Fla. Admin. Code Ann. R. 62-780.650 - Risk Assessment

(1) If the PRSR elects to perform a risk assessment, then during the risk assessment process, the PRSR is encouraged to have discussions with the Department at various decision points to establish applicable exposure factors, relevant receptors, and risk management options based on the current and projected land use(s) at the site. If a risk assessment is performed, the following risk assessment task elements shall be performed, as applicable:

(a) An exposure assessment that identifies pathways and routes by which human and environmental receptors may be exposed to contaminants and determines levels of contaminants to which human and environmental receptors may be exposed. The exposure assessment shall:

1. Identify actual and potential exposure pathways and routes,

2. Identify actual and potential human and environmental receptors for each exposure pathway, and sensitive sub-populations such as children, where applicable,

3. Determine expected concentrations of contaminants to which actual and potential human and environmental receptors may be exposed, with the most recent sampling of representative monitoring wells having occurred no more than 270 days prior to Risk Assessment Report submittal,

4. Determine exposure factors (e.g., exposure duration, exposure frequency, body weight and ingestion rate) based on:

a. Site-specific characteristics, including consideration of current and plausible projected land uses. Institutional and engineering controls may be proposed in order to ensure that exposure factors do not change, or

b. Non-site-specific exposure factors contained in the USEPA Exposure Factors Handbook (2011 Edition), hereby adopted and incorporated by reference, (http://www.flrules.org/Gateway/reference.asp?No=Ref-03403), or other information on exposure factors relevant or applicable to the actual conditions of exposure.

5. Estimate the contaminant doses received by relevant receptors.

(b) A toxicity assessment that determines human health and environmental criteria for contaminants found at the site.

1. The criteria, taking into consideration acute and chronic health effects associated with short-term and long-term exposure, shall be applicable to exposure pathways and routes identified in the exposure assessment, including, as applicable:

a. Potable water exposure from ingestion, dermal contact, and inhalation of vapors and mists,

b. Non-potable water exposure from dermal contact, inhalation of vapors and mists, ingestion of food crops irrigated with such water, lawn watering, and other related exposures, and exposures to pets and livestock from ingestion,

c. Soil exposure from ingestion, dermal contact, inhalation, and ingestion by humans or animals of food crops grown in contaminated soil; and,

d. Non-potable surface water exposure from ingestion, dermal contact, and inhalation of vapors and mists. Adverse effects on freshwater or marine biota (including any bio-accumulative effects in the food chain) and on humans (for example, through incidental ingestion and dermal contact while using the resource for recreational purposes or fish consumption) shall be considered.

2. Input assumptions different from those used to develop default CTLs may be used to propose alternative CTLs. The appropriate equations from chapter 62-777, F.A.C., must be used in calculating the alternative CTLs. Toxicity values for quantifying human health risks and for developing alternative CTLs may be taken from the following information sources listed in rule 62-780.100, F.A.C., in order of preference:

a. USEPA Integrated Risk Information System (IRIS) database.

b. Provisional Peer Reviewed Toxicity Values (PPRTV) derived by EPA's Superfund Technical Support Center for the USEPA Superfund program.

c. Values proposed by a PRSR from other sources. Such values must be accompanied with a justification for using the proposed value and are subject to review and acceptance by FDEP based upon statutory requirements for the protection of human health and the environment. The referenced guidelines in subsections 62-780.100(12) through 62-780.100(20), F.A.C., are available for reference when selecting or justifying alternative values.

(c) A risk characterization that utilizes the results of the exposure assessment, the toxicity assessment, and any other relevant public health and epidemiological assessments, to characterize cumulative risks to the affected population(s) and the environment from contaminants found at the site. Based on the concentrations of contaminants found at the site, the characterization shall include:

1. Risks to human health and safety from exposure to the contamination,

2. Risks from the contamination to non-human species and ecosystems; and,

3. Derivation of alternative CTLs, as applicable. [Refer to Appendix C of the technical report referenced in subsection 62-780.100(2), F.A.C., for guidance on the derivation of alternative CTLs for TRPHs based on a sub-classification methodology; and to chapter 62-777, F.A.C., Table III for methods that may be used in determining soil properties for the derivation of alternative CTLs based on site-specific soil characteristics, if soil properties are used to derive alternative CTLs.] In developing alternative CTLs, the dose additivity of chemicals shall be considered [Refer to the "Dose Additivity" document referenced in subsection 62-780.100(24), F.A.C., for guidance].

