestion and dermal routes of exposure. 

Slope factor based on reanalysis of Kociba et al. (1978) data using updated (1986) NTP methodology. 

10-5 DCC derivation 

methodology is available online. 

MN 20 Jun-09 1,400,000 Soil reference value, 

residential scenario, direct contact for TCDD (or TCDD TEQs). 

General equation considers incidental ingestion, dermal contact, and inhalation. 

Draft upper-bound slope factor from EPA (2003), which was derived from Kociba et al. (1978) data. 

10-5 Methodology and 

updates to parameter values are available onlin

December 2009 
TABLE 4 Representative Soil Cleanup Level for Dioxin by State: Unrestricted/Residential Usea 

State 

Soil 

Conc 

(ppt) 

Date 

Toxicity 

Value 

(mg/kg-d)-1 

Term and Scenario 

Context 

Scientific Basis 

Exposure Toxicity Risk 

Peer Review and 

Availability 

MS 4.26 Feb-02 150,000 Tier 1, target 

remediation goal for TCDD, unrestricted land use scenario. (See right-most column for Tier 1 context.) 

General equation from EPA (1996) Soil Screening Guidance; incidental ingestion is the primary contributor. 

Slope factor source is given as HEAST (undated; field review feedback cited pg. 3-33 of that document). 

10-6 Equations from 

EPA are available online; the HEAST information is not. 

NE 3.9 Oct-08 150,000 Remediation goal 

established under the NDEQ Voluntary Cleanup Program guidance for TCDD, based on direct contact. 

General equation; considers ingestion, inhalation, and dermal exposure routes. 

Slope factor source given as HEAST. 

10-6 Cleanup levels an

remediation goals are available onlin

NH 9 May-07 150,000 Risk-based S-1 soil 

category for sensitive uses of property and accessible soils. (See right-most column for context.) 

General equation for direct contact; considers ingestion and dermal exposure routes. 

Slope factor cites RAIS (ORNL, 2005/2006); appears to reflect HEAST. 

10-6 Risk 

characterization and derivations aravailable online. 

NMI 450 Oct-08 130,000 Tier 2 action level for 

dioxin TEQ, residential use, direct contact. (Tier 1 is a screening level; see right-most column for Tier 2 context.) 

General equation for direct contact; considers ingestion, inhalation, and dermal routes of exposure. 

Slope factor reflects the value listed in the 2008 EPA RSL table. 

10-4 Information is 

available online. 

OH 35.8 Oct-09 150,000 Generic cleanup 

numbers for TCDD TEQ, direct contact with soil. 

General equation; considers ingestion, inhalation, and dermal exposure routes. 

Slope factor source is given as HEAST. 

10-5 Derivation 

methodology is available online. 

December 2009 
TABLE 4 Representative Soil Cleanup Level for Dioxin by State: Unrestricted/Residential Usea 

State 

Soil 

Conc 

(ppt) 

Date 

Toxicity 

Value 

(mg/kg-d)-1 

Term and Scenario 

Context 

Scientific Basis 

Exposure Toxicity Risk 

Peer Review and 

Availability 

OR 4.5 Sep-09 130,000 Risk-based 

concentration for TCDD, residential scenario, direct contact. 

General equation adopted from RSLs; considers ingestion, inhalation, and dermal routes of exposure 

Slope factor underlying the RSL is from CalEPA. 

10-6 Values and 

derivation methodology are available online. 

PA 120 Nov-01 150,000 Medium-specific 

concentration (MSC) for TCDD, residential scenario, direct contact. 

General equation; considers ingestion route. 

Slope factor source is given as HEAST. 

10-5 PADEP document

are available onlin

TX 1,000 Mar-09 Not found; 

see note at 

right for the 

toxicity 

basis. 

Protective concentration level for dioxin TEQ, residential scenario. 

Exposure equation accounts for ingestion, inhalation, dermal contact, and vegetable consumption. 

Reflects the OSWER value, for which the derivation basis is the evaluation by Kimbrough et al. (1984) of data from Kociba et al. (1978). 

Soil concentration is available onlinebut TX does not describe derivation basis. Toxicity values and some chemical-specific parameter values are not provided. 

WA 11 Jun-09 150,000 Cleanup level for 

TCDD, unrestricted scenario, direct contact. 

General equation; considers ingestion exposure route. 

Slope factor source indicated as HEAST. 

10-6 Equations, cleanu

levels, and risk calculations are available online. 

WY 4.5 (Jul-09) 130,000 Cleanup level for 

TCDD. 

Exposure equation takes into account exposure from ingestion, inhalation, and dermal contact. 

Slope factor source is given as CalEPA. 

10-6 EPA RSL equation

are available onlin

a See Notation section and report text for acronym definitions. Field input from the review phase is in italics, and the input 

December 2009 
AK, Jun-08 AL, Apr-08 AS, Oct-08 AZ, May-07 DE, Dec-99 FL, Feb-05 GA, 1992 GM, Oct-08 HI, Sum-08 IA, Jul-09 IN, 2006 (Jun-09) KS, Jun-07 MD (Jul-09) ME (Jul-09) MI, Jan-06 MN, Jun-09 MS, Feb-02 NE, Oct-08 NH, May-07 NMI, Oct-08 OH, Oct-09 OR, Sep

P

1,1001,000

900800700600500400300200100

0

1,000 

450 450 450

390

45 90 80

(60) 60 38 35.8 19 20 

4.5 4 7 4.5 10 4.26 3.9 9 

Soil Dioxin Concentration (ppt) 

FIGURE 2a Soil Cleanup Levels: Unrestricted/Residential Use, by State 

(Standard arithmetic scale; a dark border indicates the basis is TEQ vs. TCDD; a dashed borde

indicates a draft value; parenthetical dates reflect field inputs for values not yet found online.) 

December 2009 
AK, Jun-08 AL, Apr-08 AS, Oct-08 AZ, May-07 DE, Dec-99 FL, Feb-05 GA, 1992 GM, Oct-08 HI, Sum-08 IA, Jul-09 IN, 2006 (Jun-09) KS, Jun-07 MD (Jul-09) ME (Jul-09) MI, Jan-0I, Jan-06 MN, Jun-09 MS, Feb-02 NE, Oct-08 NH, May-07 NMI, Oct-08 OH, Oct-09 OR, Sep-09 PA, No

T

10,000

Soil Dioxin C Soil Dioxin Concentration ncentration (ppt) 1,000 

450 450 450 390 

90 45 80 (60) 60 38 35.8 19 20 

10 9 7 4.5 4.5 

4 4.26 4.5 3.9 1,000 10010

1

FIGURE 2b Soil Cleanup Levels: Unrestricted/Residential Use, by State 

(Logarithmic scale; a dark border indicates the basis is TEQ vs. TCDD; a dashed border and light

draft value; parenthetical dates reflect field inputs for values not yet found online.) 

December 2009 
AL, Apr-08 TX, Mar-09 AS, Oct-08 GM, Oct-08 NMI, Oct-08 HI, Sum-08 PA, Nov-01 MI, Jan-06 GA, 1992 KS, Jun-07 

IN, 2006 (Jun-09) AK, Jun-08 OH, Oct-09 MN, Jun-09 IA, Jul-09 WA, Jun-09 ME (Jul-09) NH, May-07 FL, Feb-05 MD (Jul-09) WY (Jul-09) AZ, Ma

O

10,000

1,000 

100

10

1

Soil Diox Diox in Conc Conc entration (ppt) 1,000 1,000450 450 450 390 120 90 45 80 60 (60) 38 35.8 20 19 11 10 9 7 4.5 4.5 

FIGURE 3 Soil Cleanup Levels: Unrestricted/Residential Use, by Concentration 

(A dark border indicates the basis is TEQ vs. TCDD; a dashed border and lighter shading in

parenthetical dates reflect field inputs for values not yet found online.) 

December 2009 
ME (Jul-09) NH, May-07 DE, Dec-99 MD (Jul-09) PA, Nov-01 AL, Apr-08 FL, Feb-05 GA, 1992 MS, Feb-02 

N, 2006 (Jun-09) MI, Jan-06 MN, Jun-09 OH, Oct-09 TX, Mar-09 IA, Jul-09 KS, Jun-07 NE, Oct-08 WY (Jul-09) AS, Oct-08 AZ, May-07 GM, Oct-08 HI, Sum

NM

10,0 0 0 

1 3 4 5 6 7 8 

1 

10 

10 0 

1,0 0 0 

10 9 

4 

12 0 

4. 5 

7 

1, 0 0 0 

4.2 6 

80 45 

(60) 

90 

35 . 8 

20 

1, 0 0 0 

19 

60 

3. 9 4.5 

45 

4. 5 

45 0 

Soil Dioxin Co Co ncentration (ppt) 

I

FIGURE 4 Soil Cleanup Levels: Unrestricted/Residential Use, by Region 

(EPA Regions are numbered across the top; a dark border indicates the basis is TEQ vs. TCDD; lighter shading indicates a draft value; parenthetical dates reflect field inputs for values not yet found 

December 2009 
 

 

TABLE 5 Additional State Concentrations Potentially Relevant to Soil Cleanupa 

State Conc 

(ppt) Context 

AR 4.5 

18 

No cleanup level was found for dioxin, but ARDEQ used U.S. EPA Region 6 mediumspecific screening levels (MSSLs) as a point of departure. (These values were recently 

harmonized as EPA RSLs.) Also, "Arkansas has not implemented a single set of soil 

cleanup levels for general usage. Instead, the State uses standards set in Regulation 

No. 23 ..., usually arriving at a site-specific standard for each clean-up.” (For further 

information including the citation, see the AR entry in Table B.6 of the appendix.) 

CA 4.6 

19 

No cleanup levels were identified for dioxin, but CA has developed human health 

screening levels (HHSLs) for TCDD. 

KY 4.5 

18 

KY regulations indicate that the state uses Region 9 PRGs for screening purposes. 

(These values were recently harmonized as EPA RSLs.) 

MA 20 

50 

300 

MA has developed Method 1 soil standards for dioxin TEQ for three different exposure 

scenarios. Field review feedback indicated that Method 1 standards are “essentially a 

screening approach. If dioxin concentrations exceed this level a risk assessment can be 

used to evaluate the site and derive cleanup levels.” (For further information including 

the citation, see the MA entry in Table B.1 of the appendix.) 

MT 4.5 

18 

State-specific risk-based screening levels (RBSLs) are listed on the MTDEQ website; 

none were found for dioxin or dioxin congeners. Instead, the MTDEQ flow chart directs 

users to screen soil dioxin concentrations based on the EPA RSLs. 

NC 1,000 

0.64 

NC identifies two preliminary soil remediation goals (PSRGs) for TCDD TEQ: a 

“preliminary health-based PSRG” (1,000) and “protection of groundwater SRG” (0.64). 

NV 3.9 

17.7 

38.1 

NDEP has developed basic comparison levels for dioxin in soil for residential, 

commercial/industrial worker, and indoor worker (without dermal contact) scenarios. 

BCLs essentially represent a screening approach. 

NY 600 

60,000 

NYDEC has developed an allowable soil concentration and a soil cleanup objective 

(SCO) for dioxin TEQ, both of which are to be protective of groundwater quality. The 

allowable concentration assumes contaminated soil is in direct contact with the water 

table; the SCO value assumes contaminated soil is in the unsaturated zone above the 

water table and is subject to attenuating processes during transport to groundwater. 

Neither was used to develop a “recommended” cleanup objective for the State of NY. 

OK 3.9 

18 

38 

OK indicates that EPA Region 6 MSSLs were used for screening purposes, 

representing residential, industrial outdoor worker, and industrial indoor worker 

scenarios. (The MSSLs were recently harmonized as EPA RSLs.) 

SC 3.9 

16 

SCDHEC fact sheet suggests EPA Region 9 PRGs were used for screening purposes. 

(The PRGs were recently harmonized as EPA RSLs.) 

TN 50 Soil screening level for dioxin TEQ, based on 10-6 lifetime cancer risk over a 70-year life 

(reflects the recent ATSDR [2008a] guideline). 

VA 4.5 

18 

VADEQ indicates that EPA RSLs are used for screening purposes. 

VT 4.5 

18 

VTDEC indicates that EPA RSLs are used for screening purposes. 

WI 1.2 

0.5 

WIDNR identifies risk-based standards for human and wildlife protection, as total dioxin 

equivalent; values of 0.5 and 1.2 ppt are identified for agricultural land with and without 

grazing, respectively. 

WV 4.1 

370 

WVDEP identifies these values for 2,3,7,8-TCDD, for the residential and industrial 

scenario, respectively, based on EPA Region 3 risk-based concentrations (screening 

values) from July 1996, except industrial value is for 10-5 risk rather than 10-6 . 

a This table emphasizes levels developed for unrestricted/residential use; values for some other 

scenarios are also included; italics indicate information from the field review phase. See Appendix B for 

further details. See Notation and text for acronym definitions. Many states consider the EPA Regional 

screening values to assess dioxin-contaminated soil (U.S. EPA, 2009b). 

December 2009 Page 17 
(Page intentionally left blank.) 

December 2009 Page 18
 
1 

10 

100 

AK, Jun-08 AK, Jun-08 AK, Jan-04 AK, Jun-08 AL, Apr-08 AL, Apr-08 AL, Apr-08 AR, May-09 AS, Oct-08 AS, Oct-08 AS, Oct-08 AZ, May-07 AZ, May-07 CA, Jan-05 DE, Dec-99 FL, Feb-05 GA, 1992 GM, Oct-08 GM, Oct-08 GM, Oct-08 HI, Sum-08 HI, Sum-08 HI, Sum-08 IA (Jul-09) IA (Jul-09) IA, Jul-04 IN (Jun-09) IN, 2006 KS, Jun-07 KY, Apr-09 MA , Dec-07 MA , Dec-07 MD (Jul-09) ME, Jul-09 MI, Jul-08 MI, Jan-06 MI, Aug-98 MI, Jan-06 MN , Jun-09 MS, Feb-02 MT, Dec-09 NC, Oct-09 NC, Oct-09 NE, Oct-08 NH, May-07 NH, May-07 NJ, Mar-01 NMI, Oct-08 NMI, Oct-08 NMI, O

NV

100,000 

10,000 

1,000 

3, 00 0 

1, 00 0 

38 5 

45 0 45 0 

39 0 

1, 00 0 1, 000 1, 00 0 

45 0 

212 

63 

47 

39 38 42 45 

80 

42 42 

72 

60 

45 

60 

9 0 90 90 

50 

4. 5 4. 5 4. 5 4. 6 4 

7 

4. 5 

3. 9 

19 

14 

4. 5 

20 

4. 5 

10 

20 

4. 26 4. 5 3. 9 

9 

0. 64 

Soil Dioxin Concentration (ppt) 

0 

FIGURE 5 Soil Cleanup Levels and Screening Values: Unrestricted/Residential Use, by State 

(Cleanup levels are solid bars, dark borders indicate the basis is TEQ not TCDD, dashed borders are for draft or supporting values; scree

December 2009 
100,000 

10,000 

Soil Dioxin Concentration (ppt) 1,000 100 

10 

1 0 

60,000 

3,000 

1,000 

1,000 

1,000 

1,000 

1,000 

1,000 

600 

450 450 450 

390 385 

212 

120 

90 90 90 

80 72 66 63 60 60 

50 50 50 47 45 45 42 42 42 42 39 38 35.8 

20 20 19 19 

14 

12 11 10 9 

7 

FIGURE 6 Soil Cleanup Levels and Screening Values: Unrestricted/Residential Use, by Concentration 

(Cleanup levels are solid bars, dark borders indicate the basis is TEQ not TCDD, dashed borders are for draft or supporting values; scree

December 2009 
ME, Jul-09 MA , Dec-07 MA , Dec-07 NH, May-07 NH, May-07 VT, May-09 NJ, Mar-01 NY, Jan-94 NY, Jan-94 DE, Dec-99 MD (Jul-09) PA, Nov-01 VA, Jul-09 WV, Mar-01 AL, Apr-08 AL, Apr-08 AL, Apr-08 FL, Feb-05 GA, 1992 KY, Apr-09 MS, Feb-02 NC, Oct-09 NC, Oct-09 TN, Sep-03 IN (Jun-09) IN, 2006 MI, Jul-08 MI, Jan-06 MI, Aug-98 MI, Jan-06 MN , Jun-09 OH, Oct-09 AR, May-09 OK, Feb-03 TX, Mar-09 IA (Jul-09) IA, Jul-04 IA (Jul-09) KS, Jun-07 NE, Oct-08 MT, Dec-09 WY (Jul-09) WY, Jun-09 WY (Jul-09) AS, Oct-08 AS, Oct-08 AS, Oct

AZ

1 2 3 4 5 6 7 8 

100, 000 

6 0 , 000 

10, 000 

3, 00 0 

1, 000 

1, 00 0 

60 0 

1, 00 0 

38 5 

1, 00 0 1, 00 0 1, 00 0 

45 0 

10 

100 

10 

20 

9 

4. 5 

50 

4 4. 5 

120 

4. 5 4. 1 

21 2 

7 

80 

4. 5 4. 26 

50 

60 

45 

90 90 90 

20 

35. 8 

4. 5 

3. 9 

19 

14 

72 

60 

3. 9 

4. 5 4 . 5 4. 5 

4

1 

0. 64 

0 

0. 15 

Soil Dioxin Concentration (ppt) 

. 

FIGURE 7 Soil Cleanup Levels and Screening Values: Unrestricted/Residential Use, by Region 

(EPA Regions are numbered across the top; cleanup levels are solid bars; a dark border indicates the basis is TEQ; a dashed border ind

December 2009 
AK, Jul-96 AR, Sep-96 AZ, Apr-01 CA, Mar-99 CA, Sep-03 CA, Mar-08 CA, May-08 CA, Feb-95 CT, Sep-05 DC, Sep-07 FL, Sum-97 FL, Sum-97 FL, Sep-06 FL, Aug-06 FL, Sum-97 GA, Sum-97 GM, Jul-02 GM, Aug-07 GM, Dec-03 GM, Dec-03 ID, Apr-03 ID, Aug-02 IL, Apr-02 IN, Jun-89 LA, Apr-93 LA, Nov-97 LA, Jun-02 LA, Jul-95 MA , Sep-04 MN, Sep-08 MO, Apr-93 MO, Sep-05 MO, Sep-86 MS, Sep-07 MT, Jun-08 NC, Jul-05 NC, Sep-06 NC, S

100,000 

Dioxin Soil Concentration (ppt) 

10,000 

1,000 

100 

10 

1 0 

20,000 

1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 

390 

200 200 

120 

62.5 

50 

38 

9.13 

7 7 

3.9 3.9 4.3 3.9 

2 

1.2 

0.4 

FIGURE 8 Supporting Context: Cleanup Levels Identified for Unrestricted/Residential Use from Contaminated Site Applications, by State 

December 2009 
1 

10 

MO, Apr-93 CA, Mar-99 CA, Sep-03 MO, Sep-05 MO, Sep-86 AR, Sep-96 CT, Sep-05 GM, Jul-02 ID, Apr-03 ID, Aug-02 IL, Apr-02 IN, Jun-89 LA, Apr-93 LA, Nov-97 LA, Jun-02 LA, Jul-95 MA , Sep-04 MN, Sep-08 MS, Sep-07 NJ, May-04 NY, Mar-03 OH, Jun-89 PR, Apr-04 SD, Jun-96 TN, Jul-03 TX, Jun-00 TX, Oct-98 WA, May-93 GM, Aug-07 FL, Sum-97 GA, Sum-97 NC, Jul-05 WA, Feb-00 MT, Jun-08 FL, Sum-97 PA, Sep-07 AZ, Apr-01 WY, May-04 NC, S

G

100,000 

10,000 

1,000 

100 

1, 000 1, 000 1, 000 1, 000 1, 000 1, 000 1, 000 1, 00 0 1 , 0 0 0 1, 0 0 0 1 , 000 1 , 000 1, 000 1, 000 1, 000 1, 000 1, 000 1, 000 1, 000 1, 000 1, 000 1, 000 1, 000 1, 000 1, 000 1, 000 

400 390 

200 200 

120 10 7. 7 

62 .5 

50 

40 38 

20, 000 

Soil Dioxin Concentration (ppt) 

0 

FIGURE 9 Supporting Context: Cleanup Levels Identified for Unrestricted/Residential Use from Contaminated Site Applications, by ConceDecember 2009 
(Page intentionally left blank.) 

December 2009 
TABLE 6 States without Formal Soil Cleanup Levels for Dioxin 

State Context 

CO CODPHE has developed and tabulated CO soil evaluation values (CSEVs), but no value for 

dioxin or TCDD was found in the table. Field feedback during the review phase indicated CO uses 

the equations and toxicity value from the EPA Regional screening level tables to develop 

preliminary remediation goals for dioxin in soil. 

CT No state-specific dioxin soil cleanup or screening levels were found. 

DC No dioxin cleanup or screening level was identified for DC. Field review feedback indicated “DC 

does not have a dioxin level for site cleanups for the RCRA Corrective Action Program, since DC 

does not have this authority. The Voluntary Cleanup Program relies on the EPA RBCs Table for 

screening criteria for all chemicals but may be developing their own cleanup standards for the 

Voluntary Cleanup Program which may be used by other environmental programs in the District.” 

ID No state-specific dioxin soil cleanup or screening levels were identified for ID. Field review 

feedback indicated that Region 10 states (which include ID) are “using (with some chemical- or 

exposure-specific exceptions) the Regional Screening Level tables that Superfund is sponsoring.” 

IL No state-specific dioxin soil cleanup (or screening) value was found. 

LA No state-specific dioxin soil cleanup (or screening) value was found. 

MO No state-specific dioxin soil cleanup (or screening) value was found. 

ND No state-specific dioxin soil cleanup (or screening) value was found. Field review feedback 

indicated ND uses the equations and toxicity value from the EPA Regional screening level tables 

to develop preliminary remediation goals for dioxin in soils. 

NJ No state-specific dioxin soil cleanup (or screening) value was found. Field review feedback 

indicated NJ follows the 1998 OSWER directive in coordinating with responsible parties and uses 

the 2008 ATSDR value of 50 ppt as a screening level to consider the need for further evaluation 

of sites. Final cleanup levels are site-specific. 

NM No state-specific dioxin soil cleanup (or screening) value was found. 

PR No state-specific dioxin soil cleanup (or screening) value was found. 

RI No state-specific dioxin soil cleanup (or screening) levels were found. 

SD No state-specific dioxin soil cleanup (or screening) value was found. Field review feedback 

indicated SD uses the equations and toxicity value from the EPA Regional screening level tables 

to develop preliminary remediation goals for dioxin in soil. 

TT No state-specific dioxin soil cleanup (or screening) value identified (per field review feedback). 

UT No state-specific dioxin soil cleanup (or screening) value was found. Field review feedback 

indicated UT uses the equations and toxicity value from the EPA Regional screening level tables 

to develop preliminary remediation goals for dioxin in soil. 

VI No state-specific dioxin soil cleanup (or screening) value was found. 

a 

 

Italics indicate information from the field review phase; see tables in Appendix B for further details. 

See Notation and text for acronym definitions. 

December 2009	 Page 25 
 

 

 

 

 

3.1.2 Commercial/Industrial (Restricted) Use 

Soil Cleanup Levels 

The figures and tables outlined below parallel those given for unrestricted use in Section 3.1.1. 

This information is presented to support consideration of a potential interim guideline for 

commercial/industrial scenarios. 

	 Cleanup levels identified by states for commercial/industrial (restricted) use are identified 

in Table 7, focusing on one representative value per state where multiple levels were 

identified. Figure 10a presents these soil cleanup levels on the standard arithmetic 

scale, alphabetized by state. 

	 Figure 10b illustrates the same data as Figure 10a, on a logarithmic scale to facilitate 

readability and comparisons. 

	 Figure 11 shows the same data as Figure 10b, organized by concentration in decreasing 

order, for possible insight into concentration groupings. 

	 Figure 12 gives the same information as Figure 11 but organized by EPA Region, for 

potential insights regarding similarities and differences, if any, across regions. 

Supporting Context: Screening Values and Illustrative Site-Specific Cleanup Levels 

	 Additional state levels identified for commercial/industrial use are identified in Table 8. 

Figure 13 includes these values as the counterpart to Figure 5 (which addresses 

unrestricted land use), extending beyond state cleanup levels for dioxin in soil to also 

present screening values for these restricted land uses. As in Figure 9b, the data are 

alphabetized by state and shown on a logarithmic scale 

	 Figure 14 shows the same information as Figure 12, organized by concentration in 

decreasing order, for potential insights into concentration groupings. Figure 15 shows 

the same information organized by EPA Region to facilitate comparisons. 

	 Figure 16 illustrates cleanup levels identified in documents prepared for contaminated 

sites, organized by state. Figure 17 presents the same information as Figure 16, 

ordered by concentration. 

	 Table 9 and Figure 18 present information for subsurface cleanup levels. 

3.2 TOXICITY VALUES AND TARGET RISKS 

	 Table 10 identifies the slope factors used by states to determine cleanup levels. The 

distribution of toxicity values is shown in Figure 19. Supporting information on toxicity 

values from other agencies is presented in Table 11. 

	 The target risks applied to determine state cleanup levels for dioxin in soil are identified 

in Table 12 (states are alphabetized within each risk level). Figure 20 presents the 

distribution of states by target risk for the unrestricted/residential scenarios, and 

Figure 21 presents this information for the commercial/industrial (restricted) scenarios. 

December 2009	 Page 26 
TABLE 7 Representative Soil Cleanup Levels for Dioxin per State: Commercial/Industrial (Restricted) Use 

State 

Soil 

Conc 

(ppt) 

Date 

Toxicity 

Value 

(mg/kg-d)-1 

Term and Scenario 

Context 

Scientific Basis 

Exposure Toxicity Risk 

Peer Review and 

Availability 

AL 5,000 Apr-08 Not found; 

see note at 

right for the 

toxicity 

basis. 

Preliminary screening or cleanup value for TCDD, commercial scenario, direct contact. 

(Adopted value from OSWER directive.) 

Reflects the OSWER value; derivation basis is the evaluation by Kimbrough et al. (1984) of data from Kociba et al. (1978). 

Cleanup value and toxicological conteare available online

AS 1,800 Oct-08 130,000 Tier 2 action level for 

nonresidential scenario (upper end) for dioxin TEQ. Remedial action guide varies for dioxin concentrations between 170 and 1,800 ppt. 

General equation for direct contact; considers ingestion, inhalation, and dermal routes of exposure. 

Slope factor reflects the value listed in the 2008 EPA Regional screening level (RSL) table. 

10-4 The information 

summarized here iavailable online. 

AZ 160 May-07 

(Jul-09) 

Not 

identified 

Soil remediation level for TCDD, nonresidential scenario. 

General equation; considers ingestion, inhalation, and dermal exposure. Adopted from Region 9 PRGs. 

Not identified. Remediation levels 

and the guidance document are available online. Specific toxicity value not provided

DE 40 Dec-99 150,000 Uniform risk-based 

remediation standard for TCDD, restricted use with protection of human health. 

General equation for direct contact; incidental ingestion is primary contributor. 

Slope factor from HEAST. 

10-6 Calculations and 

risk-based tables are available online

December 2009 
TABLE 7 Representative Soil Cleanup Levels for Dioxin per State: Commercial/Industrial (Restricted) Use 

State 

Soil 

Conc 

(ppt) 

Date 

Toxicity 

Value 

(mg/kg-d)-1 

Term and Scenario 

Context 

Scientific Basis 

Exposure Toxicity Risk 

Peer Review and 

Availability 

FL 30 Feb-05 150,000 Soil cleanup target level 

for dioxin TEQ, commercial/industrial use based on direct contact. 

General equation for direct contact; considers incidental ingestion, inhalation, and dermal exposure routes. 

Slope factor from HEAST. 

10-6 Derivation basis an

equations are available online. (Default and chemical-specific parameter values are given in the FDEP 2005 technical report.) 

GM 1,800 Oct-08 130,000 Tier 2 action level for 

nonresidential scenario (upper end) for dioxin TEQ. Remedial action guide varies for dioxin concentrations between 170 and1,800 ppt. 

General equation for direct contact; considers ingestion, inhalation, and dermal routes of exposure. 

Slope factor reflects the value listed in the 2008 EPA RSL table. 

10-4 The information 

summarized here iavailable online. 

HI 1,600 Sum-08 150,000 Tier 2 action level for 

nonresidential scenario (upper end of range) for dioxin TEQ. Remedial actions vary when soil dioxin concentration is between 170-1,600 ppt. 

General equation for direct contact; considers incidental ingestion, inhalation, and dermal exposure routes. 

Slope factor from HEAST. 

10-4 The information 

summarized here iavailable online. 

IA 360 (Jul-09) RfD: 1×10-9 

mg/kg-d 

Cleanup level for nonresidential land use based on noncancer endpoint, if dioxin is the only chemical of concern. 

Specific source not identified (RfD is same as the ATSDR chronic MRL; field input indicated as an EPA source). 

The formula used for the risk calculations is available online. 

December 2009 
TABLE 7 Representative Soil Cleanup Levels for Dioxin per State: Commercial/Industrial (Restricted) Use 

State 

Soil 

Conc 

(ppt) 

Date 

Toxicity 

Value 

(mg/kg-d)-1 

Term and Scenario 

Context 

Scientific Basis 

Exposure Toxicity Risk 

Peer Review and 

Availability 

IN 180 2006 150,000 Commercial/industrial 

provisional default 

General equation uses incidental 

Slope factor from HEAST. 

10-5 The extant technic

guide is available 

(Jun-09) (130,000) 

closure level for TCDD in soil, based on direct contact. (The 2009 internal draft value is the same.) 

ingestion as primary contributor. (More recent slope factor is 

being considered as part of the internal update.) 

online. (2009 values have not yebeen published anare pending any changes in algorithms or toxicological data.) 

KS 100 Jun-07 150,000 Tier 2 risk-based 

standard for TCDD, nonresidential scenario. “Chemical-specific and media-specific riskbased cleanup goals.” (See Tier 2 context in right-most column.) 

Exposure equation considers ingestion, inhalation, and dermal exposure routes. 

Slope factor from HEAST. 

10-5 The cleanup level 

and equation with soil exposure factors are availabonline. 

MD 18 (Jul-09) 130,000 Cleanup level for 

industrial scenario. 

Exposure equation considers ingestion, inhalation, and dermal exposure routes. 

Slope factor from CalEPA. 

10-6 EPA RSL equation

are available online

December 2009 
TABLE 7 Representative Soil Cleanup Levels for Dioxin per State: Commercial/Industrial (Restricted) Use 

State 

Soil 

Conc 

(ppt) 

Date 

Toxicity 

Value 

(mg/kg-d)-1 

Term and Scenario 

Context 

Scientific Basis 

Exposure Toxicity Risk 

Peer Review and 

Availability 

ME 31 Jul-09 130,000 Draft generic soil 

cleanup level for dioxin TEQ, based on a commercial worker scenario. 

Value considers incidental ingestion, dermal contact, and inhalation of fugitive dust. 

Slope factor from CalEPA. 

10-6 Equations and a 

summary of calculations are available online. 

MN 35 Jun-09 1,400,000 Soil reference value for 

industrial worker, direct contact, for dioxin TEQ. 

Exposure equation takes into account exposure from ingestion, inhalation, and dermal contact. 

Draft slope factor from EPA (2003), which was derived from Kociba et al. (1978). 

10-5 Derivation 

methodology and updates to parameter values are available online

MS 38.2 Feb-02 150,000 Tier 1, target 

remediation goal for TCDD, restricted land use scenario. 

General equation uses incidental ingestion as primary contributor. 

Slope factor source is given as HEAST. 

10-6 Equations taken 

from EPA sourcesfor EPA RAGS are available online. 

NE 160 Oct-08 150,000 Remediation goal 

established under the NDEQ Voluntary Cleanup Program guidance for TCDD, based on direct contact. 

General equation uses incidental ingestion as primary contributor. 

Slope factor source is given as HEAST. 

10-5 Cleanup levels and 

remediation goals are available online

December 2009 
TABLE 7 Representative Soil Cleanup Levels for Dioxin per State: Commercial/Industrial (Restricted) Use 

State 

Soil 

Conc 

(ppt) 

Date 

Toxicity 

Value 

(mg/kg-d)-1 

Term and Scenario 

Context 

Scientific Basis 

Exposure Toxicity Risk 

Peer Review and 

Availability 

NH 300 May-07 150,000 Risk-based S-2 soil 

category for workers who come into contact with soil as part of their employment. 

General equation for direct contact; considers ingestion and dermal exposure routes. 

Slope factor taken from RAIS (ORNL, 2005/2006), appears to reflect 1997 HEAST. 

10-6 Risk 

characterization angeneral derivations are available online

NMI 1,800 Oct-08 130,000 Tier 2 action level for 

nonresidential scenario (upper end) for dioxin TEQ. Remedial action guide varies for dioxin concentrations between 170 and 1,800 ppt. 

General equation for direct contact; considers ingestion, inhalation, and dermal routes of exposure. 

Slope factor from 2008 EPA RSL table. 

10-4 The information 

summarized here iavailable online. 

OR 20 Sep-09 130,000 Risk-based 

concentration for TCDD, occupational scenario. 

Equation is based on exposure from direct contact, ingestion, dermal, and inhalation. 

Equations adopted from former EPA Region 9 PRG document. 

10-6 Values and 

derivation methodology are available online. 

PA 530 Nov-01 150,000 Medium-specific 

concentration for TCDD, based on nonresidential scenario and direct contact. 

General equation; considers ingestion route. 

Slope factor source is given as HEAST (undated). 

10-5 PADEP documents 

are available online

TX 5,000 Mar-09 Not found; 

see note at 

right for the 

toxicity 

basis. 

Protective concentration level for dioxin TEQ in soil, commercial/ industrial scenario. 

Exposure equation takes into account ingestion, inhalation, dermal contact, and vegetable consumption. 

Reflects the OSWER value; derivation basis is the evaluation by Kimbrough et al. (1984) of data from Kociba et al. (1978). 

Soil values availabonline, but the derivation basis is ambiguous. Toxicitvalues and some chemical-specific parameter values are not provided. 

December 2009 
TABLE 7 Representative Soil Cleanup Levels for Dioxin per State: Commercial/Industrial (Restricted) Use 

State 

Soil 

Conc 

(ppt) 

Date 

Toxicity 

Value 

(mg/kg-d)-1 

Term and Scenario 

Context 

Scientific Basis 

Exposure Toxicity Risk 

Peer Review and 

Availability 

WA 1,500 Jun-09 150,000 Cleanup level for TCDD 

in soil, direct contact, industrial scenario. 

Equation considers ingestion as primary contributor. 

Slope factor source is given as HEAST. 

10-5 Equations, cleanup 

levels, and risk calculations are available online. 

Notes: Field input from the review phase is in italics, and the input date is in parentheses. More details including citations For the AZ concentration, it is not clear from information available whether the state may still be using a cancer slope facto

and a target risk of 10-5 for the nonresidential scenario; specific values were not provided for this compilation. 

December 2009 
AL, Apr-08 AS, Oct-08 AZ, May-07 DE, Dec-99 FL, Feb-05 GM, Oct-08 HI, Sum-08 IA, Jul-09 IN, 2006 KS, Jun-07 MD (Jul-09) ME (Jul-09) MN, Jun-09 MS, Feb-02 NE, Oct-08 NH, May-07 NMI, Oct-08 OR, Sep-09 PA, No

Soil Dioxin Concentration (ppt) 

6,000 5,000 

5,000 (C) 

4,000 3,000 2,000 1,800 (I) 1,800 (I) 1,800 (I) 

1,600 (I) 

1,000 

160 (C/I)40 (C/I) 30 (C/I) 

360 (C/I) 

180 (C/I)100 (I) 18 (I) 31 (I) 35 (I) 38.2 (C/I)160 (I) 300 (I) 20 (C/

0 

FIGURE 10a Soil Cleanup Levels: Commercial/Industrial (Restricted) Use, by State 

(Standard arithmetic scale; a dark border indicates the basis is TEQ; a dashed border indicates a C = commercial; I = industrial.) 

December 2009 
AL, Apr-08 AS, Oct-08 AZ, May-07 DE, Dec-99 FL, Feb-05 GM, Oct-08 HI, Sum-08 IA, Jul-09 IN, 2006 KS, Jun-07 MD (Jul-09) ME (Jul-09) MN, Jun-09 MS, Feb-02 NE, Oct-08 NH, May-07 NMI, Oct-08 OR, Sep-0

P

5,000 (C) 

1,800 (I) 

160 (C/I) 

40 (C/I) 

30 (C/I) 

1,800 (I)1,600 (I) 

360 (C/I) 

180 (C/I) 

100 (I) 

18 (I) 

31 (I) 35 (I) 38.2 (C/I) 

160 (I) 

300 (I) 

1,800 (I) 

1 

10 

100 

1,000 

10,000 

Soil Dioxin Concentration (ppt) 

FIGURE 10b Soil Cleanup Levels: Commercial/Industrial (Restricted) Use, by State 

(Logarithmic scale; dark border indicates basis is TEQ rather than TCDD; draft values have dash

December 2009 
AL, Apr-08 TX, Mar-09 AS, Oct-08 GM, Oct-08 NMI, Oct-08 HI, Sum-08 WA, Jun-09 PA, Nov-01 IA, Jul-09 NH, May-07 IN, 2006 NE, Oct-08 AZ, May-07 KS, Jun-07 DE, Dec-99 MS, Feb-02 MN, Jun-09 ME (Jul-09

F

35 (I) 

38.2 (C/I) 40 (C/I) 

100 (I) 

160 (I) 160 (C/I) 180 (C/I) 

300 (I) 360 (C/I) 

530 (C/I) 

1,500 (I) 

1,600 (I) 1,800 (I)1,800 (I)1,800 (I) 

5,000 (C/I)

5,000 (C) 

1 

10 

100 

1,000 

10,000 

Soil Dioxin Concentration (ppt) 

FIGURE 11 Soil Cleanup Levels: Commercial/Industrial (Restricted) Use, by Concentration 

(A dark border indicates the basis is TEQ; a dashed border indicates draft values; parentheses indica

December 2009 
ME (Jul-09) NH, May-07 DE, Dec-99 MD (Jul-09) PA, Nov-01 AL, Apr-08 FL, Feb-05 MS, Feb-02 IN, 2006 MN, Jun-09 TX, Mar-09 IA Jul-09 KS, Jun-07 NE, Oct-08 AS, Oct-08 AZ, May-07 GM, Oct-08 HI, Sum-0

NM

Soil Dioxin Concentration (ppt) 

10,000 1 3 

5,000 (C) 

4 5 

5,000 (C/I) 

6 7 9 

1,800 (I) 1,800 

100 

1,000 

31 (I) 

300 (I) 

40 (C/I) 

18 (I) 

530 (C/I) 

30 (C/I) 

38.2 (C/I) 

180 (C/I) 

35 (I) 

360 (C/I) 

100 (I) 

160 (I) 160 (C/I) 

10 

1 

FIGURE 12 Soil Cleanup Levels: Commercial/Industrial (Restricted) Use, by Region (EPA Regions are across top; a dark border indicates TEQ; a dashed border indicates draft values; parentheses 

December 2009 
TABLE 8 Additional State Concentrations for Dioxin: Commercial/Industrial (Restricted) Use 

State 

Soil 

Conc 

(ppt) 

Date 

Toxicity 

Value 

(mg/kg-d)-1 

Term and Scenario 

Context 

Scientific Basis Peer Review 

and Availability 

Exposure Toxicity Risk 

AS 170 Oct-08 1,400,000 Tier 2 action level for 

TCDD TEQ, lower bound for nonresidential scenario, where remedial actions vary when soil dioxin concentration is between 170 and 1,800 ppt. 

General equation for direct contact, incidental ingestion as primary contributor but inhalation also considered. 

From MNDOH (2003), animal bioassay upper bound derived from Kociba et al., tapped from range of values in EPA draft reassessment (2003a). 

10-4 Information is 

available online. 

GM 170 Oct-08 1,400,000 Tier 2 action level for 

TCDD TEQ, lower bound for nonresidential scenario, where remedial actions vary when soil dioxin concentration is between 170 and 1,800 ppt. 

General equation for direct contact, incidental ingestion as primary contributor but inhalation also considered. 

From MNDOH (2003), animal bioassay upper bound derived from Kociba et al., tapped from range of values in EPA draft reassessment (2003a). 

10-4 Information is 

available online. 

HI 170 Mar-06 1,400,000 Tier 2 action level for 

TCDD TEQ, lower bound for nonresidential scenario, where remedial actions vary when soil dioxin concentration is between 170 and 1,800 ppt. 

General equation for direct contact, incidental ingestion as primary contributor but inhalation also considered. 

From MNDOH (2003), upper bound derived from Kociba et al. (1978) bioassay, from range of values in EPA reassessment (2003a). 

