Compliance Status Report
Comparison of Existing Contamination to Risk Reduction Standards
391-3-19-.07
(http://rules.sos.state.ga.us/docs/391/3/19/07.pdf)
RAGS Equations
Toxicity Factors and Physical Properties Description
Risk Reduction Standard (RRS) values should be calculated for each regulated substance. The chosen RRS “Type” will depend on site use and the potential of exposure. There are 5 “Types” of RRS values:
- Type 1 RRS will pose no significant risk on the basis of standardized exposure assumptions and defined risk level for residential properties.
- Type 2 RRS will pose no significant risk on the basis of site-specific risk assessment for residential properties.
- Type 3 RRS will pose no significant risk on the basis of standardized exposure assumptions and defined risk level for non-residential properties.
- Type 4 RRS will pose no significant risk on the basis of site-specific risk assessment for non-residential properties.
- Type 5 RRS are allowed only in instances where Type 1-4 standards are not appropriate. This standard allows contamination to remain provided the principal threats at the site are controlled by engineering and institutional controls. Type 5 is only appropriate for sites where it is determined to not be practical to remove source area (landfills, etc.). Institutional controls should not be substituted for active remedial measures. ** NOTE: Please contact a compliance officer at our office (404-657-8600) for additional information regarding the minimum requirements relating to a Type 5 risk reduction standard and additional guidance. **
The Compliance Status Report (CSR) should include a discussion on the calculation of RRS values that were selected for the site, a discussion of why that “Type(s)” was/were selected, and how the regulated substances compare to the RRS values. If non-default values are used in the calculation of a Type 2 or 4 RRS, then the discussion must include a description of why these values are appropriate for use at your site. Specific tables that should be included are:
- A table containing all exposure parameters and toxicity factors, with references, used in risk-based calculations, as well as, the equation and the results.
- A table comparing the Maximum Detected Concentrations (MDCs) in soil and groundwater to their respective RRS values.
A site, where the concentration of regulated substances in soil or groundwater exceeds the RRS values, is out of compliance and a Corrective Action Plan is required.
** Note: Calculating site-specific RRS (Type 2 and/or Type 4) may NOT result in higher clean up standards. **
** Note: Descriptions relating to the calculations of the risk reduction standards have been simplified wherever possible to address common regulated substances; however, this guidance does not supersede the Rules for Hazardous Site Response. In the event of conflict, the Rules for Hazardous Site Response take precedence. **
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** Note: Descriptions relating to the calculations of the risk reduction standards have been simplified wherever possible to address common regulated substances; however, this guidance does not supersede the Rules for Hazardous Site Response. In the event of conflict, the Rules for Hazardous Site Response take precedence. **
Type 1 Risk Reduction Standards
Source materials must be removed or decontaminated to Type 1 media criteria below.
- Groundwater shall not exceed the following concentrations:
** Note, in cases where the Georgia Maximum Contaminant Level (MCL) is lower than the groundwater criterion, the MCL takes precedence. Please see the Georgia Rules for Safe Drinking Water (http://rules.sos.state.ga.us/docs/391/3/5/18.pdf) for the most up to date information on the MCLs. Please note that this rule is only applicable to regulated substances that are currently listed in Table 1 of Appendix III.
- Soil at any point above the uppermost groundwater zone shall not exceed the following concentrations
- Metals: concentrations in Table 2 of Appendix III, or
- For regulated substances not listed in Table 2 of Appendix III, the least of 1-3 below:
- Highest of the following:
- Notification Concentration, excluding values in brackets;
- Type 1 groundwater value multiplied by 100;
- Toxicity Characteristic Leaching Procedure (TCLP), SW-846 Method 1311, or any other method approved by the Director showing that soil will not generate leachate concentrations that exceed the Type 1 groundwater RRS. **NOTE: must be a test method, not modeled.
- Concentration unlikely to cause non-cancer toxic effects from soil ingestion and inhalation of volatiles and particulates using Equation 7 of RAGS Part B and residential exposure assumptions in Table 3 of Appendix III.
- Concentration for which the target excess cancer risk is less than or equal to 10-05 (10-04 for class C carcinogens) from soil ingestion and inhalation of volatiles and particulates using Equation 6 of RAGS Part B and residential exposure assumptions in Table 3 of Appendix III.
Appendix I- III: http://rules.sos.state.ga.us/docs/391/3/19/AP.pdf
** Note: Descriptions relating to the calculations of the risk reduction standards have been simplified wherever possible to address common regulated substances; however, this guidance does not supersede the Rules for Hazardous Site Response. In the event of conflict, the Rules for Hazardous Site Response take precedence. **
Type 2 Risk Reduction Standards
Source materials must be removed or decontaminated to Type 2 media criteria below.
