Appendix A. Sources of Toxicity Values

Section 5.1.1 discusses choosing among toxicity valuesDerived values (for example, reference doses and slope factors) that can be used to estimate the incidence or potential for adverse human health effects in receptor (USEPA 2015h). from multiple sources and references this table. In addition, Section 5.2.1 discusses understanding uncertaintyThe lack of perfect knowledge of values or parameters used in a risk assessment. Uncertainty may be reduced by collection of additional data. in the toxicity values and references this table.

Table A-1. Sources of toxicity values

Name

Regulatory Agency

Available Toxicity Value

Review Process

Additional Notes

Noncancer Oral

Noncancer Inhalation

Cancer Oral

Cancer Inhalation

Federal

The Integrated Risk Information System (IRIS)

(USEPA 2013b)

USEPA

RfD

RfC

SF

UR

Rigorous review process which includes: internal agency review, inter-agency science consultation, independent external review, public comment, inter-agency science discussion, and final approval by the Office of Research and Development

Intended for use by all USEPA programs

Provisional Peer Reviewed Toxicity Values (PPRTVs)

(USEPA 2013f)

USEPA (Superfund Health Risk Technical Support Center for the USEPA Superfund Program)

RfD

RfC

SF

UR

Internal review by USEPA scientists followed by external peer-review by independent scientific experts

Revised Health Effects Assessment Summary Table (HEAST) values are values that have been derived as per the request of Regional Superfund Offices for chemicals that are not covered under IRIS

In 2009, for certain PPRTV assessments, screening toxicity values were appended. While these values have utility for screening purposes, caution should be taken when using these screening toxicity values to support final remedial action decisions.

Similar to IRIS assessment but does not go through as rigorous review.

Agency for Toxic Substances and Disease Registry (ATSDR)

(ATSDR 2013)

US Department of Health and Human Services

MRL1,2

MRL1,3

--

--

Rigorous review process which includes: Human Health Effects/MRL workgroup within the Division of Toxicology  & Environmental Medicine; expert panel of peer reviewers; agency wide MRL workgroup (participation from other federal agencies)

MRLs set below levels that may cause adverse human health effectsTypically defined as an incremental lifetime cancer risk (for example, exceeding a range of 1E-4 to 1E-6) or a hazard quotient or hazard index (for example, one). in sensitive sub-populations

Not intended to define clean-up or action levels

Serve as screening values

Does not provide cancer toxicity values

 

Health Effects Assessment Summary Tables (HEAST)

(USEPA 1997d)

USEPA (Superfund and RCRA) hazardous waste programs

RfD

RfC

SF

UR

Updated regularly from the early to mid-1990s; known as the Quarterly;

Last update was 1998

Historical database of human health toxicity values

State

Toxicity Criteria Database

(CalEPA 2013)

Cal EPA

ChRFD; PHG4

REL

SF5

UR5

Submitted for public comments and external peer-review

Developed by the Office of Environmental Health Hazard Assessment (OEHHA) under SB32, the California Land Environmental Restoration and Reuse Act

Energy and Environmental Affairs Risk Assessment Web Site (MADEP 2014)

Mass DEP

 

 

 

 

Peer-reviewed within the Office of Research and Standards

 

Health Risk Values & Health Risk Limits (MPCA 2014)

Minnesota Pollution Control Agency

HRL/RfD (noncancer)

HRV/RfC (noncancer)

HRL/SF (cancer)

HRV/UR (cancer)

Have adopted the USEPA guidelines for derivation and review

For air and water; derived with stakeholder involvement

Toxicity Values (used to develop Soil Cleanup Objectives)

(NYDEC 2014)

New York State DEC

RfD

RfC

SF

UR

Selected from values published by established regulatory agencies; acute

internally and externally reviewed

 

Toxicity Factors

(TCEQ 2014)

Texas Commission on Environmental Quality

RfD

ReV

SF

URF

Developed and reviewed by TCEQ toxicologists; posted for public review and comment and internally revised prior to finalizing the toxicity factors.

 

International

WHO/ International Programme on Chemical Safety’s (IPCS) Concise International Chemical Assessment Documents (CICADs)

(WHO 2013)

WHO

TDI

TC

--

--

Document is first reviewed by IPCS followed by international peer-review which is then proceeded by final review by the Review Board

Can be used in conjunction with the Environmental Health Criteria documents

National Institute of Public Health and Environmental Protection, Netherlands provides Maximum Permissible Risk (MPR)

(Netherlands National Institute for Public Health and the Environment 2013)

RIVM

TDI

TCA

CR

CR

International committee of experts has reviewed the existing toxicological reviews for substances for which an MPR is to be developed

Provisional and temporary values presented

Toxicological Reference Values

(Health Canada 2010)

Health Canada

TDI; ADI

TC

SF

UR

Sources of TRVs include:  Health Canada Water Quality; Health Canada Priority Assessments Program; US USEPA IRIS; Cal EPA; WHO; ATSDR

--

--No Value Provided

1. Acute, sub-chronic and chronic duration values available

2. Oral MRLs analogous to RfDs

3. Inhalation MRLs analogous to RfCs

4. Derived for drinking water only and are not intended to be used as target levels for other environmental media

5. Cancer Potency Values

USEPA- United States Environmental Protection Agency

RfD- Reference Dose

RfC- Reference Concentration

SF- Slope Factor

UR- Unit Risk

MRL- Minimal Risk Level

Cal EPA- California Environmental Protection Agency

ChRfD- Child-specific Reference Dose

 

PHG- Public Health Goal

REL- Reference Exposure Level

Mass- Massachusetts

DEP- Department of Environmental Protection

DEC- Department of Environmental Conservation

ReV- Reference Value

URF- Unit Risk Factor

TCEQ- Texas Commission on Environmental Quality

WHO- World Health Organization

TC- Tolerable Concentration

TDI- Total Daily Intake

RIVM- National Institute of Public Health and the Environment

TCA- Tolerable Concentration in Air

CR- Cancer Risk

ADI- Acceptable Daily Intake

 

 

Publication Date: January 2015

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