10-4 Information is 

available online. 

December 2009 
December 2009 

TABLE 8 Additional State Concentrations for Dioxin: Commercial/Industrial (Restricted) Use 

State 

Soil 

Conc 

(ppt)

Date 

Toxicity 

Value 

(mg/kg-d)-1

Term and Scenario 

Context 

Scientific Basis Peer Review 

and Availability 

Exposure Toxicity Risk 

ME 310 (Jul-09) 130,000 Generic soil cleanup level 

for dioxin TEQ, based on a construction/excavation worker. 

Value considers incidental ingestion, dermal contact, and inhalation of fugitive dust. 

Slope factor from CalEPA. 

10-6 Equations and a 

summary of calculations are available online. 

NH 5,000 May-07 Soil standard for TCDD 

TEQ, commercial scenario.

Reflects OSWER directive, per the Kimbrough et al. (1984) evaluation of Kociba et al. (1978) data. 

OR 140 

150 

Sep-09 Risk-based concentration 

(RBC) for TCDD, occupational scenario protective of groundwater. RBC for TCDD, construction scenario, direct contact, considering ingestion, dermal, and 

General equation for direct contact, incidental ingestion, dermal contact, and inhalation all considered. 

 10-6

 10-6

4,200 

inhalation. RBC for TCDD, excavation scenario, direct contact, considering ingestion, dermal, and inhalation. 

 10-6
AL, Apr-08 AR, May-09 AS, Oct-08 AS, Oct-08 AS, Oct-08 AZ, May-07 CA, Jan-05 DE, Dec-99 FL, Feb-05 GM, Oct-08 GM, Oct-08 GM, Oct-08 HI, Sum-08 HI, Sum-08 IA, Jul-09 IN (Jun-09) IN, 2006 KS, Jun-07 KY, Apr-09 MA , Dec-07 MA , Dec-07 MD, Feb-99 MD (Jul-09) ME, Jul-09 MI, Jan-06 MN, Jun-09 MN, Jun-09 MS, Feb-02 MT, Dec-09 NE, Oct-08 NH, May-07 NH, May-07 NH, May-07 NH, May-07 NMI, Oct-08 NMI, O

N

100,000 

5, 00 0 

18 18 

17 0 

1, 80 0 

16 0 

19 

40 

30 

18 

17 0 

1, 80 0 

17 0 

1, 6 0 0 

36 0 

18 0 1 8 0 

10 0 

18 

50 

30 0 

1, 00 0 

18 . 0 

31 .0 

90 

35 

75 

38 .2 

18 

16 0 

30 

30 0 

5, 00 0 

20 , 0 0 0 

10,000 

1,000 

Soil Dioxin Concentration (ppt) 100 

10 

1 

FIGURE 13 Soil Cleanup Levels and Screening Values: Commercial/Industrial (Restricted) Use, by State (Cleanup levels are solid bars; screDecember 2009 
NH, May-07 AL, Apr-08 NH, May-07 TX, Mar-09 OR, Sep-09 TN, Jul-02 AS, Oct-08 GM, Oct-08 NMI, Oct-08 HI, Sum-08 WA, Jun-09 MD, Feb-99 PA, Nov-01 WV, Mar-01 IA, Jul-09 MA , Dec-07 NH, May-07 IN (Jun-09) IN, 2 006 AS, Oct-08 GM, Oct-08 HI, Sum-08 NMI, Oct-08 AZ, May-07 NE, Oct-08 OR, Sep-09 OR, Sep-09 KS, Jun-07 MI, Jan-06 MN, Jun-09 MA , Dec-07 DE, Dec-99 MS, Feb-02 NV, Feb-09 OK, Feb-03 MN, J

100,000 

10,000 

1,000 

100

10

1

20,000 

5,000 5,000 5,000 

4,200 

2,500 

1,800 1,800 1,800 1,600 1,500 

1,000 

530

370 360

300 300

180 180 170 170 170 170 160 160 150 140

100

90

75

50

40 38.2 38.1 

Soil Dioxin Concentration (ppt) 

FIGURE 14 Soil Cleanup Levels and Screening Values: Commercial/Industrial (Restricted) Use, by Concentration (Cleanup levels are solid December 2009 
MA , Dec-07 MA , Dec-07 ME, Jul-09 NH, May-07 NH, May-07 NH, May-07 NH, May-07 VT, May-09 DE, Dec-99 MD (Jul-09) MD, Feb-99 PA, Nov-01 VA, Jun-09 WV, Mar-01 AL, Apr-08 FL, Feb-05 KY, Apr-09 MS, Feb-02 TN, Jul-02 IN (Jun-09) IN, 2006 MI, Jan-06 MN, Jun-09 MN, Jun-09 AR, May-09 OK, Feb-03 OK, Feb-03 TX, Mar-09 IA Jul-09 KS, Jun-07 NE, Oct-08 MT, Dec-09 AS, Oct-08 AS, Oct-08 AS, Oc

AZ

10 0, 000 

1 3 4 5 6 7 8 

20 ,0 00 

10 0 

1, 000 

10 ,0 00 

50 

30 0 

31 30 

30 0 

5,0 0 0 

18 

40 

18 

1, 000 

53 0 

18 

37 0 

5, 00 0 

30 

18 

38 . 2 

2, 50 0 

18 0 1 80 

90 

35 

75 

18 1 8 

38 

5, 0 0 0 

36 0 

10 0 

160 

18 18 

1

10 

1 

Soil Dioxin Concentration (ppt) 

FIGURE 15 Soil Cleanup Levels and Screening Values: Commercial/Industrial (Restricted) Use, by Region 

(EPA Regions are across the top; cleanup levels are solid bars; a dark border indicates the basis is TEQ; a dashed border indicates a dr

December 2009 
AK, Jun-03 AR, Sep-96 AR, Sep-96 AZ, Apr-01 CA, Feb-95 CA, Feb-01 FL, Aug-06 FL, Aug-06 FL, Feb-06 FL, Sep-06 FL, Aug-06 FL, Sep-06 FL, Sum-97 GA, Aug-04 ID, Aug-02 ID, Aug-02 IL, Apr-02 MD, Sep-07 MI, Feb-98 MN, Sep-99 MS, Sum-97 MS, Sum-97 MT, Jun-08 NC, Sep-08 NJ, Sep-07 NY, Nov-04 SC, May-04 SC, Aug-04 TN, Jul-02 TX

100,000 

440 

3,500 

5,000 

240 

300 

27 30 30 30 30 30 3 0 

7 

1,000 

5,0 0 0 

20,000 

60 

25 

990 1 , 000 

5 

10 0 103 

1 , 000 

19 

40 

3.2 

16 

2

10,000 

1,000 

100 

10 

1 0 

Soil Dioxin Concentration (ppt) 

FIGURE 16 Supporting Context: Cleanup Levels Identified for Restricted Use from Contaminated Site Applications, by State (Reflects site-December 2009 
WA, May-93 ID, Aug-02 TX, Oct-98 AR, Sep-96 ID, Aug-02 UT, Dec-97 AR, Sep-96 TN, Jul-02 WA, May-93 GA, Aug-04 MN, Sep-99 NC, Sep-08 UT, Jun-00 UT, Sep-92 MI, Feb-98 WA, Sep-03 TX, Sep-06 AK, Jun-03 CA, Feb-95 WA, Sep-97 AZ, Apr-01 WA, May-93 MT, Jun-08 MS, Sum-97 IL, Apr-02 NY, Nov-04 UT, Dec-97 FL, Sep-06 FL, Au

100,000 

20, 000 20,000 

5, 000 5, 000 

3, 700 3, 500 

2, 5 0 0 

2 , 000 

1, 000 1, 000 1, 000 1, 000 1,000 990 875 

520 

440 

30 0 270 240 

200 

103 100 

60 

40 37 

30 

50, 00 0 

10,000 

1,000 

100 

10 

1 0 

Soil Dioxin Concentration (ppt) 

FIGURE 17 Supporting Context: Cleanup Levels Identified for Restricted Use from Contaminated Site Applications, by Concentration (RefDecember 2009 
(Page intentionally left blank.) 

December 2009 
TABLE 9 Supporting State Context: Subsurface Values 

State 

Soil 

Conc 

(ppt) 

Date 

Toxicity 

Value 

(mg/kg-d)-1 

Term and Scenario 

Context Exposure 

Scientific Basis 

Toxicity Ris

AS, 

GM, 

NMI 

1,500 Oct-08 130,000 Tier 1 environmental 

screening level (ESL) for dioxin TEQs, deep soil (>3 m bgs) for construction/trench worker scenario. 

General equation based on direct contact. 

The slope factor was taken from the 2008 EPA RSL table, based on a CalEPA maximum likelihood estimate (MLE) and linearized 95% upper confidence value (UCL) citing NTP animal data from 1980 and 1982 converted to equivalent human exposures per scaling factors. (See Table B.9 for more information.) 

10-

PA 1.9×1011 Nov-01 150,000 Medium-specific 

concentration for TCDD, based on nonresidential subsurface soil (2-15 ft). 

General equation uses incidental ingestion as primary contributor. 

Reflects earlier EPA value indicated in HEAST. 

10-

December 2009 
Soil Dioxin Concentration (ppt) 

1,000,000,000,000 

100,000,000,000 

10,000,000,000 

1,000,000,000 

100,000,000 

10,000,000 

1,000,000 

100,000 

10,000 

1,000 

100 

10 

1 0 

1,500 1,500 1,500 

AS, Oct-08 GM, Oct-08 NMI, Oct-08 

FIGURE 18 Supporting State Context: Subsurface Values, by State 

December 2009 
TABLE 10 Dioxin Toxicity Values Underlying the State Cleanup Levelsa 

Cancer 

Toxicity Value 

(mg/kg-d)-1 

Number 

of States 

Specific 

States Scientific Basis 

150,000 13 AK, DE, 

FL, HI, 

IA, IN, 

KS, MS, NE, NH, OH, PA, 

WA 

The source of this value is commonly given as EPA HEAST1997, which lists several citations including the Health Assessment Document for Polychlorinated Dibenzo-p-dioxin. (U.S. EPA, 1985). This slope factor is based on the female rat bioassay by Kociba et al. from 1978. The two-year dietary study of TCDD in female Sprague-Dawley rats indicated the highest dose (0.1 μg/kg-d, or estimated dietary amount 2,200 ppt) produced multiple toxicological effects, with lesser effects reported at 0.01 μg/kg-d (210 ppt). (This was considered to support a previous study indicating chronic ingestion of 5,000 ppt caused many toxicological effects.) No adverse effects were reported at 0.001 μg/kg-d (22 ppt), and no carcinogenic effects reported at 0.01 or 0.001 μg (210 or 22 ppt). This older toxicity value reflects earlier methodology for classifying liver tumors, which was updated by the National Toxicology Program (NTP) in 1986. Many states cite the (outdated, indirect) EPA HEAST as the source. 

(Note this earlier EPA value from HEAST was also listed in the previous 

Region 9 PRG table – which preceded the 2008 harmonization of regional screening levels, or RSLs.) 

HEAprovas bSpecwas EPA docusourrevieHEAon ththat 156,HEA(Fro“The listinprovinforentriundeconcProgsuppreferenouas hconsHEAwhenatunote

December 2009 
TABLE 10 Dioxin Toxicity Values Underlying the State Cleanup Levelsa 

Cancer 

Toxicity Value 

(mg/kg-d)-1 

Number 

of States 

Specific 

States Scientific Basis 

75,000 1 MI This value is based on a reevalution of the tumor data from the 1978 rat study 

by Kociba et al. (see above), using the 1986 NTP update of the liver tumor classification scheme. This reevaluation indicated lower tumor incidence rates, which resulted in a slope factor of 52,000 (mg/kg-d)-1 based on liver 

tumors alone, and a slope factor of 75,000 (mg/kg-d)-1 based on total 

significant tumors – which updated the factor of 150,000 (mg/kg-d)-1 that had 

been based on the older methodology. 

Severeasthe KanalconsAsse

1,400,000 1 

(+4, 

to derive a supporting 

lower 

bound for 

a cleanup 

range) 

MN 

(AS, GM, 

HI, NMI) 

MN adopted this draft value, the upper bound slope factor based on animal data that was included in the EPA (2003) draft reassessment, which was derived from the Kociba et al. (1978) bioassay described above. (This value is 40 percent higher than the draft upper bound slope factor from the reassessment based on epidemiological data.) The MNDOH documentation notes: driving pathway-oral; endpoints-immune, repro, cancer; cancer target organ-liver; class-human carcinogen. Per the MNDOH overview, concerns about the quality of exposure estimates in human epidemiological studies preclude quantitative use of these data in developing a slope factor, but results from modeling the human studies are consistent with the cancer slope derived by modeling data from animal studies. MNDOH also notes this slope factor was derived from the same study as the previous value of 156,000 (mg/kg-d)-1 , 

and that its development utilized current methods of analysis, including use of body burden as the dose metric for animal-to-human dose equivalence calculations (i.e., adjustments to account for the differences in half-life of dioxins in the bodies of laboratory animals and humans), and a re-evaluation of liver tumors in the Kociba study using the latest pathology criteria. 

These four entries are shown in parenthetical italics because this value only underlies supporting soil concentrations, not the basic cleanup levels for this Pacific island set. That is, this draft toxicity value was used to generate a lower bound as a companion to the standard cleanup levels based on 150,000 (mg/kg-d)-1 for HI, and on 130,000 (mg/kg-d)-1 for the other three 

islands. This toxicity value supports the lower end of the cleanup range, while the main cleanup level above which remedial action is to be considered is based on the two other slope factors applied by nearly all other states: 130,000 and 150,000 (mg/kg-d)-1 . 

The undeextesubsinde2004 

basiupdarecobut arecoguidcarcinclulife apote

December 2009 
TABLE 10 Dioxin Toxicity Values Underlying the State Cleanup Levelsa 

Cancer 

Toxicity Value 

(mg/kg-d)-1 

Number 

of States 

Specific 

States Scientific Basis 

130,000 8 AS, AZ, 

GM, MD, 

ME, NMI, 

OR, WY 

This slope factor is listed in the current EPA Regional screening level table for residential soil, with the source given as CalEPA; its derivation is documented by California EPA (CalEPA). (As a note, the CalEPA soil screening level for 2,3,7,8-TCDD is 4.6 ppt.) The asterisk * in the RSL table for the cancer basis indicates that a screening level based on the noncancer endpoint is <1% of that based on the cancer endpoint (indicated as "[n SL < 100X c SL]"). This toxicity value is based on the NTP rat gavage studies from 1982. Summarizing from the CalEPA derivation document: a linearized multistage model was used with the NTP male mouse hepatocellular adenoma/carcinoma tumor data for TCDD, providing point estimates of extra risk for both maximum likelihood estimate (MLE) and linearized 95% upper confidence value (UCL); the UCL was calculated by maximizing the linear term, or forcing a best fit (method consistent both with expected low-dose linearity and linear nonthreshold theory). The slope of 95% UCL (q1*) was taken as the plausible upper bound cancer potency of TCDD at low doses. Rodent exposure data were converted to equivalent human exposures with scaling factors. Assumptions include: oral and inhalation routes are equivalent, air concentration is assumed to be daily oral dose, route of exposure does not affect absorption, and no difference exists in metabolism/ pharmacokinetics between animals and humans. Total weekly dose levels were averaged for a daily dose level; this assumes daily dosing in the NTP studies would give the same results as the actual twice weekly dosing schedule (as described, the TCDD half-life is relatively long so both schedules should give similar tissue concentrations). A significant increase in hepatocellular hyperplastic nodules was observed in female rats exposed to 0.1 or 0.01 μg/kg-d, while the next lower dose (0.001 μg/kg-d) 

showed no effect. (Note CalEPA is currently evaluating more recent toxicity data, notably the 2004 NTP study. Implications for an updated oral toxicity value are anticipated to be available later in 2009 or early 2010, following completion of the external review process.) 

This CalifServin thfor thConundeby thBoapanewheincluSpotExtepanewas that 1983toxic1980CalEcomstudevalToxiprogdocuand 

(+1) (IN) This entry is in parenthetical italics because 130,000 (mg/kg-d)-1 underlies the 

internal draft cleanup level being considered by Indiana (60 ppt), based on field input during the review phase of this data compilation effort. The slope factor of 150,000 (mg/kg-d)-1 underlies the current provisional level of 45 ppt. 

December 2009 
December 2009 

TABLE 11 Supporting Context from Other Agencies Endpoint Toxicity Value Unit Agency Date Scientific Basis 

Cancer Slope factor In final 

review 

(mg/kg-d)-1 CalEPA* Final 

publication 

anticipated in 

late 2009 or 

early 2010 

Based on an NTP (2004) chronic gavage study of female Harlan Sprague-Dawley rats (chosen per their high incidence of hepatocarcinogenicity), dosed 5 d/wk for up to 105 wk. The study design, species, and dose range of 1 to 100 ng/kg-d were based on the dosedfeed chronic study by Kociba et al. (1978), which reflected continuous dietary exposure of SpragueDawley rats. Increased incidences of neoplasms were observed in the liver, lung, oral mucosa, uterus, and pancreas. "The recent chronic NTP (2004) gavage study in female Harlan Sprague-Dawley rats appears to provide a superior basis for risk assessment, due to its careful design and conduct, as well as improved survival rate, compared to Kociba et al. (1978)." Cal EPA (2007) also offers this historical context: "The non-significant risk level for TCDD calculated for California’s Proposition 65 is 5 pg/day (OEHHA, 2004). This calculation uses a TCDD cancer potency factor of 1.3×105 (mg/kg-day)-1 derived by the Air Toxics group in 

1986 (DHS, 1986; OEHHA, 2005) ... based on the incidence of liver tumors in a gavage study in male mice (NTP, 1982a). The potency factor derived [in] this PHG document, ... based on the latest NTP study (NTP, 2004) in female rats ... derived using updated methodology, is considered to represent a more accurate estimate of potential human cancer risk." 

Noncancer 

Chronic 1×10-9 mg/kg-d ATSDR Current Developmental endpoint from Schantz et al. (1992); 

minimal risk Dec-08 point of departure (POD): 0.12 ng/kg-d, LOAEL for level (oral) (established 

Dec-98) 

altered social behavior in offspring. UFs: 3 for minimal LOAEL, 3 for animal-human extrapolation, 10 for human variability. 
TABLE 11 Supporting Context from Other Agencies 

Endpoint Toxicity Value Unit Agency Date Scientific Basis 

Policy (Toxicity 

ATSDR 

Nov-08 ATSDR (2008a) explains that this screening level 

guideline value 

underlying 

recent soil 

guideline of 

50 ppt 

is not 

specified, 

see notes 

below) 

"should be used as the comparison value when following the PHAGM. The comparison value is not a threshold for toxicity and should not be used to predict adverse health effects." The note accompanying dioxin health assessment values: slope factors for congeners (including 130,000 per mg/kg-d for TCDD): "Linearized multistage procedure (GLOBAL79), fitted to male mouse hepatic adenoma and carcinoma data (NTP, 1982), body weight scaling, cross-route extrapolation (CDHS, 1986)." 

Notes: The recent ATSDR (2008a) policy modified its 1998 policy guideline for dioxins and dioxin-like compounds in residential soaction level was eliminated in the 2008 update). The current policy guideline of 50 ppt for residential soil represents a screincluding 2,3,7,8-TCDD, and dioxin-like compounds. This level is defined to serve as an initial comparison value for site-spassessments evaluating exposure to dioxin directly from residential soils. As presented in ATSDR (1998/2008), this policy Appendix B of the dioxin toxicological profile and eliminates two categories of the 1998 policy guideline – namely the action 

evaluation level – retaining only the 0.5 ppb screening level, to avoid confusion and maintain consistency with the ATSDR 2Assessment Guidance Manual (PHAGM). This value is based on the noncancer endpoint for ingestion of soil in residentia

Note that EPA (2008) also indicates: "EPA generally uses 1 ppb dioxin as a starting point for setting cleanup levels for RCR

based on the direct contact exposure pathway for human health (does not apply to other exposure pathways, such as migrcontaminants to ground water or to agricultural products)." December 2009 
FIGURE 19 Dioxin Toxicity Values Underlying the State Cleanup Levels 

(Italics indicate the toxicity value is used for a draft or supporting cleanup level.) 

December 2009 
TABLE 12 Target Risks for the State Cleanup Levels 

State per 

Risk Level 

Soil Concentration (ppt) per Land Use Scenario 

Unrestricted/Residential Commercial/Industrial 

Terminology for Dioxin Cleanup Level 

(as TCDD or Dioxin TEQ) 

10-6 Incremental Lifetime Cancer Risk 

NE 3.9 (see entry under 10-5) Remediation goal for TCDD 

DE 4 40 Uniform risk-based remediation standard 

for TCDD 

MS 4.26 38.2 Target remediation goal for TCDD 

AZ 4.5 (see notes below) Soil remediation level for TCDD 

MD 4.5 18 Cleanup level for TCDD 

OR 4.5 20 Risk-based concentration for TCDD 

WY 4.5 - Cleanup level for TCDD 

FL 7 30 Soil cleanup target level for TCDD TEQ 

NH 9 300 Risk-based soil standard for TCDD 

ME 10 31 Generic soil cleanup level for dioxin TEQ 

WA 11 (see entry under 10-5) Cleanup level for TCDD 

5×10-6 Incremental Lifetime Cancer Risk 

IA 19 (see notes below) Cleanup level for TCDD 

10-5 Incremental Lifetime Cancer Risk 

MN 20 35 Soil reference value for TCDD or TEQ 

OH 35.8 - Generic cleanup number for TCDD TEQ 

AK 38 - Risk-based concentration for TCDD 

IN 45 (60) 180 Soil default closure level for TCDD 

KS 60 100 Risk-based standard for TCDD 

GA 80 - Notifiable concentration for TCDD 

MI 90 - Direct contact criterion; risk-based 

screening level for TCDD TEQ 

PA 120 530 Medium-specific concentration for TCDD 

NE (see entry under 10-6) 160 Remediation goal for TCDD 

WA (see entry under 10-6) 1,500 Cleanup level for TCDD 

10-4 Incremental Lifetime Cancer Risk 

HI 390 1,600 Action level for dioxin TEQ 

AS 450 1,800 Action level for dioxin TEQ 

GM 450 1,800 Action level for dioxin TEQ 

NMI 450 1,800 Action level for dioxin TEQ 

Notes: Values are given for states where target risk assumptions are provided for cancer-based cleanup levels. AL 

has adopted residential and commercial soil cleanup levels for dioxin from the 1998 OSWER directive. TX has 

adopted similar values but does not explicitly state they are from OSWER. Although the AZ nonresidential soil 

remediation level of 160 ppt is not accompanied by an explicit target risk level, general language in the regulation 

indicates the cumulative excess lifetime cancer risk should not exceed 10-4. The IA nonresidential cleanup level for 

dioxin is based on the noncancer endpoint. The current IN (2006) value is 45 ppt; 60 ppt is under consideration. 

December 2009 Page 53 
10-6 510-6 10-5 

Soil Dioxin Concentration (ppt) 

500 400 300 200 100 

0 

120 

90 

80 

60 

45 

(60) 

35.8 38

19 20 9 10 11 4.26 4.5 4.5 4.5 4.5 7 3.9 4

NE DE MS OR AZ MD WY FL NH ME WA IA MN OH AK IN KS GA MI PA 

FIGURE 20 Distribution of States Listing Specific Risk Targets for Dioxin Cleanup Levels: Unrestricte

(A dark border indicates the basis is TEQ rather than TCDD; a dashed border and lighter shading i

December 2009 
10-6 10-5 

2,000 1,800 1,600 1,400 1,200 1,000 

800 600 400 200 

0 

MD OR FL ME MS DE NH MN KS AZ NE IN PA WA H

18 20 30 31 38.2 40 

300 

35 

100 

1,500 

1,6

160 160 180 

530 

Soil Dioxin Concentration (ppt) 

FIGURE 21 Distribution of States Listing Specific Risk Targets for Dioxin Cleanup Levels: Commercial/

(Dark border indicates the basis is TEQ rather than TCDD; dashed border indicates a draft value

December 2009 
 

3.3 DERIVATION METHODOLOGY 

States have applied standard methods to determine soil cleanup levels for dioxin. The 

exposure and toxicity components of these methods are highlighted in Sections 3.3.1 and 3.3.2, 

respectively. The following discussion addresses the scientific basis of cleanup levels with an 

emphasis on the calculations for unrestricted/residential scenarios. However, the tables and 

figures also include information for commercial/industrial (restricted) cleanup levels, and the 

approach for those scenarios involves the same basic concepts. 

3.3.1 Exposure Calculations 

The review of soil cleanup levels for dioxin indicates that states follow the standard EPA 

approach for deriving such concentrations, commonly tapping the equation from the EPA (1989) 

risk assessment guidance for Superfund or EPA (1996) soil screening guidance. The same 

basic equation also underlies the recently harmonized EPA Regional screening levels (RSLs), 

which have been adopted as cleanup levels by some states. 

In most cases, dioxin is one of many chemicals for which states have derived soil cleanup 

levels, so the agencies have identified generic exposure calculations for broad application. 

Although terms vary somewhat and other relatively minor differences exist in the equation 

structures, the basic concepts and routes considered in calculating exposures to guide cleanup 

levels are essentially the same. 

For soil contaminated with dioxin, the exposure basis for unrestricted/residential cleanup levels 

is direct contact, and incidental soil ingestion is the key route. Four states base their cleanup 

values on this pathway alone (Delaware, Mississippi, Pennsylvania, and Washington), and for 

most of the remaining states with cleanup levels, incidental ingestion accounts for at least 

90 percent of the total. The relative contribution is somewhat lower for six states, ranging from 

50 percent (for Michigan and Minnesota) to about 75 to 85 percent (for Arkansas, Indiana, 

Kansas, and Ohio). 

While some variations exist in the specific terms and acronyms used, the common components 

of the incidental ingestion equation applied across the states that provide derivation information 

are: intake rate (IR), exposure frequency (EF), exposure duration (ED), body weight (BW), and 

averaging time (AT); a units conversion factor (CF) is also often included. Extending to the 

health endpoint, the common components are cancer slope factor (CSF or SF) (or oral 

reference dose, RfD for the noncancer endpoint) and total target cancer risk (TR) (or total 

hazard quotient, THQ, for the noncancer endpoint). 

The general equation used to calculate a soil cleanup concentration for the residential scenario 

based on incidental ingestion for the cancer endpoint is: 

December 2009 Page 56 
Most states consider different exposure factors for children and adults – including child and 

adult ingestion rates (IRc and IRa), exposure durations (EDc and EDa), and body weights (BWc 

and BWa). For this reason, an age-adjusted soil ingestion factor (IFSadj) is commonly applied to 

account for these age-specific inputs under the residential scenario. Thus, a combined 

residential scenario (which covers the same hypothetical individual from childhood to adulthood) 

often reflects an IFSadj calculated as follows: 

The age-specific ingestion rates, exposure durations, and body weights can be lumped into a 

single variable, which simplifies this equation to: 

The equations and parameter values identified by the states to derive soil cleanup levels for 

dioxin are summarized in Table 13; further information (including citations) is given in 

Appendix B. Similarities and differences in the values used for the soil ingestion pathway are 

highlighted in Table 14. (Shading is used to distinguish different values within related entries.) 

Regarding the parameter values applied, most states use traditional EPA default assumptions 

so the exposure factors are generally similar. However, relatively minor differences exist, some 

of which reflect state-specific context. For example, the Washington averaging time and the 

Minnesota exposure duration are slightly longer than the EPA default values for the typical 

residential scenario. 

The selected inputs presented in Table 14 illustrate that the combined exposure factors produce 

differences within a factor of ten for this key exposure pathway. Although incidental soil 

ingestion is the main contributor to dioxin cleanup levels for unrestricted/residential use, most 

states also consider inhalation and/or dermal absorption – as shown in Table 13. (These routes 

include modeling components unique to volatile compounds that are carried as part of the 

overall calculation process.) In some cases, including for certain nonresidential scenarios, 

these additional exposure routes can contribute more substantially to the calculated cleanup 

level for dioxin. 

December 2009 Page 57 
;

;

TABLE 13 Basic Components of the Derivation Methodology (see Appendix B for further details) 

State Conc 

(ppt) 

Equation Parameters Expo

Rou

AK 38 CL = TR×AT×365d/y

 EF×[(SFo×IFsoil/adj×CF) + (SFS×ABS×SFd×CF)] 

CL = cleanup level, (mg/kg) TR = target cancer risk, 10-5 

AT = averaging time, 70 y EF = 330 d/y SFo = oral slope factor, 150,000 (mg/kg-d)-1 

IFsoil/adj = age-adjusted soil ingestion factor, 

114 (mg-y/kg-d)-1 

SFS = soil dermal factor, 361 mg-y/kg-d ABS = absorption factor, 0.03 SFd = dermal slope factor, 

300,000 (mg/kg-d)-1 

CF = conversion factor, 10-6 kg/mg 

Inges

der

AL 1,000 Not available Not available. A

AS 450 See EPA RSL equation (last entry of this table). AS uses the EPA RSL equation and toxicity 

values to derive its cleanup level, but applies a TR of 10-4 instead of 10-6 . 

A

AZ 4.5 See EPA RSL equation (last entry of this table). As given for the EPA RSL. A

DE 4 RBCres = TR ×ATc

 EFr×IFSadj×CSFo×CF 

RBCres = residential risk-based concentration, 

(mg/kg) 

TR = target cancer risk, 10-6 

ATc = averaging time carcinogens, 

25,550 d 

EFr = exposure frequency, 350 d/y 

Inge

IFSadj = soil ingestion factor, 114.3 mg-y/kg-d 

CSFo = oral cancer slope factor, 

150,000 (mg/kg-d) ̄1 

CF = 10-6 kg/mg 

December 2009 
;

TABLE 13 Basic Components of the Derivation Methodology (see Appendix B for further details) 

State Conc 

(ppt) 

Equation Parameters Expo

Rou

FL 7 SCTL = (TR×BW×AT×RBA) 

 EF×ED×FC(EXPoral+EXPderm+EXPinhal) 

where: EXPo = oral term = CSFo×IRo×CF 

EXPd = dermal term = CSFd×SA×AF×DA×CF 

EXPi = inhalation term = CSFi×IRi×(1/VF+1/PEF) 

SCTL TR BW AT RBA EF ED FC CSFo,i 

CSFd 

IRo IRi CF SA AF DA VF PEF 

= = 

= = 

= 

= = 

= = = 

= 

= 

= 

= 

= = = = 

soil cleanup target level (mg/kg) 

target cancer risk, 10-6 

body weight, 51.9 kg resident averaging time, 25,550 d 

relative bioavailability factor, 1.0 

exposure frequency, 350 d/y 

exposure duration, 30 y 

fraction from cont. source, 1.0 oral and inhalational slope factor, 150,000 (mg/kg-d)-1 

dermal slope factor, 166,667 (mg/kg-d)-1 

oral ingestion rate, 120 mg/d 

inhalation rate, 12.2 m3/d 

10-6 kg/mg 

surface area of skin exposed, 

4,810 cm2/d resident 

adherence factor, 0.1 mg/cm2 

dermal absorption, 0.01 volatilization factor, 4.619×106 m3/kg 

particulate emission factor, 1.24×109 m3/kg 

A

December 2009 
;

TABLE 13 Basic Components of the Derivation Methodology (see Appendix B for further details) 

State Conc 

(ppt) 

Equation Parameters Expo

Rou

GA 80 NC = (TR×BW×AT×365 d/y) 

 EF×ED (EXPoral+EXPinhal) 

where: 

NC = notifiable concentration (mg/kg) TR = target cancer risk, 10-5 

BW = body weight, 70 kg AT = averaging time, 70 y 

Inges

inhal

EXPo = oral term = CSFo×IRsoil×CF 

EXPi = inhalation term = CSFi×IRi×(1/VF+1/PEF) 

EF = exposure frequency, 350 d/y 

resident, 250 d/y nonresident 

ED = exposure duration, 30 y resident,, 

25 y nonresident 

CSFo, i = cancer slope factor, (mg/kg-d)-1 

IRsoil = soil ingestion rate, 114 mg/d 

resident, 50 mg/d nonresident 

IRi = inhalation rate, 15 m3/d resident,,, 

20 m3/d nonresident 

CF = conversion factor, 10-6 kg/mg 

VF = equation given but not all chemicalspecific parameters are provided PEF = particulate emission factor, 

4.63×109 m3/kg 

GM 450 See EPA RSL equation (last entry of this table). GM uses the EPA RSL equation and toxicity 

values to derive its cleanup level, but applies a TR of 10-4 instead of 10-6 . 

A

HI 390 See EPA RSL equation (last entry of this table). HI uses the EPA RSL equation to derive its 

cleanup level but applies a TR of 10-4 instead 

of 10-6 and an oral slope factor of 

150,000 (mg/kg-d)-1 instead of 

130,000 (mg/kg-d)-1 . 

A

December 2009 
.

. 

TABLE 13 Basic Components of the Derivation Methodology (see Appendix B for further details) 

State Conc 

(ppt) 

Equation Parameters Expo

Rou

IA 19 CL = 

1 

1/C oral+1/Cderm 

where: Coral,derm = RF×AT

 Abs×CF×(A+B) 

and A = (ERc×EFc×EDc)

 BWc 

B = (ERa×EFa×EDa)

 BW a 

CL EDa 

EDc EFa 

EFc ERa 

ERc BWa 

BWc CF Abs AT RF TR SF 

= 

= = = = = = = = 

= 

= = 

= 

= 

= 

cleanup level (mg/kg) 

exposure duration for adult, 24y exposure duration for child, 6y exposure frequency for adult, 350d/y exposure frequency for child, 350d/y exposure rate for adult,100 mg/d oral, 400 mg/d dermal exposure rate for child, 200 mg/d oral, 560 mg/d dermal body weight adult, 70 kg body weight child, 15 kg 

conversion factor, 10-6 kg/mg 

absorption factor, 1 oral, 0.03 dermal averaging time, 25,550 d 

TR / SF 

target risk, 5×10-6 

slope factor, 150,000 (mg/kg-d)-1 

Inges

der

December 2009 
;

TABLE 13 Basic Components of the Derivation Methodology (see Appendix B for further details) 

State Conc 

(ppt) 

Equation Parameters Expo

Rou

IN 45 DCL = TR×ATc×365 d/y

 EF r×(A + B) 

where: A = SFo×(IngFadj+[SFSadj×ABS])

DCL TR ATc 

EFrs SFo 

= default closure level (mg/kg) 

= target risk, 10-5 

= averaging time, 70 y = exposure frequency residential, 

250 d/y 

= oral slope factor, 150,000 (mg/kg-d)-1 

A

10

6 mg/kg 

B = InhFadj×SFi (1/VF + 1/PEF) 

IngFadj 

SFSadj 

ABS InhFadj 

SFi 

VF PEF 

= ingestion factor soil, age-adjusted, 

114 mg-y/kg-d 

= skin factor soil, age-adjusted, 

1,257 mg-y/kg-d 

= skin absorbance factor, 0.03 

= inhalation factor, age-adjusted, 

10.9 m3-y/kg-d 

= inhalation slope factor, 

150,000 (mg/kg-d)-1 

= volatilization factor, m3/kg 

= particulate emission factor, 

1.316×109 m3/kg 

December 2009 
TABLE 13 Basic Components of the Derivation Methodology (see Appendix B for further details) 

State Conc 

(ppt) 

Equation Parameters Expo

Rou

KS 60 RBC (mg/kg) = (TR × BW × AT × 365d/y)

 EF×ED×[(A)+(B)+(C)] 

where: A = INGs×CF×SFo 

B = INH×SFi×{1/VFs+1/PEF} 

C = SFo×CF×SA×AF×ABS 

RBC = risk based concentration (mg/kg) TR = target cancer risk, 10-5 

BW = body weight, 70kg AT = averaging time, 70 y EF = exposure frequency, 350 d/y ED = exposure duration, 30 y INGs = soil ingestion rate, 100 mg/d 

CF = conversion factor, 10-6 kg/mg 

SFo = oral cancer slope factor, 

150,000 (mg/kg-d)-1 

INH = soil inhalation rate, 20 m3/d 

SFi = inhalation cancer slope factor, 

150,000 (mg/kg-d)-1 

VFs = soil volatilization factor, m3/kg 

PEF = particulate emission factor, 

1.18×109 m3/kg 

SA = surface area of skin, 5000 cm2/d 

AF = adherence factor, 0.2 mg/cm2 

ABS = absorption factor, 0.1 

A

MD 4.5 See EPA RSL equation (last entry of this table) See EPA RSL parameters (last entry). A

December 2009 
.

.

.

.

;

TABLE 13 Basic Components of the Derivation Methodology (see Appendix B for further details) 

State Conc 

(ppt) 

Equation Parameters Expo

Rou

ME 10 RAG = 

1 

(1/EPC ing) + (1/EPCinh) + (1/EPCderm) 

where: EPCing = ILCR × AT

 SFo×[{EDyc×EFyc×(IRyc×CF/BWyc)}+{EDa× EFa×(IRa×CF/BWa)}] 

Shortened versions of EPC equations with several exposure parameters lumped were available for inhalation and dermal pathways. EPCinh = 0.68 × 10-4 

[IUR(μg/m3)-1×(1,000μg/mg)×(1/PEF + 1/VF)] 

RAG EPC ILCR AT SF EDyc 

EDa 

EFyc EFa 

IRyc 

IRa 

BWyc BWa 

CF 

= 

= 

= 

= = 

= = = = = = = = 

= 

remedial action guideline (mg/kg) 

exposure point conc. (mg/kg) 

incremental lifetime cancer risk, 10-6 

averaging time, 25,550 d oral slope factor, 130,000 (mg/kg-d)-1 

exposure duration (child), 6 y exposure duration (adult), 24 y 150 d/y 150 d/y soil contact rate (child), 200 mg/d soil contact rate (adult), 100 mg/d body weight (child), 14 kg body weight (adult), 70 kg 

conversion factor, 10-6 kg/mg 

A

EPCderm = 0.45 (kg BW × day/kg soil) × 1 

SF o DAF 

IUR PEF DAF 

= 

= 

= 

inhalation unit risk, 38 (μg/m3)-1 

1.36 x 109 m 3/kg 

dermal absorbance factor, 0.03 

MI 90 DCC = (TR×AT×CF) 

 SFo×[(EFi×IF×AEi)+(EFd×DF×AEd)] 

DCC TR AT CF SFo 

= 

= 

= 

= = 

direct contact criterion, (μg/kg) 

target risk, 10-5 cancer risk 

averaging time, 25,550 d 

correction factor, 109 μg/kg 

75,000 (mg/kg-d)-1 

Inges

der

EFi 

IF AEi 

EFd 

DF AEd 

= 

= 

= = 

= 

= 

ingestion exposure frequency, 350 d/y 

age-adjusted soil ingestion factor, 

114 mg-y/kg-d oral absorption efficiency, 0.5 dermal exposure frequency, 245 d/y 

age-adjusted soil dermal factor, 

2442 mg-y/kg-d dermal absorption efficiency, chemical-specific, 0.03 

December 2009 
.

. 

. 

;

TABLE 13 Basic Components of the Derivation Methodology (see Appendix B for further details) 

State Conc 

(ppt) 

Equation Parameters Expo

Rou

MN 20 

SRV = TR×AT 

 (A) + (B) + (C) 

where: 

SRV = concentration of contaminant in soil (or 

Cs)), mg/kg 

SFo,d = 1,400,000 (mg/kg-d)-1 

TR = 10-5 cancer risk 

ECR = estimated cancer risk, route-specific 

A

A (ing term) = IR× SF×CF×FI×EFo×ED×SF×AE

 BW 

B (derm term) = SF×CF×SA×AF×ABS×EFd×ED

 BW 

AT = 25,550 d IR = soil intake rate, 68 mg/d (ageadjusted) CF = correction factor, 10-6 kg/mg 

FI = fraction from contaminated area, 1.0 EFo,i = exposure frequency oral and 

inhalational, 350 d/y 

C (inh term) = IUR×(1,000 μg/mg)×EFi×ED×(1/PEF+ 1/VF) 

Original equations from 1999 MPCA guidance document: ADDing = ECRing/(SF×AE) = Cs×IR×CF×FI×EFo×ED

 BW×AT 

ADDderm = ECRderm/SF = Cs× CF×SA×AF×ABS×EFd×ED

 BW×AT 

ADCinh = ECRinh/IUR = Cs×(103 μg/mg)×EFi×ED×(1/PEF+ 1/VF) 

EFd = exposure frequency dermal, 74 d/y 

(adult), 97 d/y (age-adjusted) 

ED = exposure duration, 33 y AE = oral absorption efficiency, 0.55 SA = skin surface area, 3,609 cm2 (ageadjusted) 

AF = adherence factor, 0.17 mg/cm2 (ageadjusted) ABS = absorption factor, 0.03 IUR = inhalation unit risk, 400 (μg/m3)-1 

VF = volatilization factor, 2.49 ×108 (m3/kg) 

PEF = particulate emission factor, 

 7.7×108 (m3/kg) 

BW = body weight, 51 kg (age-adjusted) 

MS 4.26 TRG = TR ×AT

 EF×IFSadj×CSFo×CF 

TRG = target remediation goal (mg/kg) TR = target risk,10-6 

CSFo = 150,000 (mg/kg-d)-1 

BW = body weight AT = averaging time, 25,550 d EF = exposure frequency, 350 d/y ED = exposure duration, IFSadj = soil ingestion factor, 114 mg-y/kg-d 

CF = conversion factor, 10-6 kg/mg 

Inge

(a

indica

fie

feed

and o

MSD

web

December 2009 
.