- Groundwater shall not exceed the least of 1 and 2 below. If 1 and 2 cannot be calculated, then highest of values in Table 1 of Appendix III value, background concentration or detection limit.
- Concentration unlikely to cause non-cancer toxic effects from ingestion of and inhalation of volatiles from groundwater using Equation 2 of RAGS Part B and site-specific residential exposure factors.
- Concentration for which the target excess cancer risk is less than or equal to 10-5 from ingestion of and inhalation of volatiles from groundwater using Equation 1 of RAGS Part B and site specific residential exposure factors.
- Soil shall not exceed the least of 1-4 below at any point above the upper most groundwater zone. If 1-4 cannot be calculated, then highest of values in Table 2 of Appendix III, background and detection limit.
- Concentration that will not cause groundwater to exceed the higher of Type 1 and 2 groundwater RRS through use of a laboratory test or fate-and-transport model recognized by USEPA and approved by the Director.
- Concentration unlikely to cause non-cancer toxic effects from soil ingestion, inhalation of volatiles and particulates using Equation 7 of RAGS Part B and site specific residential exposure factors.
- Concentration for which the target excess cancer risk is less than or equal to 10-5 from soil ingestion, inhalation of volatiles and particulates using Equation 6 of RAGS Part B and site specific residential exposure factors.
- For lead, the least of a concentration that will not cause a 6 year old child (averaged over preceding 84 mo.) to exceed a 5% chance of a blood lead level greater than 10mg/dL using the IEUBK model (http://epa.gov/superfund/health/contaminants/lead/guidance.htm) and site specific residential exposure factors, and item 1 above.
** Note: Descriptions relating to the calculations of the risk reduction standards have been simplified wherever possible to address common regulated substances; however, this guidance does not supersede the Rules for Hazardous Site Response. In the event of conflict, the Rules for Hazardous Site Response take precedence. **
Type 3 Risk Reduction Standards
Source materials must be removed or decontaminated to Type 3 media criteria below.
- Groundwater Type 3 RRS values are the same as the Type 1 RRS values for groundwater. For those regulated substances not listed in Table 1 of Appendix III, the RRS values is either the background or detection limit concentration.
** Note, in cases where the Georgia Maximum Contaminant Level (MCL) has changed, the groundwater criterion will also change. For example, the current MCL for arsenic is 0.010mg/L. Please see the Georgia Rules for Safe Drinking Water (http://rules.sos.state.ga.us/docs/391/3/5/18.pdf) for the most up to date information on the MCLs. Please note that this rule is only applicable to regulated substances that are currently listed in Table 1 of Appendix III.
- Soil shall not exceed the following concentrations:
- For lead, 400 mg/kg
- For other regulated substances:
Soil at any point above the water table, higher of a-c below:
a. Notification Concentration, excluding values in brackets
b. Type 1 groundwater value multiplied by 100;
c. Toxicity Characteristic Leaching Procedure (TCLP), SW-846 Method 1311, or any other method approved by the Director showing that soil will not generate leachate concentrations that exceed the Type 1 groundwater RRS. **NOTE: must be a test method, not modeled.
AND
Concentration within 2 feet of the surface, shall meet item 1 above and least of i-ii below.
i. Concentration unlikely to cause non-cancer toxic effects from soil ingestion and inhalation of volatiles and particulates using Equation 7 of RAGS Part B and non-residential assumptions in Table 3 of Appendix III.
ii. Concentration for which the upper bound excess cancer risk is less than or equal to 10-5 (10-4 for class C carcinogens) from soil ingestion and inhalation of volatiles and particulates using Equation 6 of RAGS Part B and non-residential assumptions in Table 3 of Appendix III.
** Note: Descriptions relating to the calculations of the risk reduction standards have been simplified wherever possible to address common regulated substances; however, this guidance does not supersede the Rules for Hazardous Site Response. In the event of conflict, the Rules for Hazardous Site Response take precedence. **
Type 4 Risk Reduction Standards
Source materials must be removed or decontaminated to Type 4 media criteria below.
- Groundwater shall not exceed the least of 1 and 2 below. If 1 and 2 cannot be calculated, then highest of values in Table 1 of Appendix III, background and detection limit.
- Concentration unlikely to cause non-cancer toxic effects from ingestion of and inhalation of volatiles from groundwater using Equation 2 of RAGS Part B and site-specific non-residential exposure factors.
- Concentration for which the upper bound excess cancer risk is less than or equal to 10-5 from ingestion of and inhalation of volatiles from groundwater using Equation 1 of RAGS Part B and site specific non-residential exposure factors.
