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Risk Assessment

Regional Screening Levels (RSLs) - Generic Tables

Tables as of:  

The screening level (SL) tables are available for download in Excel and PDF formats. All tables are presented with target cancer risk (TR) of 1E-06, however, tables are presented with target hazard quotients (THQ) of 1.0 and 0.1. Use the tables appropriate for your region. These tables are considered ready for use. The tables contain both SL calculations and the toxicity values that were used. The download tables do not include the ingestion of fish exposure pathway, the outdoor worker and the indoor worker exposure to soil exposure pathway that are presented in the User's Guide. These exposure pathways can be considered on a site-specific basis in the Calculator.

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Screening Levels (TR=1E-06
THQ=1.0)
(TR=1E-06
THQ=1.0)
(TR=1E-06
THQ=0.1)
(TR=1E-06
THQ=0.1)
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Resident Soil Loading... Loading... Loading... Loading...
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Other Tables PDF XLS
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Subchronic Toxicity Values Loading... Loading...
Descriptions of annotations and abbreviations used in RSL tables and calculator output
Annotation/Abbreviation Definition Links to detailed discussion
Toxicity Related
CAS Chemical Abstracts Services Registry Number

https://www.cas.org/ 

CAS is a unique numerical identifier assigned to every chemical substance described in the open scientific literature, including organic and inorganic compounds.

SF, SFO, CSFo Oral Slope Factor (mg/kg-day)-1

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#toxicity

See section 2.3.3

IUR Inhalation Unit Risk (µg/m3)-1

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#toxicity

See section 2.3.4

RfD or RfDo Chronic Oral Reference Dose (mg/kg-day)

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#toxicity 

See section 2.3.1

RfC Chronic Inhalation Reference Concentration (mg/m3)

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#toxicity 

See section 2.3.2

I or IRIS EPA's Integrated Risk Information System

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#toxicity 

https://www.epa.gov/iris

P or PPRTV The Provisional Peer Reviewed Toxicity Values

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#toxicity 

https://hhpprtv.ornl.gov/

D or DWSHA EPA's Office of Water Drinking Water Standards and Health Advisories https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#toxicity
O or OPP EPA's Office of Pesticide Programs Human Health Benchmarks for Pesticides

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#toxicity 

https://iaspub.epa.gov/apex/pesticides/f?p=HHBP:home

A or ATSDR The Agency for Toxic Substances and Disease Registry Minimal Risk Levels (MRLs)

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#toxicity 

https://www.atsdr.cdc.gov/mrls/index.html

C or Cal EPA The California Environmental Protection Agency Office of Environmental Health Hazard Assessment

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#toxicity 

https://oehha.ca.gov/

Screening toxicity values in an appendix to certain PPRTV assessments

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#toxicity 

https://hhpprtv.ornl.gov/

H The EPA Superfund program's Health Effects Assessment Summary Table

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#toxicity 

https://epa-heast.ornl.gov/

E Toxicity Equivilence Factors (TEF) applied

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#toxicity 

See section 2.3.5 for description of TEFs for dioxins, furans, and dioxin-like PCBs

W Relative Potencey Factors (RPFs) applied

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#toxicity 

See section 2.3.6 for description of RPFs for polycyclic aromatic hydrocarbons (PAHs)

L

See user's guide section on lead

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#lead 

EPA has no consensus RfD or SFO for inorganic lead, so it is not possible to calculate SLs as with other chemicals. EPA considers lead to be a special case because of the difficulty in identifying the classic "threshold" needed to develop an RfD.

M Mutagen

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#mutagens

Some of the cancer causing analytes in this tool operate by a mutagenic mode of action for carcinogenesis. Special equations are used.

S Surrogate

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#special 

Section 5 of the User's Guide presents many surrogates.

GIABS Fraction of contaminant absorbed in gastrointestinal tract (unitless)

https://www.epa.gov/superfund/superfund-soil-screening-guidance

See Exhibit 4-1. Note: if the GIABS is >50% then it is set to 100% for the calculation of dermal toxicity values.

ABS or ABSd Fraction of contaminant absorbed dermally from soil (unitless)

https://www.epa.gov/superfund/superfund-soil-screening-guidance 

See Exhibit 3-4

Csat Soil saturation concentration (mg/kg)

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#csat 

The soil saturation concentration, Csat, corresponds to the contaminant concentration in soil at which the absorptive limits of the soil particles, the solubility limits of the soil pore water, and saturation of soil pore air have been reached.

RBA Relative bioavailability factor

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#arsenic 

Arsenic screening levels for ingestion of soil are now calculated with the default  relative bioavailability factor (RBA) of 0.6.

RSL Related
SL screening level

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#intro 

https://www.epa.gov/risk/regional-screening-levels-frequent-questions#FQ1

TR target risk https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#target
THQ target hazard quotient

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#target 

https://www.epa.gov/risk/regional-screening-levels-frequent-questions#FQ6

THI target hazard index

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#target 

https://www.epa.gov/risk/regional-screening-levels-frequent-questions#FQ6

c or ca cancer is more protective screening level

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#target 

Cancer and noncancer screening levels are presented in the supporting tables. The most protective value is chosen for the summary table.

n or nc noncancer is more protective screening level

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#target 

Cancer and noncancer screening levels are presented in the supporting tables. The most protective value is chosen for the summary table.

* The noncancer screening level is less than 100 times the cancer screening level

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#target 

Some users of this SL Table may plan to multiply the cancer SL concentrations by 100 to set 'action levels' for triggering remediation or to set less stringent cleanup levels for a specific site after considering non-risk-based factors such as ambient levels, detection limits, or technological feasibility. 

** The noncancer screening level is less than 10 times the cancer screening level

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#target 

Some users of this SL Table may plan to multiply the cancer SL concentrations by 10 to set 'action levels' for triggering remediation or to set less stringent cleanup levels for a specific site after considering non-risk-based factors such as ambient levels, detection limits, or technological feasibility. 

max The screening level has exceeded the theoretical maximum concentration.

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#ceiling 

The ceiling limit of 10+5 mg/kg is equivalent to a chemical representing 10% by weight of the soil sample. At this contaminant concentration (and higher), the assumptions for soil contact may be violated (for example, soil adherence and wind-borne dispersion assumptions) due to the presence of the foreign substance itself.

sat The screening level has exceeded the  theoretical absorption limit of the soil.

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#csat 

The soil saturation concentration, Csat, corresponds to the contaminant concentration in soil at which the absorptive limits of the soil particles, the solubility limits of the soil pore water, and saturation of soil pore air have been reached. Above this concentration, the soil contaminant may be present in free phase (i.e., nonaqueous phase liquids (NAPLs) for contaminants that are liquid at ambient soil temperatures and pure solid phases for compounds that are solid at ambient soil temperatures). 

DAF Dilution attenuation factor

https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide#soiltogw 

See section 4.8.5

U User-provided In user-provided mode all the input values are given a reference of U.

For assistance/questions please use the Regional Screening Levels (RSLs) contact us page. For general risk assessment questions, separate from the RSLs, please use the link below.