. 

.

.

6

.

TABLE 13 Basic Components of the Derivation Methodology (see Appendix B for further details) 

State Conc 

(ppt) 

Equation Parameters Expo

Rou

NE 3.9 CL = 1 

 [(1/ Cres soil ingestion)+(1/Cres soil dermal)+(1/Cres soil inhalation)] 

where: Cres soil ingestion = TRr×ATc

 EF r×IFSadj×SFo×10-6 mg/kg 

Cres soil dermal = TRr×ATc

 EF r×SFSadj×ABSd×(SFo/ABSGI)×10-6 mg/kg 

Cres soil inhalation = TRr×ATc

 EFr×EDa×[(URF×1000 μg/mg)] 

PEF 

CL = cleanup level, (mg/kg) TR = target risk, 10-6 

SFo = oral slope factor,150,000 (mg/kg-d)-1 

ATc = averaging time, 25,550 d 

EFr = exposure frequency, 350 d/y 

EDa = exposure duration, 30 y 

IFSadj = age-adjusted soil ingestion factor, 

114 (mg-y/kg-d)-1 

SFSadj = age-adjusted soil dermal factor, 

361 mg-y/kg-d 

ABSd = dermal absorption fraction, 0.03 

ABSGI = gastrointestinal absorption eff., 1.0 

URF = unit risk factor, 3.3×10-3 ( μg/m3)-1 

PEF = particulate emission factor, 

1.2×109 m3/kg 

A

NH 9 Concsoil = (ELCR×CF) 

 {CSF×(∑A+∑B)} 

where: A = (IRi×EF×EDi×RAFo) 

 (AT×BWi) 

B = (SAi×EF×ED×AF×RAFd) 

 (AT×BWi) 

Concsoil = soil concentration (mg/kg) 

ELCR = excess lifetime cancer risk, 10-6 

CF = conversion factor, 106 mg/kg 

CSF = slope factor,150,000 (mg/kg-d)-1 

IRi = soil ingestion rate, 200 mg/d (2-6 y), 

100 mg/d (7-31 y) 

EF = exposure frequency (160 d/y) EDi = exposure duration,2-6 (5 y), 

7-16(10y), 17-31 (15 y) 

RAFo = relative absorption factor ingestn, 1 AT = averaging time, 25,550 d BWi = body weight,17kg (2-6y), 

40kg (7-16y), 70 kg (17-31 y) 

SAi = skin surface area, 2632 cm2 (2-6 y), 

3432 cm2(7-16 y),5044 cm2(17-31y) 

AF = soil-to-skin adherence factor (adult, 

0.013 mg/cm2, child, 0.014 mg/ cm2 , 

2-6 year old 0.36 mg/cm2) 

RAFd = relative absorption factor for soil 

dermal contact 0.03 

Inges

der

December 2009 
TABLE 13 Basic Components of the Derivation Methodology (see Appendix B for further details) 

State Conc 

(ppt) 

Equation Parameters Expo

Rou

NMI 450 See EPA RSL equation (last entry of this table) NMI uses the EPA RSL equation and toxicity 

values to derive its cleanup level for dioxin. However, they use a TR of 10-4 instead of 10-6 . 

A

OH 35.8 GCN = TR × AT .

 A + B + C 

Where: A = SFo×(IFSadj×CF×FI×EF) 

B = SFo/OABS×(SFSadj×ABS×CF×EF) 

C = SFi×[InhFadj×EF×(1/PEF)+(1/VF)] 

GCN = generic cleanup number, mg/kg TR = target risk, 10-5 

AT = averaging time, carcinogens, 

25,550 d 

SFo,i = oral and inhalation slope factor, 

150,000 mg/kg-d 

IFSadj = age-adjusted soil ingestion factor, 

114.3 mg-y/kg-d 

CF = conversion factor, soil 10-6 

FI = soil fraction ingested, 1.0 

A

EF = exposure frequency, 350 d/y OABS = oral absorption factor, 0.5 

SFSadj = age-adjusted soil dermal contact 

factor, 360.8 mg-y/kg-d 

ABS = dermal absorption factor, 0.03 InhFadj = age-adjusted inhalation factor, 

10.9 m3-y/kg-d 

PEF = particulate emission factor, 

1.36×109 m3/kg 

VF = volatilization factor, none given 

December 2009 
.

.

 .

TABLE 13 Basic Components of the Derivation Methodology (see Appendix B for further details) 

State Conc 

(ppt) 

Equation Parameters Expo

Rou

OR 4.5 Conc = 

TR×AT 

EF r [(IFSadj×SFo×CF)+(SFSadj×ABS×SFo×CF)+(InhFadj×SFi)/PEF] 

TR = target cancer risk, 10-6 

ATr = averaging time, 25,550 d 

EFr = exposure frequency, 350 d/y 

IFSadj = age-adjusted soil ingestion factor, 

114 (mg-y/kg-d)-1 

SFo = oral slope factor, 130,000 (mg/kg-d)-1 

A

CF = 10-6 kg/mg 

SFSadj = soil dermal contact factor, 

361 mg-y/kg-d 

ABS = dermal absorption fraction, 0.03 InhFadj = 11 (m3-y/kg-d) 

SFi = inh. slope factor, 130,000 (mg/kg-d)-1 

PEF = particulate emission factor, 

1.316×109 

PA 120 MSC = TR×ATc×365d/y

 CSF o× Abs×EF×IFadj×CF 

TR = target risk, 10-5 

ATc = averaging time for carcinogens, 70 y 

CSFo = oral cancer slope factor, 

150,000 (mg/kg-d) ̄1 

Abs = absorption, 1.0 EF = exposure frequency, 250 d/y IFadj = ingestion factor, 57.1 (mg-y/kg-d) 

CF = conversion 

Inge

TX 1,000 otSoilComb = 1 

[(1/

AirSoilInh-VP)+(1/SoilSoilIng)+(1/SoilSoilDerm)] 

Not found 

December 2009 
.

.

.

. 

.

TABLE 13 Basic Components of the Derivation Methodology (see Appendix B for further details) 

State Conc 

(ppt) 

Equation Parameters Expo

Rou

WA 11 SCL = (RISK×ABW×AT×UCF) 

 (CPF×SIR×AB1×ED×EF) 

SCL = soil cleanup level, mg/kg RISK = acceptable cancer risk level, 10-6 

ABW = average body weight over the 

exposure duration, 16 kg 

AT = averaging time, 75 y UCF = unit conversion factor, 106 mg/kg 

CPF = 150,000 (mg/kg-d)-1 

SIR = soil ingestion rate, 200 mg/d AB1 = gastrointestinal absorption fraction, 

0.6 

ED = exposure duration, 6 y EF = exposure frequency, 1.0 

Inge

WY 4.5 See EPA RSL equation (last entry of this table) See EPA RSL parameters (last entry) A

EPA Regional Screening Level Derivation for Residential Scenario 

EPA 

RSL 

4.5 RSLres = 1 

[(1/Cres soil ingestion –ca)+(1/Cres soil dermal – ca)+(1/Cres soil inhalation – ca)] 

where: Cres soil ingestion = TRr×ATr

 CSF o×ERr×IFSadj×CF 

Cres soil dermal = TRr×ATr

 CSFo×ERr×DFSadj×ABSd×CF 

Cres soil inhalation = TRr × ATr

 IUR(μg/m3)-1×(1,000μg/mg)×ERr×(1/VFs+1/PEF)×EDr 

TR = target cancer risk, 10-6 ATr = averaging time, 25,550 d 

CSFo = slope factor, 130,000 (mg/kg-d)-1 

ERr = exposure frequency, 350 d/y 

EDr = exposure duration, 30 y 

IFSadj = age-adjusted soil ingestion factor, 

114 (mg-y/kg-d) 

CF = 10-6 kg/mg 

DFSadj = soil dermal contact factor, 

361 mg-y/kg-d 

ABSd = dermal absorption fraction, 0.03 IUR = 38 (μg/m3)-1 

VF = volatilization factor PEF = particulate emission factor, 

1.4×109 m3/kg 

A

December 2009 
December 2009 

TABLE 14 Summary Comparison of State Derivations for Incidental Soil Ingestion (main route for residenGeneric equation for residential/unrestricted scenario,(incidental ingestion: Cres_ing = TR×AT / SFo×EF×IFSadj×10-6 kg/mg 

State Conc 

(ppt)

Oral Cancer Slope Factor. 

SFo (mg/kg-d)-1 Target Cancer Risk, TR Averaging Time (d) Exposure Frequency, EF (d/y) Soil Ing

or (IR×

NE 3.9 150,000 10-6 25,550 350 

DE 4 150,000 10-6 25,550 350 

MS 4.26 150,000 10-6 25,550 350 

AZ 4.5 130,000 10-6 25,550 350 

MD 4.5 130,000 10-6 25,550 350 

OR 4.5 130,000 10-6 25,550 350 

WY 4.5 130,000 10-6 25,550 350 

FL 7 150,000 10-6 25,550 350 

NH 9 150,000 10-6 25,550 160 

ME 10 130,000 10-6 25,550 150 

WA 11 150,000 10-6 27,375 365 

IA 19 150,000 5×10-6 25,550 350 

MN 20 1,400,000 10-5 25,550 350 

OH 35.8 150,000 10-5 25,550 350 

AK 38 150,000 10-5 25,550 330 

IN 45 150,000 10-5 25,550 250 

KS 60 150,000 10-5 25,550 350 

GA 80 (not specified) 10-5 25,550 350 

MI 90 75,000 10-5 25,550 350 

PA 120 150,000 10-5 25,550 250 

HI 390 150,000 10-4 25,550 350 

AS 450 130,000 10-4 25,550 350 

GM 450 130,000 10-4 25,550 350 

NMI 450 130,000 10-4 25,550 350 

a Shading highlights variations within related entries. Note the internal draft provisional value of 60 ppt for Indiana uses a 

AL and TX identify a cleanup level of 1,000 ppt, which is the concentration recommended in the OSWER directive for a residential sce
 

3.3.2 Toxicity Values 

Most states that list soil cleanup levels for dioxin also indicate the health basis (24 of 26). Only 

one cleanup level is based on the noncancer endpoint: the Iowa nonresidential level, which 

applies only when dioxin is the only chemical of concern. This soil concentration (360 ppt) 

reflects a reference dose of 10-9 mg/kg-d, which is the same as the ATSDR (1998/2008) chronic 

oral MRL. (An MRL represents the estimate of daily human exposure to a hazardous substance 

likely to be without appreciable risk of adverse noncancer health effects for exposure extending 

over a year to a lifetime.) 

For the rest of the cleanup levels across both land use categories, cancer is the driver. (This 

includes the Iowa residential level of 19 ppt, although the state also identifies a residential level 

of 72 ppt based on the noncancer endpoint, when dioxin is the only contaminant.) Incidental 

ingestion is the key exposure route, and the oral slope factor is the toxicity value of interest. (As 

a note, although online information for Texas indicates that both the residential and commercial/ 

industrial cleanup levels are based on the noncancer endpoint [“n”], no information is given for 

the toxicity value, and field followup confirmed that the basis is cancer; see Table B.6.) 

Four different cancer slope factors have been applied across the 24 states that identify a toxicity 

value: 75,000; 130,000; 150,000; and 1,400,000 (mg/kg-d)-1. These slope factors are based on 

one of two rodent bioassays published more than 25 years ago, combined with modeling 

derivations by CalEPA, U.S. EPA, and other scientific groups to estimate the incremental risk to 

humans of getting cancer over a lifetime. The data sources cited by the various states range 

from old HEAST tables to CalEPA, the EPA (2003a) draft dioxin reassessment, and former and 

current EPA Regional screening level tables. 

All but two states use a slope factor of either 130,000 or 150,000 (mg/kg-d)-1 for their soil 

cleanup levels. These very similar values are based on two different bioassays. The first is 

derived from the chronic rodent bioassay from NTP (1982). The second is based on the twoyear dietary study of Sprague-Dawley rats by Kociba et al. (1978), as are the lowest and highest 

of the four values listed above (75,000 and 1,400,000). These two original toxicity studies were 

independently peer reviewed as part of the scientific publication process, as were the 

subsequent derivations of the slope factors. 

In the Kociba et al. (1978) bioassay, female rats that were exposed to the highest study dose 

(0.1 μg/kg-d, or a dietary level of 2,200 ppt) exhibited a higher incidence of hepatocellular 

carcinoma and squamous cell carcinoma of lungs, hard palate, nasal turbinates, and tongue, yet 

a decreased incidence of other tumors. Lesser effects were reported at 0.01 μg/kg-d (210 ppt), 

while no adverse effects were reported at 0.001 μg/kg-d (22 ppt), and no carcinogenic effects 

were reported at either 0.01 or 0.001 μg (210 or 22 ppt). These findings were considered to 

support a previous study that had indicated chronic intake of 5,000 ppt TCDD could lead to 

many toxicological effects. The initial evaluation of these data to derive a slope factor produced 

a value of 150,000 (mg/kg-d)-1, which is used by more than half the states (13 of 24). As a note, 

this value has also been used to determine supporting concentrations for other states, such as 

the Nevada basic comparison (screening) level. 

Updated evaluations of the same data were used by Michigan and Minnesota, the two states 

with different slope factors than the rest. In 1986, the NTP revised its tumor classification 

scheme, and scientists (including Kociba and his colleague Squire, as well as EPA work groups) 

used that methodology to reevaluate the incidence of female rat liver tumors and other tumors 

from the 1978 data. This reevaluation identified a lower tumor incidence, which produced a 

December 2009 Page 71 
 

lower toxicity value. A slope factor of 52,000 (mg/kg-d)-1 was determined based on liver tumors 

alone, and a slope factor of 75,000 (mg/kg-d)-1 was determined based on total significant 

tumors. Michigan used the latter (half the older slope factor) to determine its soil cleanup level. 

In 2003, the Minnesota Department of Health (MNDOH) selected the draft slope factor of 

1,400,000 (mg/kg-d)-1 from the range of values presented in the EPA 2003 draft dioxin 

reassessment. This value, derived from the Kociba study, was identified as the upper bound for 

animal bioassays. At roughly 10 times the two most commonly applied toxicity values (and 

nearly 20 times the Michigan value), this slope factor was also used in a supporting role by the 

Pacific island group. That is, it was used to estimate a concentration that could be used as the 

lower bound of an operational cleanup range, as a companion to the standard cleanup levels 

above which remedial action should be considered. Those main cleanup levels (which are the 

representative concentrations shown in key figures and tables of this report) were derived using 

a toxicity value of either 150,000 (mg/kg-d)-1 (for Hawaii) or 130,000 (mg/kg-d)-1 (American 

Samoa, Guam, and the Northern Mariana Islands). 

The slope factor of 130,000 (mg/kg-d)-1 is used by a third of the states and is being considered 

by an additional state for a provisional level. This value is derived from a chronic study of 

Osborne-Mendel rats dosed by gavage 3 times/week, and B6C3F1 mice gavaged 2 days/week 

(NTP, 1982). Summarizing the toxicity basis from the ATSDR toxicological profile for 

chlorinated dibenzo-p-dioxins (ATSDR, 1998/2008): a dose of about 0.007 μg/kg-d significantly 

increased the incidence of thyroid follicular cell adenoma; a dose ten times higher increased the 

incidence of neoplastic nodules in the liver and hepatocellular carcinoma in females. At 0.1 and 

0.01 μg/kg-d, females exhibited a significant increase in hepatocellular hyperplastic nodules, 

while those at the next lower dose (0.001 μg/kg-d) did not. Total weekly doses were averaged 

to estimate a daily dose level, which assumes daily dosing would give the same results. (As 

described in the ATSDR summary, because the TCDD half-life is relatively long, both schedules 

were expected to give similar tissue concentrations.) The rat data were converted to equivalent 

human exposures with basic scaling factors; assumptions included: oral and inhalation routes 

are equivalent, air concentration is assumed to be the daily oral dose, the exposure route does 

not affect absorption, and TCDD metabolism/pharmacokinetics do not differ between animals 

and humans. 

CalEPA (2002/2003) documents the application of a linearized multistage model to these NTP 

rodent hepatocellular adenoma/carcinoma tumor data to derive the slope factor. Early 

development of this slope factor is documented in the 1986 California Department of Health 

Services derivation report prepared for the CalEPA Toxic Air Contaminant program. This value 

underwent external peer review by the California Air Resources Board (CARB) scientific review 

panel and was endorsed in 2002 when it was summarized and included in the CalEPA (2002) 

Air Toxics Hot Spots Program Technical Support Document for Describing Available Cancer 

Slope Factors. External review by the scientific panel (primarily members of academia) was in 

accordance with a process that has been in place since 1983, per the original state air toxics 

legislation from the early 1980s as documented by CalEPA (1999). 

This slope factor of 130,000 (mg/kg-d)-1 underlies the basic soil cleanup levels identified for 

Arizona and Oregon, as well as the three Pacific island territories (American Samoa, Guam, and 

the Northern Mariana Islands), as indicated above. This oral toxicity value is also reflected in the 

current EPA Regional screening level (RSL), which has been adopted by Maryland and 

Wyoming. In addition, it underlies the draft cleanup level recently developed by Maine and the 

internal draft being developed by Indiana – bringing the total number considering this slope 

factor to nine. 

December 2009 Page 72 
 

 

3.3.3 Target Risk Levels 

The target risks used by states to back-calculate a soil cleanup concentration by combining 

exposure inputs with the toxicity value range from 10-4 to 10-6, consistent with the EPA target 

incremental risk range for contaminated sites. As shown in Tables 12 and 14 and the 

accompanying figures, almost half the states that identify a target risk for their residential or 

unrestricted cleanup levels (11 of 24) apply the lower-end value of 10-6. Eight use 10-5, and one 

(Iowa) applies a value between these two (5 x 10-6). The last four (Hawaii, American Samoa, 

Guam, and the Northern Mariana Islands) use the upper value of 10-4. Most apply the same 

values for the companion commercial/industrial cleanup levels, but 2 of the 11 states that use 

10-6 for residential cleanup (Nebraska and Washington) use 10-5 instead for the restricted 

scenarios. Spanning two orders of magnitude, this component of the derivation calculation is 

the key reason for differences among state cleanup levels. 

3.3.4 Differences among State Cleanup Levels 

The biggest reason for the fairly wide range of state-derived cleanup levels is the target risk 

applied, which accounts for 100-fold differences. A second reason is the slope factor, which 

accounts for differences of about 20-fold, with the Minnesota value about 10 times higher than 

the two values used by most states, and the Michigan value about half those values. 

A third reason is the variation in the exposure assumptions applied, generally accounting for 

differences of less than 10-fold. This is illustrated by the comparison of input values used by 

different states for incidental soil ingestion, the primary route contributing to 

unrestricted/residential cleanup levels. Highlighting the values for this exposure alone offers a 

quick indication of similarities and differences across states, as was shown in Table 14. 

Beyond that single-route comparison, it is also helpful to compare the contributions from 

additional routes. For this evaluation, the calculation used to derive the U.S. EPA Regional 

screening level (RSL) for unrestricted use was selected as the starting point. This equation and 

parameter values provide a useful anchor not only because the state calculations follow this 

same general form, but also because several states have actually adopted the RSLs as cleanup 

levels for residential and industrial scenarios, respectively. 

The state cleanup values were normalized to their target risks to control the impact of that 

factor. The route-specific soil concentrations were also normalized to target risk. Table 15 

presents these route-specific comparisons to the parallel RSL values. This table also identifies 

the contribution of each exposure route to the ultimate soil cleanup level (as a percent), to 

highlight the main contributors. 

An additional consideration is the chemical basis, i.e., whether the value is for TCDD or TEQ. 

This can account for differences of at least several-fold; the factor can be higher depending on 

the environmental mixture. Seven states and three Pacific island territories define their cleanup 

levels as TEQs: Florida, Hawaii, Maine, Michigan, Minnesota, Ohio, Texas, American Samoa, 

Guam, and the Northern Mariana Islands. (Wyoming adopts the EPA Regional screening level 

for TCDD and indicates TEFs may be considered for others.) While values reported as TEQs 

would generally be expected to be higher than those for TCDD alone, and indeed five of the six 

highest residential levels are TEQ, these values are also found at the other end of the 

concentration range. For example, half of the ten TEQ-based cleanup levels are less than 

120 ppt, and 30 percent of the state cleanup levels below 36 ppt are as TEQ. 

December 2009 Page 73 
December 2009 

Table 15 Main Factors Leading to Differences in Cleanup Levels for the Unrestricted/Residential Scenarioa 

Comparison basis, RSLres = 1 _ = 4.5×10-6 mg/kg TR = target cancer risk

EPA RSL equation for cancer endpoint, unrestricted/residential scenario:

 [(1/Cres soil ingestion)+(1/Cres soil dermal)+(1/Cres soil inhalation)] 

Where: 

AT CSFo

EF 

 = averaging time, 2

= slope factor, 130,

= exposure frequen

ED = exposure duration

Cres soil ingestion = TR×AT _= 4.9 ×10-6 mg/kg 

 CSFo×EF×IFSadj×CF 

IFSadj

CF 

= age-adjusted soil = 10-6 kg/mg 

DFSadj = soil dermal conta

Cres soil dermal = TR×AT _= 5.2 ×10-5 mg/kg 

 CSFo×EF×DFSadj×ABSd×CF 

ABSd

IUR 

 = dermal absorption 

= 38 (μg/m3)-1

VF = volatilization facto

Cres soil inhalation = TR × AT = 8.7×10-2 mg/kg 

 IUR(μg/m3)-1×(1,000μg/mg)×EF×(1/VFs+1/PEF)×ED 

PEF = particulate emiss

(Table 15) 

State Conc (ppt)

Component and Comparison to EPA RSL Values

Target 

Risk 

(TR)

Ratio 

to RSL 

TR 

Ingestn 

Subtotal

(ppt) 

Ratio 

to 

Ingestn 

RSL 

Ingestion 

Contribution 

to Cleanup 

Level (%)

Dermal 

Subtotal

(ppt) 

Ratio 

to 

Dermal 

RSL 

Dermal 

Contribution 

to Cleanup 

Level (%)

Inhaln 

Subtotal

(ppt) 

Ratio 

to 

Inhaln 

RSL 

Inhalation 

Contribution 

to Cleanup 

Level (%)

Expla

EPA 

RSL 4.5 10-6 1 4.9 1 91 5.2 ×101 1 9 8.7×104 1 <1 -

The CSF

for the d

NE 3.9 10-6 1 4.3 0.9 91 4.5 ×101 0.9 9 8.9×108 >104 <1 negligible 

value, N

lower tha

DE 4 10-6 1 4.3 0.9 100 Ingestion 

150,000 

MS 4.26 10-6 1 4.3 0.9 100 Ingestion 

150,000 

AZ 4.5 10-6 1 4.9 1 91 5.2 ×101 1 9 8.7×104 1 <1 AZ has a

unrestric
December 2009 

(Table 15) 

State Conc (ppt)

Component and Comparison to EPA RSL Values

Target 

Risk 

(TR)

Ratio 

to RSL 

TR 

Ingestn 

Subtotal

(ppt) 

Ratio 

to 

Ingestn 

RSL 

Ingestion 

Contribution 

to Cleanup 

Level (%)

Dermal 

Subtotal

(ppt) 

Ratio 

to 

Dermal 

RSL 

Dermal 

Contribution 

to Cleanup 

Level (%)

Inhaln 

Subtotal

(ppt) 

Ratio 

to 

Inhaln 

RSL 

Inhalation 

Contribution 

to Cleanup 

Level (%)

Expla

MD 4.5 10-6 1 4.9 1 91 5.2 ×101 1 9 8.7×104 1 <1 MD has 

unrestric

OR 4.5 10-6 1 4.9 0.9 91 5.2 ×101 0.9 9 6.7×104 0.7 <1 

OR 2003 previous update inCalEPA 

also und

WY 4.5 10-6 1 4.9 1 91 5.2 ×101 1 9 8.7×104 1 <1 WY has 

unrestric

FL 7 10-6 1 7.0 1.4 94 1.6 ×102 3.1 4 3.2×102 .004 2 

DifferencFL-speciresident ingestion IRo = 120 

these va

only 60 pcalculatio

150,000 

the differ

the dermhigher thVF accoinhalatio

NH 9 10-6 1 1.0 ×101 2.1 92 1.2 ×102 2.2 8 

DifferencEF (160 used in twith a CS

accounts RSL. Altuse diffearea (SA
December 2009 

(Table 15) 

State Conc (ppt)

Component and Comparison to EPA RSL Values

Target 

Risk 

(TR)

Ratio 

to RSL 

TR 

Ingestn 

Subtotal

(ppt) 

Ratio 

to 

Ingestn 

RSL 

Ingestion 

Contribution 

to Cleanup 

Level (%)

Dermal 

Subtotal

(ppt) 

Ratio 

to 

Dermal 

RSL 

Dermal 

Contribution 

to Cleanup 

Level (%)

Inhaln 

Subtotal

(ppt) 

Ratio 

to 

Inhaln 

RSL 

Inhalation 

Contribution 

to Cleanup 

Level (%)

Expla

ME 10 10-6 1 1.1 ×101 2.2 91 1.2 ×102 2.2 9 2.4 ×106 27.6 <1 

Similar to level can EF (150 in the RSnegligiblBW of 14 

WA 11 10-6 1 1.1 ×101 2.2 100 

WA uses assumptother staderived bfor a chilIR = 200 

IA 19 5×10-6 5 4.3 0.9 91 4.5 ×101 0.9 9 

The diffethat is fivthe RSL, 

150,000 

MN 20 10-5 10 2.1 0.4 77 1.5 ×101 0.3 11 1.3 ×101 0.0001 12 

MN uses 

1,400,00

inputs esrespect tthe RSL 10 times and the T

differencparticulahelp expMN value include: age-adj dthe inhala given Vtimes hig
December 2009 

(Table 15) 

State Conc (ppt)

Component and Comparison to EPA RSL Values

Target 

Risk 

(TR)

Ratio 

to RSL 

TR 

Ingestn 

Subtotal

(ppt) 

Ratio 

to 

Ingestn 

RSL 

Ingestion 

Contribution 

to Cleanup 

Level (%)

Dermal 

Subtotal

(ppt) 

Ratio 

to 

Dermal 

RSL 

Dermal 

Contribution 

to Cleanup 

Level (%)

Inhaln 

Subtotal

(ppt) 

Ratio 

to 

Inhaln 

RSL 

Inhalation 

Contribution 

to Cleanup 

Level (%)

Expla

OH 35.8 10-5 10 4.3 0.9 84 2.3 ×101 0.4 16 6.1 ×104 0.7 <1 

Differencthe OH T

(mg/kg-ddermal te

oral abs half the vConsequeffect in level. Throute is n

AK 38 10-5 10 4.5 0.9 84 2.4 ×101 0.5 16 

The AK dby a TR 

(mg/kg-dCSF of 3impact is 330 d ins

IN 45 10-5 10 6.0 1.2 75 1.8 ×101 0.34 25 8.2 ×104 0.9 <1 

For the i150,000 

instead oIN uses a 

3.5 highecalculatiofor derm
(Table 15) 

State Conc (ppt) 

Component and Comparison to EPA RSL Values 

Target 

Risk 

(TR) 

Ratio 

to RSL 

TR 

Ingestn 

Subtotal 

(ppt) 

Ratio 

to 

Ingestn 

RSL 

Ingestion 

Contribution 

to Cleanup 

Level (%) 

Dermal 

Subtotal 

(ppt) 

Ratio 

to 

Dermal 

RSL 

Dermal 

Contribution 

to Cleanup 

Level (%) 

Inhaln 

Subtotal 

(ppt) 

Ratio 

to 

Inhaln 

RSL 

Inhalation 

Contribution 

to Cleanup 

Level (%) 

Expla

KS 60 10-5 10 1.1 ×101 2.3 50 1.1 ×101 0.2 50 6.8 ×104 0.78 <1 

In additio

150,000 

exposure dermal robetween particulabut ratheBW of 70 Consequ42 (mg-y

smaller tRSL. Thingestionassumptroute. T

makes thsmaller, the overa

GA 80 10-5 10 Not found 

Cannot 

be 

determined 

Cannot be 

determined 

Not 

found 

Cannot 

be 

determined 

Cannot be 

determined 

Not 

found 

Cannot 

be 

determined 

Cannot be 

determined 

Online ina TR of 1

not apply an EF = BW = 70 value of less than 

explain tit has be

December 2009 
December 2009 

(Table 15) 

State Conc (ppt)

Component and Comparison to EPA RSL Values

Target

Risk 

(TR)

Ratio 

to RSL 

TR 

Ingestn 

Subtotal

(ppt) 

Ratio 

to 

Ingestn 

RSL 

Ingestion 

Contribution

to Cleanup 

Level (%)

Dermal 

Subtotal

(ppt) 

Ratio 

to 

Dermal 

RSL 

Dermal 

Contribution

to Cleanup 

Level (%)

Inhaln

Subtotal

(ppt) 

Ratio 

to 

Inhaln

RSL 

Inhalation 

Contribution

to Cleanup 

Level (%)

Expla

MI 90 10-5 10 1.7 ×101 3.5 53 1.9 ×101 0.4 47

In additio

of 75,000 

absorptio

ingestion account 

than the normalizDFSadj (2

higher thRSL. Thconcentrgreater i

PA 120 10-5 10 1.2 ×101 2.4 100

In additio

150,000 (57.1 mg

used to duses an These di

contribut

equivale

normaliz

HI 390 10-4 100 4.3 0.9 91 4.5 ×101 0.9 9 8.7×104 1 <1 

HI uses t

values a

a TR of 1

150,000 

AS 450 10-4 100 4.9 1 91 5.2 ×101 1 9 8.7×104 1 <1 AS adop

paramete

10-4. 

GM 450 10-4 100 4.9 1 91 5.2 ×101 1 9 8.7×104 1 <1 GM adop

paramete

10-4. 

NMI 450 10-4 100 4.9 1 91 5.2 ×101 1 9 8.7×104 1 <1 NMI ado

paramete

10-4. 
 

 

 

a Table 15 notes: 

Ingestn = incidental soil ingestion; inhaln = inhalation. 

To facilitate comparisons, cleanup concentrations were calculated for each route (i.e. ingestion, dermal, inhalation) 

contributing to an individual state cleanup level and normalized by the total target risk applied for the state. This 

allowed for a more direct comparison of component values across states. The EPA RSL was used as the standard 

reference point. Individual route-based concentrations for each state were compared to the parallel concentrations 

for the RSL as a ratio. The contributions to total target risk and overall cleanup levels were also compared as 

ratios. Entries shaded gray indicate those routes are not included in the state cleanup level calculation. 

AL and TX identify a cleanup level of 1,000 ppt, which is the concentration recommended in the OSWER directive 

for a residential scenario. 

These normalized comparisons show that incidental ingestion accounts for nearly 75 to 

85 percent of the cleanup levels for Arkansas, Indiana, Minnesota, and Ohio (which range from 

20 to 45 ppt). For Kansas and Michigan, incidental ingestion accounts for half the cleanup 

concentrations (which are 60 and 90 ppt, respectively), while the other half comes from the 

dermal route. The dermal route also accounts for the rest of the Arkansas, Indiana, and Ohio 

values, while for Minnesota this route roughly splits the remaining portion with inhalation (jointly 

accounting for 23 percent of the 20 ppt cleanup level). For the rest of the states, incidental 

ingestion accounts for at least 90 percent of the cleanup concentration. Contributions of these 

other routes are also higher for selected nonresidential scenarios, such as the trench worker. 

3.4 EVALUATION CRITERIA 

The four criteria considered in evaluating information compiled for the state soil dioxin cleanup 

levels are: 

 Nature of peer review. 

 Transparency-public availability. 

 Scientific basis. 

 Incorporation of most recent science. 

In many cases, only limited information was found to address these criteria during the online 

search. For this reason, a checklist that emphasized the type of documentation needed to 

effectively consider these criteria was provided to the field (Appendix A), together with sitespecific clarification questions, to guide review and feedback. The feedback did little to address 

gaps in this area – particularly with regard to the nature of the peer review and transparency. 

Context for the evaluation criteria is included in the data tables of Appendix B and highlighted in 

overview tables of Chapter 3. Key information for the criteria is summarized in Section 4.3. 

4 SUMMARY AND DISCUSSION 

This chapter summarizes the range of soil concentrations identified in the search for state dioxin 

cleanup levels (Section 4.1), indicates key contributors to similarities and differences 

(Section 4.2), and considers the context provided by the evaluation criteria (Section 4.3). 

4.1 STATE SOIL CLEANUP LEVELS FOR DIOXIN 

Information on dioxin cleanup levels was pursued for all 50 states plus DC, Puerto Rico, the 

Virgin Islands, and four Pacific Rim islands. Online checks extended from state and other 

December 2009 Page 80 
 

 

government agency websites to the EPA database of site cleanup decisions, and peer-reviewed 

scientific literature. 

About 280 cleanup values were identified for dioxin in soil. Nearly half the states and territories 

(26), including three Pacific island territories, have established cleanup levels for unrestricted/ 

residential use, and 21 of these have also established levels for commercial/industrial use. 

These cleanup levels address scenarios ranging from intensive residential use to occupational 

activities such as outdoor maintenance and excavation work. Within each of these sets 

(unrestricted/residential and commercial/industrial), the cleanup concentrations span three 

orders of magnitude. A key reason for this spread is that different states have adopted different 

existing values as their cleanup levels. At the upper end are states that tap the recommended 

concentration from the OSWER directive. At the lower end are those that adopt a screening 

value as their cleanup level. 

For those states that have derived cleanup levels, the following factors contribute to differences: 

 Target risk. 

	 Cancer slope factor. 

 Exposure assumptions. 

	 Reporting basis (as TCDD or dioxin TEQ). 

Frequency distributions of the representative state soil cleanup values for dioxin addressing 

both unrestricted and restricted scenarios are presented in Figure 22. 

(Although online information for the Trust Territories appears to suggest the same values as for 

Guam, American Samoa, and the Northern Mariana Islands, those values have not been 

included in the tables and figures of this report per limited field feedback, which indicated that 

the Trust Territories determine cleanup levels on a site-specific basis.) 

Because many states identify multiple cleanup levels for dioxin in soil, to facilitate comparisons, 

the figures and tables focus on a representative cleanup level for each state and land use 

category (where available) – i.e., unrestricted/residential and commercial/industrial (restricted). 

Although some states indicate cleanup levels should be determined on a site-specific basis, the 

representative state values do not include any concentrations from site-specific decisions. 

For unrestricted/residential land use: 

	 Cleanup levels range from about 4 to 1,000 ppt. Two states use the value of 1,000 ppt 

recommended in the OSWER directive as TEQ. Texas reports this value as TEQ, and 

Alabama reports it as TCDD. (As a note, North Carolina identified this value as a 

preliminary soil remediation goal in December 2009.) 

	 More than 75 percent of the values (20) are at or below 120 ppt, and most of these (15) 

are less than 40 ppt. 

The seven lowest concentrations are consistent with values commonly used for preliminary 

screening evaluations at contaminated sites, 3.9 to 4.5 ppt. This indicates that nearly a third of 

the states with cleanup levels have essentially adopted a value intended for screening 

purposes. The screening levels are based on a target risk of 10-6 and relatively conservative 

residential exposure assumptions. 

December 2009	 Page 81 
3.9 to 11 >11 to 120 >120 to <1,000 16 to 40 >40 to 160 >160 to <1,000 

Frequency of Value 

12 11 10 

9 8 7 6 5 4 3 2 1 0 

Unrestricted (Residential) Restricted (Commercial/In

11 

WA 

10 

ME 

9 

NH 

120 

PA 

7 

FL 

90 

MI 

80 GA 

40 

DE 

4.5 

60 

KS (IN) 

38.2 

MS 

AZ, MD, 

OR, WY 45 

IN 

35 

MN 

38 

AK 

31 

ME 

5

P

4.26 

MS 

35.8 

OH 

450 

AS, GM, 

NMI 

30 

FL 160 

3

4 

DE 

20 

MN 

1,000 

TX 

20 

OR 

AZ, NE 3

N

3.9 

NE 

19 

IA 

390 

HI 

1,000 

AL 

18 

MD 

100 

KS 

1

Soil Dioxin Concentration (ppt) 

FIGURE 22 Distribution of Soil Cleanup Levels by Concentration: Unrestricted and Restricted Uses 

(A dark border indicates the basis is TEQ rather than TCDD; italics in parenthesis indicate a draft 

December 2009 
 

	 The concentration group above 120 ppt contains four values that are 100 times higher 

than these "screening" parallels – at 390 to 450 ppt – for Hawaii and three Pacific Rim 

islands (documented in 2006 and 2008, respectively). These concentrations reflect the 

higher target risk of 10-4 and are as dioxin TEQ. Several other states also report cleanup 

levels as TEQs, notably Florida, Maine, Michigan, Minnesota, and Ohio. 

	 Five of the six highest concentrations are reported as TEQ, as are 30 percent of the 

lowest 14 values. 

For restricted commercial/industrial land use: 

	 21 states and territories have established restricted cleanup levels. The five states for 

which values were identified for residential but not restricted use are Alaska, Georgia, 

Ohio, Michigan, and Wyoming. 

	 These cleanup levels are higher than those for unrestricted use by roughly a factor of 5, 

as expected based on less extensive exposures and in some cases less restrictive 

target risks. These concentrations are also more broadly distributed – spanning a factor 

of 270 (compared to 250 for the residential cleanup levels). 

	 The lowest third of restricted use levels falls between 16 and 40 ppt, the middle third 

ranges from 100 to just above 500 ppt, and the top third (which includes Hawaii and 

three Pacific island territories) ranges from 1,500 to 5,000 ppt. Alabama and Texas 

identify the top soil concentration, which is the lowest end of the range identified in the 

OSWER directive for commercial/industrial use (5,000 to 20,000 ppt). 

The plots of cleanup values organized by EPA Region indicate: 

	 No clear regional patterns exist for either land use category, beyond the similarities in 

concentrations identified for the Pacific island set in Region 9 (for which development of 

the guidance included the same experts). 

	 States in U.S. EPA Regions 2, 3, 6, and 8 have established the fewest cleanup levels for 

dioxin in soil, although screening levels have been established by most. 

Factors affecting these totals by region include: (1) some states do not have the same issue 

(extent) of dioxin-contaminated sites as others, and (2) a number of states have eschewed 

establishing a general cleanup level, calling instead for these to be determined on a site-specific 

basis to incorporate consideration of local conditions. For this reason, concentrations 

established for cleanup decisions were also reviewed as supporting context, with an emphasis 

on states that had not established a cleanup level or screening value; these data are tabulated 

Appendix B. This review of site applications indicates: 

	 More cleanup levels were found for states and territories within Regions 9 and 10 (nearly 

100 combined) than for the other regions. 

	 About half the site-specific cleanup levels reflect the concentration of 1,000 ppt, 

particularly in states that had not established cleanup values for dioxin in soil at the time 

of those decisions. 

December 2009	 Page 83 
 

 

4.2 FACTORS CONTRIBUTING TO SIMILARITIES AND DIFFERENCES 

Key contributors to similarities among the state cleanup levels include: the common underlying 

approach, the use of generally similar exposure factors, and in several cases, adoption of the 

same values as cleanup levels. Key contributors to differences include: the target risk levels, 

toxicity values, and selected exposure assumptions. 

It is also noteworthy that a number of states are similar in having deferred establishing generic 

cleanup levels, invoking instead a risk-based determination of these levels that account for sitespecific conditions. Thus, no generic cleanup levels for dioxin were identified for 15 states and 

one territory. 

In fact, this approach is also taken by the same number of states that identify screening values 

but no cleanup levels. For example, while Arkansas lists concentrations of 4.5 and 18 ppt as 

screening levels for residential and industrial scenarios, respectively, and Massachusetts lists 

values of 20, 50, and 300 ppt (as TEQ) for specific residential to restricted scenario categories 

from essentially a screening approach, both refer to the need for site-specific determinations of 

actual cleanup levels. 