- Soil shall not exceed the following concentrations:
- Concentration in subsurface soil that will not cause groundwater to exceed higher of Type 3 and 4 groundwater RRS through use of a laboratory test or fate-and-transport model recognized by USEPA and approved by the Director.
AND
- Concentration in surface soil (defined as depth based on site specific exposure factor approved by the Director, or assumed to be the upper 2 feet), shall meet item 1 above and the least of i-iii below.
i. Concentration unlikely to cause non-cancer toxic effects from soil ingestion and inhalation of volatiles and particulates using Equation 7 of RAGS Part B and site specific residential exposure factors.
ii. Concentration for which the upper bound excess cancer risk is less than or equal to 10-5 from soil ingestion and inhalation of volatiles and particulates using Equation 6 of RAGS Part B and site specific residential exposure factors.
iii. For lead, the least of the concentration determined through the GA Adult Lead Model and item 1 above. If children frequently visit the site it may require use of IEUBK model as under a Type 2 RRS.
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RAGS Equations 1 and 2
Equation 2
C (mg/L) = (THI)(BW)(AT)(365 days/year)
(EF)(ED)[(1/RfDi)(K)(IRa) + (1/RfDo)(IRw)]
Equation 1
C (mg/L) = (TR)(BW)(AT)(365 days/year)
(EF)(ED)[(SFi)(K)(IRa) + (SFo)(IRw)]
C – Concentration in water (mg/L)
AT – Averaging Time (years)
EF – Exposure Frequency (days/year)
BW – Body Weight (kg)
ED – Exposure Duration (years)
THI – Target Hazard Index
TR – Target Excess Risk
K – Water –to-air volatilization factor (L/m3)
RfDi – Inhalation reference dose (mg/kg-day)
IRa – Ingestion rate of air (m3/day)
RfDo – Oral reference dose (mg/kg-day)
IRw – Ingestion rate of water (L/day)
SFi – Inhalation cancer slope factor (mg/kg-day)-1
SFo – Oral cancer slope factor (mg/kg-day)-1
Please refer to http://www.epa.gov/oswer/riskassessment/ragsb/ to obtain additional information concerning these equations.
RAGS Equations 6 and 7
Equation 7
C (mg/kg) = (THI)(BW)(AT)(365 days/year)
(EF)(ED)[(1/RfDo)(10-6 kg/mg)(IRs) + (1/RfDi)(IRa){(1/VF) +(1/PEF)}]
Equation 6
C (mg/kg) = (TR)(BW)(AT)(365 days/year)
(EF)(ED)[(SFo)(10-6 kg/mg)(IRs) + (SFi)(IRa){(1/VF) +(1/PEF)}]
C – Concentration in soil (mg/kg)
THI – Target Hazard Index
TR– Target Excess Risk
BW – Body Weight (kg)
ED – Exposure Duration (years)
AT – Averaging Time (years)
VF – Volatilization Factor (m3/kg)
EF – Exposure Frequency (days/year)
IRs – Ingestion rate of soil (mg/day)
IRa – Ingestion rate of air (m3/day)
RfDi – Inhalation reference dose (mg/kg-day)
RfDo – Oral reference dose (mg/kg-day)
SFi – Inhalation cancer slope factor (mg/kg-day)-1
SFo – Oral cancer slope factor (mg/kg-day)-1
PEF – Particulate Emission Factor (m3/kg)
Please refer to http://www.epa.gov/oswer/riskassessment/ragsb/ to obtain additional information concerning these equations.
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Toxicity Factors and Physical Properties
- Conversation Equations for Inhalation Reference Concentrations and Inhalation Unit Risk Factors:
- Inhalation Reference Concentration (mg/m3) to Inhalation Reference Dose (mg/kg-day).
- Multiply by 20
- Divide by 70
RfDi (mg/kg-day) = [RfCi(mg/m3) x 20 (m3/day)]/70 (kg)
- Inhalation Unit Risk Factor (mg/m3)-1 to Inhalation Slope Factor (mg/kg-day)-1.
- Multiply by 70
- Multiply by 1000
- Divide by 20
SFi (mg/kg-day)-1= [IUR(ug/m3)x70(kg)x1000(ug/mg)]/20(m3/day)
- Physical Properties: Sources for Chemical Specific Properties for soil screening values
- Regional Chemical Specific Properties:
http://www.epa.gov/reg3hwmd/risk/human/rb-concentration_table/Generic_Tables/pdf/params_sl_table_run_12SEP2008.pdf
http://www.epa.gov/superfund/health/conmedia/soil/toc.htm
- Risk Assessment Information System:
http://rais.ornl.gov/tox/tox_values.shtml
- Superfund Chemical Data Matrix:
http://www.epa.gov/superfund/sites/npl/hrsres/tools/scdm.htm
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Common Mistakes
- Failure to use the default groundwater standards for the Type 1 and 3 RRS for groundwater. For Type 1 and 3 groundwater RRS values, concentrations shall not exceed those listed in Table 1 of Appendix III (http://rules.sos.state.ga.us/docs/391/3/19/AP.pdf) of the rules. For regulated substances not listed in this table, concentrations shall not exceed the background or detection limit concentration.