(d) A justification for alternative CTLs, as applicable, for groundwater or soil. The justification for the alternative CTLs shall be based upon site-specific or other relevant data and information, risk assessment, modeling results, including results from probabilistic risk assessment modeling, risk assessment studies, risk reduction techniques or a combination thereof. In establishing the alternative CTLs for groundwater or soil, the following factors shall be used, as applicable: calculations using a lifetime excess cancer risk level of 1.0E-6 and a hazard index of 1, and (for groundwater only) nuisance, organoleptic, and aesthetic considerations. However, the Department shall not require site rehabilitation to achieve a CTL for an individual contaminant that is more stringent than the site-specific background concentration for that contaminant or the best achievable detection limit for that contaminant. The justification shall be based on:

1. State-wide, as applicable, or site-specific characteristics pertinent to the site, including:

a. The present and projected uses of the affected aquifer(s) and adjacent surface water, with particular consideration of the probability that the contamination is substantially affecting, or will migrate to and substantially affect, a known public or private source of potable water,

b. The technical feasibility of achieving the soil or water quality criteria based on a review of available technology; and,

c. Site soil characteristics; and,

2. The results of the exposure assessment, toxicity assessment, and risk characterization pursuant to paragraphs 62-780.650(1)(a), 62-780.650(1)(b), and 62-780.650(1)(c), F.A.C.

(2) Fate and transport models for contaminants may be employed, pursuant to rule 62-780.610, F.A.C., to document that human health and environmental risks are acceptable, and to document that potential risks associated with the establishment of alternative CTLs are acceptable. If a fate and transport model for contaminants is used, the model shall be validated during subsequent monitoring to justify a No Further Action Proposal, or during natural attenuation monitoring or active remediation monitoring, and adjusted as appropriate using empirical data as the data are obtained.

(3) Where a PRSR elects to perform a risk assessment pursuant to subsection 62-780.650(1), F.A.C., Probabilistic Risk Assessments may be employed to document that human health and environmental risks are acceptable, and to document that potential risks associated with the establishment of alternative CTLs are acceptable provided:

(a) The equations in chapter 62-777, F.A.C., Figures (1)-(10), as applicable, shall be used as the basis for calculation of cumulative risks and for the calculation of the alternative CTL.

(b) The selection of the alternative CTL shall be the value that is protective for the pathways and routes by which human and environmental receptors may be exposed representing the 90th percentile of the final exposure or risk variability distributions produced by the model for the general population, or for any identified sensitive life stages, where applicable (or the 10th percentile of the CTL distribution if demonstrated to be equivalent); and,

(c) The following information regarding the Probabilistic Risk Assessment model is submitted to and approved by the Department pursuant to subsection 62-780.610(2), F.A.C.:

1. All information required by paragraph 62-780.610(2)(b), F.A.C.,

2. The type of simulation used,

3. Whether the simulation used is an open-source model or a proprietary model,

4. The source(s) for the distribution(s), as well as any point values, used in the model,

5. A description of the applicability and scientific basis for each of the distribution(s) and point values used in the model,

6. The shapes and parameters of distribution(s) used in the model and the basis for these assumptions,

7. The extent of correlation, if any, assumed between specific input distributions and the scientific rationale for that correlation,

8. Any default model parameter values that were replaced with other values for the purposes of the Probabilistic Risk Assessment and the rationale for such replacement, specifically including any methods used for sampling or resampling from the input distributions. The PRSR may submit the information listed in paragraph 62-780.650(3)(c), F.A.C., above, for review and approval in advance of the submittal of the model results; and,

9. A discussion of the uncertainties associated with the models and inputs used in the probabilistic risk assessment, including contributions from:

a. The nature and sources of exposure and toxicity information,

b. The shape of input distributions and limits, and choice of point value inputs, if any, used in the analysis; and,

c. The selection of specific models used in the analysis.

d. If the uncertainty discussion includes quantitative information, it may be presented in the form of a parameter sensitivity analysis, or calculation of risk in two dimensions where uncertainty is expressed as the confidence bounds on the risk variability distribution.