4.2.1 Exposure Calculations 

States that have identified soil cleanup levels generally follow the standard EPA approach to 

determine such values, including common default assumptions. Variations in cleanup levels 

reflect the scenarios and exposure routes considered and the parameter values applied, which 

in some cases account for regional context. For example, a trench worker scenario is included 

for the development of cleanup levels for several Pacific islands. 

The summary of inputs for incidental ingestion in Table 14 illustrate that a key difference 

underlying the state cleanup levels is the target risk – by a factor of 100, while the slope factors 

differ by a factor of about 20. For this ingestion calculation, which is the key exposure route for 

direct contact (unrestricted use), the values for exposure frequency differ by a factor of 2.4, and 

those for the age-adjusted soil ingestion factor differ by less than a factor of 3. Inhalation and 

dermal exposures also contribute measurably to some cleanup levels, especially for certain 

nonresidential (restricted) scenarios. The exposure equations presented in Table 13 underlie 

the summary of key differences captured in Table 15, including relative route contributions. A 

further consideration is whether the cleanup level is for TCDD or dioxin TEQ. 

4.2.2 Toxicity Values 

Cancer is the driving endpoint, and the toxicity value of interest is the oral slope factor. The four 

values identified across the 24 states that provide this information are within a factor of 20. 

The slope factor of 150,000 (mg/kg-d)-1 underlies the cleanup level for more than half the states: 

Alaska, Delaware, Florida, Hawaii, Iowa, Indiana, Kansas, Mississippi, Nebraska, New 

Hampshire, Ohio, Pennsylvania, and Washington. This is an older value based on the data 

from Kociba et al. (1978) using outdated methodology. 

These Kociba et al. (1978) data were reevaluated with the updated (1986) NTP tumor 

classification scheme, which is based on all significant tumors rather than liver tumors alone. 

This updated evaluation halved the slope factor to 75,000 (mg/kg-d)-1. One state, Michigan, 

uses this number. 

December 2009 Page 84 
The slope factor of 1,400,000 (mg/kg-d)-1 is a draft value that was among those discussed in the 

EPA draft dioxin reassessment (EPA, 2003a). This was presented as the upper bound value 

from animal bioassay data, and it too was based on analyses of the Kociba et al. (1978) data. 

This draft value (40 percent higher than the upper bound based on human epidemiological data) 

was used by Minnesota to calculate its soil cleanup level. At roughly ten times the values 

commonly used by most other states (and about 20 times higher than the Michigan value), this 

value was also used in a supporting role by the Pacific island set: American Samoa, Guam, 

Hawaii, and the Northern Mariana Islands. That is, it was used to estimate a lower-bound soil 

concentration to create an operational cleanup range, as a companion to the standard cleanup 

levels established for these islands using the more commonly applied slope factors. 

The slope factor of 130,000 (mg/kg-d)-1 is based on a slightly more recent study (NTP, 1982), 

and it is used by a third of the states. This toxicity value was derived by CalEPA using the 

updated tumor classification method and the linearized multistage model, and its derivation was 

extensively documented and peer reviewed. This slope factor serves as the basis of the 

cleanup levels identified for Arizona, Maryland, Maine, Oregon, and Wyoming, as well as the 

three Pacific island territories: American Samoa, Guam, and the Northern Mariana Islands. It is 

also being considered by Indiana in internal updates of provisional default closure levels. 

In addition to its cancer-based value for the residential scenario, Iowa has identified a cleanup 

level for nonresidential use based on a reference dose that is the same as the ATSDR chronic 

oral MRL (ATSDR, 1998/2008). The MRL underwent extensive peer review prior to being 

finalized in 1998, under the standard process documented by ATSDR (2008b). 

4.2.3 Target Risk Levels 

Nearly half the states that identify a target risk for their unrestricted-use cleanup level apply the 

low-end value of 10-6, eight use the middle value of 10-5, one lists a risk between these two, and 

four use the upper-end value of 10-4. Most states use the same risk target for the companion 

commercial/industrial cleanup levels, except two that use 10-6 to derive the unrestricted/ 

residential cleanup level use a target risk 10 times higher for the restricted scenarios. Thus, 

target risk is a major reason for differences among cleanup levels, by a combined factor of 100. 

4.3 EVALUATION CONTEXT 

The four evaluation criteria can be grouped into two sets: (1) scientific basis, including the 

recency of the studies and methodology on which the value is based; and (2) nature of the value 

in terms of draft or final published value, and its peer review. Even though information and field 

input in these areas was relatively limited, some context is available as summarized in individual 

tables within the body of the report and as part of the data compilations in Appendix B. This 

information can be used to guide interpretation of the final values presented, in terms of 

scientific strength and transparency of the process, including public availability and the pedigree 

of the scientific peer review, with an emphasis on independent review by external experts. 

Toxicity values from CalEPA are considered to address the evaluation components relatively 

well. Values from this agency are extensively peer reviewed in accordance with a long-standing 

external review process. The current CalEPA slope factor of 130,000 (mg/kg-d)-1 for dioxin, 

which is used by one-third of those states that identify an underlying toxicity value, is well 

documented in terms of scientific basis, methodology, and peer review. This value was derived 

from a slightly more recent bioassay (1982 NTP study) than the other toxicity values (which are 

December 2009 Page 85 
 

 

based on 1978 bioassay data from Kociba and colleagues) using the linearized multi-stage 

model, and its derivation and review process are publicly available online. 

In contrast, documentation for the slope factor of 150,000 (mg/kg-d)-1 used by more than half 

the states is limited. It is based on an outdated methodology, and the general citation is an 

outdated EPA HEAST source. That HEAST cancer slope factor was indicated as being a 

provisional value, and it was qualified as being under further evaluation. HEAST tables were 

described in the 1997 document as containing “provisional risk assessment information” that 

“have not had enough review to be recognized as high quality, Agency-wide consensus 

information.” Specific peer review information has not been found; however, the 1985 EPA 

Health Assessment Document (which is listed as one of the sources for the HEAST value) 

underwent external peer review. Note it is not clear that the HEAST value was based solely on 

this document, since EPA (1985) lists a cancer slope factor of 156,000 (mg/kg-d)-1, while the 

HEAST value is 150,000 (mg/kg-d)-1. Thus, this value is considered not as strong overall in 

terms of the combined evaluation criteria. 

The third slope factor, the value of 1,400,000 (mg/kg-d)-1 used by Minnesota, is a draft taken 

from the draft EPA dioxin reassessment (which is still under review). The lack of a final peerreviewed publication basis for this value limits its broader strength. 

The fourth slope factor, the value of 75,000 (mg/kg-d)-1 used by Michigan, is a final published 

value based on an updated and peer-reviewed evaluation of the Kociba data using the updated 

NTP tumor classification. Documentation of this derivation, independent peer review, and public 

availability of supporting information were not found to be as extensive as for the CalEPA value. 

More recent scientific data (such as the 2004 NTP study) are currently being evaluated by 

U.S. EPA, CalEPA, and other organizations. As indicated by certain states (including California 

and Minnesota), information from these ongoing evaluations may offer useful insights for 

consideration in developing updated context for soil cleanups. 

With regard to the range of cleanup levels, concentrations at the lower end (about 4 ppt) were 

identified by a number of states that essentially adopted values developed for screening 

purposes (not cleanup decisions), as reflected in the recently harmonized U.S. EPA Regional 

screening level table and related data sources. The scientific basis, external peer review, and 

transparency of these values for this application do not appear to be well documented, i.e., for 

purposes other than the preliminary screening for which they were designed. 

5 ACKNOWLEDGEMENTS 

The authors wish to express their appreciation to colleagues who contributed to the compilation 

of detailed data tables in Appendix B and integrated plots, notably Aisha Ahmad, Jessica 

Chung, John Jacobi, Prakriti Joshi, James Shannon, Rebecca Williamson, and David Wyker of 

the Argonne team. We also wish to extend our deep appreciation to the many dioxin experts in 

the EPA Regions and states who provided input to this summary. Their combined inputs and 

insights have been invaluable. 

(Argonne National Laboratory's work was supported by the U.S. Environmental Protection 

Agency under an interagency agreement, through U.S. Department of Energy contract 

DE-AC02-06CH11357.) 

December 2009 Page 86 
6 REFERENCES 

Below are selected references cited in the body of this report; others are listed in Appendix B. 

ATSDR (Agency for Toxic Substances and Disease Registry), 1998/2008, Toxicological Profile 

for Chlorinated Dibenzo-p-Dioxins, U.S. Department of Health and Human Services (DHHS), 

Atlanta, GA (Dec.) http://www.atsdr.cdc.gov/toxprofiles/tp104.pdf; Appendix B (policy 

guideline) updated Sept. 2008. 

ATSDR, 2008a, Update to the ATSDR Policy Guideline for Dioxins and Dioxin-Like Compounds 

in Residential Soil, DHHS, Atlanta, GA (Oct. 15, 73 Federal Register [FR] 61:133; with minor 

editorial update Nov. 28, 73 FR 72:484); 

http://www.atsdr.cdc.gov/substances/dioxin/policy/Dioxin_Policy_Guidelines.pdf. 

ATSDR, 2008b, Minimal Risk Levels (MRLs), DHHS, Atlanta, GA (Dec.); 

http://www.atsdr.cdc.gov/mrls (identifies 1998 as date of final (extant) dioxin MRL) 

CalEPA (California Environmental Protection Agency), 1986, Technical Support Document, 

Report on Chlorinated Dioxins and Dibenzofurans, Part B - Health Effects of Chlorinated 

Dioxins and Dibenzofurans, Department of Health Services (Feb.); 

http://www.arb.ca.gov/toxics/id/summary/dioxptB.pdf. 

CalEPA, 1999, 1999-08-12 California Air Toxics Program Background, Air Resources Board; 

http://www.arb.ca.gov/toxics/background.htm (page last reviewed June 23; accessed Sept.). 

CalEPA, 2002/2003, Air Toxics Hot Spots Program, Risk Assessment Guidelines, Part II, 

Technical Support Document for Describing Available Cancer Potency Factors, Office of 

Environmental Health Hazard Assessment (OEHHA), Sacramento, CA; 

http://www.oehha.ca.gov/air/hot_spots/pdf/TSDNov2002.pdf. 

CalEPA, 2005, Technical Support Document for Describing Available Cancer Potency Factors, 

Air Toxics Hot Spots Program Risk Assessment Guidelines, Office of Environmental Health 

Hazard Assessment, Sacramento and Oakland, CA (May); 

http://www.oehha.ca.gov/air/hot_spots/pdf/May2005Hotspots.pdf. 

CalEPA, 2007, Public Health Goal for TCDD in Drinking Water (June) (review draft for second 

public comment period); http://www.oehha.ca.gov/water/phg/pdf/PHGDioxin062907.pdf. 

CalEPA, 2009a, Air Toxics Hot Spots Risk Assessment Guidelines Part II: Technical Support 

Document for Cancer Potency Factors (May); 

http://www.oehha.ca.gov/air/hot_spots/2009/TSDCancerPotency.pdf. 

CalEPA, 2009b, Proposition 65 Status Report, Safe Harbor Levels: No Significant Risk Levels 

for Carcinogens and Maximum Allowable Dose Levels for Chemicals Causing Reproductive 

Toxicity, OEHHA, CA (Feb.); http://oehha.ca.gov/prop65/pdf/2009FebruaryStat.pdf. 

CalEPA, 2009d, Technical Support Document for Cancer Potency Values, Appendix H (July); 

http://www.oehha.ca.gov/air/hot_spots/2009/AppendixHexposure.pdf. 

Cal EPA, 2009c, Human Health Risk Assessment (HHRA), Note 2, Interim, Remedial 

Goals for Dioxins and Dioxin-like Compounds for Consideration at California 

Hazardous Waste Sites, (May); 

http://www.dtsc.ca.gov/AssessingRisk/upload/HHRA_Note2_dioxin-2.pdf. 

CalEPA, 2009d, Technical Support Document for Cancer Potency Values, Appendix H (July); 

http://www.oehha.ca.gov/air/hot_spots/2009/AppendixHexposure.pdf. 

ECOS (Environmental Council of the States), 2007, Identification and Selection of Toxicity 

Values/Criteria for CERCLA and Hazardous Waste Site Risk Assessments in the Absence 

of IRIS Values, ECOS-DoD Sustainability Work Group, Emerging Contaminants Task 

Group, Risk Assessment Provisional Values Subgroup Issue Paper, Washington, DC 

(April 23); http://www.ecos.org/files/2733_file_FINAL_ECOS_PV_Paper_4_23_07.doc. 

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Kimbrough R.D., Falk H., Stehr Pl, Fries G., 1984, Health Implications of 

2,3,7,8-Tetrachlorodibenzodioxin (TCDD) Contamination of Residential Soil, Journal of 

Toxicology and Environmental Health, 14(1):47-93. 

Kociba R.J., Keyes D.G., Beyer J.E., Cerreon R.M., Wade C.E., Dittenber D.A., Kalnins R.P., 

Frauson L.E., Park C.N., Barnard S.D., Hummel R.A., Humiston C.G., 1978, Results of a 

Two-Year Chronic Toxicity and Oncogenicity Study of 2,3,7,8-Tetrachlorodibenzo-p-Dioxin 

in Rats, Toxicology and Applied Pharmacology, 46(2):279-303. 

MIDEQ (Michigan Department of Environmental Quality), 1998, More Details on Dioxin 90 ppt 

value, Excerpt from Part 201, Generic Soil Direct Contact Criteria, Technical Support 

Document (Aug. 31); http://www.michigan.gov/documents/deq/deq-whm-hwp-dowexcerpt_of_dcc_tsd_251913_7.pdfNAS (National Academy of Sciences), 2006, Health Risks 

from Dioxin and Related Compounds: Evaluation of the EPA Reassessment, National 

Academies Press, Washington, DC (July); 

http://www.nap.edu/catalog.php?record_id=11688. 

MNDOH (Minnesota Department of Health), 2003, Cancer Risk Assessment for Dioxins, 

prepared by MDOH at the request of the Risk Evaluation/Air Modeling Unit, Environmental 

Standards and Analysis Section, Minnesota Pollution Control Agency (March 17); 

www.canceractionny.org/cancerriskassessment.htm. 

NTP (National Toxicology Program), 1982, Carcinogenesis Bioassay of 2,3,7,8­

Tetrachlorodibenzo-p-Dioxin (CAS no. 1746-01-6) in Osborne-Mendel Rats and B6C3F1 

Mice (Gavage Study), : DHHS Publication No. (NIH) 82-1765, Carcinogenesis Testing 

Program, National Cancer Institute, National Institutes of Health, Bethesda, MD; National 

Toxicology Program, Research Triangle Park, NC. 

NTP, 2004, Toxicology and Carcinogenesis Studies of 2,3,7,8-Tetrachlorodibenzo-p-Dioxin 

(TCDD) in Female Harlan Sprague-Dawley Rats (Gavage Study), NIH publication No. 04­

4455, NTP TR 521, DHHS, PHS, NIH, Research Triangle Park, NC; 

http://ntp.niehs.nih.gov/ntp/htdocs/LT_rpts/tr201.pdf. 

ORNL (Oak Ridge National Laboratory), 2005/6, The Risk Assessment Information System, 

online RAIS database (cited as the source of toxicity values used by states, from Feb. 2005 

and 2006); http://rais.ornl.gov/. 

Sauer M., 1990, Pathology Working Group: 2,3,7,8-Tetrachloro-dibenzo-p-dioxin in SpragueDawley Rats, PATHCO Inc., submitted to Maine Scientific Advisory Panel (per TSG 1990). 

TSG (Toxic Steering Group), 1990, Carcinogenicity Slope Factor for 2,3,7.8-TCDD: Overview 

and Recent Developments, Toxic Steering Group Meeting (July 10); 

http://www.michigan.gov/documents/deq/deq-whm-hwp-dow-slope_factor_251918_7.pdf. 

U.S. EPA (U.S. Environmental Protection Agency), 1985, Health Assessment Document for 

Polychlorinated Dibenzo-p-Dioxins, Final Report, EPA/600/884/014F, Office of Health and 

Environmental Assessment, Washington, DC (Sept.); 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=38484. 

U.S. EPA, 1996, Soil Screening Guidance: Technical Background Document, 

EPA/540/R-95/128, Office of Solid Waste and Emergency Response (May); 

http://www.epa.gov/superfund/health/conmedia/soil/index.htm#user 

U.S. EPA, 1997a, Health Effects Assessment Summary Tables (HEAST): Annual Update, FY 

1997, National Center for Environmental Assessment (NCEA), Office of Research and 

Development and Office of Emergency and Remedial Response, Washington, DC. 

U.S. EPA, 1989, Risk Assessment Guidance for Superfund Volume 1, Human Health Evaluation 

Manual, Interim Final, Washington D. C., Office of Emergency and Remedial Response. 

EPA/540/1-89/002 (Dec.); http://www.epa.gov/oswer/riskassessment/ragsa/pdf/rags-vol1­

pta_complete.pdf. 

December 2009 Page 88 
U.S. EPA, 1998, Approach for Addressing Dioxin in Soil at CERCLA and RCRA Sites. OSWER 

Directive 9200.4-26, Office of Solid Waste and Emergency Response, Washington, DC 

(Apr. 13); http://www.epa.gov/superfund/resources/remedy/pdf/92-00426-s.pdf. 

U.S. EPA, 2003a, Exposure and Human Health Reassessment of 2,3,7,8-Tetrachlorodibenzo-pDioxin (TCDD) and Related Compounds, NAS Review Draft, Volumes 1-3 

(EPA/600/P-00/001Cb, Volume 1), National Center for Environmental Assessment, 

Washington, DC (Dec.); http://www.epa.gov/nceawww1/pdfs/dioxin/nas-review/. 

U.S. EPA, 2003b, Human Health Toxicity Values in Superfund Risk Assessments, OSWER 

Directive 9285.7-53, Office of Solid Waste and Emergency Response, Washington, DC 

(Dec. 5); http://www.epa.gov/oswer/riskassessment/pdf/hhmemo.pdf. 

U.S. EPA, 2008, Frequently Asked Questions on the Update to the ATSDR Policy Guideline for 

Dioxins and Dioxin-Like Compounds in Residential Soil, OSWER 9285.7-84FS (Dec.); 

http://www.epa.gov/superfund/additions.htm; 

http://www.epa.gov/oswer/riskassessment/pdf/92-857-84fs.pdf. 

U.S. EPA, 2009a, EPA’s Science Plan for Activities Related to Dioxins in the Environment, 

Washington, DC (May 26); http://www.epa.gov/dioxin/scienceplan; 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=209690. 

U.S. EPA (Region 3), 2009b, Regional Screening Level (RSL) Table Residential Soil (April); 

http://www.epa.gov/reg3hwmd/risk/human/rbconcentration_table/Generic_Tables/index.htm; 

http://www.epa.gov/reg3hwmd/risk/human/rbconcentration_table/Generic_Tables/pdf/ressoil_sl_table_run_APRIL2009.pdf 

(page last updated June 8, 2009; accessed December 2009). 

December 2009 Page 89 
December 2009 Page 90 
APPENDIX A: SUPPORTING DETAILS FOR THE APPROACH
 

December 2009 Page A-1
 
December 2009 Page A-2 
December 2009 Page A-3 

APPENDIX A: 

SUPPORTING INFORMATION FOR THE APPROACH

This appendix presents additional context for Phase II. 

The Phase I searches produced varying levels of information. Gaps across the key entries were 

addressed via review and input from knowledgeable experts from the U.S. EPA Regions and 

individual states – which is essential to ensuring that OSWER has the best understanding of 

existing state cleanup levels to frame the development of an updated interim soil cleanup level. 

To support field feedback on the preliminary data tables, a checklist was provided that 

emphasized two main themes (see Table A.2): (1) assure the data table reflects current soil 

cleanup levels for dioxin, and (2) provide supporting information not found online, particularly for 

the scientific basis and other evaluation criteria. State-specific questions were also offered to 

help guide field clarifications and additions. 

TABLE A.1 Checklist to Support Field Review of Data Tables 

Table Element Field Input Needed Notes 

Current Entries 

Soil concentration Please specify if the basis is wet or dry 

weight. 

Reminder: Our scope is TCDD or 

dioxin TEQs (not other DLCs). 

Please confirm or revise as indicated. Note 

some units are converted for consistency 

across all entries 

If you add or revise here, please 

also update corresponding entries 

(including the information source). 

Endpoint basis If missing, please identify “ca” (cancer) or 

“nc” (noncancer) where known. 

If another agency value is 

adopted, please indicate which 

one so we can characterize this. 

Toxicity reference value Please confirm/revise as above, also noting 

same conversion for overall unit consistency.

Please see the evaluation criterion 

for scientific basis (below). 

Information source Confirm or revise as indicated; also add 

sources to account for any change 

Please include any supporting 

weblinks in this table field. 

Context basis Definition-application: Please confirm or 

define (if missing) the nature of the 

concentration term and its application specific 

to soil cleanup. In particular: if a screening 

level, please indicate if (a) the value is 

defined to not be used as a cleanup objective 

or goal, and (b) the value has in fact been 

used as a soil cleanup level (in some case). 

Many state values appear to be 

screening levels, so this 

clarification is crucial – to know 

whether they have essentially 

been used as cleanup levels. If 

so, please provide that 

documentation (including weblink 

if available). 

Further: If a value is identified as ecologicalbased, please indicate if it has also been 

used as a health-based cleanup level.

Context basis (cont’d.) Scenario and risk target: Please confirm or 

identify (if missing) the land use/scenario for 

which the value applies – as well as the 

primary receptor, exposure route(s), and 

target risk, where specified (e.g., 10-6 or 10-5), 

or the hazard index (for “nc”-based levels). 

Regarding the scenario: The 

primary focus is levels considered 

acceptable for unrestricted use. 

(with equations and parameter 

values to be given in the “scientific 

basis” column, see below.) 

Coverage: Please confirm or identify (if 

missing) whether the value is for TCDD only, 

or TCDD equivalents or total dioxins. 

Reminder: We do not need any 

information for DLCs (e.g., PCBs).
December 2009 Page A-4 

Table Element Field Input Needed Notes 

Evaluation Criteria 

Nature of peer review Please characterize the peer review of both 

the soil concentration value and its derivation 

methodology, including assumptions. 

Please at least indicate if any 

external peer review was 

conducted. 

For example, types of review may include: 

a. Internal: by same agency, same division or 

department responsible for the level. 

b. Internal-independent: by same agency but 

another division or department. 

c. External: please indicate general type/ 

number of peers (e.g., “international panel 

including 6 state university toxicologists and 

epidemiologists” or “remote individual 

review by 3 state university toxicologists”). 

Please provide further context as feasible 

(e.g., “2-year process with external review, 

internal revision, and reconsideration by the 

external reviewers”). 

Transparency-public 

availability 

Transparency/clarity and public availability: 

Please identify whether the dioxin level and 

derivation approach are publicly available 

and clearly described – including specific 

calculations and scientific study(ies) on which 

the soil and toxicity values are based. 

If this information is publicly 

available but the source is not yet 

identified in the table, please 

provide it in the “information 

source” column. 

Public comment: Please indicate if the public 

had an opportunity to review and comment 

on the dioxin cleanup and/or toxicity value. 

Provide any further information for 

public input to the dioxin cleanup 

level or derivation methodology. 

Public comment: Please indicate if the public 

had an opportunity to review and comment, 

specific to the soil cleanup level for dioxin. 

Feel free to give any further useful 

information on public input directly 

relevant to the soil dioxin level. 

Scientific basis Please confirm//revise or provide if missing –

including: specific equation(s) used, specific 

input values (per scenario), the toxicity value 

basis, and supporting documentation – 

including original literature or evaluation 

reports underlying the toxicity value or soil 

concentration, particularly if these have not 

yet been found online (and please provide if 

possible, e.g., as weblink, pdf, or hard copy). 

Review input is especially key, 

because this is a data gap for 

many values and the information 

is essential for a solid evaluation. 

Note some entries may have 

general placeholder notes for the 

moment, which will need to be 

replaced by the specific scientific 

basis. 

Incorporation of most 

recent science 

Please check to confirm or update, e.g., if 

ongoing state initiatives reflect more recent 

scientific studies or methodology. 

Note also pursuing original 

documentation cited as the basis 

The main intent of this phase was to obtain primary documentation underlying soil cleanup 

values (not found online), ranging from state derivation methodology or guidance documents to 

the original scientific literature studies and calculation approaches that underlie the toxicity 

values applied. (Similarly, many basic evaluation documents with derivation details underlying 

the supporting context from RODs were not found online.) 

 
APPENDIX B: DETAILED DATA TABLES 

December 2009 Page B-1
 
December 2009 Page B-2 
APPENDIX B: 

DETAILED DATA TABLES 

B.1 DATA ORGANIZED BY U.S. EPA REGION 

To facilitate field review and input, data from the Phase I online searches were compiled in 

tables organized alphabetically by state within U.S. EPA Regions 1 through 10. The Regional 

distribution of states is illustrated in Figure B.1. 

FIGURE B.1 States in U.S. EPA Regions (Source: EPA, 2008x, Regional Map, Office of Solid 

Waste and Emergency Response, http://www.epa.gov/oswer/regionalmap.htm; 

last updated Dec. 26, 2008; accessed Aug. 2009.) 

These Regional tables presented on the following pages include: 

 State: using the standard abbreviations. 

 Soil concentration: as ppt to facilitate comparisons (several were converted to this unit). 

 Date: as month-year where available (to help indicate timing per the extant OSWER 

directive, as well as recent scientific studies and harmonization efforts). 

 Endpoint basis: cancer (c) or noncancer (n). 

 Type of toxicity reference value: such as SF (slope factor) or RfD (reference dose); 

December 2009	 Page B-3 
 

	 Toxicity value units: as consistent unit: (mg/kg/d)-1 (or mg/kg-d for noncancer endpoint), 

to facilitate comparisons. 

	 Information source: streamlined reference (for quick indication of the nature of this 

source, e.g., state agency or other), with weblink to facilitate direct checks. 

	 Context notes: to indicate, where available: 

 contaminant addressed – TCDD or toxic equivalents (TEQ); 

 land use scenario – e.g., unrestricted or commercial/industrial; 

 name of the value – e.g., cleanup level, or screening or comparison level; and 

 application context. 

 Evaluation criteria: To highlight information relevant to the four criteria, as available. 

Formatting to facilitate quick-glance checks Includes: 

1. Concentration column 

- No state cleanup level: this entry is blank if the state has not developed a soil cleanup 

level for dioxin. (Note in some cases states have developed cleanup levels for other 

chemicals and conditions but those documents did not include dioxin). 

- Same concentration as OSWER directive values: the shading is more intense for 

values that are the same as those identified in the 1998 directive – i.e., 1,000 ppt for 

the residential scenario, and 5,000 to 20,000 ppt for commercial/industrial scenarios. 

2. Sources other than state agencies 

- Lighter font and italics are used to distinguish entries that summarize site-specific 

applications or articles from journals or others sources beyond the primary focus, 

which is direct state agency information. (Site-specific levels are included in 

supporting context figures within the report, but those entries that provide no context of 

basis for corroboration are not.) 

As a further note, in a few cases, dioxin values were found for joint human-ecological protection 

or in conjunction with concentrations for ecological protection as part of the search for healthbased levels; these limited entries have been retained (in green font) simply for related insights 

they may offer. 

December 2009	 Page B-4 
December 2009 

TABLE B.1 State Cleanup Levels for Dioxin in Soil: Region 1 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value 

150,000 (mg/kg-d) ̄1 

(CSF) 

150,000 (mg/kg-d) ̄1 

(CSF) 

Information Source 

EPA (2005d), ROD Summary, Solvents Recovery Service of New England, Inc (SRSNE) Site, Southington(http://www.epa.gov/superfund/sites/rods/fulltext/r0105008.pdf).

MADEP (2007), The Massachusetts Contingency Plan, 310, CMR 40 (http://www.mass.gov/dep/service/regulations/310cmr40.pdf); Standard from MADEP [undated A], Documentation for S1 Standards (http://www.mass.gov/dep/cleanup/laws/prop_s1.htm). MADEP (undated B), Documentation for S2 Standards (http://www.mass.gov/dep/cleanup/laws/prop_s2.htm). MADEP (undated C), Documentation for S3 Standards (http://www.mass.gov/dep/cleanup/laws/prop_s3.htm). MADEP (undated D), Upper Concentration Limits (http://www.mass.gov/dep/cleanup/laws/ucls.htm). 

Context Notes Nature of Peer 

Review 

Transparency

Public Availabi

ROD is available online (via RODS database). 

MADEP (2007 & undated A, B, C, documents are available online. 

CT MA 

1,000

300 

2050 

300 

3,000 

 Sep-05  Dec-07 

c 

eco 

c 

For TCDD toxicity equivalents (TEQ), based on EPA 1998 OSWER directive; as the lower value of that 1 ppb level or background 2,3,7,8-TCDD TEQ. (ROD indicates there are no residential direct exposure criteria or pollutant mobility criteria for dioxin in the CT Remediation Standard Regulations.) 

Ecological toxicity benchmark of 0.3 μg/kgTCDD TEQ identified as the concentration “not to be exceeded in soil according to MDNR (1988) (primary citation not provided).

For 2,3,7,8-TCDD equivalents, dry weight basis residential scenario, unrestricted use, accessible soil (<3 ft below surface, not completely paved), direct contact (ingestion, dermal contact) also considering leaching; high frequency or intensity for child use, or high frequency and intensity for adult use , or high frequency and intensity for child use but soil potentially accessible (3 to15 ft below surface) (category S-1); e.g., residential areas, school yards, playgrounds, gardens. For 2,3,7,8-TCDD equivalents, dry weight basis, considering moderate direct exposure (ingestion, dermal contact) also considering leaching; accessible soil with no child use, or high frequency or intensity of adult use, or potentially accessible soil with high frequency or intensity of child use or high frequency and intensity of adult use (category S-2), e.g., retail space, landscaping. For 2,3,7,8-TCDD equivalents, dry weight basis, direct contact (ingestion, dermal contact), and inhalation of airborne particulates; potentially accessible soil with low child use, or low adult frequency or intensity of use, or isolated soil (deeper than 15 ft, or 3 ft beneath the floor of a structure) (category S-3); addresses short but intense construction/ excavation exposure scenarios. For 2,3,7,8-TCDD equivalents, upper concentration limit in soil applicable as public welfare and environmental resource standards. 
December 2009 

TABLE B.1 State Cleanup Levels for Dioxin in Soil: Region 1 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparency

Public Availabi

MA(cont’d.)

4 2006 

(2004) 

Easthope (2006), ATSDR 1,000 ppt dioxin soil 

standard: Letter from concerned citizens, environmental groups (http://www.trwnews.net/Documents/TRW/Request%20to%20atsdr%20to%20clarify%201000ppt.pdf); Lists same values identified in: EC (2004), Dioxin Soil Cleanup Levels in Other States, cited in table available via Tittabawassee River Watch (TRW) News (http://www.trwnews.net/images/StateCleanup2006.PDF). 

Basis not provided. Limited informatio

available via the weblinks at left, wneither the derivamethodology or bof underlying toxivalues. 

1,000 Sep-04 c EPA (2004f), EPA Region 1, Shpack Landfill 

Superfund Site Record of Decision Summary, 

Norton/Attleboro (http://www.epa.gov/superfund/sites/rods/fulltext/r0104694.pdf). 

For dioxin TEQ, based on 1998 OSWER directive: "one ppb is to be generally used as a starting point for setting cleanup levels for setting cleanup levels for CERCLA removal sites and as a cleanup level for remedial sites for dioxin in surface soil involving a residential exposure. The "adjacent resident, w/o groundwater exposure" scenario on which the remedy is based assumes approximately 150 days of exposure to site soils, which is essentially equivalent to an on-site exposure. Therefore, the cleanup goal for dioxin protective of human health is being set at 1 ppb TEQ.” 

ROD is available online (via RODS database). 

ME 10 

17 31 

310 

Jul-09 c 130,000 

(SFo) 

(mg/kg-d) ̄1 MEDEP (2009a), Maine Remedial Action 

Guidelines for all Scenarios http://www.maine.gov/dep/rwm/publications/gu

For dioxin TEQ, residential scenario, based on sites with more than one contaminant of concern For dioxin TEQ, park user scenario, based on sites with more than one contaminant of concernFor dioxin TEQ, commercial worker scenario, 

based on sites with more than one contaminant of concern 

For dioxin TEQ, excavation/construction worker scenario, based on sites with more than one contaminant of concern 

MEDEP (2009a,bare available onlinthe values are draand are currently open for public comment. 

idance/rags/MERAGS%20APPENDIX%201_2_3%20Numbers_Public_Rev_Draft_7-17-09.xls); based on calculations in MEDEP (2009b), Technical Basis and Background for the Maine Remedial Action Guidelines (http://www.maine.gov/dep/rwm/publications/guidance/rags/MERAG_Basis_Draft_For_Public_Comment_2009_july_14_V2-rhd.DOC)’ from Wright (2009) (personal communication). 

NH 9

30 

300 

1,000 5,000 

20,000 

 May-07 c 150,000 

(CSF) 

(mg/kg-d) ̄1 NHDES (2007), Risk Characterization and 

Management Policy, Groundwater Quality Table 2, Appendix A-E with soil values (http://des.nh.gov/organization/divisions/waste/hwrb/documents/rcmp.pdf); the higher values are estimated using EPA (1998a), Approach for Addressing Dioxin in Soil at CERCLA and RCRA Sites, OSWER Directive 9200.4-26 (http://www.epa.gov/superfund/resources/remedy/pdf/92-00426-s.pdf). 

For 2,3,7,8-TCDD, risk-based S-1 soil category, for sensitive uses of property and accessible soils, either currently or in the foreseeable future. For these soil concentration entries, TCDD is marked as “negative contaminant migration” so groundwater was considered for each of the NH soil concentrations listed here and determined to not be a contributing factor. For 2,3,7,8-TCDD, risk-based S-2 category, for moderate exposure to accessible soil, currently or foreseeable future (e.g., maintenance worker) 

For 2,3,7,8-TCDD, risk-based S-3 soil category, for restricted access property with limited potential for exposure, currently or foreseeable future (e.g., excavation worker). For 2,3,7,8-TCDD TEQs, based on OSWER directive approach using TEQs, S-1 category. For 2,3,7,8-TCDD TEQs, based on OSWER directive approach using TEQs, S-2 category. For 2,3,7,8-TCDD TEQs, based on OSWER directive approach using TEQs, S-3 category. 

The May 2007 NHDES document is referred to as being under review; intraagency. 

Both the NH risk characterization document and EPOSWER directive available online. 
TABLE B.1 State Cleanup Levels for Dioxin in Soil: Region 1 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source 

RIDEM (2004), Rules and Regulations for the Investigation and Remediation of Hazardous Material Releases (http://www.dem.ri.gov/pubs/regs/regs/waste/remreg04.pdf). 

DoN (1997), Final Record of Decision: Site 09 – Allen Harbor Landfill, Naval Construction Battalion, OU 01, Davisville (http://www.epa.gov/superfund/sites/rods/fulltext/r0197157.pdf). 

Context Notes Nature of Peer 

Review 

Transparency

Public Availabi

RI 

40

Feb-04 

 Sep-97 

These RIDEM Remediation Regulations (updated February 2004) contain tables listing direct exposure criteria for residential and commercial/industrial soils for a number of contaminants. They were checked for dioxin entries but none were found (nor was other input provided during the field review phase). For 2,3,7,8-TCDD equivalents, determined using toxic equivalency factors from EPA (1994), specific citation not provided; represents riskbased concentration for soils up to a depth of 10 ft. (As a note, the entry for TCDD soil screening level is ND, no data.) This risk-based concentration was developed for a recreational scenario. 

The RIDEM (2004document is availonline. ROD is available online (via RODS database).Public comments includesupport for no aclimited action, two the proposed plan(one of which was implemented), anlandfill excavation

VT 4.5 May-09 c 130,000 (mg/kg-d) ̄1 VTDEC, Brownfields Reuse Initiative For 2,3,7,8-TCDD in residential soils, total risk. The VT context a

18 

(SFO) (http://www.anr.state.vt.us/dec/wastediv/SMS/

RCPP/Cleanup-Stand-Guid.htm); for soil and air, links to EPA (2009), Regional Screening Levels (RSL) for Chemical Contaminants at Superfund Sites, RSL Table Update (http://www.epa.gov/region09/superfund/prg/). 

The VT website introduces the link to the Regional EPA screening values (and VT links for other environmental media) with: “The following links are provided to standards and guidance utilized by the Department in the management of brownfield projects.” 

For 2,3,7,8-TCDD in industrial soils, total risk; with further note as above. Note the supporting documentation includes an RfD0 of 1.0×10-9 mg/kg-d; however, cancer was 

the limiting endpoint for the residential and industrial screening levels. (Note this RfD is the same as the ATSDR chronic MRL finalized in 1998.) 

the EPA RSL taband User's Guide (EPA 2009e,f), including equationare available onlin

December 2009 
December 2009 

TABLE B.2 State Cleanup Levels for Dioxin in Soil: Region 2 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparency

Public Availabi

NJ 50 Mar-01 c NJDHSS (2001), Public Health Assessment: 

Franklin Burn Site (http://www.state.nj.us/health/eoh/assess/fb_pc.pdf). 

For 2,3,7,8-TCDD TEQs, adopted from the ATSDR screening value used as a “comparison value” for public health assessment at that time. (See related information in the ATSDR entry in Table 11 of the report.) 

See information for the ATSDR entry in Table 11. 

See ATSDR entry Table 11; toxicity value not found in the NJ documentation. 

19 Sep-07 c DoA (2007b), ROD, Site 180 (PICA 093) 

Waste Burial Area, Final, Picatinny

(http://www.epa.gov/superfund/sites/rods/fulltext/r2007020002538.pdf). 

For 2,3,7,8-TCDD toxic equivalency concentration (TEC) for surface and subsurface soil, based on the EPA Region 3 risk-based concentration for the industrial scenario; IRBCs were used when NJ had not established a nonresidential direct contact soil cleanup criterion. 

ROD available on(RODS databaseToxicity value not found. 

1,000 May-04 c EPA (2004d), ROD, Franklin Burn, OU 01, 

Franklin Township (http://www.epa.gov/superfund/sites/rods/fullte

xt/r2004020001417.pdf). 

For dioxin, the surface soil risk-based preliminary remedial goal is described in the text as a policy-driven value, the 1 ppb cleanup level for dioxins/furans is consistent with OSWER Directive 9200.4-26.” 

ROD available on(RODS databaseToxicity value not found. 

NY Sep-06 NYDEC (2006), New York State Brownfield This document states that 2,3,7,8-TCDD was NYSDEC (2006) 

Cleanup Program, Development of Soil Cleanup Objectives, Technical Support 

deleted from the list of priority contaminants requiring a soil cleanup objective because dioxin 

document availabonline. 

Document (http://www.dec.ny.gov/docs/remediation_hudson_pdf/techsuppdoc.pdf); link provided in feedback during field review, from Olsen (2009) (personal communication). 

is rarely found at sites. If dioxins are listed as a contaminant of concern at Brownfield sites by the EPA, then NYSDEC would consider dioxin in its remedial programs. 

600 Jan-94 NYDEC (2009), TAGM 4046, Table 3 

(http://www.dec.ny.gov/regulations/30582.html); the document that established these levels is dated 1994, but the specific tables from this document are shown by themselves on a webpage that was updated in 2009. 

For 2,3,7,8-TCDD TEQs, identified as the “allowable soil concentration” protective of groundwater, which assumes the contaminated soil is in direct contact with the water table. That is, the value assumes leachate from contaminated soil does not violate groundwater/drinking water standards.

Alternative and recommended cleanup objectiveare available onlinas is part of the derivation methodology and context (notably fthe soil water concentration). Specific toxicity values and bases underlying the cleanup objectivehave not been fouonline. 
TABLE B.2 State Cleanup Levels for Dioxin in Soil: Region 2 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparency

Public Availabi

NY (cont’d) 

60,000 Jan-94 NYDEC (2009), TAGM 4046, Table 3 (as 

above).

For 2,3,7,8-TCDD TEQs, “Soil cleanup objective” that is protective of groundwater quality. This value assumes that contaminated soil in the unsaturated zone above the water table is subject to attenuating processes during transport to groundwater. (NY DEC TAGM 4046 states that alternative cleanup objectives are derived considering a number of criteria including HEAST and RfD values, concentrations protective of groundwater, detection limits, and background 

40 Nov-04 U.S. AF (2004a), Final ROD for the 

Electrical Power Substation, Area of Concern (SS-44) at the Former Griffiss Air Force Base, 

concentrations. “Recommended” cleanup objectives are based on the criterion that produces the most stringent value. No such “recommended” cleanup objective value is provided for TCDD.) For 2,3,7,8-TCDD, soil guidance value. This value is reported within the comments section of the ROD, which cites a report that has not been found online (Law Engineering and 

ROD available on(via RODS database), but nothe report referen

1,000 Mar-03 c 

Rome (http://www.epa.gov/superfund/sites/rods/fulltext/r0205015.pdf). U.S. AF (2003a), SiteSS-026 Explosive Ordinance Disposal Range: ROD, Plattsburgh Air Force Base, Installation Restoration Program, Plattsburgh (http://www.epa.gov/superfund/sites/rods/fulltext/r0203022.pdf). 