- Failure to include concentrations listed in Table 2 of Appendix III (http://rules.sos.state.ga.us/docs/391/3/19/AP.pdf) when calculating the Type 1RRS for metals in soil. .
- Failure to address the protection of groundwater via migration from soil as it pertains to Type 2 and/or Type 4 Risk Reduction Standard (RRS) values.
- Improperly calculating Soil Screening Level (SSL) values:
- Improperly calculating site-specific distribution coefficient (Kd).
- Using a referenced Kd value from an improper reference.
- Improperly calculating a site-specific dilution attenuation factor (DAF).
- Using the EPA default DAF of 20 for source areas larger than ½ acre.
- Using an foc of 0.02 instead of 0.002
- Not utilizing the toxicity factor hierarchy and/or using incorrect input parameters for RAGS equations.
- For Type 2 and 4 RRS values, supporting documentation for site-specific exposure assumptions is not provided.
- Failure to eliminate the inhalation pathway for non-volatile regulated substances in groundwater. In groundwater, if the regulated substance is not volatile, then the inhalation pathway is incomplete and can be removed from the RAGS Equation.
- Failure to eliminate the inhalation pathway for non-volatile regulated substances in soil. In soil, if the regulated substance is not volatile, then the inhalation pathway due to volatiles is incomplete and the (1/VF) term can be removed from the RAGS equation. However, the inhalation pathway due to particulates (1/PEF) must be addressed.
- For Non-Carcinogenic risk, not setting the Averaging Time (AT) equal to the Exposure Duration (ED).
- When calculating the Type 2 RRS, failure to include a child as a potential residential receptor. Default child exposure parameters are below. Alternate child exposure parameters can be used; however, justification for their use needs to be provided.
- Body Weight (BW): 15 kg
- Exposure Duration (ED): 6 years
- Daily Water Ingestion Rate (IRw): 1 L/day
- Daily Inhalation Rate (IRair): 15 m3/day
- Soil Ingestion Rate (IRsoil): 200 mg/day
- Averaging Time (AT) Carcinogens: 70 years
- Averaging Time (AT) Non-Carcinogens: 6 years
- Failure to run the Integrated Exposure Uptake Biokinetic (IEUBK) Model for Lead in children in the determination of the Overall Soil Type 2 RRS value for Lead. Please provide all model input and output parameters for review.
- Failure to run the Georgia Adult Lead Model (GALM) in the determination of the Overall Soil Type 4 RRS value for Lead. Please provide all model input and output parameters for review.
- Entering a groundwater concentration for lead in the IEUBK and GALM models that exceeds the federal action limit of 15 micrograms/liter.
- Use of surrogates. Only substances regulated under HSRA are listed in Appendix I of the HSRA Rules. If a substance is not listed in this Appendix then Risk Reduction Standards (RRSs) do not apply.
- Using the notification concentrations for risk reduction standards.
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Ecological Health
- Based on the 8 Step Ecological Risk Assessment Process for Superfund Sites: http://www.epa.gov/oswer/riskassessment/ecorisk/ecorisk.htm.
- Process is divided into two stages:
- Screening Level Ecological Risk Assessment (SLERA) – Steps 1 and 2
- Baseline Ecological Risk Assessment (BERA) – Steps 3 thru 8
- SLERA: involves the comparison of Regulated Substances’ Maximum Detected Concentrations (MDCs) with appropriate Ecological Screening Values (ESVs) and approved Background Values (Inorganics only). This comparison results in a Hazard Quotient (HQ) [HQ = MDC/ESV].
- Appropriate ESVs for use at this stage with respect to exposure media
- Surface Water:
- Soil:
- Sediment:
- Any regulated substance, which lacks a Water Quality Criteria (WQC) or a Region 4 ESV or has a Hazard Quotient (HQ) greater than 1.0, must be carried forward in the risk assessment process (Steps 3 thru 8).
- BERA: includes Step 3A, the Refinement step, which always for the use of:
- A 95% Upper Confidence Limit (UCL) of the mean as the Exposure Point Concentration (EPC) rather than MDCs.
- Alternate Screening Values (ASVs):
- Surface Water:
- Soil:
- Sediment:
- Any regulated substance, which lacks an Alternate Screening Value (ASV) or has Hazard Quotient (HQ) greater than 1.0, must be carried forward in the risk assessment process (Steps 4 thru 8).
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