10. A quantitative assessment of uncertainty is not required, but if submitted as part of the risk assessment, should quantify how alternative inputs and models would change the 90th percentile risk (and associated CTL) for the population(s) of interest.

(4) Within the time frames specified in Table A, located at the end of rule 62-780.900, F.A.C., or the CAD, the PRSR shall submit to the Department for review an electronic or paper copy of the Risk Assessment Report.

(5) The Risk Assessment Report shall contain a description of the task elements undertaken, summarize the conclusions obtained, include the tables required pursuant to subparagraph 62-780.600(8)(a) 27., F.A.C., updated as applicable, include a scaled site map for each contaminated medium, that illustrates the degree and extent of contamination (and, for groundwater, the flow direction), and include one of the following:

(a) A No Further Action Proposal without institutional and engineering controls shall be included if the site meets the applicable No Further Action criteria of subsection 62-780.680(1), F.A.C., or a No Further Action Proposal with institutional controls or both institutional and engineering controls may be included if the site meets the applicable No Further Action criteria of subsection 62-780.680(2), F.A.C., or a No Further Action Proposal with or without institutional controls or both institutional and engineering controls may be included if the site meets the applicable No Further Action criteria of subsection 62-780.680(3), F.A.C.

(b) A Natural Attenuation Monitoring Plan may be included if the site meets the Natural Attenuation Monitoring criteria of rule 62-780.690, F.A.C., or

(c) A recommendation to prepare a Remedial Action Plan pursuant to rule 62-780.700, F.A.C., shall be included, unless a recommendation pursuant to paragraph 62-780.650(4)(a) or 62-780.650(4)(b), F.A.C., is included.

(6) The Department shall:

(a) Provide the PRSR with written approval of the Risk Assessment Report and:

1. If the No Further Action Proposal is approved, with a Site Rehabilitation Completion Order as referenced in subsection 62-780.680(7), F.A.C.,

2. If the Natural Attenuation Monitoring Plan is approved, with a Natural Attenuation Monitoring Plan Approval as referenced in paragraph 62-780.690(5)(a), F.A.C., or

3. If the recommendation to prepare a Remedial Action Plan is approved, with a written notification that the Remedial Action Plan shall be prepared pursuant to rule 62-780.700, F.A.C., or

(b) Notify the PRSR in writing, stating:

1. The reason(s) why the Risk Assessment Report does not contain information adequate to support the proposed alternative CTLs, or

2. The reason(s) why the proposal, plan, or recommendation submitted pursuant to subsection 62-780.650(3), F.A.C., is not supported by the applicable criteria.

(7) If a Risk Assessment Report or Risk Assessment Report Addendum is incomplete in any respect, or is insufficient to satisfy the objectives set forth in subsection 62-780.650(5), F.A.C., the Department shall inform the PRSR pursuant to paragraph 62-780.650(6)(b), F.A.C., of the basis for a rejection or determination of insufficiency, including the technical and scientific basis for any such rejection. The PRSR shall submit to the Department for review an electronic or paper copy of a Risk Assessment Report Addendum that addresses the deficiencies within 60 days after receipt of the notice.

Notes

Fla. Admin. Code Ann. R. 62-780.650

Rulemaking Authority 376.303, 376.3071, 376.30701, 376.3078(4), 376.81, 403.061 FS. Law Implemented 376.3071, 376.30701, 376.3078(4), 376.81, 403.021, 403.061, 403.062 FS.

New 4-17-05, Amended 6-12-13, 2-4-14, Amended by Florida Register Volume 43, Number 011, January 18, 2017 effective 2/2/2017. Editorial Note: Portions of this rule were copied from rule 62-770.650; 62-782.650; and 62-785.650, F.A.C.

Portions of this rule were copied from rule 62-770.650; 62-782.650; and 62-785.650, F.A.C.

New 4-17-05, Amended 6-12-13, 2-4-14, 2-2-17.