Environmental Services, Inc., December 1996, Draft-Final Primary Report, Volume 7, Remedial Investigation, Griffiss Air Force Base, New York, Contract No. DACA41-92-D-8001, Kennesaw, GA). Residential, recreational, and commercial/industrial future land use scenarios were evaluated. As dioxin toxicity equivalence. The ROD states that the regulatory criteria used in the assessment for soil include the NY TAGM 4046 Soil Cleanup Guidelines (1994, see earlier entry in this table) and EPA dioxin toxic equivalency 

guidelines (EPA, 1989), and refers to the EPA recommended action level of 1 μg/kg TEQ. 

for the indicated guidance value. Toxicity context nfound. ROD available on(via RODS database) Toxicitvalue not found. 

PR 1,000 Apr-04 c EPA (2004c), ROD, Vega Baja Solid Waste 

Disposal, OU 01, Rio Abajo Ward (http://www.epa.gov/superfund/sites/rods/fulltext/r2004020001421.pdf). 

For dioxin; the ROD mentions the EPA recommended action level of 1 ppb (which suggests the basis was the OSWER directive). Dioxin was not considered a chemical of concern at the site because soil concentrations did not exceed 1 ppb. 

ROD available on(via RODS database); toxicity value not found. 

December 2009 
December 2009 

TABLE B.3 State Cleanup Levels for Dioxin in Soil: Region 3 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparenc

Public Availab

 DE 4

40 

3 4 

 Dec-99 

2006 

(2004) 

c 

eco 

150,000 

(CSFo) 

(mg/kg-d) ̄1 DEDNREC (1999), Remediation Standards 

Guidance under the Delaware Hazardous Substance Cleanup Act (http://www.dnrec.state.de.us/dnrec2000/divisions/awm/sirb/docs/pdfs/misc/remstnd.pdf). Easthope (2006), ATSDR 1,000 ppt dioxin soil standard: Letter from concerned citizens, environmental groups (http://www.trwnews.net/Documents/TRW/Request%20to%20atsdr%20to%20clarify%201000

For 2,3,7,8-TCDD, dry weight basis, unrestricted use scenario. ["Where current or future use will not be restricted in any way to ensure the protection of human health" (DEDNREC 1999)]. Based on both critical and non-critical water resource area in both surface and subsurface soil, from DE Uniform Risk-Based Remediation Standards (URS) for protection of human health. For 2,3,7,8-TCDD, based on restricted use, ["Where current or future use will be restricted in some way (either through deed restriction, risk management or engineering control measures) to ensure the protection of human health" (DEDNREC 1999)]. Based on both critical and non-critical water resource area in both surface and subsurface soil, from DE URS for protection of human health. URS for protection of the environment for surface soil from ORNL May 1998 screening benchmark levels for ecological risk assessmentBasis not provided. 

Intra-agency Calculations an

risk-based tablecan be found in the DEDNREC Remediation Standards, Attachment 4, athe PA Bulletin (1997), both of which are availaonline. Original ORNL document not foLimited informais available via weblinks at left, neither the derivation methodology or basis of underlytoxicity values. 

ppt.pdf); lists same values identified in: 

EC (2004), Dioxin Soil Cleanup Levels in Other States, cited in table available via Tittabawassee River Watch News (http://www.trwnews.net/images/StateCleanup

2006.PDF). 
December 2009 

TABLE B.3 State Cleanup Levels for Dioxin in Soil: Region 3 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparenc

Public Availab

DC 

4 

4.3

Jul-09 

2006 

(2004) 

 Sep-07 c 

Rios Jafolla (2009) (personal communication). 

Easthope (2006), ATSDR 1,000 ppt dioxin soil standard: Letter from concerned citizens, environmental groups (http://www.trwnews.net/Documents/TRW/Request%20to%20atsdr%20to%20clarify%201000

Feedback during the field review phase indicated DC has not identified a soil dioxin level for site cleanups because it does not have the authority. The DC Voluntary Cleanup Program relies on the EPA RBC Table for screening levels, but DC may be developing its own cleanup standards. Those standards may also be used by other environmental programs in DC. Basis not provided. For total dioxin TEQ, screening toxicity value reflects toxicity equivalency factors (TEFs) for dioxins/furans from EPA (2000); the full citation was not found in the ROD. 

Limited informais available via weblinks at left, neither the derivation methodology or basis of underlytoxicity values. Available online RODS databas

ppt.pdf); lists same values identified in: 

EC (2004), Dioxin Soil Cleanup Levels in Other States, cited in table available via Tittabawassee River Watch News (http://www.trwnews.net/images/StateCleanup

2006.PDF). NAVFAC (2007b), FFA Final ROD for Sites 1, 2, 3, 7, 9, 11, and 13, Washington Navy Yard (http://www.epa.gov/superfund/sites/rods/fulltext/r2008030002103.pdf). 

MD 4.5

18 

4 

25

1,000

 Jul-09 

2006 

(2004) 

 Sep-07 

 Feb-99 

c 

 c 

c 

130,000 

150,000 

(CSF) 

(mg/kg-d) ̄1(mg/kg-d) ̄1 

Rios Jafolla (2009) (personal communication). Easthope (2006), ATSDR 1,000 ppt dioxin soil standard: Letter from concerned citizens, environmental groups (http://www.trwnews.net/Documents/TRW/Request%20to%20atsdr%20to%20clarify%201000

Feedback during the field review phase identified the EPA residential RSL as the MD cleanup level . Feedback indicated MD generally uses screening levels as cleanup levels, however site-specific factors are considered, including what other contaminants may be present. Basis not provided. Based on total dioxin TEQ; this final cleanup level is the risk-based goal for a site worker based on a 10-6 risk target. From the 2005 

feasibility study by Shaw Group (that document has not been found online). 

Indicates the MD Department of Transportation (DOT) discovered soil contaminated with dioxin and pursued remediation at the site to a level of 1,000 ppt, based on the EPA OSWER directive. 

Limited informais available via weblinks at left, neither the derivation methodology or basis of underlytoxicity values. Available online RODS databas

ppt.pdf); lists same values identified in: 

EC (2004), Dioxin Soil Cleanup Levels in Other States, cited in table available via Tittabawassee River Watch News (http://www.trwnews.net/images/StateCleanup

2006.PDF). 

DoA (2007a), Canal Creek Study Area, ROD for Remedial Action – G-Street Salvage Yard, Final, Aberdeen Proving Ground (http://www.epa.gov/superfund/sites/rods/fullte

xt/r2007030001944.pdf). EPA (Region 3) (1999a), Documentation of Environmental Indicator Determination (http://www.epa.gov/reg3wcmd/ca/md/hhpdf/hh_mdd981041601.pdf). 
December 2009 

TABLE B.3 State Cleanup Levels for Dioxin in Soil: Region 3 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparenc

Public Availab

PA 120

530 

1.9×1011

120

40 

4.3 

 Nov-01 

 2006 

(2004) 

Sep-07 

Apr-06 

c 

 c 

c 

150,000 

(CSF) 

150,000 

(CSF) 

(mg/kg-d) ̄1 

(mg/kg-d) ̄1 

PADEP (2001), Medium-Specific Concentrations (MSCs) for Organic Regulated Substances in Soil (http://www.depweb.state.pa.us/landrecwaste/lib/landrecwaste/land_recycling/table_3a.pdf); developed as part of the PADEP (2002) Land Recycling Program Technical Guidance Manual (http://www.depweb.state.pa.us/ocrlgs/cwp/view.asp?a=1459&q=518850); equations based on PA (1997), Pennsylvania Bulletin, Environmental Quality Board Administration of the Land Recycling Program (Act 2), Ingestion Numeric Values (http://www.pacode.com/secure/data/025/chapter250/s250.306.html).Easthope (2006), ATSDR 1,000 ppt dioxin soil standard: Letter from concerned citizens, environmental groups (http://www.trwnews.net/Documents/TRW/Request%20to%20atsdr%20to%20clarify%201000ppt.pdf); lists same values identified in: 

EC (2004), Dioxin Soil Cleanup Levels in Other States, cited in table available via Tittabawassee River Watch News (http://www.trwnews.net/images/StateCleanup

2006.PDF). NAVFAC Mid-Atlantic (2007a), ROD, Site 5 Soil, OU 4, Naval Air Station, Joint Reserve Base, Willow Grove (http://www.epa.gov/superfund/sites/rods/fulltext/r2007030001999.pdf). U.S. ACE (2006), ROD for the Phase IV BRAC Parcels, Groundwater Southeastern (SE) Area Operable Unit 3B and Part of Soil Operable Unit SE OU 8, AEDBR Sites LEAD016, -114, -115, Letterkenny Army Depot, Chambersburg (http://www.epa.gov/superfund/sites/rods/fulltext/r2006030001362.pdf). 

For 2,3,7,8-TCDD, residential scenario, soil (0-15 ft), direct contact, based on ingestion. Based on cancer risk; noncancer toxicity value also identified. 

For 2,3,7,8-TCDD, nonresidential scenario, surface soil (0-2 ft), direct contact, based on ingestion. Based on cancer risk; noncancer toxicity value also identified. For 2,3,7,8-TCDD, direct contact, cap (maximum) concentration for nonresidential subsurface soil (2-15 ft), 190,000 mg/kg. Based on cancer risk; noncancer toxicity value also identified. Basis not provided. For 2,3,7,8-TCDD equivalents, preliminary remediation goal (PRG) for resident, based on 10-5 cancer risk; described as agreed upon by 

EPA, PADEP, and Navy, "developed by EPA Region III and the Navy using EPA Region III RBCs and based on site-specific risk for lifetime resident exposure scenarios." For 2,3,7,8-TCDD TEQ. Soil concentration calculated from the RBC equation. The ROD identifies the calculations and parameter values for developing age-adjusted RBCs. 

The PADEP documentation available onlineLimited informais available via weblinks at left, neither the derivation methodology or basis of underlytoxicity values. Available online RODS databasAvailable online RODS databas
December 2009 

TABLE B.3 State Cleanup Levels for Dioxin in Soil: Region 3 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparenc

Public Availab

 PA (cont’d.) 

4.1

48 

10,000

0.32

1.6

 Aug-03 c 

 eco  (eco)  eco 

150,000 

(CSF) 

(mg/kg-d) ̄1 U.S. ACE (2003), ROD for Phase III Parcels, 

Letterkenny Army Depot, Chambersburg (http://www.epa.gov/superfund/sites/rods/fullte

xt/r0303065.pdf). 

2,3,7,8-TCDD TEQ soil risk-based health screening concentration (RBSC) for future child or adult resident. For 2,3,7,8-TCDD equivalents, subsurface soil, represents the soil screening level for groundwater protection, basis indicated as carcinogen; considered a total hazard quotient of 0.1; dilution attenuation factor of 20. The ROD refers to the remedial investigation/risk assessment for the methodology explanation. 

2,3,7,8-TCDD TEQ ecological benchmark, EPA Region III BTAG screening level for fauna; from EPA (Region 3) (1995a). For 2,3,7,8-TCDD TEQ, identified as NOAELbased benchmark for humans/mammals, from ORNL (1997); ROD indicates PRGs were adjusted to NOAEL-based criteria using a factor of 10. For 2,3,7,8-TCDD TEQ, NOAEL-based benchmark for birds, from ORNL (1997); ROD indicates PRGs were adjusted to NOAEL-based criteria using a factor of 10. 

Available online RODS databas

 VA 4.5

18

4 

 Jul-09 

 Jun-09 

2006 

(2004) 

May-05 

c 

c 

130,000 

(SFo) 

(mg/kg-d) ̄1 VADEQ (2009b), Contaminants of Concern 

Soil: Unrestricted (http://www.deq.virginia.gov/export/sites/default/vrprisk/files/screen/vrp25.xls); SFo from 

VADEQ (2009c) Table 4.2, (http://www.deq.virginia.gov/export/sites/default/vrprisk/files/toxicity/vrp42.xls); 

VADEQ (2009a), Contaminants of Concern Soil: Restricted (http://www.deq.virginia.gov/export/sites/default/vrprisk/files/screen/vrp29.xls). Easthope (2006), ATSDR 1,000 ppt dioxin soil standard: Letter from concerned citizens, environmental groups (http://www.trwnews.net/Documents/TRW/Request%20to%20atsdr%20to%20clarify%201000

For 2,3,7,8-TCDD, residential scenario, EPA regional screening level and VA Voluntary Remediation Program (VRP) Tier II screening level. 

For 2,3,7,8-TCDD, commercial/industrial scenario, EPA regional screening level and VRP Tier III screening level. Basis not provided. For dioxin toxicity equivalents; the document indicates the TEQ risk falls within the target range (10-4 to 10-6) and indicates PRGs were 

developed based on the EPA Region III RBCs, but does not provide the concentrations used; cites the site evaluation document by Tetra Tech (2004), which has not yet been found online. 

Intra-agency VADEQ (2008c

provides toxicity tables, risk calculations and route-specific (dermal, ingestinhalation) equations for remediation levthis document iavailable onlineLimited informais available via weblinks at left, neither the derivation methodology or basis of underlytoxicity values. Decision documis available onli(via RODS database). 

ppt.pdf); lists same values identified in: 

EC (2004), Dioxin Soil Cleanup Levels in Other States, cited in table available via Tittabawassee River Watch News (http://www.trwnews.net/images/StateCleanup

2006.PDF). DoA (2005), Decision Document, EBS-13 Parcel, OU 6, Blackstone, (http://www.epa.gov/superfund/sites/rods/fulltext/r0305061.pdf). 
December 2009 

TABLE B.3 State Cleanup Levels for Dioxin in Soil: Region 3 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparenc

Public Availab

 WV 4.1 

370 

4 

Mar-01 

2006 

(2004) 

c 156,000 

(CPSo) 

(mg/kg-d) ̄1 WVDEP (2001), Voluntary Remediation and 

Redevelopment Act: Guidance Manual, Version 2.1 (http://www.wvdep.org/Docs/3200_RemediationGuidanceVersion2-1.pdf). Easthope (2006), ATSDR 1,000 ppt dioxin soil standard: Letter from concerned citizens, environmental groups (http://www.trwnews.net/Documents/TRW/Request%20to%20atsdr%20to%20clarify%201000ppt.pdf); lists same values identified in: 

EC (2004), Dioxin Soil Cleanup Levels in Other States, cited in table available via Tittabawassee River Watch News (http://www.trwnews.net/images/StateCleanup

2006.PDF). 

For 2,3,7,8-TCDD, residential scenario, based on soil ingestion; slope factor from HEAST (specific citation not provided); value reflects EPA Region III risk-based concentrations from July 1996. For 2,3,7,8-TCDD, industrial scenario, based on soil ingestion; slope factor from HEAST (citation not provided); concentration reflects EPA Region III risk-based concentration from July 1996, multiplied by 10 to yield a value based on 10-5 risk. 

Basis not provided. 

Expert peer review coordinated by the National Institute for Chemical Studies 

The equations agiven in WVDE(2001) which is available onlineThe WVDEP document cites EPA (1989, 1991996b). Limited informais available via weblinks at left, neither the derivation methodology nobasis of underlytoxicity values. 
December 2009 

TABLE B.4 State Cleanup Levels for Dioxin in Soil: Region 4 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparency

Public Availabil

AL 1,000 Apr-08 c ADEM (2008), AL Risk Based Corrective For 2,3,7,8-TCDD, residential scenario. The ADEM 

Action Guidance Manual (http://www.adem.state.al.us/LandDivision/Gui

Preliminary screening level adopted as a cleanup level for "Direct Contact Exposure 

screening value and basis (OSWE

dance/ARBCAApril2008final.pdf). Pathway” from 1998 OSWER directive. directive) are 

5,000 

212385 

 c 150,000 

(SFo)

(mg/kg-d)-1

For 2,3,7,8-TCDD, commercial scenario. Preliminary screening level adopted as a cleanup level for "Direct Contact Exposure Pathway” from 1998 OSWER directive. For 2,3,7,8-TCDD, large soil source (4047.5m2), 

soil screening level protective of groundwater resource protectionRM-1 levels per ADEM AL Risk Based Corrective Action Guidance Manual (ARBCA). For 2,3,7,8-TCDD, small soil source (225m2), 

soil screening level protective of groundwater resource protection, Risk Management-1 (RM-1) Levels per ADEM ARBCA. 

available online. 

FL 7

30 

 Feb-05 c 150,000 

(CSFo) 

(mg/kg-d)-1 FDEP (2005), Technical Report: Development 

of Cleanup Target Levels (CTLs) for Chapter 62-77, F.A.C., Table 2 (http://www.dep.state.fl.us/waste/quick_topics/rules/documents/62-777/TableIISoilCTLs4-17-05.pdf, from http://toxicology.ufl.edu/documents/TechnicalFeb05.pdf.

For 2,3,7,8-TCDD TEQ, residential direct contact soil cleanup target level (SCTL). Derivation provided in FDEP (2005). The value reported in the CTL table (7 mg/kg-d), is also cited by Paustenbach et al. (2006) as the cleanup target level for FL (as 7 ng TEQ/kg, riskbased calculation). For 2,3,7,8-TCDD TEQ, commercial/industrial direct contact SCTL. 

Paustenbach et al. (2006) was peer reviewed as part of the journal publication process. 

Derivation basis and equations values clear for residential and commercial/ industrial SCTLsDefault and chemical-specific values for equatiovariables providein FDEP (2005), Technical ReportEPA (1997a) Health Effects Assessment Summary Tables (HEAST) values nonradionuclides have not been found via open access online. 
December 2009 

TABLE B.4 State Cleanup Levels for Dioxin in Soil: Region 4 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparency

Public Availabil

FL (cont’d.) 

7 2 7 

200 

2006 

(2004) 

1997 c 

Easthope (2006), ATSDR 1,000 ppt dioxin soil standard: Letter from concerned citizens, environmental groups (http://www.trwnews.net/Documents/TRW/Request%20to%20atsdr%20to%20clarify%201000ppt.pdf); lists same values identified in: 

EC (2004), Dioxin Soil Cleanup Levels in Other States, cited in table available via Tittabawassee River Watch News (http://www.trwnews.net/images/StateCleanup

2006.PDF). Hirschhorn (1997a), Cleanup Levels for Dioxin Contaminated Soils; Hirschhorn (1997b), Two Superfund Environmental Justice Case Studies (http://www.trwnews.net/Documents/Cleanup/two_superfund_environmental_just.htm) 

Basis not provided. Indicated as TCDD TEQ in soil. Escambia Treating Company Superfund site, Pensacola, FL, for residential scenario (reflecting ingestion, inhalation, and dermal exposure), 10-6 risk. 

Coleman-Evans Wood Preserving Superfund site cleanup level; 10-6 risk. 

Escambia Treating Company Superfund Site, Pensacola (1996) cleanup level for off-site residential areas (from EPA Region 4); corresponds to 10-4 cancer risk level (ignoring 

noncancer health effects). 

Article peer reviewed as part of journal publication process. 

Limited informatiis available via thweblinks at left, with neither the derivation methodology nor basis of underlyintoxicity values. 

50 1997 n Hirschhorn (1997a), Cleanup Levels for Dioxin 

Contaminated Soils; Hirschhorn (1997b), Two Superfund Environmental Justice Case Studies (http://www.trwnews.net/Documents/Cleanup/t

Indicated as TCDD TEQ in soil; 1995 “ATSDR Public Health Assessment for Escambia Superfund site cited 50 ppt level for noncancer effects.” (Note: not found in the ROD for this site, from the RODS database.) 

Article peer reviewed as part of journal publication process. 

wo_superfund_environmental_just.htm). 

7 

30 

Sep-06 EPA (2006g), ROD Summary of Remedial 

Alternative Selection: Coleman-Evans Wood Preserving Company: Superfund Site, OU 02 (Residual Dioxin in Soil), Whitehouse (http://www.epa.gov/superfund/sites/rods/fulltext/r2006040001242.pdf). 

Based on FL Department of Environmental Protection Dioxin (FDEP) Toxic Equivalent (TEQ) Soil Cleanup Target Levels (SCTLs) for residential and commercial/industrial scenario; 7 ppt for attributable off-facility property, 30 ppt for on facility property. 

Available online (via RODS database).

30 Aug-06 EPA (2006d), ROD Summary of Remedial Based on FDEP Dioxin TEQ SCTLs for Available online 

Alternative Selection: Jacksonville Ash Site, 

Jacksonville (http://www.epa.gov/superfund/sites/rods/fulltext/r2006040001162.pdf). 

commercial/industrial scenario. (via RODS 

database).

7

30 

 Aug-06 EPA (2006c), ROD Summary of Remedial 

Alternative Selection: Brown’s Dump Site, Jacksonville (http://www.epa.gov/superfund/sites/rods/fulltext/r2006040001161.pdf); equations given in (http://toxicology.ufl.edu/documents/TechnicalFeb05.pdf).

Remediation goals as TEQ were adopted from FDEP SCTLs: 7 ppt for residential scenario, 30 ppt for commercial/industrial scenario; calculated for 10-6 risk level. 

Available online (via RODS database). See information fFDEP (2005) above. 

30 Feb-06 EPA (2006a), ROD Summary of Remedial 

Alternative Selection: Escambia Wood Treating Company: Superfund Site, Operable Unit 01 (Soil), Pensacola (http://www.epa.gov/superfund/sites/rods/fulltext/r2006040001445.pdf). 

For 2,3,7,8 TCDD TEQ, based on FDEP SCTL for commercial scenario, lifetime cancer risk of 10-6. (ROD notes the Department shall not 

require site rehabilitation to achieve a cleanup target level for an individual contaminant that is more stringent than the site-specific, naturally occurring background concentration for that contaminant. Florida Statute 376.30701.) 

Available online (via RODS database).
December 2009 

TABLE B.4 State Cleanup Levels for Dioxin in Soil: Region 4 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparency

Public Availabil

GA 80

5 

4.8 

200 

1,000 

 1992 

2006 

(2004) 

1997 

1997 

Aug-04 

c GADNR (1992), Chapter 391-3-19 - 

Appendix 1: Regulated Substances and Soil Concentrations that Trigger Notification (http://rules.sos.state.ga.us/docs/391/3/19/AP.pdf) Part of GA Hazardous Site Response Act (HSRA). Lund (2009) (personal communication). 

Easthope (2006), ATSDR 1,000 ppt dioxin soil standard: Letter from concerned citizens, environmental groups (http://www.trwnews.net/Documents/TRW/Req

uest%20to%20atsdr%20to%20clarify%201000

For 2,3,7,8-TCDD, notifiable concentration for the unrestricted use scenario. “These rules are promulgated to protect and enhance the quality of Georgia’s environment and to protect the public health, safety, and wellbeing of its citizens.” From feedback during field review, when this level is found in soil, it is a requirement to notify the state. Not an official soil cleanup level, this concentration is a default starting point for the cleanup level that is determined on a sitespecific basis, which in some cases may be this same concentration. Basis not provided. “The state of Georgia publishes a cleanup value corresponding to 4.8 ppt and North Carolina uses 4.1 ppt, both presumably following EPA risk 

methods, but probably with some minor change in one or more exposure parameters.” No basis provided, no further information given.

Marzone Inc./Chevron Chemical Company Superfund Site, Tifton (1996), indicated as cleanup level for residential scenarios (from EPA Region 4); corresponds to 10-4 cancer risk level,

even though risk-based cleanup levels for pesticides at the site were based on 10-6 cancer 

risk for residential exposure. For 2,3,7,8 TCDD TEQ, commercial/industrial scenario. Value is given as SCTL. 

Article peer reviewed as part of journal publication process. 

Soil values are readily available GADNR website, but derivation bais ambiguous. Some chem. specific values (e.g. diffusivity) used in the derivation of VF are not provided. Slope factors usein derivation are not provided in thAppendix, calling instead for using current values frothe EPA IntegrateRisk Information System (IRIS) or not listed in IRIS, from HEAST. Limited informatiois available via thweblinks at left, with neither the derivation methodology nor basis of underlyintoxicity values.Available online (RODS database

ppt.pdf); lists same values identified in: 

EC (2004), Dioxin Soil Cleanup Levels in Other States, cited in table available via Tittabawassee River Watch News (http://www.trwnews.net/images/StateCleanup

2006.PDF). Hirschhorn (1997a), Cleanup Levels for Dioxin Contaminated Soils. 

Hirschhorn (1997b), Two Superfund Environmental Justice Case Studies (http://www.trwnews.net/Documents/Cleanup/t

wo_superfund_environmental_just.htm). 

EPA (2004e), Woolfolk Chemical Works Site, OU #3: Amended Record of Decision (http://www.epa.gov/superfund/sites/rods/fulltext/a0404664.pdf). 
TABLE B.4 State Cleanup Levels for Dioxin in Soil: Region 4 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparency

Public Availabil

KY Aug-09 Martin (2009) (personal communication). Feedback from field review phase indicates that 

although KY is required by statue to screen against 2002 PRGs, they also recommend considering updated 2009 RSLs. They do accept site-specific parameters that may allow a soil concentration higher than that in the PRGs or RSLs, however this generally requires an Environmental Covenant to ensure that the parameters remain valid. 

4.5 Apr-09 c 130,000 (mg/kg-d)-1 KY Legislature (2009), Kentucky For 2,3,7,8-TCDD, residential scenario. KY The PRG 

(SFO) Administrative Regulations 

(http://www.lrc.state.ky.us/kar/401/100/030.ht

regulation dictates that the state use EPA Region 9 Preliminary Remediation Goals (PRGs) 

documentation is available online. 

m); based on EPA (2009a) Preliminary (see Table13 of the report for recently 

Remediation Goals harmonized regional levels). 

18 (http://www.epa.gov/region09/superfund/prg/p df/ressoil_sl_table_run_APRIL2009.pdf) & 

(http://www.epa.gov/region09/superfund/prg/pdf/indsoil_sl_table_run_APRIL2009.pdf). 

For 2,3,7,8-TCDD, industrial scenario. KY regulation dictates that the state use EPA Region 9 PRGs (see Table 13 of the report for recently harmonized regional levels). 

MS 38.2

4.26 

5 

 Feb-02 

2006 

(2004) 

c 150,000 

(CSFo) 

(mg/kg-d)-1 MSDEQ (2002), Final Regulations Governing 

Brownfield Voluntary Cleanup and Redevelopment in MS (http://www.deq.state.ms.us/MDEQ.nsf/pdf/Main_HW-2/$File/HW-2.pdf?OpenElement); based on EPA (2000) Supplemental Guidance to RAGS (http://www.epa.gov/Region4/waste/ots/healtbul.htm). Hess (2009) (personal communication), verified that EPA (1996), Soil Screening Guidance: User’s Guide (http://www.epa.gov/superfund/health/conmedia/soil/pdfs/ssg496.pdf) was used to derive MS target remediation goal (TRGs).Easthope (2006), ATSDR 1,000 ppt dioxin soil standard: Letter from concerned citizens, environmental groups (http://www.trwnews.net/Documents/TRW/Request%20to%20atsdr%20to%20clarify%201000

For 2,3,7,8-TCDD, restricted scenario, based on ingestion. Calculated using equations in EPA RAGS (2000). Slope factors (hierarchy) from EPA IRIS, HEAST, ATSDR or peer-reviewed literature. For 2,3,7,8-TCDD, unrestricted land-use scenario, based on ingestion. Calculated using equations in EPA RAGS (2000). Slope factors are to be taken from EPA IRIS, HEAST, ATSDR or peer-reviewed literature. Basis not provided. 

Target remediatiogoals are availabonline. Toxicological basfrom HEAST (outdated) is not publicly availableLimited informatiois available via thweblinks at left, with neither the derivation methodology nor 

ppt.pdf); lists same values identified in: 

EC (2004), Dioxin Soil Cleanup Levels in basis of underlyinOther States, cited in table available via toxicity values.Tittabawassee River Watch News (http://www.trwnews.net/images/StateCleanup

2006.PDF). 

5 

100 

1,000

1997 

 Sep-07 

 c Hirschhorn (1997a), Cleanup Levels for Dioxin 

Contaminated Soils. EPA (2007), ROD Summary of Remedial Alternative Selection: Picayune Wood Treating Site, Picayune (http://www.epa.gov/superfund/sites/rods/fulltext/r2007040001948.pdf). 

Indicated for Naval Seabees Center, Gulfpoint, MS; to remove contaminated soil with about 100 ppt dioxins. Commercial scenario in Gulfport, MS in 1987; “first commercial dioxin cleanup in the United States ... goal of the Air Force project is to reduce dioxin levels in the soil to less than 0.1 ppb and then to delist the soil as safe.“ Based on EPA 1998 OSWER directive. 

Article peer reviewed as part of journal publication process. 

Available online (via RODS database). 

December 2009 
December 2009 

TABLE B.4 State Cleanup Levels for Dioxin in Soil: Region 4 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparency

Public Availabil

NC 1,000 Oct-09 c NCDENR (2009), Inactive Hazardous Sites 

Branch Soil Remediation Goals (http://www.wastenotnc.org/soiltable.pdf) (link updated in October 2009); Inactive Hazardous Sites Program Guidelines for Assessment and Cleanup (http://www.wastenotnc.org/sfhome/stateleadguidance.pdf) 

For TCDD TEQ, preliminary health-based preliminary soil remediation goal (PSRG) for unrestricted land use; NCDENR indicates a target risk of 10-6 is used preliminary healthbased PSRGs based on cancer. (1,000 ppt is 

the OSWER value for residential soil, which is not based on that risk level.) NCDENR also indicates the PSRGs are adapted from the April 2009 EPA RSL tables. (Note the current 

The PSRGs are available online. 

0.64 

4 

4.1 

1,000 

4 

14.5 

2006 

(2004) 

1997 

Sep-08 

Sep-06 Sep-06 

Easthope (2006), ATSDR 1,000 ppt dioxin soil standard: Letter from concerned citizens, environmental groups (http://www.trwnews.net/Documents/TRW/Request%20to%20atsdr%20to%20clarify%201000ppt.pdf);lists same values identified in: EC (2004), Dioxin Soil Cleanup Levels in Other States, cited in table available via Tittabawassee River Watch News (http://www.trwnews.net/images/StateCleanup2006.PDF). Hirschhorn (1997a), Cleanup Levels for Dioxin Contaminated Soils. EPA (2008e), Lower Roanoke River, Weyerhaeuser Operable Unit 2, Martin County, NC, Part 2: The Decision Summary(http://www.epa.gov/superfund/sites/rods/fulltext/r2008040002458.pdf). EPA (2006e), Record of Decision Summary of Remedial Alternative Selection, Sigmon's Septic Tank Site, Statesville (http://www.epa.gov/superfund/sites/rods/fulltext/r2006040001281.pdf). DoD (2006), Final ROD, Operable Unite 6, Site 12, Marine Corps Air Station Cherry Point, Havelock (http://www.epa.gov/superfund/sites/rods/fulltext/r2006040001306.pdf); Calculation given in Appendix 2, NC DENR (2005) (http://wastenot.enr.state.nc.us/hwhome/guida

nce/pdf/HWScleanup5-05draft.pdf). 

1,000 ppt replaces the October 2008 residential value of 4.5 ppt, which is the EPA RSL for TCDD; an industrial level no longer appears in the 2009 documentation (18 ppt in 2008). For TCDD TEQ, protection of groundwater SRG. (For comparison, the EPA RSL risk-based soil screening level for protection of groundwater is 0.15 ppt.) Basis not provided. “The state of Georgia publishes a cleanup value corresponding to 4.8 ppt and North Carolina uses 4.1 

ppt, both presumably following EPA risk 

methods, but probably with some minor change in one or more exposure parameters.” No basis provided, no further information given. Mentions EPA cleanup level of 1 ppb from 1998 OSWER directive and states soil levels are below this level. The ROD calls for "monitored natural recovery" given that soil dioxin is <1 ppb.Indicated as NC soil remediation goal for dioxins. Indicates the NC soil screening level for TCDD of 14.5 ppt is back-calculated from the concentration protective of groundwater. NC Hazardous Waste Section (HWS) soil screening process sets the unrestricted use level as the lowest of the background concentration, a SSL protective of GW, or the EPA Region 9 residential PRG. In this case, the regional PRG of 3.9 was used as a final remediation goal. 

Article peer reviewed as part of journal publication process. 

Limited informatiois available via thweblinks at left, with neither the derivation methodology nor basis of underlyintoxicity values.Available online (via RODS database).Available online (via RODS database). Available online (via RODS database).

120 Jul-05 150,000 

(SFo)

(mg/kg-d)-1 EPA (2005b), Amendment to the ROD, 

Carolina Transformer Site, Fayetteville (http://www.epa.gov/superfund/sites/rods/fulltext/a0405038.pdf). 

For 2,3,7,8 TCDD TEQ, based on cancer risk. Derivation of the remediation goal was not found in this document. Action selected to “protect the local community and the environment”. 

Available online (via RODS database). 
December 2009 

TABLE B.4 State Cleanup Levels for Dioxin in Soil: Region 4 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparency

Public Availabil

SC 

3.9

16 

Aug-09 

 Aug-04 

Byrd (2009) (personal communication). 

SCDHEC (2004), Evaluation of the Koppers Inc. Site under the RCRIS Corrective Action Environmental Indicator Event Code CA723 (Human Exposures), with attachment (1999), Documentation of Environmental Indicator 

Feedback from field review indicates no state cleanup value exists for dioxin. SC uses EPA screening values, toxicity values, and guidance for risk-based cleanup levels. PRG for residential scenario. Memo with attachment does not provide derivation basis. PRG for industrial scenario. Memo does not provide derivation basis.

Memo with attachment in which values are cited is available online. 

3.2 May-04 c 150,000 

(SFo) 

(mg/kg-d)-1

Determination (http://www.scdhec.gov/environment/lwm/pubs/eipdfs/Koppers%20CA725,%20dated%20August%2019,%202004.pdf). DOE (2004), ROD, Remedial Alternative Selection for the R-Area Burning/Rubble Pits (131-R and 131-1R) and Rubble Pile (631-25G) Operable Unit (U), Aiken (http://www.epa.gov/superfund/sites/rods/fulltext/r0404088.pdf). 

Remedial goal (RG) for TCDD isomers identified, selected as the lower of the most restrictive human health RG objectives (RGOs) for expected future land use and lowest LOAELbased RGO. (RGOs calculated in WSRC 2003, RFI/RI/WPA with Baseline Risk Assessment for the R -Area Burning Rubble Pits (131-R and 131-1R) and Rubble Pile (631-25G) Operable Unit (U), WSRC-RP-2002-4183, Rev.1, June.) 

Available online (via RODS database). 

TN 50

2,5001,000 

 Sep-03  Jul-02 

Jul-03 

cc 

 c 

DHHS (2003), Residential Dioxin Contamination (http://health.state.tn.us/Environmental/PDFs/hc-e-easygoer.pdf); based on ATSDR (1998), Toxicological Profile for Chlorinated Dibenzo-p-Dioxins (http://www.atsdr.cdc.gov/toxprofiles/tp104.pdf). Bates et al. (2002), American Creosote Site Case Study: Solidification/Stabilization of Dioxins, PCP and Creosote for $64 per Cubic Yard. 

EPA (2003e), ROD, Summary of Remedial Alternative Selection for the Soil and Groundwater at the Wrigley Charcoal Site, Wrigley (http://www.epa.gov/superfund/sites/rods/fullte

xt/r0403576.pdf). 

For 2,3,7,8 TCDD TEQ. Soil screening level for dioxins based on 10-6 lifetime cancer risk over a 

70-year life span. Reflects recent ATSDR guideline. 

For 2,3,7,8 TCDD TEQ. Soil action level based on 10-4 lifetime cancer risk for future adult 

worker. For 2,3,7,8 TCDD TEQ. The ROD indicates that soil was tested for dioxin on two separate occasions and found to be below the EPA cleanup level of 1 ppb. 

ATSDR follows an external review process (e.g., the 1998 policy with the screening value was reviewed by a panel of university and Canadian health officials). 

Article peer reviewed as part of journal publication process. 

Available online. 

Available online. Available online (RODS database
December 2009 

TABLE B.5 State Cleanup Levels for Dioxin in Soil: Region 5 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparenc

Public Availab

IL 14 Jun-05 n 

(eco) 

1.4×10-5

(NOAEL) 

mg/kg-d CWLP (2005), Springfield, IL, City Water, 

Light & Power, Supplement to Part 7 of PSD Permit Application, Additional Impact Analysis for Metals (http://yosemite.epa.gov/r5/r5ard.nsf/c408a200

9710018f8625716f004d9038/df97027430f55b6

Screening level of 1.4×10-5 (or 14×10-6) mg/kg soil is 

based on the no observed adverse effect level (NOAEL) for a ring-necked pheasant – which was "used to represent closest available species and was the worst-case screening level for dioxins" – taken from ORNL technical report for DOE, "Toxicology Benchmarks for Wildlife: 

(1996 ORNL report underwent technical review; nature of peer review for the screening level 

Full derivation approach not foSummary information from toxicological stuis available onliORNL (1996). (

d862571a3005a188e/$FILE/CWLP%20Metals%20Analysis_3_14_06.pdf); based on wildlife 1996 Revision." derivation not original Nosek 

benchmark in Sample et al. (1996) found.) [1992] article is (http://www.esd.ornl.gov/programs/ecorisk/doc publicly availab

uments/tm86r3.pdf). online.) 

1,000 Apr-02 c ROD; OU 04, Sangamo Electric Dump/ Crab For Site 36, 2,3,7,8 TCDD TEQ levels exceeded Methodology an

Orchard National Wildlife Refuge, Carterville Region 9 PRGs (screening values); no cleanup assumptions fo

(http://www.epa.gov/superfund/sites/rods/fullte action was taken because concentrations deriving BHRG

xt/r0502044.pdf). were below the 1,000 ppt cleanup level from EPA provided in the 

1998 OSWER directive; that level TEQ translates is 1996 human heindicated to translate to 2.5×10-4 risk for residential baseline risk 

use. Site use is not residential so applying this value assessment anis conservative; all concentrations were less than ecological risk 1 ppb. A baseline human health potential assessment, foremediation goal (BHRG) of 1,000 ppt was identified site, not yet foufor recreational use. via open acces

60 For Site 22A, For 2,3,7,8 TCDD TEQ, a BHRG of 60 online. 

ppt was established for site workers. 

45 n For 2,3,7,8 TCDD TEQ, ecological risk-based The FS that 

 (eco) concentration (RBC) identified as interim cleanup level, based on the LOAEL per assumptions given in provides basis information has 

the feasibility study (FS) ecological risk model. been found onli

IN 45 

180 

2006 c 150,000 

(SFo) 

(mg/kg-d)-1 IDEM (2006), Risk Integrated System of 

Closure (RISC), Provisional 2006 Default Closure Levels (data sheet); personal communication from Anderson (2009); algorithms and data, including hierarchies, are stated as being from IDEM (2001), RISC Technical Guide (http://www.in.gov/idem/files/risctechguidance.pdf); also note IDEM (2009), RISC Technical Guide, Appendix 1, Default Closure Tables (http://www.in.gov/idem/files/risctech_appendix1_2006_r1.pdf), this technical guide reflects revisions since IDEM (2001) and IDEM (2006) (note the internal 2009 tables are not yet available online). 

Current provisional default closure level for TCDD in residential soil, is 4.5 ×10-5 mg/kg (direct contact); it 

is based on the cancer endpoint, with HEAST (undated) identified as the source of the SF, 150,000 per mg/kg-d. (From field feedback during the review phase, the draft internal proposed value for the residential scenario is 60 ppt, based on the slope factor of 130,000 per mg/kg-d from CalEPA.) 

Current provisional closure level for TCDD for the 

commercial/industrial scenarios is 1.8 × 0-4 mg/kg, 

the basis is the same as for the residential level. This concentration is also the default level for residential soil based on migration to ground water. (It is also the draft internal proposed value from July 

Not identified. The RISC techn

guide (2006/20which does not contain any diovalues) is availaonline. The provisional and proposed valueand their compderivation incluparameter valuand citations/ context for the toxicity values anot yet found online. 

2009, based on feedback during the field review phase.) Note the supporting documentation includes an RfD0

of 1.0×10-9 mg/kg-d; however, cancer was the 

limiting endpoint for the residential and industrial screening levels. (Note this RfD is the same as the ATSDR chronic MRL finalized in 1998.) 
December 2009 

TABLE B.5 State Cleanup Levels for Dioxin in Soil: Region 5 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparenc

Public Availab

IN (cont’d)

60

180 

1,000

 Jun-09  Jun-89 

c 

c 

130,000 

(SFo) 

(mg/kg-d)-1 IDEM (2009), Risk Integrated System of 

Closure (RISC), Proposed 2009 Default Closure Levels (data sheet); personal communication from Anderson (2009); updated levels reflect proposed changes in default algorithms and hierarchies in IDEM (2009) (same information source identified above); per feedback during field review, proposed levels may be released in late 2009 or 2010. EPA (1989c), ROD; OU 01, Wedzeb Enterprises, Inc., Lebanon (http://www.epa.gov/superfund/sites/rods/fulltext/r0589097.pdf). 

From feedback during field review, represents the Internal draft proposed residential soil default closure level for TCDD, given as 6.0 ×10-5 mg/kg 

(this is also the default closure level for residential soil, direct contact); it is based on the cancer endpoint; CALEPA (undated) is given as the basis of the oral slope factor of 130,000 per mg/kg-d (and inhalation unit risk of 38 per μg/m3). 

The proposed commercial/industrial default level for soil direct contact, and the proposed residential and commercial/ industrial level for migration to groundwater, are the same as the 2006 provisional level (180 ppt). Proposed commercial/industrial soil default closure level for TCDD, given as 1.8 ×10-4 mg/kg; with the 

same basis as the preceding entry. (This value is also the default closure level for industrial soil, as well as the default level for residential soil based on migration to ground water.) The supporting documentation also considers the noncancer endpoint, noting the chronic ATSDR MRL of 1×10-9 mg/kg-d, (and intermediate MRL of 2×10-8 mg/kg-d), as well as the CalEPA reference 

concentration of 4×10-7 mg/m3. However, cancer is 

the driving endpoint for the closure levels. For 2,3,7,8 TCDD TEQ. Dioxin found at very low levels; no cleanup action taken because the concentration was less than the cleanup level of 1,000 ppt. 

Not identified. As above. 

ROD indicates community involvement wanot significant; concerns expreby citizens and officials on remimplementation were addressed the 6/1/89 publimeeting so no formal commenwere received bWedzeb on the remedy. 
December 2009 

TABLE B.5 State Cleanup Levels for Dioxin in Soil: Region 5 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparenc

Public Availab

MI 90

90

1,000

90

 Jan-06  Aug-98 

 Jul-08 

 2006 

c c 

 c 

c 

75,000 

(SF) 

75,000 

(SF) 

(mg/kg-d) ̄1 (mg/kg-d) ̄1 

MIDEQ (2006), Attachment 1, Table 2, Soil: Residential and Commercial, (http://www.michigan.gov/documents/deq/deqrrd-OpMemo_1-Attachment1Table2SoilResidential_283553_7.pdf); from Technical Support Document, Part 201 Generic Cleanup Criteria and Screening Levels, Part 213 Tier 1 Risk-Based Screening Levels (http://www.michigan.gov/deq/0,1607,7-135-3311_4109_9846_30022-101581--,00.html); basis and equations from MIDEQ (2005), Attachment 6 (from same main document as above) (http://www.michigan.gov/documents/deq/deqrrd-OpMemo_1-Attachment6_285488_7.pdf). 

MIDEQ (1998), More Details on Dioxin 90 ppt value, Excerpt from Part 201, Generic Soil Direct Contact Criteria, Technical Support Document; developed under MIDEQ 1994 Natural Resources and Environmental Protection Act 451, Part 201 (http://www.michigan.gov/documents/deq/deqwhm-hwp-dowexcerpt_of_dcc_tsd_251913_7.pdf); 

SF context given in TSG (1990), Carcinogenicity Slope Factor for 2,3,7.8-TCDD: Overview and Recent Developments, Toxic Steering Group Meeting (http://www.michigan.gov/documents/deq/deqwhm-hwp-dow-slope_factor_251918_7.pdf). 

(Also see CalEPA [2007] for further context and citations, in Table 11 of the report.) Heltman (2008), EPA Requires Limited Dioxin Cleanup at Dow Site Absent Final Risk Levels (http://www.trwnews.net/Documents/EPA/epa072908.htm). Paustenbach (2006), Identifying Soil Cleanup Criteria for Dioxins In Urban Residential Soils: How Have 20 Years of Research and Risk Assessment Experience Affected the Analysis? (http://ndep.nv.gov/bmi/docs/060406_dioxin%20paper.pdf). 

For 2,3,7,8 TCDD TEQ. Direct contact criteria (DCC) and risk-based screening level (RBSL), protective against adverse health effects from longterm ingestion and dermal contact with soil. MIDEQ notes “of all polychlorinated and polybrominated dibenzodioxin and dibenzofuran isomers present at a facility, expressed as an equivalent concentration of 2,3,7,-tetrachlorodibenzo-p-dioxin based upon their relative potency, shall be added together and compared to the criteria for 2,3,7,8-tetrachlorodibenzo-p-dioxin. The generic cleanup criteria for 2,3,7,8-tetrachlorodibenzo-p-dioxin are not calculated according to the algorithms presented in R 299.5714 to R 299.5726. The generic cleanup criteria are being held at the values that the DEQ has used since August 1998, in recognition of the fact that national efforts to reassess risks posed by dioxin are not yet complete. Until these studies are complete, it is premature to select a revised slope factor and/or reference dose for calculation of generic cleanup criteria.” Concentration is based on a risk target of 10-5 (note 

the hazard quotient of 1 for noncancer endpoint was not used for the 90 ppt level). The slope factor (SF) is for total significant tumors per the 1986 NTP classification scheme, context is given in TSG (1990); the earlier SF from the initial Kociba et al. (1978) analysis was higher. (Note that study served as a key basis for the earlier 1 ppb value from ATSDR, and the EPA 1998 OSWER value.) TSG (1990) includes historical context from the 1980s, including the EPA Carcinogen Assessment Group (CAG) SF of 156,000 (mg/kg-d)-1 based on 

significant female tumors (liver, lung, nasal turbinates/hard palate), as the geometric mean of the Kociba analysis (151,000) and Squire analysis (161,000), adjusted for early mortality (deaths in year 1). Reanalysis per the NTP 1986 liver classification scheme produced an SF of 52,000 (mg/kg-d)-1 per liver tumors only. TSG (1990) 

cites EPA regarding FDA, CDC, and CA using SFs of 151,000 or 161,000 per mg/kg-d based on liver tumors only, from the Kociba or Squire analysis, respectively. Indicates MI waived its standard in consenting to 1 ppb for cleanup of the Riverside Blvd. site near Dow Chemical Co., and notes State regulations allow for a different cleanup level based on site-specific and other information; the amount of contaminated soil was considered too large for interim remediation; article indicates (per state officials) that this level was selected as matter of practicality. For 2,3,7,8 TCDD-TEQ; risk-based calculation reported for soil ingestion pathway, which indicates this is the driving pathway. 

(Underlying studies are from peer-reviewed literature.) Article peer reviewed as part of journal publication process. 

The DCC derivamethodology is available online

The DCC derivamethodology is available onlineis summary confor the slope fa
December 2009 

TABLE B.5 State Cleanup Levels for Dioxin in Soil: Region 5 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparenc

Public Availab

MI 990 Feb-98 c EPA (1998c), AMD, OU 03, Ott/Story/Cordova For 2,3,7,8 TCDD TEQ concentrations do not 

(cont’d.) Chemical Co., Dalton Township (http://www.epa.gov/superfund/sites/rods/fullte exceed any State or Federal requirement for industrial land use, and the MI direct contact value 

xt/a0598101.pdf). (DCV) of 0.99 ppb applies (rather than the default 

standard of 1 ppt for residential use). “If anyone were to perform any future excavation, soils 1 to 3 feet below grade may present a 1 in 100,000 chance of an individual developing cancer if that individual performs industrial work on the site for 70 years.” (Note this ROD preceded the OSWER directive and refers to the RCRA Land Disposal Restriction Universal Treatment Standard, with excavated soil greater than 1 ppb requiring off-site incineration.) Target method detection limit (TMDL) is the lowest 

value accepted by MI that lab can measure. 

MN 20 Jun-09 c 1,400,000 (mg/kg-d) ̄1 MPCA (2009), Risk-Based Guidance for the For 2,3,7,8 TCDD TEQ. The Tier 1 and 2 soil (The preceding The derivation 

(SFo) Soil - Human Health Pathway, Tier 1 and Tier 

2 SRV Spreadsheets 

reference values (SRVs) are as dry weight, for direct exposure via incidental ingestion, dermal contact, 

1999 working draft was 

methodology is described in MP

(http://www.pca.state.mn.us/cleanup/riskbased and inhalation (e.g., soil, dust), with excess lifetime provided for (1999), and upd

oc.html#pathway); 

These soil reference values (SRVs) update the Jan 1999 working draft values that were based on an SFo of 1,400,000 (mg/kg-d)-1, from 

MPCA (1999), Draft Guidelines: Risk-Based Guidance for the Soil - Human Health Pathway, Volume 2, Technical Support Document (http://www.pca.state.mn.us/cleanup/pubs/srv3_99.pdf). Hansen (2009) (personal communication). 

cancer risk (ELCR) not to exceed 10-5. The ELCR 

for chronic scenarios is 10-5; that for subchronic 

scenarios (e.g., short-term worker) is 10-6. 

Tier 1 (screening) is for residential scenarios, typically using maximum concentrations with default exposure factors (to determine if further investigation and/or remediation may be indicated). Tier 2 (simple site-specific) uses representative concentrations and site-specific conditions; standard residential, recreational and industrial use scenarios reflect reasonable maximum exposures. The SRV for Tier 1 and Tier 2 residential scenario (ELCR 10-5) 

is 20 per mg/kg-d. (Note the 1999 value was 200 per mg/kg-d and applied to chronic residential and recreational scenarios and subchronic child scenarios based on an ELCR of 10-5 – except for the 

Tier 2 child subchronic scenario, which was based on 10-6 risk; that scenario is no longer included in 

public review, with the comment period ending July 31; the 1999 working draft has remained available online.)

of specific parameter valuare given in the individual spreadsheets. MNDOH (2003is cited as the bfor the SFo is no

provided. (Note the 1999 working draft document is available online

the 2008 update.) The feedback from field review (Hansen, 2009) indicates that the Tier 1 SRV is based on an 

assumption of age-adjusted soil ingestion, rounded 

to 20 ppt. 
December 2009 

TABLE B.5 State Cleanup Levels for Dioxin in Soil: Region 5 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparenc

Public Availab

MN 25 Jun-09 c 1,400,000 (mg/kg-d) ̄1 MPCA (2009), Risk-Based Guidance for the For 2,3,7,8 TCDD TEQ. Tier 2 recreational (cont’d.)

35 75 

(SFo) Soil - Human Health Pathway, Tier 1 and Tier 

2 SRV Spreadsheets (http://www.pca.state.mn.us/cleanup/riskbasedoc.html#pathway); These soil reference values (SRVs) update the Jan 1999 working draft values that were based on an SFo of 1,400,000 (mg/kg-d)-1, from 

MPCA (1999), Risk-Based Guidance for the Soil - Human Health Pathway, Volume 2 (http://www.pca.state.mn.us/cleanup/pubs/srv3_99.pdf). Hansen (2009) (personal communication). 

scenario; ELCR of 10-5 (updated from the 1999 

value of 200 per mg/kg-d). For 2,3,7,8 TCDD TEQ. Tier 2 industrial worker; ELCR of 10-5 (updated from the 1999 value of 350 

per mg/kg-d for the chronic industrial scenario). For 2,3,7,8 TCDD TEQ. Tier 2 short-term worker scenario; ELCR of 10-6 (updated from the 1999 

value of 800 per mg/kg-d). 

1,000 Sep-08 n MPCA (2008), Second Five-Year Review 

Report for Ritari Post and Pole Superfund Site, Sebeka, Wadena County, September 2008 (http://www.epa.gov/superfund/sites/fiveyear/f2008050002503.pdf). 

For 2,3,7,8 TCDD TEQ. Action level identified in 1994 ROD, sustained through 1999 and 2008 explanation of significant difference (ESD) documents, and five-year review reports in 2003 and 2008. "Based on calculations by the Agency for Toxic Substance and Disease Registry (ASTDR) and the Centers for Disease Control (CDC), a residential cleanup criterion of 1 ppb or microgram/kilogram (g/kg) was established for 

TCDDeq." (See context for value in Tables 11 and 13 of the report.) As of the September 2008 5-year review, the site is zoned "Mixed (Agricultural/ Residential/Forestry District)" and is assessed as "Agricultural - Non-homestead." 

Adopted the ATSDR residential soil value available in 1994. 

Basis for using ATSDR value athe soil cleanup level for the site was available to public. (See subsequent information in thATSDR entry in Table 11 of the report.) 

1,000 Sep-99 c EPA (1999d), ROD AMD; OU 01, 03, MacGillis 

& Gibbs Co./ Bell Lumber & Pole Co., New Brighton (http://www.epa.gov/superfund/sites/rods/fulltext/a0599147.pdf). 

Amendment did not alter cleanup level from the 1994 ROD, with total risk meeting the 10-4 limit for 

commercial and industrial use; the surrounding area is commercial and residential. From the 1994 ROD: MN generally establishes its cleanup goals at the 10-5 level ... for PCDDs/PCDFs, the cleanup 

level is 1 g/kg. This cleanup level was developed 

by ATSDR and has been established as EPA policy. This concentration was also the practical detection limit for laboratory analysis of PCDDs/PCDFs in soil. The 1 g/kg cleanup level does exceed the 10-5 risk 

level that MPCA uses as a goal. However, the remaining cleanup levels for other site contaminants have been calculated so that total risk from all contaminants at the site will not exceed 10-4 which is 

within U.S. EPA's acceptable risk range.” 
December 2009 

TABLE B.5 State Cleanup Levels for Dioxin in Soil: Region 5 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparenc

Public Availab

OH 35.8 Oct-09 c 150,000 

(SFo) 

(mg/kg-d)-1 OHEPA (2009), Closure Plan Review 

Guidance for RCRA Facilities (http://epa.ohio.gov/portals/32/pdf/2008CPRG.pdf ); 

For 2,3,7,8 TCDD TEQ. Values are for single chemicals, direct contact with soil. Considers ingestion, dermal contact, and inhalation, with ingestion as the primary pathway. 

OHEPA documand tables avaionline. Cites E(1996) Soil Screening Guidance and E(2002) supplemental 

guidance (availonline). 

1,000 Jun-89 c 156,000 (mg/kg-d)-1 EPA (1989b), ROD; OU 01, Laskin/Poplar Oil 

Co., Jefferson Township (http://www.epa.gov/superfund/sites/rods/fulltext/r0589091.pdf). 

No cleanup action was taken because soil concentrations were below the 1,000 ppt TCDD equivalent cleanup level from the EPA 1998 OSWER directive. 

ROD displays cancer slope fafrom Superfund Public Health Evaluation Man(SPHEM) (US E1986), but SF is used to derive asite-specific diocleanup level. 

WI 0.5 May-00 n 0.0001 mg/kg-d Wheat (2000), [USCC] Dioxins and Furans Identified as risk-based standards for human and Underlying study Memo from WI 

(eco) (NOAEL) (http://mailman.cloudnet.com/pipermail/compo

st/2000-May/006755.html); WDNR, cites WI Dept. of Health memo (May 4, 1994, from Goldring, Bureau of Public Health, subject: "Revision of DOH Guidelines for Dioxin in Landspread Sludge"). 

wildlife protection, as total dioxin equivalent (TDE); indicates wildlife emphasis [hence "(eco)" in endpoint column]: Using this methodology, WI DNR “has derived ... wildlife dioxin criterion for surface spreading (i.e., no incorporation) ...” these are meant to be applied "in situations where contaminated material is spread in a thin layer on 

is from peerreviewed literature. 

Dept. of Health found online; Tet al. (1995) available via Journal of Environmental Toxicology and 

Toxicity value is from Thiel et al. (1995). the surface and not incorporated" (Thiel et al. 1995). Chemistry. 

Standard for agricultural land with grazing. 

1.2 TDE, standard for agricultural land without grazing. 
December 2009 

TABLE B.6 State Cleanup Levels for Dioxin in Soil: Region 6 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparency

Public Availabi

AR 4.5 May-09 c 130,000 

(SFo) 

(mg/k-d)-1 ARDEQ (2009a,b) AR Corrective Action 

Strategy (http://www.adeq.state.ar.us/hazwaste/branch_tech/risk_assessment.htm), (http://www.adeq.state.ar.us/hazwaste/branch_tech/cas.htm#CAS); ARDEQ website links to the EPA (Region 6) Corrective Action Strategy (http://www.epa.gov/earth1r6/6pd/rcra_c/pdo/riskman.htm). 

For 2,3,7,8-TCDD, the RSL for residential soil; AR Dept. of Environmental Quality (ARDEQ) uses EPA Region 6 medium-specific screening levels (MSSLs) as a point of departure (these are now harmonized with Regions 3 and 9 as regional screening levels, see Table 13 of the report). These generic screening levels are used early in the process, before the development of actual cleanup levels based on site-specific risk evaluations. "Arkansas has not implemented a single set of soil clean-up levels 

Regional screeninlevels are availabonline from EPA Region 6 (and Regions 3 and 9)

18 

(1,000) Apr-08 APEC (2008), Regulation No. 23, Hazardous 

Waste Management (http://www.adeq.state.ar.us/regs/files/reg23_final_080526.pdf); 

for general usage. Instead, the State uses standards set in Regulation No. 23 ..., usually arriving at a site-specific standard for each clean-up.” For 2,3,7,8-TCDD, RSL for industrial scenario. Regulation No. 23 identifies a treatment standard of 1,000 ppt for TCDD TEQ in nonwastewater hazardous waste. 

1,000 Sep-96 c EPA (1996e), ROD, OU 02, Vertac, Inc., 

Jacksonville (http://www.epa.gov/superfund/sites/rods/fulltext/r0696102.pdf); EPA (1998b), ESD, OU 02, Vertac, Inc., Jacksonville (http://www.epa.gov/superfund/sites/rods/fulltext/e0698160.pdf); 

For TCDD, the remedial objective for offsite areas OU, residential and agricultural soil, 1 ppb (also identified as the residential action level); prevent direct public contact to soil above this level, and assure risks meet 10-4 to 10-6 range. 

The ESD sustains this cleanup level and indicates further excavation was warranted (to 12 inches) where new samples exceeded 1 ppb. The five-year review stated no reassessment 

3,500 

CH2MHILL (2003), Second Five-Year Review for the Vertac Incorporated Superfund Site, Jacksonville (prepared for EPA Region 6) (http://www.epa.gov/superfund/sites/fiveyear/f04-06002.pdf). 

was needed as 1 ppb was still accepted; 2,3,7,8-TCDD was still present. For TCDD, the cleanup goal for onsite soils, based on a site-specific determination that TCDD accounted for 70% of the TCDD TEQ (thus scaled from 5 ppb remedial objective for 

5,000 

industrial use). For TCDD TEQs, remedial objective for OU 2 (soils, foundations, curbs, and underground utilities, onsite), 5 ppb based on industrial use. 

LA LDEQ (2003a), Recap Table 1 Screening 

Option: Screening Standards for Soil and Groundwater (http://www.deq.louisiana.gov/portal/LinkClick.aspx?fileticket=bIPYm4ICf9g%3d&tabid=293

The list was checked for TCDD and dioxin, and no standards were found. 

0). 
December 2009 

TABLE B.6 State Cleanup Levels for Dioxin in Soil: Region 6 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparency

Public Availabi

LA 1,000 Mar-03 LDEQ (2003b), Title 33 Part V. Hazardous For all TCDDs (as TEQ.) the treatment standard(cont’d.) Waste and Hazardous Materials, Subpart 1. Table 2 Treatment Standards for Hazardous 

Wastes (Final Rule) (http://www.deq.louisiana.gov/portal/portals/0/planning/regs/pdf/HW083fin.pdf). 

(acceptable level) for "non-waste waters" is 0.001 mg/kg. 

1,000 Jun-02 c 150,000 

(SF) 

(mg/kg-d)-1 EPA (2002), ROD, OU 01, Marion Pressure 

Treating (http://www.epa.gov/superfund/sites/rods/fulltext/r0602009.pdf); ATSDR (2006), Health Consultation: A 

For 2,3,7,8-TCDD total TEQ (note 2,3,7,8-TCDD 

had not been detected). Dioxin screening value is “based on the OSWER residential preliminary remediation goal of 0.001 mg/kg, and therefore is not directly based on a 10-6 cancer risk.” 

Review of Soil Data, Marion Pressure Treating Co., Marion, Union Parish, LA (http://www.atsdr.cdc.gov/HAC/PHA/Marion%20Pressure%20Treating%20Company/MarionPressureTreatingCoHC013106.pdf). 

From the health consultation, the health-based assessment comparison value (environmental 

medium evaluation guide) is 5×10-5 mg/kg 

(50 ppt), also indicated as the ATSDR screening value. For recreational and industrial scenario; the dioxin screening value reflects the EPA PRG for the residential scenario, 1 ppb. 

1,000 Nov-97 c 150,000 

(SFo) 

(mg/kg-d)-1 EPA (1997c), ROD, OU 01, Lincoln 

Creosote, Bossier City (http://www.epa.gov/superfund/sites/rods/fulltext/r0698047.pdf). 

For TCDD TEQ, residential scenario; ingestion of soil with dioxins/ furans meets the target risk 

range (10-4 to 10-6.) for the adult resident (RME) 

and child 5-13 (CTE) for current and assumed future conditions. “All detections of dioxins/ furans in soil and sediment were less than the 1 μg/kg (ppb) cleanup level used by EPA in some Records of Decision for residential sites.” 

1,000

10,000 

 Jul-95 c EPA (1995e), ROD, OU 01, Southern 

Shipbuilding, Slidell (http://www.epa.gov/superfund/sites/rods/fulltext/r0695093.pdf). 

For 2,3,7,8-TCDD TEQ residential scenario; remedial goal for treatment alternatives, per EPA and ATSDR. (No 2,3,7,8-TCDD was found at the site; neither TCDD nor dioxin was mentioned in either the first or second five-year review.) 

For 2,3,7,8-TCDD TEQ, extending to subsurface soil: up to 10 ppb of 2,3,7,8-TCDD allowed if the contaminated soil is covered with at least 

12 inches of clean soil, per EPA and ATSDR. 
December 2009 

TABLE B.6 State Cleanup Levels for Dioxin in Soil: Region 6 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparency

Public Availabi

LA 1,000 Apr-93 c EPA (1993a), ROD, OU 01, American For 2,3,7,8-TCDD equivalents, residential 

(cont’d.) Creosote Works, Inc., Winnfield (http://www.epa.gov/superfund/sites/rods/fullt scenario, remedial goal for alternatives with dioxin treatment. The five-year review did not 

ext/r0693086.pdf); indicate any change (2005 is most recent). No 

CH2M HILL (2005a), Second Five-Year 2,3,7,8-TCDD had actually been found. 

10,000 Review for American Creosote Works, Inc., For 2,3,7,8-TCDD TEQ, extending to subsurface 

Winnfield soil: up to 10 ppb of 2,3,7,8-TCDD allowed if the (http://www.epa.gov/superfund/sites/fiveyear/ contaminated soil is covered with at least 

f05-06003.pdf). 12 inches of clean soil, per EPA and ATSDR. 

(“It has been determined by EPA and the Agency for Toxic Substances and Disease Registry (ATSDR) as presented in the RI/FS that levels of 2,3,7,8 TCDD between 1 to 10 μg/kg do not represent a significant residential risk provided they are covered with at least 12 inches of clean soil.”) 

 NM Jun-06 NMED (2006), Technical Background 

Document For Development of Soil Screening Levels, Revision 4.0 Vol. 1 Tier 1: Soil Screening Guidance Technical Background Document, Table A-1 (ftp://ftp.nmenv.state.nm.us/hwbdocs/HWB/g

uidance_docs/NMED_June_2006_SSG.pdf). 

This table was checked for 2,3,7,8-TCDD and dioxin, and no entries were found (nor was other input provided during the field review phase). 

OK 3.9 Feb-03 c 150,000 (mg/kg-d)-1 OKDEQ (2004), Site Cleanup Using Risk- For 2,3,7,8-TCDD, screening level, residential 

(SFо) Based Decision Making (http://www.deq.state.ok.us/lpdnew/FactShee scenario; this OK website links to the earlier table of Region 6 medium-specific screening 

ts/RiskbasedDecisionGuidanceFinal.pdf); levels (now represented by joint regional 

18 38 

EPA (Region 6) (2003), Medium-Specific Screening Levels (http://www.deq.state.ok.us/LPDnew/HW/02screentable.pdf); 

screening levels, see Table 13 of the report). OKDEQ represents the target risk level of 10-5

as a policy; calculations also follow EPA (1989). For 2,3,7,8-TCDD, screening level, industrial scenario, outdoor worker. For 2,3,7,8-TCDD, screening level, industrial scenario, indoor worker. 
December 2009 

TABLE B.6 State Cleanup Levels for Dioxin in Soil: Region 6 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparency

Public Availabi

TX 1,000

5,000 

 Mar-09 c TRRP (2009), TRRP Protective 

Concentration Levels, Tables 1-5 (http://www.tceq.state.tx.us/remediation/trrp/tr

rppcls.html); TXCEQ (2005), TXCEQ Regulatory Guidance RG-366/TRRP-22: Tiered Development of Human Health PCLs (http://www.tceq.state.tx.us/comm_exec/forms_pubs/pubs/rg/rg-366_trrp_22.html); Haney (2009) (personal communication). 

Tier 1 residential soil PCL for 2,3,7,8-TCDD TEQ for both a 0.5-acre and 30-acre source area, total and combined; includes ingestion, dermal, inhalation, and vegetable consumption. "The TRRP Tier 1 protective concentration levels (PCLs) are the default cleanup standards in the TX Risk Reduction Program." A level of 1 ng TEQ/kg was cited by Paustenbach et al. (2006) as the promulgated TX value. Note the 2005 guidance indicates 2,3,7,8-TCDD TEQs, but the TX 2009 tables reflect TCDD alone; Haney (2009) clarified the basis as TEQs. 

Tier 1 commercial/industrial scenario for 2,3,7,8-TCDD TEQ for both a 0.5-acre and 30-acre source area, total and combined, as above. 

Paustenbach et al. (2006) was peer reviewed as part of the journal publication process. 

TCEQ documents available online. 

520 Sep-06 c EPA (2006f), ROD, OU 1, Jasper Creosoting Industrial scenario for 2,3,7,8-TCDD TEQ, 

17.7 

Company, Inc. (http://www.epa.gov/superfund/sites/rods/fullt

ext/r2006060001482.pdf). 

worker. The lower values of the soil direct contact PRGs for protection of both human health and the ecological receptors were selected as the final soil direct contact PRGs; 10-5 risk level. (No 2,3,7,8-TCDD was detected.)

For 2,3,7,8-TCDD toxicity equivalents, represents the Region 6 medium-specific screening level (note these are now harmonized as joint regional screening levels, see Table 11 of the report). 

1,000 Jun-00 TXNRCC (2000), Proposed Remedial Action 

Document: Toups State Superfund Site: Sour Lake, Hardin County (http://www.tceq.state.tx.us/assets/public/remediation/superfund/register/pdf0100.pdf).

Residential scenario for 2,3,7,8-TCDD; cleanup goal based on soil-to-groundwater pathway or soil ingestion/inhalation/dermal contact, whichever is lower. 

1,000 Oct-98 c EPA (1998d), ROD AMD, OU 02, United 

Creosoting Co., Conroe (http://www.epa.gov/superfund/sites/rods/fulltext/a0699032.pdf); CH2M HILL (2005b), Second Five-Year Review for the United Creosoting Company Superfund Site (http://www.epa.gov/superfund/sites/fiveyear/

Residential soil target action level for 2,3,7,8-TCDD equivalents. Based on the EPA OSWER directive. Cleanup values for sediment were the same as those for soil. (2,3,7,8-TCDD itself was not detected). The AMD states no changes were necessary from the 1989 ROD. Both fiveyear reviews found the same, no changes needed to the cleanup level. 

20,000 f05-06008.pdf); 

TDH under cooperative agreement with ATSDR (2003) Health Consultation: Sediments in Stewarts Creek, Conroe Creosoting Co. (http://www.dshs.state.tx.us/epitox/consults/cccsed_hc_fnl.pdf). 

Industrial soil target action level for 2,3,7,8-TCDD equivalents. 
December 2009 

TABLE B.7 State Cleanup Levels for Dioxin in Soil: Region 7 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

TransparencyPublic Availabilit

IA 19

72

360

1414

 Jul-09 

 2006 

(2004) 

 Jul-04 

c 

 n  n 

c 

c 

150,000 

(SFo) 

10-9 

(RfD) 

(mg/kg-d)-1

mg/kg-d 

IADNR (undated), Statewide Soil Standards, IA Land Recycling Program (LRP); personal communication from Drustrup (2009); based on risk calculation in: IA General Assembly (1998), Environmental Protection [567], Chapter 137, Iowa Land Recycling Program and Response Action Standards (http://www.iowadnr.gov/land/consites/documents/chap137.pdf) 

Easthope (2006), ATSDR 1,000 ppt dioxin soil standard: Letter from concerned citizens, environmental groups (http://www.trwnews.net/Documents/TRW/Request%20to%20atsdr%20to%20clarify%201000ppt.pdf); lists same values identified in: EC(2004), Dioxin Soil Cleanup Levels in Other States, cited in table available via TRW News (http://www.trwnews.net/images/StateCleanup2006.PDF). MIDEQ (2004), Dioxin Contamination in the Midland Area (http://www.michigan.gov/documents/deq/deqwhm-hwp-Dow-FactsFinal_251769_7.pdf). 

Residential cleanup level for TCDD based on cancer risk. Residential cleanup level for TCDD where it is the only contaminant of concern; field review feedback indicated basis is noncancer endpoint Nonresidential cleanup level for TCDD; field review feedback indicated basis is noncancer endpoint. Basis not provided.For dioxin TEQ, residential scenario. No cleanup level found from searches of IA websites or RODS database, but the MI document notes: “Of the other states that have derived safe levels for dioxin in soil, seven are lower than Michigan ... Iowa [is] at 14 ppt.” No specific reference for IA was cited or located, thus no other information was found (including for toxicity value and basis). 

Residential cleanup value based on cancer risk found online, noncancer values provided from the field via personal communication during the field review phase. Limited informatiois available via the weblinks at left, with neither the derivation methodology nor basis of underlying toxicity values.
December 2009 

TABLE B.7 State Cleanup Levels for Dioxin in Soil: Region 7 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

TransparencyPublic Availabilit

KS 60

100 

 Jun-07 c 150,000 

(SFo = 

SFi = 

SFd) 

(mg/kg-d)-1 KDHE (2007), Risk-Based Standards for KS 

RSK Manual - 4th Version (http://www.kdheks.gov/remedial/download/RSK_Manual_07.pdf); Nightingale (2009) (personal communication). 

For 2,3,7,8 TCDD, residential scenario. “Chemical-specific and media-specific risk-based cleanup goals were calculated using guidance and directives from the United States Environmental Protection Agency and various other technical resources.” For 2,3,7,8 TCDD, industrial (non-resident) scenario. 

Cleanup levels anRBC equations with soil exposure factors are available online; 1997 Health Effects Assessment. Summary Tables (HEAST), are no longer maintained

MO (1,000) Jul-09 Garoutte (2009) (personal communication). Feedback during field review indicated MO has 

not established or adopted any specific cleanup level for dioxin in soil, while also stating that the MO Department of Health and Senior Services (MDHSS) had been involved with the EPA and MDNR in establishing 1 ppb as a surface soil cleanup level for contaminated sites in MO. 

 Apr-06 MDNR (2006), MRBCA Technical Guidance 

(Appendices) (http://www.dnr.mo.gov/env/hwp/mrbca/docs/mrbca-append6-06.pdf). 

MDNR MRBCA Technical Guidance document (updated June 2008) contains guidelines for surface soil. This document was searched for 

TCDD and dioxin, but no information was found. 

MDNR document available online. 

1,000 1997 Hirschhorn (1997a), Cleanup Levels for 

Dioxin-Contaminated Soil. 

Indicated for 2,3,7,8 TCDD, residential scenario; 1 ppb for residential land use from EPA 1988 decision for Superfund cleanup at Times Beach, MO, set the stage for the policy-based level. 

 Article peer 

reviewed as part ojournal publication process. 

1,000 Sep-05 c EPA (2005c), Missouri Electric Works Sites, 

OU 02, Cape Girardeau (http://www.epa.gov/superfund/sites/rods/fulltext/r0705052.pdf ). 

For 2,3,7,8-TCDD TEQ, residential scenario. TCDD was a combustion byproduct of concern during thermal treatment of PCB-contaminated soil. TCDD soil concentrations were monitored to ensure levels below 1 ppb. 

Available online (RODS database)
December 2009 

TABLE B.7 State Cleanup Levels for Dioxin in Soil: Region 7 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

TransparencyPublic Availabilit

MO 20,000 Apr-93 c EPA (1993b), Ground Water OU 02, Syntex For 2,3,7,8-TCDD, residential scenario. Toxicity Available online 

(cont’d.) Agribusiness, Inc., Verona 

(http://www.epa.gov/superfund/sites/rods/fulltext/r0793071.pdf). 

value not found. Action level provided for excavation and treatment of surface soils (with maintenance of a vegetative cover over soils containing between 1 and 20 ppb dioxin). 

(RODS database)

1,000 Sep-86 c EPA (1986) Ellisville Site, OU 02, Ellisville 

(http://www.epa.gov/superfund/sites/rods/fulltext/r0786006.pdf). 

For 2,3,7,8-TCDD, residential scenario. Toxicity value not found. (Document updates the 1985 ROD and 1991 ROD Amendment.) Toxicity value not found. 

Available online (RODS database)

NE 

3.9

160 

Jul-09 

 Oct-08 c 150,000 

(SFo) 

(mg/kg-d)-1

Borovich (2009) (personal communication). 

NDEQ (2008), NE Voluntary Cleanup Guidance (http://www.deq.state.ne.us/Publica.nsf/23e5e39594c064ee852564ae004fa010/d243c2b56e34ea8486256f2700698997/$FILE/VCP%20Guidance%20Oct%202008.pdf). NDEQ (2006), Protocol for VCP Remediation Goals Lookup Tables (http://www.deq.state.ne.us/Publica.nsf/23e5e39594c064ee852564ae004fa010/d243c2b56e34ea8486256f2700698997/$FILE/ATTEBI5L/RG%20Protocol%20August%202006.pdf). 

Feedback during field review indicates that the remediation goals here are both screening levels and preliminary cleanup goals. The NDEQ Voluntary Cleanup Program (VCP) does allow a site to develop different risk-based cleanup levels based on site characterization and NDEQ approval. For sites not under VCP regulations, the NDEQ may use EPA RGs or mediumspecific screening levels as cleanup levels, given proper documentation. For 2,3,7,8-TCDD, residential soil; based on direct contact. For 2,3,7,8-TCDD, industrial soil; based on direct contact. 

Cleanup levels anRG equations with soil exposure factors available to public; EPA (1997a) Health Effects Assessment Summary Tables (HEAST) values fononradionuclides have not been found via open access online. 
December 2009 

TABLE B.8 State Cleanup Levels for Dioxin in Soil: Region 8 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparency

Public Availabil

CO Dec-07 CODPHE (2007), CO Soil Evaluation Values 

(CSEV) (http://www.cdphe.state.co.us/hm/csev.pdf).

The CODPHE has developed CO soil evaluation values (CSEVs), but no dioxin value was found in the table. 

CODPHE (2007) document is available online. 

MT 4.5 Dec-09 c 130,000 (mg/kg-d) ̄1 MTDEQ (2009), Soil Screening Process Some state-specific risk-based screening levels Intra-agency MTDEQ documen

18 (SFo) (Attachment C) (http://www.deq.state.mt.us/StateSuperfund/vc

raguide.asp). 

(RBSLs) are provided on website but no specific value was found for dioxin. Newly updated guidance (Attachment C) shows 2-part process, 

review. and the EPA RSL 

Table and User's Guide (EPA 

to address both direct contact and leaching to groundwater. For Part 1, flow chart directs users to screen soil dioxin concentrations based on 2009 EPA Regional Screening Levels (RSLs), which are as TCDD. (Regional EPA values were recently harmonized, see Table 13 of this report.) Values at left are for residential and industrial use, respectively. For Part 2, site contaminants are compared to the risk-based soil screening level using a dilution attenuation factor of 10. 

Beyond this value for TCDD (e.g., for other dioxins) “The DEQ uses the most current toxicity data, including toxicity equivalency factors (TEFs), as much as possible. Because of this, the DEQ requires dioxin/furan calculations for soil and water samples to use the World Health Organization (WHO) 2005 TEFs.” (These TEFs are presented in Van den Berg et al. [2006].) 

2009e,f) with equations are available online. 

62.5

103 

 Jun-08 MTDEQ (2008), Final Feasibility Study Report, 

KRY Site(http://www.deq.state.mt.us/StateSuperfund/K

PT/FinalFSJuly2008/FinalFSreportComplied.pdf).

For 2,3,7,8-TCDD TEQ, residential scenario. For 2,3,7,8-TCDD TEQ, industrial scenario. Limited information; the document states that the cleanup levels are based on risk analysis and soil modeling in Appendix C, which cannot be found 

MTDEQ (2008a) available online, bnot the appendix with the key data

736 736 

online. For 2,3,7,8-TCDD TEQ, residential subsurface scenario. For 2,3,7,8-TCDD TEQ, industrial subsurface scenario. 

ND No state-specific guidelines for dioxin soil 

cleanup levels were identified from the ND Department of Health, Division of Waste Management website.

SD Nov-09 SDDENR (2009), Lookup Table For Surface 

Soil (0-3.2 feet) (http://denr.sd.gov/des/gw/LookUpTables/Lookup_Tables.aspx). 

No soil screening or cleanup values for dioxin were identified on the SDDENR website. The SDDENR has developed look-up tables with Tier 1 action levels calculated for some soil contaminants leaching to ground water based on 10-5 cancer risk, but no value was identified for 

dioxin. 

SDDENR (2009) website and lookutables are availabonline (website laupdated November 24). 

1,000 Jun-96 c U.S. AF (1996), ROD, Ellsworth Air Force 

Base, OU 08, Ellsworth AFB (http://www.epa.gov/superfund/sites/rods/fulltext/r0896124.pdf). 

For dioxin TEQ, international toxic equivalents corresponding to dioxin concentrations were below the 1,000 ppt level of concern for residential soil; risk associated with dioxins in surface soil is in the 10-5 range. 

 Available online. 
December 2009 

TABLE B.8 State Cleanup Levels for Dioxin in Soil: Region 8 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparency

Public Availabil

UT 

1,000

May-06 

 Jun-00 

UT (2006), UT LUST Program Screening Levels for Soil and Groundwater (http://www.undergroundtanks.utah.gov/docs/tank_news_sum06.pdf). U.S. ACE (2000), Final OU 4 Hotspot, ROD Amendment for OU 4, Ogden Hill (http://www.epa.gov/superfund/sites/rods/fulltext/a0800533.pdf). 

UTDEQ has developed initial screening levels (ISLs), for leaking underground storage tanks (LUSTs). No screening level was found for dioxin. 

For 2,3,7,8-TCDD TEQ, remedial action goals for site soils where future land use is commercial/industrial. 

LUST table (2006is available online at the UTDEQ website. 

Available online (RODS database

37

3,700 1,0001,000 

 Dec-97 

 Sep-92 

c 150,000 

(SFO) 

(mg/kg-d)-1 EPA (1997d), Explanation of Significant 

Difference, Petrochem Recycling Corp./Ekotek Plant, Salt Lake City, OU 01 (http://www.epa.gov/superfund/sites/rods/fulltext/e0898175.pdf). 

EPA (1992b), ROD, Ogden Defense Depot (DLA), OU 04, Ogden (http://www.epa.gov/superfund/sites/rods/fulltext/r0892061.pdf). 

RMCOEH-UT DFPM (undated), A Comparison of Dioxin Levels Found in Residential Soils of Davis County Utah with Those Found in Residential Soils in the Denver Front Range (http://www.wasatchintegrated.org/PDF/Davis

%20Dioxin%20Study.pdf). 

For 2,3,7,8-TCDD TEF, derived from the soil performance standard, based on a combination of soil preliminary remediation goals (PRGs) and applicable or relevant and appropriate requirements (ARARs). Value is for a cancer risk of 10-6 (site wide) for the commercial worker for 

exposure to soil via ingestion and dermal absorption. These performance standards “represent the levels of protection that must be achieved through containment of the low-level contaminated soils”. For 2,3,7,8-TCDD TEF, derived from the soil hot spot performance standard based on a combination of soil PRGs and applicable or relevant and appropriate requirements (ARARs). Value is for localized areas with elevated cancer risk above 10-4 (hot spots) for the industrial worker for exposure to soil via ingestion and dermal absorption. These performance standards “establish the levels of soils that must be excavated and shipped for offsite disposal”. 

For 2,3,7,8-TCDD TEQ. Value derived from the Dioxin Disposal Advisory Group as the recommended total equivalency value of less than 1 ppb of dioxin in contaminated soil. (Note this document preceded the 1998 OSWER directive.) 

For 2,3,7,8-TCDD TEQ. Davis County study sampled soil for dioxin, using the ATSDR screening and action levels as a point of reference, based on De Rosa et. al. (1997). (Note the date of this document is at least 2001, per its most recent internal citation.) 

Available online (RODS database

Available online (RODS database

 Available online. 
December 2009 

TABLE B.8 State Cleanup Levels for Dioxin in Soil: Region 8 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparency

Public Availabil

WY 4.5 

0.15 

4.5

(Jul-09) 

 Jun-09 

c 

c

130,000 (mg/kg-d) ̄1 Griffin (2009) (personal communication). 

WYDEQ (2009), Fact Sheet #12: Soil Cleanup Level Lookup Table (http://deq.state.wy.us/volremedi/downloads/Current%20Fact%20Sheets/FS_12.pdf), 

Field feedback indicated this was the cleanup level for dioxin (unrestricted/residential scenario).Field feedback indicated this was the value for the residential scenario based on migration to groundwater. For 2,3,7,8-TCDD, residential scenario, based on direct contact; the fact sheet links to the Region 9 PRG table. Prior to the WYDEQ June update, the residential value was 3.9 ppt. Regional EPA values were recently harmonized, see related entry in Table 13 of the report. The fact sheet indicates: “Note that prior to evaluation, concentrations of dioxins and furans may be adjusted using appropriate toxicity equivalency factors (TEF) [see EPA (1989) for further information].” Nevertheless, the fact sheet links to the Regional screening value, which is based on TCDD. (Thus, in this report, the latter is indicated as the general basis for the WY value.) For 2,3,7,8-TCDD, industrial scenario, based on direct contact. Prior to the WYDEQ June update, the Regional screening value of 16 ppt was identified for the industrial value. No industrial cleanup levels were identified in the June update of the WY fact sheet, leaving this instead to a site-specific determination. (Regional EPA values were recently harmonized, see related entry in Table 13 of the report.) 

130,000 

(SFo) 

(mg/kg-d) ̄1 The WYDEQ 

document is available online. 

4.3

38

 May-04 150,000 

(SFo) 

(mg/kg-d) ̄1 U.S. AF (2004b), ROD, OU 10, Landfill 7 and 

Fire Protection Area 1, F.E. Warren Air Force Base (http://www.epa.gov/superfund/sites/rods/fulltext/r0804104.pdf). 

For 2,3,7,8-TCDD; used 2001 EPA Region 3 industrial and residential RBCs for dioxin as initial screening levels. Levels of 2,3,7,8- TCDD did not exceed RBCs. One dioxin and one furan did exceed RBC levels and further evaluation is provided in the baseline risk assessment (BRA) (Landfill 7/FPTA 1 RI [U.S. AF 2002d]) (which could not be found online)). The ROD indicates the SFo is from IRIS. 
December 2009 

TABLE B.9 State Cleanup Levels for Dioxin in Soil: Region 9 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transpare

Public Avai

AS 4.5 Oct-08 c 130,000 (mg/kg-d)-1 GEPA (2008)/HDOH (2008a), Evaluation of For dioxin TEQs, environmental screening levels The equation

(Amer. Samoa) 

(SFo) Environmental Hazards at Sites with Contaminated Soil and Groundwater – Pacific 

Basin Edition 

(ESLs), based on direct soil contact, 10-6 risk 

(except for construction/trench worker: 10-5 risk per lower exposure frequency and duration). 

toxicity value derive Tier 1 environmenta

18 

(http://hawaii.gov/health/environmental/hazard/pdf/pbvolume1mar2009.pdf); Volume 2, Appendix 1 (http://hawaii.gov/health/environmental/hazard/pdf/pbvolume2app1mar2009.pdf); Volume 2, Appendices 2-9 (http://hawaii.gov/health/environmental/hazard/pdf/pbvolume2app2to9mar2009.pdf). Approach is based on Guam EPA procedures; calculations are supported by the spreadsheet at HDOH (2008b), Evaluation of Environmental Hazards at Sites with Contaminated Soil and Groundwater - Hawai‘i Edition (http://www.hawaiidoh.org/references/HDOH%202008.pdf). 

“Although prepared specifically for Guam EPA, the use of well-accepted, US Environmental Agency (USEPA) standards, models and protocols should permit flexible use of the guidance throughout tropical and subtropical areas of the Pacific Basin region with little or no modification.” “The screening levels are based on slight modifications to the USEPA Region IX Preliminary Remediation Goals and more recent Regional Screening Levels (USEPA 2004, 2008). The modifications as used in Hawai’i have been discussed in detail with USEPA Region IX. No adjustment of the HDOH Tier 2 screening levels is necessary for use in Guam and other areas of the Pacific Basin.” 4.5 ppt is the Tier 1 environmental screening level for unrestricted use, shallow soil: ≤3 m, below ground surface (bgs). Tier 1 environmental screening level for commercial/industrial land use scenario, shallow 

screening levdifferent exposcenarios are available onliEquations proAppendix 2, afrom 2008 EPdocumentatio[“The Tier 1 environmentascreening levupdated in Oc2008 to incorupdates to the USEPA RegioScreening Le(USEPA 2008This informatavailable onli

soil (≤3 m bgs). 

1,500 Tier 1 environmental screening level, deep soil 

(>3 m bgs) for: unrestricted (residential) use, 

commercial/industrial use, and construction/trench 

worker. 

42 1,400,000 (mg/kg-d)-1 For dioxin TEQs, Tier 2 action levels, direct 

(SFo) contact, 10-4 risk; especially intended for redevelopment of former agricultural fields but 

apply to any site. Guidelines rather than strict, 

regulatory, cleanup requirements; alternate values can be proposed in site-specific assessments. Unrestricted (residential) land use: <42 ppt: No action required. 42-450 ppt: “Within USEPA range of acceptable health risk.” Removal and offsite disposal of small, easily identifiable hot spots is recommended. 

Consider other measures to reduce daily soil exposure. For large areas, notify future homeowners of elevated levels. 

450 130,000 (mg/kg-d)-1 >450 ppt: Unrestricted (residential) land use is not 

(SFo) recommended in the absence of remedial action to reduce exposure. 

170 1,400,000 (mg/kg-d)-1 <170 ppt: Commercial/industrial use, no action. 

(SFo) 170-1,800 ppt: Within USEPA range of acceptable 

health risk. Remedial actions vary depending on site-specific factors, including current and planned 

use, available options for onsite isolation or offsite 

disposal, and technical/economical constraints. 

1,800 130,000 (mg/kg-d)-1 >1,800 ppt: Commercial/industrial use not 

(SFo) recommended in absence of remedial actions to reduce potential exposure. 
December 2009 

TABLE B.9 State Cleanup Levels for Dioxin in Soil: Region 9 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transpare

Public Avai

AZ 4.5 May-07 c 130,000 (mg/kg-d)-1 AZDEQ (2007), Title 18. Environmental Quality For 2,3,7,8-TCDD, residential use, 10-6 risk level. The AZDEQ 

Chapter 7. Remedial Action (http://www.azsos.gov/public_services/Title_18/18-07.htm); ADHS (1999), Deterministic Risk Assessment 

The 2007 soil remediation levels (SRLs) update the 1997 values and apply unless the site was characterized before May 5, 2007 and remediated or a risk assessment completed before May 5, 2010 (in which case the 1997 values apply). The 

documentatioADHS guidandocument are available onliHowever, spe

45 

160

3838

 2006 

(2004) 

 Apr-01 

 c 

c 

c 

Guidance (http://www.azdhs.gov/phs/oeh/pdf/guidance.pdf). Easthope (2006), ATSDR 1,000 ppt dioxin soil standard: Letter from concerned citizens, environmental groups (http://www.trwnews.net/Documents/TRW/Request%20to%20atsdr%20to%20clarify%201000ppt.pdf); lists same values identified in: EC (2004), Dioxin Soil Cleanup Levels in Other States, cited in table available via Tittabawassee River Watch News (http://www.trwnews.net/images/StateCleanup2006.PDF). EPA (2001), ESD, Tucson International Airport Area, OU 02 (http://www.epa.gov/superfund/sites/rods/fulltext/e0901612.pdf).

target risk of 10-6 must be used if current or 

intended future use of a contaminated site is a child care facility or school where children <18 are reasonably expected to be in frequent, repeated contact with soil. Per field feedback (Stralka, 2009), AZDEQ has adopted the recently harmonized RSL (see Table 13 in this report). 

For 2,3,7,8-TCDD, residential use, 10-5 risk level. 

This value updates the 1997 residential SRL of 38 ppt (provided here as context for entries below). As stated: a risk level of 10-5 may be used for any 

carcinogen other than a known human carcinogen.For 2,3,7,8-TCDD, nonresidential use, based on cancer risk; this updates the 1997 SRL of 240 ppt (provided here as context for the entry below). Basis not provided, but appears to reflect the AZDEQ 1997 residential SRL (which was updated to 45 ppt in 2007, see entry above). 

For 2,3,7,8-TCDD, residential scenario; shown in table excerpted from AZ Administrative Code Title 18, Chapter 7, Article 2, Appendix A, Soil Remediation Levels (listed as current through December 31, 1999). 

toxicity values to derive the Sare not provideither documeLimited informavailable via tweblinks at leneither the demethodology basis of undetoxicity values

Available onliRODS databa

240 For 2,3,7,8-TCDD, nonresidential scenario. 
December 2009 

TABLE B.9 State Cleanup Levels for Dioxin in Soil: Region 9 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transpare

Public Avai

CA 4.6

19 

4 

 Jan-05 

2006 

(2004) 

c 130,000 

(SFo) 

(mg/kg-d)-1 CalEPA (2005a), Human-Exposure-Based 

Screening Numbers Developed to Aid Estimation of Clean-Up Costs for Contaminated Soil (http://www.oehha.ca.gov/risk/pdf/screenreport010405.pdf). CalEPA (2005b), Use of CA Human Health Screening Levels (HHSLs) in Evaluation of Contaminated Properties (http://www.calepa.ca.gov/Brownfields/documents/2005/CHHSLsGuide.pdf); CalEPA (2009d), Human Health Risk Assessment (HHRA) Note 2, Interim, Remedial Goals for Dioxins and Dioxin-Like Compounds for Consideration at California Hazardous Waste Sites; (http://www.dtsc.ca.gov/AssessingRisk/upload/HHRA_Note2_dioxin-2.pdf). 

Easthope (2006), ATSDR 1,000 ppt dioxin soil standard: Letter from concerned citizens, environmental groups (http://www.trwnews.net/Documents/TRW/Req

uest%20to%20atsdr%20to%20clarify%201000ppt.pdf); lists same values identified in: EC (2004), Dioxin Soil Cleanup Levels in Other States, cited in table available via Tittabawassee River Watch News (http://www.trwnews.net/images/StateCleanup2006.PDF). 

For 2,3,7,8-TCDD, residential land use, HHSL. Note that a value of 50 ppt as dioxin TEQ was recently suggested an interim remedial goal developed for consideration at sites in California. This value is for a target risk of 10-6 and is based 

on the HHSL, with an adjustment that reflects multiplying by 10 “to account for the minimal contribution of soil and dust to the dioxin human body burden, as shown in the University of Michigan dioxin exposure study.” (Note the study has recently undergone independent technical review.) The CalEPA document is suggested residential remedial goal should only be considered if a farming scenario is not relevant. Note that the remedial goal based on noncancer effects is 78 ppt, so the cancer-based goal is protective. The noncancer-based value is calculated for the residential child, with 1 pg/kg-d considered the minimum risk level for the neurological endpoint (based on data for monkeys, described in ATSDR (1998/2008). For 2,3,7,8-TCDD, commercial/industrial land use, HHSL. Basis not provided. 

Information oHHSLs and thderivation basavailable onliincluding the of the cancer factor, via the CalEPA OEHwebsite. 

Limited informavailable via tweblinks at leneither the demethodology basis of undetoxicity values
December 2009 

TABLE B.9 State Cleanup Levels for Dioxin in Soil: Region 9 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transpare

Public Avai

CA 3.9 Mar-08 c 130,000 (mg/kg-d) ̄1 NAVFAC (2008), ESD for OU 3 ROD, Camp For 2,3,7,8-TCDD TEQ. Original remediation goal Available onli

(cont’d.) (SFo) Pendleton 

(http://www.epa.gov/superfund/sites/rods/fulltext/e2008090002747.pdf). 

of 4.1 ng/kg (from 2/21/08 ROD for OU 5) was revised to 3.9 ng/kg, based on the 2004 EPA Region 9 PRG-residential for 2,3,7,8-TCDD. The basis of the original 4.1 ng/kg was identified as the 

RODS databa

44

3.9 May-08 

eco

c 130,000 

(SFo) 

(mg/kg-d) ̄1 AFRL (2008), ROD AFRL Soil and Debris 

Sites OUs 4 and 9, Edwards AFB (http://www.epa.gov/superfund/sites/rods/fulltext/r2008090002438.pdf). 

EPA-derived mean rural soil TCDD TEQ concentration (EPA 2000). 

Site-specific ecological PRG; ESD, original ROD was written in 1996; a remediation goal was developed for 2,3,7,8 TCDD at Site 1A, burn ash 

site. "The value for both Tier 1 and Tier 2 exposure estimates for mammalian receptors was 0.000044. The upper-bound limit for an acceptable exposurepoint concentration for the dioxins (the eco PRG) is 

approximately 4.4×10-5 mg/kg (44 pg/g) or less."

For 2,3,7,8-TCDD TEQ, adopted the EPA Region 9 PRG-residential value of 3.9 ng/kg as the remediation goal for dioxin, but indicated that detected levels were not of concern. 

Available onliRODS databa

1.2

300 

27

1,000 

 Feb-95 

 Feb-01 

Mar-99 

c 

 c 

 c 

DoA (1995), Fort Ord, OU 05, Marina (http://www.epa.gov/superfund/sites/rods/fulltext/r0995138.pdf). DOE (2001), Interim Site-Wide ROD for LLNL, Site 300 (http://www.epa.gov/superfund/sites/rods/fulltext/r0901606.pdf). 

EPA (1999b), ROD, McCormick & Baxter Creosoting Co., OU 01 and 03, Stockton (http://www.epa.gov/superfund/sites/rods/fullte

xt/r0999044.pdf). 

For 2,3,7,8-TCDD, adult residential scenario; PRG taken from the Draft Final Technical Memorandum, Preliminary Remediation Goals, Fort Ord, CA (June 24, 1994). PRGs were developed per procedures in the EPA Risk Assessment Guidance for Superfund, Vols. 1-2. For 2,3,7,8-TCDD, PRG for construction worker scenario. For 2,3,7,8-TCDD TEQ, cleanup standard at building 850 Firing Table area. The Region 9 industrial PRG was adopted as the cleanup standard. For 2,3,7,8-TCDD TEQ. EPA 1998 OSWER directive (Approach for Addressing Dioxin in Soil at CERCLA and RCRA Sites) taken into account in deriving the cleanup standard. 

Available onliRODS databaHowever, the technical memorandum not found onliAvailable onliRODS databa(Note Region have since beharmonized wRegions 3 anscreening levAvailable onliRODS databa

1,000 Sep-03 c EPA (2003g) ROD AMD, Selma Treating Co. 

OU 1, Selma (http://www.epa.gov/superfund/sites/rods/fulltext/a0903016.pdf). 

For 2,3,7,8-TCDD TEQ, the actual concentration is unclear because of a units/symbol issue. The 2003 ROD amendment identifies a value for dioxins/furans TEQ from the original (1988) ROD as “1 microgram per kilogram (pg/kg)” -- and then adjacent to this entry identifies the value from the 2003 ESD as “1 pg/kg.” It is not clear if the more recent value is intended to also be 1 microgram/kg, or 1,000 ppt (which seems more likely than 0.001 ppt). (Note the 2003 update did change concentrations for two other contaminants.) 

Available onliRODS databa
December 2009 

TABLE B.9 State Cleanup Levels for Dioxin in Soil: Region 9 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transpare

Public Avai

GM (Guam) 

4.5

18 

1,500 

 Oct-08 c 130,000 

(SFo) 

(mg/kg-d)-1 GEPA (2008)/HDOH (2008a), Evaluation of 

Environmental Hazards at Sites with Contaminated Soil and Groundwater – Pacific Basin Edition (http://hawaii.gov/health/environmental/hazard/pdf/pbvolume1mar2009.pdf); Volume 2, Appendix 1 (http://hawaii.gov/health/environmental/hazard/pdf/pbvolume2app1mar2009.pdf); Volume 2, Appendices 2-9 (http://hawaii.gov/health/environmental/hazard/pdf/pbvolume2app2to9mar2009.pdf). Calculations supported by spreadsheet at HDOH (2008b), Evaluation of Environmental Hazards at Sites with Contaminated Soil and Groundwater - Hawai‘i Edition (http://www.hawaiidoh.org/references/HDOH%202008.pdf). 

For 2,3,7,8-TCDD TEQ, environmental screening levels based on direct soil contact, 10-6 risk (except 

construction/ trench worker: 10-5 risk per lower 

exposure frequency and duration). “Although prepared specifically for Guam EPA, the use of well-accepted, US Environmental Agency (USEPA) standards, models and protocols should permit flexible use of the guidance throughout tropical and subtropical areas of the Pacific Basin region with little or no modification.” “The screening levels are based on slight modifications to the USEPA Region IX Preliminary Remediation Goals and more recent Regional Screening Levels (USEPA 2004, 2008). The modifications as used in Hawai’i have been discussed in detail with USEPA Region IX. No adjustment of the HDOH Tier 2 screening levels is necessary for use in Guam and other areas of the Pacific Basin.” (This updated earlier guidance prepared for the Commonwealth of the Mariana Islands DEQ. (See the AS entry where these values are first discussed for further details, across all columns.) Unrestricted land use: 4.5 is the Tier 1 environmental screening level for shallow soil (≤3 m bgs). For 2,3,7,8-TCDD TEQ. Commercial/industrial land use, Tier 1 environmental screening level, for shallow soil (≤3 m bgs). (See the AS entry where these values are first discussed for further details.) For 2,3,7,8-TCDD TEQ. Construction/trench worker scenario, Tier 1 environmental screening level for deep soil (>3 m bgs). (See the AS entry where these values are first discussed for further details.) 

Equations are provided in H(2008) Appenadopted from 2008 EPA RSdocumentatioslope factor wtaken from thRSL table. Tinformation is available onli
December 2009 

TABLE B.9 State Cleanup Levels for Dioxin in Soil: Region 9 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transpare

Public Avai

GM (cont’d.)

42

450170 

170-

1,800 1,800 

390

 Oct-08  Aug-07 

c 

 c 

1,400,000 

(SFo) 

 130,000 

(SFo) 

 1,400,000 

(SFo) 

130,000 

(SFo) 

(mg/kg-d)-1

(mg/kg-d)-1(mg/kg-d)-1(mg/kg-d)-1

GEPA (2008)/HDOH (2008a) (cont’d.)

U.S. AF (2007a), ROD for Sites 7, 16, 17, 31, and 36, Northwest Field, Andersen AFB (http://www.epa.gov/superfund/sites/rods/fulltext/r2008090002420.pdf). 

For 2,3,7,8-TCDD TEQ, Tier 2 action levels, direct contact, 10-4 risk; especially intended for 

redevelopment of former agricultural fields but apply to any site. These are guidelines rather than strict, regulatory, cleanup requirements, and alternate values can be proposed in site-specific assessments. (See the AS entry where these values are first discussed for further details, across all columns.) Unrestricted (residential) use: <42 ppt: No action required. (See parallel AS entry for lower bound context.) 42-450 ppt: “Within USEPA range of acceptable health risk. Consider removal and offsite disposal of localized spill areas when possible in order to reduce potential exposure (not required for large, former field areas).” >450 ppt: Residential use not recommended in the absence of remedial actions to reduce potential exposure. (See parallel AS entry for SF/update context.) 

For 2,3,7,8-TCDD TEQ, Tier 2 action levels for commercial/industrial scenario: <170 ppt: No action required. (See parallel AS entry for lower bound context.) 

170-1,800 ppt: “Within USEPA range of acceptable health risk. Remedial actions vary depending on site-specific factors, including current and planned use, available options for onsite isolation or offsite disposal, and technical and economical constraints.” >1,800 ppt: Commercial/industrial use not recommended in the absence of remedial actions to reduce potential exposure. (See parallel AS entry for SF/update context.) 

For 2,3,7,8-TCDD TEQ, cleanup level, unrestricted use. Cleanup level for removal action at Site 36; Value reflects PRG for industrial use. Document states “The cleanup level for dioxins in surface soil was equivalent to 10-4 resident child 

cancer risk ... Although the cleanup level for TCDD-TEQ was initially established to be equivalent to 10-4 cancer risk, confirmation sample 

results were below the residential PRG and were therefore protective of 10-6 cancer risk. Risks to 

human receptors (future resident adults and children – the most conservative receptor population) were reduced to acceptable risk levels, allowing for unlimited use and unrestricted access to the land.” 

Equations are provided in H(2008) Appenadopted from 2008 EPA RSdocumentatiofactors were tfrom EPA RSand MNDOH This informatavailable onliAvailable onliRODS databa
December 2009 

TABLE B.9 State Cleanup Levels for Dioxin in Soil: Region 9 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transpare

Public Avai

GM (cont’d.) 

9.139.43 

 Dec-03 c 150,000 (mg/kg-d)-1 U.S. AF (2003b), ROD for Urunao Dumpsites 1 

and 2, Urunao OU, Andersen AFB (http://www.epa.gov/superfund/sites/rods/fulltext/r0904002.pdf). 

For 2,3,7,8-TCDD TEQ. For resident child, surface soil, remedial goal objective (RGO) corresponding to 10-6 risk level. 

For 2,3,7,8-TCDD TEQ. For resident child, subsurface soil, RGO corresponding to 10-6 risk 

level. 

3.9 

1,000 July-02 c 150,000 

(SFo) 

(mg/kg-d)-1 U.S. AF (2002), Final ROD for Harmon Annex 

OU, Andersen AFB (http://yosemite.epa.gov/r9/sfund/r9sfdocw.nsf/3dc283e6c5d6056f88257426007417a2/1dca993480c9ecd788257205002bf81e/$FILE/andersen%20ROD%20harmon%20annex.pdf). 

For 2,3,7,8-TCDD TEQ. The evaluation used this 

screening toxicity value “taken from USEPA Region IX Preliminary Remediation Goals (PRGs) Table, USEPA, November 2000” as a comparison value in screening site soil concentrations. For 2,3,7,8-TCDD TEQ, Considered for soil at IRP Site 39/Harmon Substation, 1,000 ppt reflects OSWER directive; Region 9 PRGs were also considered; “Subsurface soil exceeded the Region 9 residential PRG (0.0038 μg/kg), but was 

less than the industrial PRG (0.03 μg/kg). This 

TEQ concentration is considerably lower than the subsurface dioxin cleanup standard of 1.0 μg/kg established by the U.S. AF, GEPA, and the Office of Solid Waste and Emergency Response (OSWER) directive (IT/OHM, 1999c), and no further action is required. Therefore, the area on the southwest corner of Parcel A was not recommended for remediation.” 
December 2009 

TABLE B.9 State Cleanup Levels for Dioxin in Soil: Region 9 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transpare

Public Avai

HI 3.9 

42 

390 

Sum-08 

Sum-08

c 

 c 

150,000 

(SFo) 

1,400,000 

(SFo) 

150,000 

(SFo) 

(mg/kg-d) ̄1 

(mg/kg-d)-1(mg/kg-d)-1

HDOH (2008b), Evaluation of Environmental Hazards at Sites with Contaminated Soil and Groundwater - Hawai‘i Edition (http://www.hawaiidoh.org/references/HDOH%

202008.pdf); calculations supported by spreadsheet (gepatier2.deoct2008.xls) are available via this weblink. Also reflects information from: EPA (1996), Soil Screening Guidance: User's Guide (http://www.epa.gov/superfund/health/conmedia/soil/pdfs/ssg496.pdf). HDOH (2008b), Evaluation of Environmental Hazards at Sites with Contaminated Soil and Groundwater - Hawai‘i Edition (http://www.hawaiidoh.org/references/HDOH%202008.pdf); HDOH (2006), Proposed dioxin action levels for East Kapolei Brownfield Site (http://hawaii.gov/health/environmental/hazard/pdf/dioxinactionlevelsmarch2005.pdf); MNDOH (2003), Cancer Risk Assessment for Dioxins (www.canceractionny.org/cancerriskassessment.htm). 

For 2,3,7,8-TCDD TEQ. From the EPA Soil Screening Guidance, for Environmental Action Levels (EAL), Volume 1: "this document incorporates and significantly expands upon the USEPA Preliminary Remediation Goals and more recent Regional Screening Levels." Report is similar to the GEPA report of same name developed for the Pacific Basin (see Guam), much is the same, although some scenarios and terminology differ. (Note the June 2008 Brewer memo in Appendix 8 of the GEPA (2008)/HDOH (2008a) report indicates that ambient levels (as dioxin TEQ) in undisturbed areas in former sugar can fields (in HI) appear to be <50 ppt. Tier 1 environmental action level (EAL) for unrestricted use scenario, includes potential use for residential housing, schools, day care, and health care. For 2,3,7,8-TCDD TEQ. HDOH established Tier 2 action levels primarily to guide remedial actions for former agricultural fields. They do not serve as strict regulatory cleanup requirements. Tier 2 action levels were initially proposed in 2006 document but updated in 2008. GEPA updated values further to reflect toxicity value updates in 2008 RSLs (see GM). Residential/recreational, low risk, 42 ppt: no further action required; memo from Environmental Risk Assessment HEER Office to Brownfields Coordinator HEER Office. “This memo presents an 

approach for assessing dioxin contamination at the East Kapolei Brownfield site” ... ”The dioxin action levels are not recommended for use in Hawai’i.” 

For 2,3,7,8-TCDD TEQ, residential/recreational scenarios, intermediate risk; >42- 390 ppt. Residential/recreational, high risk, >390 ppt: residential use not recommended absent remedial actions to reduce potential exposure. Process: determine area-wide background total dioxins (e.g., across the 400-acre site as a whole). If background is <42 ng/kg, identify “hot spots” as areas that exceed 42 ng/kg TEQ dioxins. Evaluate the feasibility of removing or capping soil to reduce long-term exposure (see below). If background is >42 but <390, identify “hot spots” as areas that 

exceed background and similarly evaluate the feasibility of remove or capping soil. For areas that exceed 42 ng/kg dioxins (2,3,7,8-TCDD TEQ) but are within background, recommended (but not required) are exposure minimization measures and notice to future homeowners of potential health risks (e.g., include in CC&Rs, notice to deeds). 

Toxicity values considered OSWER 2003 hierarchy (IRIS, PPRTVs); EPA Supplemental Guidance for Developing Soil Screening Levels for Superfund Sites, Peer Review Draft. 

The EPA RSL and User's Gwith equationavailable onliPPRTVs are publicly availaonline. Equations are provided in H(2008) Appenadopted from 2008 EPA RSdocumentatioSlope factors taken from EPtables and MN(2003). This information is available onli
December 2009 

TABLE B.9 State Cleanup Levels for Dioxin in Soil: Region 9 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transpare

Public Avai

HI (cont’d.)

170 

1,600 

4 

Sum-08

2006 

(2004) 

 c 1,400,000 

(SFo) 

150,000 

(SFo) 

(mg/kg-d)-1

(mg/kg-d)-1

Easthope (2006), ATSDR 1,000 ppt dioxin soil standard: Letter from concerned citizens, environmental groups (http://www.trwnews.net/Documents/TRW/Req

uest%20to%20atsdr%20to%20clarify%201000ppt.pdf); lists same values identified in: EC (2004), Dioxin Soil Cleanup Levels in Other States, cited in table available via Tittabawassee River Watch News (http://www.trwnews.net/images/StateCleanup2006.PDF). 

For 2,3,7,8-TCDD TEQ, industrial/commercial, low risk, <170 ppt; see residential/recreational, low risk. 

For 2,3,7,8-TCDD TEQ, industrial/commercial, intermediate risk, 170-1,600 ppt; see residential/recreational, intermediate risk. For 2,3,7,8-TCDD TEQ , industrial/commercial, high risk, >1,600 ppt; see residential/recreational, high risk. 

Basis not provided. Limited inform

available via tweblinks at leneither the demethodology basis of undetoxicity values

NMI 4.5 Oct-08 c 130,000 (mg/kg-d)-1 GEPA (2008)/HDOH (2008a), Evaluation of For 2,3,7,8-TCDD TEQ, environmental screening Equations are 

(North’n Mariana (SFo) Environmental Hazards at Sites with Contaminated Soil and Groundwater – Pacific levels (ESLs), based on direct soil contact, 10-6 risk (except construction/ trench worker: 10-5 risk provided in H

(2008) Appen

Islands) Basin Edition per lower exposure frequency and duration). adopted from 

(http://hawaii.gov/health/environmental/hazard/pdf/pbvolume1mar2009.pdf); Volume 2, Appendix 1 and Appendices 2-9 (http://hawaii.gov/health/environmental/hazard/pdf/pbvolume2app1mar2009.pdf; http://hawaii.gov/health/environmental/hazard/pdf/pbvolume2app2to9mar2009.pdf); calculations supported by spreadsheet at HDOH (2008b), Evaluation of Environmental Hazards at Sites with Contaminated Soil and Groundwater - Hawai‘i Edition (http://www.hawaiidoh.org/references/HDOH%202008.pdf); 

“Although prepared specifically for Guam EPA, the use of well-accepted, US Environmental Agency (USEPA) standards, models and protocols should permit flexible use of the guidance throughout tropical and subtropical areas of the Pacific Basin region with little or no modification.” “The screening levels are based on slight modifications to the USEPA Region IX Preliminary Remediation Goals and more recent Regional Screening Levels (USEPA 2004, 2008). The modifications as used in Hawai’i have been discussed in detail with USEPA Region IX. No adjustment of the HDOH Tier 2 screening levels is necessary for use in Guam and other areas of the Pacific Basin.” (This updated the 

2008 EPA RSdocumentatioslope factor wtaken from thRSL table. Tinformation is available onli

GEPA 2008 updates information from HDOH (2005), Screening for Environmental Concerns at Sites with Contaminated Soil and Groundwater, Volume 1: Summary Tier 1 Lookup Tables (http://www.deq.gov.mp/artdoc/Sec8art133ID453.pdf); Stralka (2009) (personal communication). 

earlier guidance prepared for the Commonwealth of the Mariana Islands DEQ. See the AS entry where these values are first discussed for further details, across all columns.) Unrestricted land use: 4.5 is Tier 1 ESL for shallow soil (≤3 m bgs). (Field input indicated NMI follows 

current Guam guidance, which updated HDOH [2005], which previous indicated a value of 3.9 ppt). 
December 2009 

TABLE B.9 State Cleanup Levels for Dioxin in Soil: Region 9 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transpare

Public Avai

NMI 18 Oct-08 c 130,000 (mg/kg-d)-1 For 2,3,7,8-TCDD TEQ. Commercial/industrial 

(cont’d.) (SFo) land use, Tier 1 ESL for shallow soil (≤3 m bgs). (See AS where these values are first discussed for 

further details.) (Field input indicated this update from the previous value of 16 ppt from HDOH [2005].) 

1,500 For 2,3,7,8-TCDD TEQ. Construction/trench 

worker scenario, Tier 1 environmental screening level for deep soil (>3 m bgs). (See AS where these values are first discussed for further details.) (Field input indicated this update from the previous value of 2,000 ppt identified from HDOH [2005].) 

42 Oct-08 c 1,400,000 

(SFo) 

(mg/kg-d)-1 GEPA (2008)/HDOH (2008a) (cont’d.) For 2,3,7,8-TCDD TEQ, Tier 2 action levels, direct 

contact, 10-4 risk; especially intended for 

redevelopment of former agricultural fields but apply to any site. These are guidelines rather than strict, regulatory, cleanup requirements, and alternate values can be proposed in site-specific assessments. (See AS where these values are 

first discussed for further details.) Unrestricted (residential) use: <42 ppt: No action required. (See parallel AS entry for lower bound context.) 42-450 ppt: “Within USEPA range of acceptable health risk. Consider removal and offsite disposal of localized spill areas when possible in order to reduce potential exposure (not required for large, former field areas).” 

450 130,000 

(SFo) 

(mg/kg-d)-1 >450 ppt: Residential use not recommended in the 

absence of remedial actions to reduce potential exposure. (See AS for SF context.) 

170 1,400,000 

(SFo) 

(mg/kg-d)-1 For 2,3,7,8-TCDD TEQ, Tier 2 action levels, 

commercial/industrial scenario: <170 ppt: No action required. (See parallel AS entry for lower bound context.) 

170-

1,800 

170-1,800 ppt: “Within USEPA range of acceptable health risk. Remedial actions vary depending on site-specific factors, including current and planned use, available options for onsite isolation or offsite disposal, and technical and economical constraints.” 

1,800 130,000 

(SFo) 

(mg/kg-d)-1 >1,800 ppt: Commercial/industrial use not 

recommended in absence of remedial actions to reduce potential exposure. (See parallel AS entry for SF/update context.) 
December 2009 

TABLE B.9 State Cleanup Levels for Dioxin in Soil: Region 9 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transpare

Public Avai

NV 3.9

17.7 38.1 

 Feb-09 c 150,000 

(SFo) 

(mg/kg-d)-1 NDEP (2009), Basic Comparison Levels 

(http://ndep.nv.gov/bmi/docs/bcl_calculations_table09.pdf); NDEP (2009), User's Guide and Background Technical Document for NDEP Basic Comparison Levels (BCLs) for Human Health for the BMI Complex and Common Areas (http://ndep.nv.gov/bmi/docs/bcl_guidance09.pdf). 

2,3,7,8-TCDD, residential soil. (Values designed for use at the BMI Complex and Common Areas in Henderson, NV.) Identifies HEAST as the source of the toxicity value. (Note that the table title indicates Basic Comparison Levels 2008, but the footer of this document identifies the date of February 12, 2009, as supported by the weblink.) 

2,3,7,8-TCDD, for industrial/commercial worker (outdoor). 2,3,7,8-TCDD, for industrial indoor worker without dermal exposure. 

Former HEAStables not avaequations useidentify complevels for resiand industrial scenarios are available onli
December 2009 

TABLE B.9 State Cleanup Levels for Dioxin in Soil: Region 9 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transpare

Public Avai

NV 4 2006 Easthope (2006), ATSDR 1,000 ppt dioxin soil Basis not provided. Limited inform(cont’d.) (2004) standard: Letter from concerned citizens, environmental groups available via t

weblinks at le

(http://www.trwnews.net/Documents/TRW/Req neither the de

uest%20to%20atsdr%20to%20clarify%201000 methodology ppt.pdf); lists same values identified in: EC basis of unde(2004), Dioxin Soil Cleanup Levels in Other toxicity valuesStates, cited in table available via Tittabawassee River Watch News (http://www.trwnews.net/images/StateCleanup

2006.PDF). 

TT 4.5 Oct-08 c 130,000 (mg/kg-d)-1 GEPA (2008)/HDOH (2008a), Evaluation of Field feedback for TT during the review phase Toxicity value

(Trust Territories) 

(SFo) Environmental Hazards at Sites with Contaminated Soil and Groundwater – Pacific 

Basin Edition (http://hawaii.gov/health/environmental/hazard/

pdf/pbvolume1mar2009.pdf); (http://hawaii.gov/health/environmental/hazard/pdf/pbvolume2app1mar2009.pdf); 

(http://hawaii.gov/health/environmental/hazard/

pdf/pbvolume2app2to9mar2009.pdf); Stralka (2009) (personal communication). 

indicated soil cleanup levels are determined on a site-specific basis (Stralka, 2009). Other online information suggests the context summarized for AS may be considered, so that information is offered here for context.) The environmental screening levels (ESLs) are based on slight modifications to the USEPA Region IX Preliminary Remediation Goals and more recent Regional Screening Levels (USEPA 2004, 2008). The modifications as used in Hawai’i have been discussed in detail with USEPA Region IX. No adjustment of the HDOH Tier 2 screening levels is necessary for use in Guam and other areas of the Pacific Basin.” 

equations usederive Tier 1 environmentascreening levdifferent exposcenarios are available onliHDOH docum

Guam EPA (2008) updated the earlier guidance prepared for the Commonwealth of the Mariana Islands, DEQ. Although not specifically prepared for TT, the document states, “Although prepared specifically for Guam EPA, the use of well- accepted, US Environmental Agency (USEPA) standards, models and protocols should permit flexible use of the guidance throughout tropical and subtropical areas of the Pacific Basin region with little or no modification.” For 2,3,7,8-TCDD, Tier 1 ESL, residential scenario for shallow soil (≤3 m, below ground surface, bgs) 

is 4.5 ppt. 

18 For 2,3,7,8-TCDD, Tier 1 ESL, industrial scenario, 

shallow soil (≤3 m bgs). 

1,500 For 2,3,7,8-TCDD, Tier 1 ESL, construction/trench 

worker scenarios, deep soil (>3 m bgs). 
TABLE B.9 State Cleanup Levels for Dioxin in Soil: Region 9 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transpare

Public Avai

TT 42 Oct-08 c 1,400,000 (mg/kg-d)-1 GEPA (2008)/HDOH (2008a), Evaluation of (See the AS entry where these values are first Equations ar

(cont’d.) (SFo) Environmental Hazards at Sites with Contaminated Soil and Groundwater – Pacific 

Basin Edition (http://hawaii.gov/health/environmental/hazard/

pdf/pbvolume1mar2009.pdf); (http://hawaii.gov/health/environmental/hazard/pdf/pbvolume2app2to9mar2009.pdf) see Appendix 8; 

discussed for further details, across all columns.) In addition to the Tier 1 ESL values, HDOH established Tier 2 action levels primarily to guide remedial actions for former agricultural fields. They do not serve as strict regulatory cleanup requirements. Values were initially proposed in 2006 document but updated in 2008 to reflect most recent toxicological data from EPA RSLs. 

provided in Appendix 2 o2008 documadopted from 2008 RegionRSLs. Slope factors were from the EPA tables (curre

HDOH (2006), Proposed dioxin action levels for East Kapolei Brownfield Site (http://hawaii.gov/health/environmental/hazard/pdf/dioxinactionlevelsmarch2005.pdf). 

Tier 2 action levels for TCDD (TEQs), residential scenario: <42 ppt: No action required. 42-450 ppt: Removal and offsite disposal of small, easily identifiable hot spots recommended. Consider other measures to reduce daily exposure 

value) and M(2003) propovalue. This information iavailable onl

450 130,000 

(SFo) 

(mg/kg-d)-1

to soil. For new developments, notify future homeowners of elevated levels of dioxin on the property. (See parallel AS entry for lower bound context.) 

>450 ppt: Residential use not recommended in absence of remedial actions to reduce potential exposure. (See parallel AS entry for SF/update context.) 

170 

170-

1,800 1,800

 1,400,000 

(SFo) 

 130,000 

(SFo) 

(mg/kg-d)-1

(mg/kg-d)-1

For TCDD (TEQs), Tier 2 action levels, industrial scenario: <170 ppt: No action required. (See parallel AS entry for lower bound context.) 

170-1,800 ppt: “Within USEPA range of acceptable health risk. Remedial actions vary depending on site-specific factors, including current and planned use, available options for onsite isolation or offsite disposal, and technical and economical constraints.” >1,800 ppt: Commercial/industrial use not recommended in absence of remedial actions to reduce potential exposure. (See parallel AS entry for SF/update context.) 

December 2009 
December 2009 

TABLE B.10 State Cleanup Levels for Dioxin in Soil: Region 10 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparenc

Public Availab

 AK 38 

47 63 39

440 

0.4

Jun-08

 Jan-04 

Jun-03 

 Jul-96 

 c 

c 

 c 

c 

150,000 

(SFо) 

150,000 

(mg/kg-d)-1

(mg/kg-d)-1

ADEC Division of Spill Prevention and Response, Contaminated Sites Program (2008a), Cleanup Levels Guidance (http://www.dec.state.ak.us/spar/csp/guidance/cleanuplevels.pdf); 

ADEC Division of Spill Prevention and Response, Contaminated Sites Program (2008b), Cumulative Risk Guidance (http://ddoe.dc.gov/ddoe/lib/ddoe/Riggs_Remedy_

94.pdf). ADEC Division of Spill Prevention and Response (2004), Dioxin and the Haines-Alaska Pipeline (http://www.dec.state.ak.us/spar/csp/docs/hfp/hfpdioxin_factsh_1_04.pdf). 

EPA (2003d), ESD, OU 01, Arctic Surplus, Fairbanks (http://www.epa.gov/superfund/sites/rods/fulltext/e

1003009.pdf); EPA (2008d), First Five Year Review Report for Arctic Surplus Salvage Yard Superfund Site, Fairbanks (http://yosemite.epa.gov/r10/CLEANUP.NSF/sites/fiveyr/$FILE/Arctic%20Surplus%20First%20121808.pdf). EPA (1996d), ROD, OU 01, Standard Steel and Metal Salvage Yard (USDOT), Anchorage (http://www.epa.gov/superfund/sites/rods/fulltext/r1096141.pdf); U.S. ACE, (2008) Second Five-Year Review Report for Standard Steel and Metal Salvage Yard (USDOT), Anchorage (http://www.epa.gov/superfund/sites/fiveyear/f2008100002158.pdf). 

For 2,3,7,8-TCDD based on direct contact with soil, exposure frequency 330 d/y. 

For 2,3,7,8-TCDD based on direct contact with soil, exposure frequency 270 d/y. For 2,3,7,8-TCDD based on direct contact with soil, exposure frequency 200 d/y. Residential scenario, for dioxins; ADEC adopted the Region 9 PRG for TCDD but calculated value based on TR of 10-5 instead 

of 10-6

Industrial scenario for dioxins. Did not alter original 1995 ROD; value reflects risk-based concentration (RBC) for 10-5 risk level. 

For 2,3,7,8 TCDD TEQ. Residential scenario screening value for 10-6 risk level. Five-year 

reviews have not indicated any change to the cleanup level. 

Document does not mention any intra-agency or external review. 

Equations/tables each element of cleanup level equation are givethe ADEC documentation, wis available onlinEquation basis foRegion 9 PRG aADEC documenavailable online Available online (RODS databaseAvailable online (RODS database
December 2009 

TABLE B.10 State Cleanup Levels for Dioxin in Soil: Region 10 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparenc

Public Availab

ID 1,000 Apr-03 c EPA (2003c), ESD, OU 03, Idaho National 

Engineering Laboratory (USDOE), Idaho Falls (http://www.epa.gov/superfund/sites/rods/fulltext/e1003133.pdf); USDOE (2007), Five Year Review of CERCLA Response Actions at the INL (http://yosemite.epa.gov/r10/CLEANUP.NSF/sites/INEEL/$FILE/DOE-NE-ID-11201-R3.pdf). 

For 2,3,7,8-TCDD TEQ, based on EPA 1998 OSWER directive. 

Available online (RODS database

1,000 Aug-02 c EPA (2006b), Poles, Incorporated Integrated For 2,3,7,8-TCDD TEQ , residential scenario; Available online 

5,000-

20,000 

Assessment (http://yosemite.epa.gov/R10/CLEANUP.NSF/9f3c21896330b4898825687b007a0f33/434a255cbae5217d88256b560065cb04?OpenDocument); 

EPA (2002), Poles Incorporated Dioxin/Furan Sampling, Surface Soil Samples Analytical Results Summary, Oldtown (http://yosemite.epa.gov/R10/CLEANUP.NSF/9f3c21896330b4898825687b007a0f33/434a255cbae5217d88256b560065cb04/$FILE/Soil%20Results.PDF). 

EPA OSWER PRGs; based on dioxin screening of surface soil samples from a residential area nearby Poles Inc. and Idaho Hill Elementary School in Oldtown. For 2,3,7,8-TCDD TEQ , industrial scenario; per EPA OSWER PRGs based on dioxin screening of surface soil samples taken from Poles Inc. in Oldtown. 

(RODS database

 OR 4.5 Sep-09 c 130,000 (mg/kg-d)-1 ORDEQ (2009), Risk-Based Concentrations RBC for 2,3,7,8-TCDD; residential; direct Substantial Equations used 

12 20 

(http://www.deq.state.or.us/lq/pubs/docs/RBDMTable.pdf); ORDEQ (2003), Risk-Based Decision Making for the Remediation of Petroleum-Contaminated Sites (http://www.deq.state.or.us/lq/pubs/docs/RBDMGuidance.pdf); 

contact via ingestion, dermal, or inhalation. RBC for 2,3,7,8-TCDD; urban residential; direct contact via ingestion, dermal, or inhalation. RBC for 2,3,7,8-TCDD; occupational; direct contact via ingestion, dermal, or inhalation. 

revisions made in 2003 with input from TPH Generic Remedy Work Group along with DEQ employees; 

the derivation cafound online in thORDEQ (2003) document for the remediation of petroleumcontaminated sit

150 

4,200 

19 66 

140 

Bailey (2009) (personal communication). RBC for 2,3,7,8-TCDD; construction; direct 

contact via ingestion, dermal, or inhalation. RBC for 2,3,7,8-TCDD; excavation; direct contact via ingestion, dermal, or inhalation. 

RBC for 2,3,7,8-TCDD; residential; leaching to groundwater. RBC for 2,3,7,8-TCDD; urban residential; leaching to groundwater. RBC for 2,3,7,8-TCDD; occupational; leaching to groundwater. 

updated in 2009. (Appendix B). 
December 2009 

TABLE B.10 State Cleanup Levels for Dioxin in Soil: Region 10 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparenc

Public Availab

OR 

(cont’d.)

3.9

16 

3.9 

 May-05 

2006 

(2004) 

c 150,000 (mg/kg-d)-1 ORDEQ (2005), Pre-Calculated Hot Spot Look-Up 

Tables (http://www.deq.state.or.us/lq/pubs/docs/cu/PreCalculatedHotSpotLookupTables.pdf). 

Easthope (2006), ATSDR 1,000 ppt dioxin soil standard: Letter from concerned citizens, environmental groups(http://www.trwnews.net/Documents/TRW/Reques

t%20to%20atsdr%20to%20clarify%201000ppt.pdf); lists same values identified in: EC (2004), Dioxin Soil Cleanup Levels in Other States, cited in table available via Tittabawassee River Watch (TRW) News, (http://www.trwnews.net/images/StateCleanup2006.PDF). 

RBC for 2,3,7,8-TCDD, residential scenario for exposure by ingestion, inhalation of vapors/particulates, and dermal contact. RBC for 2,3,7,8-TCDD; industrial scenario for exposure by ingestion, inhalation of vapors/particulates, and dermal contact. 

Basis not provided. Limited informati

available via the weblinks at left, neither the derivmethodology nor basis of underlyitoxicity values.
December 2009 

TABLE B.10 State Cleanup Levels for Dioxin in Soil: Region 10 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparenc

Public Availab

 WA 11

1,500 

6.67 

50 

to 

1,000 

8.7 

875 

107.7

6.67 

 Jun-09 

Jan-98 

2006 

(2004) 

Sep-03 

 Feb-00 

c c 

150,000 

(SFo) 

(mg/kg-d)-1 WADEC (2009), Cleanup Levels and Risk 

Calculations (https://fortress.wa.gov/ecy/clarc/Reporting/CLARCReporting.aspx). WADEC (1998), Fact Sheet: Controlling Metals and Dioxins in Fertilizers (http://www.ecy.wa.gov/news/1998news/fert.html). 

Easthope (2006), ATSDR 1,000 ppt dioxin soil standard: Letter from concerned citizens, environmental groups (http://www.trwnews.net/Documents/TRW/Reques

t%20to%20atsdr%20to%20clarify%201000ppt.pdf); lists same values identified in: EC (2004), Dioxin Soil Cleanup Levels in Other States, cited in table available via Tittabawassee River Watch (TRW) News, (http://www.trwnews.net/images/StateCleanup2006.PDF). EPA (2003f), Final ROD, OU 10, Oeser Company Superfund Site Remedial Action, Bellingham, (http://www.epa.gov/superfund/sites/rods/fulltext/r

1003135.pdf). EPA (2000), Wyckoff Co./Eagle Harbor Superfund Site, Soil and Groundwater Operable Units, Bainbridge Island, OU 02,04 (http://www.epa.gov/superfund/sites/rods/fulltext/r1000047.pdf); U.S. ACE (2007), Second Five-Year Review Report for the Wyckoff./Eagle Harbor Superfund Site, Bainbridge Island, Kitasp County(http://www.epa.gov/superfund/sites/fiveye

ar/f2007100001727.pdf). 

For 2,3,7,8-TCDD. Unrestricted scenario; 

Method B, Carcinogen, Standard Formula Value, Direct Contact (ingestion only); Cleanup Levels and Risk Calculation (CLARC) tool, a searchable database developed and maintained by the WA Department of Ecology. 

For 2,3,7,8-TCDD. Industrial scenario; Method C, Carcinogen, Standard Formula Value, Direct Contact (ingestion only); CLARC tool, a searchable database developed and maintained by the WA Department of Ecology. 

For 2,3,7,8-TCDD TEQ. Used as a final cleanup level for dioxins but it is possible that a higher cleanup level could be used if there are no exposure pathways or the existing pathways have been mitigated. This level was established by Model Toxics Control Act (MTCA) Method B Residential Soil Standard from the MTCA. For 2,3,7,8-TCDD TEQ. Residential scenario for direct exposure via ingestion of dioxins; screening level, adopted per ATSDR (these levels are used as screens to trigger a more comprehensive, site-specific evaluation of potential human exposure). 

Basis not provided.For 2,3,7,8-TCDD TEQ, site-specific cleanup level derived from WA Dept. of Ecology, MTCA Method C for industrial scenario, 

10-5 risk level. 

Residential scenario for 2,3,7,8-TCDD toxicity equivalency factor (TEF), reasonable maximum exposure (RME) concentration, 

2.52 x 10-5 cancer risk from EPA (1994b). 

Soil cleanup levels in the ROD were based on MTCA method B TEQ calculations. The second five-year report concludes that the minor changes in the basis for TEQ calculations would not significantly change the level of protectiveness. The only changes made were for other dioxin compounds (not 2,3,7,8-TCDD). Soil cleanup level for 2,3,7,8-TCDD TEQ. 

"Although CLARC has undergone review to ensure the quality of the information provided, there is no assurance that CLARC is free from errors."

"CLARC includetechnical informarelated to the establishment of cleanup levels uthe Model Toxics Control Act CleaRegulation, chapter 173-340 WAC." 

Limited informatiavailable via the weblinks at left, neither the derivmethodology nor basis of underlyitoxicity values.

Available online (RODS database

Available online (RODS database
December 2009 

TABLE B.10 State Cleanup Levels for Dioxin in Soil: Region 10 

State 

Soil 

Conc 

(ppt)

Date 

Endpoint 

Basis 

Toxicity Reference 

Value Information Source Context Notes Nature of Peer 

Review 

Transparenc

Public Availab

WA 4 Sep-97 c EPA (1997b), ROD, OU 01, Old Navy Landfill screening level, for 2,3,7,8-TCDD, Available online 

(cont’d) Dump/Manchester Laboratory (USEPA/NOAA), Manchester 

(http://www.epa.gov/superfund/sites/rods/fulltext/r1097201.pdf); 

10-6 cancer risk; MTCA Method C for 

industrial scenario. 

(RODS database

270 

6.7 Jul-94 

U.S. ACE (2004), First Five-Year Review Report for Manchester Annex Superfund Site, Kitsap County (http://www.epa.gov/superfund/sites/fiveyear/f04-10009.pdf). EPA (1994c), ROD, OU 02, Naval Air Station, Whidbey Island (Ault Field) (http://www.epa.gov/superfund/sites/rods/fulltext/r1094077.pdf); DoN (2004), Final Five-Year Review Operable Units 1 through 5 Naval Air Station, Whidbey Island, Oak Harbor (http://www.epa.gov/superfund/sites/fiveyear/f04-10003.pdf). 

For 2,3,7,8-TCDD TEQ, cleanup level. Residential scenario for dioxin; 10-6 risk level.

Neither five-year review mention any changes in dioxin levels. 

Available online (RODS database

400 200 

2,000 

50,000 

May-93 EPA (1993c), ROD, OU 01, EPA Superfund 

Record of Decision: American Crossarm & Conduit Co., Chehalis (http://www.epa.gov/superfund/sites/rods/fulltext/r

1093060.pdf); EPA (2004g), Second Five-Year Review Report for American Crossarm & Conduit Co. Superfund Site, Chehalis (http://www.epa.gov/superfund/sites/fiveyear/f04-10004.pdf). 

For 2,3,7,8 TCDD TEQ. Residential scenario for incidental soil ingestion for dioxin, RME, calculated over a lifetime (75 y), upper-bound 95th percentile, Region 10 assumptions. 

Neither five-year review mention any changes in dioxin-contaminated soil. For 2,3,7,8 TCDD TEQ. Industrial scenario for dioxin; RME for landfill. For 2,3,7,8 TCDD TEQ. Industrial scenario for dioxin; RME for mill. For 2,3,7,8 TCDD TEQ. Industrial scenario for dioxin; RME for treatment areas. 

Available online (RODS database
 

 

B.2 REFERENCES 

ADEC (Alaska Department of Environmental Conservation), 2004, Dioxin and the HainesAlaska Pipeline, Division of Spill Prevention and Response, Contaminated Sites 

Program (Jan.); http://www.dec.state.ak.us/spar/csp/docs/hfp/hfpdioxin_factsh_1_04.pdf. 

ADEC, 2008a, Cleanup Levels Guidance, Division of Spill Prevention and Response, 

Contaminated Sites Program (June 9); 

http://www.dec.state.ak.us/spar/csp/guidance/cleanuplevels.pdf. 

ADEC, 2008b, Cumulative Risk Guidance, Division of Spill Prevention and Response, 

Contaminated Sites Program (June 9); 

http://ddoe.dc.gov/ddoe/lib/ddoe/Riggs_Remedy_94.pdf. 

ADEM (Alabama Department of Environmental Management), 2008, Alabama Risk-Based 

Corrective Action Guidance Manual (April); 

http://www.adem.state.al.us/LandDivision/Guidance/ARBCAApril2008final.pdf. 

ADHS (Arizona Department of Health Sciences), 1999, Deterministic Risk Assessment 

Guidance (March 15); http://www.azdhs.gov/phs/oeh/pdf/guidance.pdf. 

AFRL (Air Force Research Laboratory), 2008, Record of Decision Air Force Research 

Laboratory Soil and Debris Sites Operable Units 4 and 9, Edwards Air Force Base, 

CA1570024504, Kern and San Bernardino Counties, CA (May); 

http://www.epa.gov/superfund/sites/rods/fulltext/r2008090002438.pdf. 

Anderson M., (2009), personal communication from M. Anderson (IDEM, Indianapolis, IN) to 

M. Mangino (EPA Region 5, Chicago, IL) (June 19). 

APEC (Arkansas Pollution Control and Ecology Commission), 2008, Regulation No. 23, 

Hazardous Waste Management (April 25); 

http://www.adeq.state.ar.us/regs/files/reg23_final_080526.pdf. 

ARDEQ (Arkansas Department. of Environmental Quality), 2009a, Arkansas Corrective Action 

Strategy, Technical Branch, Hazardous Waste Division; 

http://www.adeq.state.ar.us/hazwaste/branch_tech/risk_assessment.htm. 

ARDEQ, 2009b, Hazardous Waste Division-Technical Branch; 

http://www.adeq.state.ar.us/hazwaste/branch_tech/cas.htm#CAS. 

ASTM (American Society for Testing and Materials), 1995, Standard Guide for Risk-Based 

Corrective Action Applied at Petroleum Release Sites, West Conshohocken, PA (DOI: 

10.1520/E1739-95R02). 

ATSDR (Agency for Toxic Substances and Disease Registry), 1998/2008b, Toxicological Profile 

for Chlorinated Dibenzo-p-Dioxins, U.S. Department of Health and Human Services 

(DHHS), Atlanta, GA (Dec.); http://www.atsdr.cdc.gov/toxprofiles/tp104.pdf; Appendix B 

(policy guideline) updated Sept. 2008. 

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Response, EPA 540-R-94-009. 

U.S. EPA (Region 10), 1994c, EPA Superfund Record of Decision: Naval Air Station, Whidbey 

Island (Ault Field), EPA ID: WA5170090059, OU 02, Whidbey Island, WA, 05/17/1994, 

EPA/ROD/R10-94/077 (July 2); 

http://www.epa.gov/superfund/sites/rods/fulltext/r1094077.pdf. 

U.S. EPA, 1995a, Assessing Dermal Exposure from Soil, Region III, Office of Superfund 

Programs, EPA/903-K-95-003 (Dec.); 

http://www.epa.gov/reg3hwmd/risk/human/info/solabsg2.htm. 

U.S. EPA (Region 3), l995b, Region III Biological Technical Assistance Group Screening 

Levels -- Draft. (Sept.), as cited in U.S. ACE (2003). 

U.S. EPA (Region 3), 1995c, Region III Risk-Based Concentration Tables (Oct. 20). 

U.S. EPA (Region 9), 1995d, EPA Superfund Record of Decision, Fort Ord, EPA ID: 

CA7210020676; Marina, CA, 04/13/1995, EPA/ROD/R09-95/138 (April 13); 

http://www.epa.gov/superfund/sites/rods/fulltext/r0995138.pdf. 

U.S. EPA (Region 6), 1995e, EPA Superfund Record of Decision: Southern Shipbuilding, EPA 

ID: LAD008149015, OU 01, Slidell, Louisiana, 07/20/1995, EPA/ROD/R06-95/093; 

http://www.epa.gov/superfund/sites/rods/fulltext/r0695093.pdf. 

U.S. EPA (Region 9), 1996a, Region 9 Preliminary Remediation Goals, San Francisco CA 

(S.J. Smucker, Regional Toxicologist). 

U.S. EPA, 1996b, Soil Screening Guidance: Technical Background Document, 

EPA/540/R-95/128, Office of Solid Waste and Emergency Response (May); 

http://www.epa.gov/superfund/health/conmedia/soil/index.htm#user 

U.S. EPA, 1996c, Soil Screening Guidance: User's Guide, Publication 9355.4-23, Office of Solid 

Waste and Emergency Response (July); 

http://www.epa.gov/superfund/health/conmedia/soil/pdfs/ssg496.pdf. 

U.S. EPA (Region 10), 1996d, EPA Superfund Record of Decision: Standard Steel & Metal 

Salvage Yard (USDOT), EPA ID: AKD980978787, OU 01, Anchorage, AK, 07/16/1996, 

EPA/ROD/R10-96/141 (July 16); 

http://www.epa.gov/superfund/sites/rods/fulltext/r1096141.pdf. 

U.S. EPA (Region 6), 1996e, EPA Superfund Record of Decision: Vertac, Inc., EPA ID: 

ARD000023440, OU 02, Jacksonville, Arkansas, 09/17/1996, EPA/ROD/R06-96/102; 

http://www.epa.gov/superfund/sites/rods/fulltext/r0696102.pdf. 

U.S. EPA (Region 7), 1996f, EPA Superfund Record of Decision: Des Moines TCE, EPA ID: 

IAD980687933, OU 02, 04, Des Moines, IA, 12/13/1996, EPA/ ROD/ EPA/ROD/R07­

97/030 (Dec. 13) http://www.epa.gov/superfund/sites/rods/fulltext/r0797030.pdf. 

U.S. EPA, 1997a, Health Effects Assessment Summary Tables (HEAST): Annual Update, FY 

1997 (July), Office of Research and Development and Office of Emergency and 

Remedial Response, Washington, DC. 

U.S. EPA (Region 10), 1997b, EPA Superfund Record of Decision: Old Navy Dump/Manchester 

Laboratory (USEPA/NOAA), EPA ID: WA8680030931, OU 01, Manchester, WA, 

09/30/1997, EPA/ROD/R10-97/201 (Sept. 30);; 

http://www.epa.gov/superfund/sites/rods/fulltext/r1097201.pdf. 

U.S. EPA (Region 6), 1997c, EPA Superfund Record of Decision: Lincoln Creosote, EPA ID: 

LAD981060429, OU 01, Bossier, Louisiana, 11/26/1997, EPA/ROD/R06-98/047 

(Nov. 26); http://www.epa.gov/superfund/sites/rods/fulltext/r0698047.pdf. 

U.S. EPA (Region 8), 1997d, EPA Superfund Explanation of Significant Differences: Petrochem 

Recycling Corp./Ekotek Plant, EPA ID: UTD093119196, OU 01, Salt Lake City, UT, 

December 2009 Page B-69 
12/09/1997, EPA/ESD/R08-98/175 (Dec. 9); 

http://www.epa.gov/superfund/sites/rods/fulltext/e0898175.pdf. 

U.S. EPA, 1998a, Approach for Addressing Dioxin in Soil at CERCLA and RCRA Sites. OSWER 

Directive 9200.4-26, Office of Solid Waste and Emergency Response, Washington, DC 

(April 13); http://www.epa.gov/superfund/resources/remedy/pdf/92-00426-s.pdf. 

U.S. EPA (Region 6), 1998b, EPA Superfund Explanation of Significant Differences: Vertac, 

Inc., EPA ID: ARD000023440, OU 02, Jacksonville, Arkansas, 01/12/1998, 

EPA/ESD/R06-98/160; http://www.epa.gov/superfund/sites/rods/fulltext/e0698160.pdf. 

U.S. EPA (Region 5), 1998c, EPA Superfund Record of Decision Amendment: 

Ott/Story/Cordova Chemical Co., EPA ID: MID060174240, OU 03, Dalton Township, MI, 

02/26/1998, EPA/AMD/R05-98/101 (Feb. 26); 

http://www.epa.gov/superfund/sites/rods/fulltext/a0598101.pdf. 

U.S. EPA (Region 6), 1998d, EPA Superfund Record of Decision Amendment: United 

Creosoting Co., EPA ID: TXD980745574, OU 02, Conroe, Texas, 10/14/1998, 

EPA/AMD/R06-99/032; http://www.epa.gov/superfund/sites/rods/fulltext/a0699032.pdf. 

U.S. EPA (Region 3), 1999a, Documentation of Environmental Indicator Determination (Feb. 5); 

http://www.epa.gov/reg3wcmd/ca/md/hhpdf/hh_mdd981041601.pdf. 

U.S. EPA (Region 9), 1999b, EPA Superfund Record of Decision, McCormick & Baxter 

Creosoting Co., EPA ID: CAD009106527, OU 01, 03, Stockton, CA 03/31/1999, 

EPA/ROD/R09-99/044 (Mar. 31); 

http://www.epa.gov/superfund/sites/rods/fulltext/r0999044.pdf. 

U.S. EPA (Region 8), 1999c, Final Superfund Preliminary Closeout Report, Ellsworth Air Force 

Base, Rapid City, South Dakota (Sept. 10); 

http://www.regulations.gov/fdmspublic/ContentViewer?objectId=090000648018a0b8&dis 

position=attachment&contentType=pdf. 

U.S. EPA (Region 5), 1999d, EPA Superfund Record of Decision Amendment: MacGillis & 

Gibbs Co./Bell Lumber & Pole Co., EPA ID: MND006192694, OU 01,03, New Brighton, 

MN, 09/30/1999, EPA/AMD/R05-99/147 (Sept. 30); 

http://www.epa.gov/superfund/sites/rods/fulltext/a0599147.pdf. 

U.S. EPA (Region 4), 2000a, Supplemental Guidance to RAGS: Region 4 Bulletins, Human 

Health Risk Assessment Bulletins, (May); 

http://www.epa.gov/Region4/waste/ots/healtbul.htm. 

U.S. EPA (Region 10), 2000b, Wyckoff/Eagle Harbor Superfund Site, Soil and Groundwater 

Operable Units, Bainbridge Island, Washington, Record of Decision; with cover sheet 

EPA Superfund Record of Decision: Wyckoff Co./Eagle Harbor, EPA ID: 

WAD009248295, OU 02, 04, Bainbridge Island, WA, 02/14/2000, EPA/ROD/R10-00/047 

(Feb. 14); http://www.epa.gov/superfund/sites/rods/fulltext/r1000047.pdf. 

U.S. EPA (Region 8), 2000c, EPA Superfund Explanation of Significant Differences: Ogden 

Defense Depot (DLA), EPA ID: UT9210020922, OU 01, Ogden, UT, 09/13/2000, 

EPA/ESD/R08-00/564 (Sept. 13); 

http://www.epa.gov/superfund/sites/rods/fulltext/e0800564.pdf. 

U.S. EPA (Region 9), 2001, EPA Superfund Explanation of Significant Differences: Tucson 

International Airport Area, AZD980737530, OU 02, Tucson, AZ, 05/04/2001, 

EPA/ESD/R09-01/612 (Apr. 4); 

http://www.epa.gov/superfund/sites/rods/fulltext/e0901612.pdf. 

U.S. EPA (Region 10), 2002a, Surface Soil Samples Analytical Results Summary: Poles 

Incorporated Dioxin/ Furan Sampling, Oldtown, ID (Aug.); 

http://yosemite.epa.gov/R10/CLEANUP.NSF/9f3c21896330b4898825687b007a0f33/434 

a255cbae5217d88256b560065cb04/$FILE/Soil%20Results.PDF. 

December 2009 Page B-70 
U.S. EPA (Region 6), 2002b, EPA Superfund Record of Decision: Marion Pressure Treating, 

EPA ID: LAD008473142, OU 01, Marion, Louisiana, 06/28/2002, EPA/ROD/R06-02/009; 

http://www.epa.gov/superfund/sites/rods/fulltext/r0602009.pdf. 

U.S. EPA (Region 5), 2002c, EPA Superfund Record of Decision: Sangamo Electric Dump/ 

Crab Orchard National Wildlife Refuge (USDOI), EPA ID: IL8143609487, OU 04, 

Carterville, IL, 09/12/2002, EPA/ROD/R05-02/044 (Sept. 12); 

http://www.epa.gov/superfund/sites/rods/fulltext/r0502044.pdf. 

U.S. EPA (Region 5), 2003a, Ecological Screening Levels (Aug. 22); 

http://www.epa.gov/reg5rcra/ca/ESL.pdf. 

U.S. EPA (Region 6), 2003b, Medium-Specific Screening Levels (Feb. 19); 

http://www.deq.state.ok.us/LPDnew/HW/02screentable.pdf. 

U.S. EPA (Region 10), 2003c, Explanation of Significant Differences for the Record of Decision 

for the Test Area North Operable Unit 1-10 (Apr.), with cover sheet EPA Superfund 

Explanation of Significant Differences: Idaho National Engineering Laboratory (USDOE), 

EPA ID: ID4890008952, OU 03, Idaho Falls, ID, 03/26/2003, EPA/ESD/R10-03/133 

(Mar. 26); http://www.epa.gov/superfund/sites/rods/fulltext/e1003133.pdf. 

U.S. EPA (Region 10), 2003d, EPA Superfund Explanation of Significant Differences: Arctic 

Surplus, EPA ID: AKD980988158, OU 01, Fairbanks, AK, 06/17/2003, EPA/ESD/R10­

03/009 (Jun. 17); http://www.epa.gov/superfund/sites/rods/fulltext/e1003009.pdf. 

U.S. EPA (Region 4), 2003e, Record of Decision, Summary of Remedial Alternative Selection 

for the Soil and Groundwater at the Wrigley Charcoal Site, Wrigley, Hickman County, 

Tennessee; with cover sheet EPA Superfund Record of Decision: Wrigley Charcoal 

Plant, EPA ID: TND980844781, OU 00, Wrigley, TN, 07/18/2003 EPA/ROD/R04-03/576 

(July 18); http://www.epa.gov/superfund/sites/rods/fulltext/r0403576.pdf. 

U.S. EPA (Region 10), 2003f, EPA Superfund Record of Decision: Oeser Co., EPA ID: 

WAD008957243, OU 10, Bellingham, WA, 09/18/2003, EPA/ROD/R10-03/135 

(Sept. 18); http://www.epa.gov/superfund/sites/rods/fulltext/r1003135.pdf. 

U.S. EPA (Region 9), 2003g, Selma Pressure Treating Superfund Site, Record of Decision 

Amendment, with cover page, EPA Superfund Record of Decision Amendment, Selma 

Treating Co., EPA ID: CAD029452141, OU 01, Selma, CA, 09/30/2003, EPA/AMD/R09­

03/016 (Sept. 30); http://www.epa.gov/superfund/sites/rods/fulltext/a0903016.pdf. 

U.S. EPA, 2003h Human Health Toxicity Values in Superfund Risk Assessments, OSWER 

Directive 9285.7-53, Office of Solid Waste and Emergency Response, Washington, DC 

(Dec. 5); http://www.epa.gov/oswer/riskassessment/pdf/hhmemo.pdf. 

U.S. EPA (Region 9), 2004a, Primary Remediation Goal Table (Oct.); 

http://www.epa.gov/region09/superfund/prg/files/04prgtable.pdf. 

U.S. EPA (Region 9), 2004b, Users Guide and Background Technical Document for US EPA 

Region 9’s Preliminary Remediation Goals (PRG) Table; 

http://www.epa.gov/region09/superfund/prg/files/04usersguide.pdf. 

U.S. EPA (Region 2), 2004c, EPA Superfund Record of Decision: Vega Baja Solid Waste 

Disposal, EPA ID: PRD980512669, OU 01, Rio Abajo Ward, PR, 04/06/2004, 

EPA/ROD/R2004020001421 (April 6); 

http://www.epa.gov/superfund/sites/rods/fulltext/r2004020001421.pdf. 

U.S. EPA (Region 2), 2004d, EPA Superfund Record of Decision: Franklin Burn, EPA ID: 

NJD986570992, OU 01, Franklin Township, NJ, 05/03/2004, 

EPA/ROD/R2004020001417 (May 3); 

http://www.epa.gov/superfund/sites/rods/fulltext/r2004020001417.pdf. 

U.S. EPA (Region 4), 2004e, Woolfolk Chemical Works Site, OU #3: Amended Record of 

Decision, August 27, 2004; with cover sheet EPA Superfund Record of Decision 

Amendment: Woolfolk Chemical Works, Inc., EPA ID: GAD003269578, OU 03, Fort 

December 2009 Page B-71 
Valley, GA, 08/30/2004, EPA/AMD/R04-04/664 (Aug. 30); 

http://www.epa.gov/superfund/sites/rods/fulltext/a0404664.pdf. 

U.S. EPA (Region 1), 2004f, U.S. Environmental Protection Agency Region 1, Shpack Landfill 

Superfund Site Record of Decision Summary, September 2004; with cover sheet EPA 

Superfund Record of Decision: Shpack Landfill, EPA ID: MAD980503973, OU 1, 

Norton/Attleboro, MA, 09/30/2004, EPA/ROD/R01-04/694 (Sept. 30); 

http://www.epa.gov/superfund/sites/rods/fulltext/r0104694.pdf. 

U.S. EPA (Region 10), 2004g, Second Five-Year Review Report for American Crossarm & 

Conduit Co. Superfund Site, Chehalis, Washington (Sept.); 

http://www.epa.gov/superfund/sites/fiveyear/f04-10004.pdf. 

U.S. EPA, 2005a, Guidelines for Carcinogen Risk Assessment, EPA/630/P-03/001F (March); 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=116283, as cited in VADEQ, 

2008cVoluntary Remediation Program Risk Assessment Guidance. 

U.S. EPA (Region 4), 2005b, Amendment to the Record of Decision Carolina Transformer Site, 

Fayetteville, Cumberland County, North Carolina, July 2005; with cover sheet EPA 

Superfund Record of Decision Amendment: Carolina Transformer Co., EPA ID: 

NCD003188844, OU 1, Fayetteville, NC, 7/22/2005, EPA/AMD/R04-05/038 (July 22); 

http://www.epa.gov/superfund/sites/rods/fulltext/a0405038.pdf. 

U.S. EPA (Region 7), 2005c, Record of Decision, Missouri Electric Works Site, Cape Girardeau, 

Missouri, prepared by USEPA, Region VII, Kansas City, Missouri, September 2005; with 

cover sheet EPA Superfund Record of Decision: Missouri Electric Works, EPA ID: 

MOD980965982, OU 02, Cape Girardeau, IA, 09/28/2005, EPA/ROD/R07-05/052 

(Sept. 28); http://www.epa.gov/superfund/sites/rods/fulltext/r0705052.pdf. 

U.S. EPA (Region 1), 2005d, Record of Decision Summary Service of New England, Inc 

(SRSNE) Site, Southington, Connecticut, September 2005; with cover sheet EPA 

Superfund Record of Decision, Solvents Recovery Service of New England, EPA ID: 

CTD009717604, OU 03, Southington, Connecticut, 09/30/2005, EPA/ROD/R01-05/008 

(Sept. 30); http://www.epa.gov/superfund/sites/rods/fulltext/r0105008.pdf. 

U.S. EPA (Region 6), 2005e, Second Five-Year Review Report: Rogers Road Municipal Landfill 

Superfund Site, EPA ID: ARD981055809, Pulaski County, Arkansas (Sept.); 

http://www.epa.gov/superfund/sites/fiveyear/f05-06017.pdf. 

U.S. EPA (Region 4), 2006a, Record of Decision Summary of Remedial Alternative Selection: 

Escambia Wood Treating Company: Superfund Site, Operable Unit 01 (Soil), Pensacola, 

Escambia County, Florida, February 2006; with cover sheet EPA Superfund Record 

of Decision: Escambia Wood – Pensacola, EPA ID: FLD008168346, OU 01, Pensacola, 

FL, 02/13/2006, EPA/ROD/R2006040001445 (Feb. 13); 

http://www.epa.gov/superfund/sites/rods/fulltext/r2006040001445.pdf. 

U.S. EPA (Region 10), 2006b, Poles, Incorporated Integrated Assessment (May 26); 

http://yosemite.epa.gov/R10/CLEANUP.NSF/9f3c21896330b4898825687b007a0f33/434 

a255cbae5217d88256b560065cb04?OpenDocument. 

U.S. EPA (Region 4), 2006c, Record of Decision Summary of Remedial Alternative Selection: 

Brown’s Dump Site, Jacksonville, Duval County, Florida, August 2006; with cover sheet 

EPA Superfund Record of Decision: Brown’s Dump, EPA ID: FLD980847016, OU 00, 

Jacksonville, FL, 08/24/2006, EPA/ROD/R2006040001161 (Aug. 24); 

http://www.epa.gov/superfund/sites/rods/fulltext/r2006040001161.pdf. 

U.S. EPA (Region 4), 2006d, Record of Decision Summary of Remedial Alternative Selection: 

Jacksonville Ash Site, Jacksonville, Duval County, Florida, August 2006; with cover 

sheet EPA Superfund Record of Decision: Jacksonville Ash Site, EPA ID: 

FLSFN0407002, OU 01, Jacksonville, FL, 08/24/2006, EPA/ROD/R2006040001162 

(Aug. 24); http://www.epa.gov/superfund/sites/rods/fulltext/r2006040001162.pdf. 

December 2009 Page B-72 
U.S. EPA (Region 4), 2006e, Record of Decision Summary of Remedial Alternative Selection, 

Sigmon's Septic Tank Site, Statesville, Iredell County, North Carolina, September 2006; 

with cover sheet EPA Superfund Record of Decision: Sigmon’s Septic Tank Service, 

EPA ID: NCD062555792, OU I, Irdell, NC, 09/19/2006, EPA/ROD/R2006040001281 

(Sept. 19); http://www.epa.gov/superfund/sites/rods/fulltext/r2006040001281.pdf. 

U.S. EPA (Region 6), 2006f, EPA Superfund Record of Decision: Jasper Creosoting Company 

Inc., EPA ID: TXD008096240, OU 01, Jasper, Texas, 09/20/2006, 

EPA/ROD/R2006060001482, Region 6 (Sept.); 

http://www.epa.gov/superfund/sites/rods/fulltext/r2006060001482.pdf. 

U.S. EPA (Region 4), 2006g, Record of Decision Summary of Remedial Alternative Selection: 

Coleman-Evans Wood Preserving Company: Superfund Site, Operable Unit 02 

(Residual Dioxin in Soil), Whitehouse, Duval County, Florida, September 2006; with 

cover sheet EPA Superfund Record of Decision: Coleman-Evans Wood Preserving Co., 

EPA ID: FLD991279894, OU 02, Whitehouse, FL, 09/28/2006, 

EPA/ROD/R2006040001242 (Sept. 28); 

http://www.epa.gov/superfund/sites/rods/fulltext/r2006040001242.pdf. 

U.S. EPA (Region4), 2007, Record of Decision Summary of Remedial Alternative Selection: 

Picayune Wood Treating Site Picayune, Pearl River County, Mississippi (Sept.); 

http://www.epa.gov/superfund/sites/rods/fulltext/r2007040001948.pdf. 

U.S. EPA, 2008a, Child-Specific Exposure Factors Handbook, EPA/600/R-06/096F, National 

Center for Environmental Assessment, Washington, DC (dated Sept., released Oct. 30); 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=199243. 

U.S. EPA, 2008b, Frequently Asked Questions on the Update to the ATSDR Policy Guideline 

for Dioxins and Dioxin-Like Compounds in Residential Soil, OSWER 9285.7-84FS 

(Dec.); http://www.epa.gov/superfund/additions.htm; 

http://www.epa.gov/oswer/riskassessment/pdf/92-857-84fs.pdf. 

U.S. EPA (Region 9), 2008c, Screening Levels for Chemical Contaminants(previous PRG 

table). 

U.S. EPA (Region 10), 2008d, First Five Year Review Report for Arctic Surplus Salvage Yard 

Superfund Site, ARCSF 24-6, Fairbanks, Alaska (Dec.); 

http://yosemite.epa.gov/r10/CLEANUP.NSF/sites/fiveyr/$FILE/Arctic%20Surplus%20Firs 

t%20121808.pdf. 

U.S. EPA (Region 4), 2008e, Lower Roanoke River, Weyerhaeuser Operable Unit 2, Martin 

County, NC, Part 2: The Decision Summary (Sept.); 

http://www.epa.gov/superfund/sites/rods/fulltext/r2008040002458.pdf. 

U.S. EPA, 2009a, Risk Assessment Guidance for Superfund, Volume I: Human Health 

Evaluation Manual, Part F, Supplemental Guidance for Inhalation Risk Assessment, 

Office of Superfund Remediation and Technology Innovation, Washington, DC (Jan.) 

http://www.epa.gov/oswer/riskassessment/ragsf/pdf/partf_200901_final.pdf. 

U.S. EPA (Region 3), 2009b, Mid-Atlantic Risk Assessment, Human Health Risk Assessment, 

Risk-Based Concentration Table; http://www.epa.gov/reg3hwmd/risk/human/index.htm
 

(last updated May 2009, accessed November 2009). 

U.S. EPA, 2009c, Record of Decision System (RODS), online database, Office of Solid Waste 

and Emergency Response, Washington, DC; http://www.epa.gov/superfund/sites/rods 

(last updated June 3, 2009; accessed December 2009). 

U.S. EPA (Region 9), 2009d, Region 9 Preliminary Remediation Goals; 

http://www.epa.gov/region09/superfund/prg/ (page last updated May 27, 2009; accessed 

December 2009). 

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http://www.epa.gov/reg3hwmd/risk/human/rbconcentration_table/Generic_Tables/index.htm; 

December 2009 Page B-73 
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accessed December 2009,). 

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Washington, DC (May 26); http://www.epa.gov/dioxin/scienceplan; 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=209690. 

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Risk Assessment Guidance (Sept. 10); http://www.deq.virginia.gov/vrprisk/raguide.html. 

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(Commercial/Industrial), Voluntary Remediation Program (June 23); 

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VADEQ, 2009b, Table 2.5, Selection of Contaminants of Concern Soil: Unrestricted 

(Residential), Voluntary Remediation Program (July 8); 

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Van den Berg M., et al., 2006, The 2005 World Health Organization Re-evaluation of Human 

and Mammalian Toxic Equivalency Factors for Dioxins and Dioxin-like Compounds, 

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from WI Dept. of Health and Family Services, Division of Health, and Dept. of Natural 

Resources, Division of Watershed Management; 

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(1995) and WI Dept. of Health memo (May 4, 1994) from Goldring, Bureau of Public 

Health, subject: "Revision of DOH Guidelines for Dioxin in Landspread Sludge.” 

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Mammalian Toxic Equivalency Factors (TEFs) of Dioxins and Dioxin-like Compounds, 

December 2009 Page B-74 
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den Berg et al., 2006); http://www.who.int/ipcs/assessment/tef_update/en/. 

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Product Approval, WI-613-05 (May) 

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Wright D., 2009, personal communication from D. Wright (Division of Remediation, MEDEP) to 

M. McDonough (EPA Region 1, Boston, MA) (July 23). 

WVDEP (West Virginia Department of Environmental Protection), 2001, Voluntary Remediation 

and Redevelopment Act Guidance Manual, Version 2.1 (March 13); 

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WYDEQ (Wyoming Department of Environmental Quality), 2009, Fact Sheet #12: Soil Cleanup 

Level Look-up Table, Voluntary Remediation Program (Jun. 30); 

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December 2009 Page B-75