Fla. Admin. Code Ann. R. 62-780.690 - Natural Attenuation Monitoring

(1) Natural Attenuation Monitoring and long-term natural attenuation monitoring are allowable strategies for site rehabilitation depending on the individual site characteristics, provided human health, public safety, and the environment are protected. The individual site characteristics may include the current and projected use of the affected groundwater and surface water in the vicinity of the site, the current and projected land use of the area affected by the contamination, the exposed population, the location of the plume, the degree and extent of contamination, the rate of migration of the plume, the apparent or potential rate of degradation of contaminants through natural attenuation, and the potential for further migration in relation to the site's property boundary. Fate and transport models as defined in rule 62-780.610, F.A.C., may be utilized to support the appropriateness of natural attenuation monitoring. Natural attenuation monitoring is allowable provided the following criteria are met:

(a) Free product is not present or free product removal is not technologically feasible and no fire or explosive hazard exists as a result of a release of non-aqueous phase liquids;

(b) Contaminated soil is not present in the unsaturated zone, except that applicable leachability-based soil CTLs may be exceeded if it is demonstrated to the Department that the soil does not constitute a continuing source of contamination to the groundwater at concentrations that pose a threat to human health, public safety, and the environment, and it is demonstrated that the rate of natural attenuation of contaminants in the groundwater exceeds the rate at which contaminants are leaching from the soil. The determination shall be based upon individual site characteristics and demonstrated by USEPA Test Method 1312 (SPLP), or USEPA Test Method 1311 (TCLP) if the contamination is derived from used oil or similar petroleum products, followed by the appropriate analyses of the leachate, and based upon groundwater modeling, site stratigraphy, or site assessment results;

(c) Contaminants present in the groundwater above background concentrations or applicable CTLs are not migrating beyond the temporary point of compliance or migrating vertically, which may contaminate other aquifers or surface water resources or result in increased site rehabilitation time;

(d) The physical, chemical or biological characteristics of each contaminant and its transformation product(s) are conducive to natural attenuation;

(e) The available data show an overall decrease in the contamination; and,

(f) One of the following is met:

1. The site is anticipated to meet the applicable No Further Action criteria of Rule 62-780.680, F.A.C., as a result of natural attenuation, the background concentrations or the applicable CTLs are not exceeded at the temporary point of compliance as established pursuant to subsection 62-780.690(2) or 62-780.690(3), F.A.C., and contaminant concentrations do not exceed the criteria specified in chapter 62-777, F.A.C., Table V, or

2. If the criteria of subparagraph 62-780.690(1)(f) 1., F.A.C., are not met, the appropriateness of natural attenuation monitoring may be demonstrated by the following:

a. A technical evaluation of groundwater and soil characteristics, chemistry, and biological activity that verifies that the contaminants have the capacity to degrade under the site-specific conditions. A listing of the site-specific conditions and geochemical parameters, as applicable, is provided in chapter 62-777, F.A.C., Table IV,

b. A scientific evaluation (historical data or modeling results, as appropriate; the model used shall be demonstrated to be appropriate for the site conditions) of the plume migration in relation to the temporary point of compliance as established pursuant to subsection 62-780.690(2) or 62-780.690(3), F.A.C., an estimation of expected annual reductions in contaminant concentrations in monitoring wells, and an estimation of the time required to meet the applicable No Further Action criteria of rule 62-780.680, F.A.C. Available technical information (including historical water quality data) shall be used for model calibration; and,

c. A life-cycle cost analysis of remedial alternatives.

(2) Provided human health, public safety, and the environment are protected, the point of compliance may be temporarily moved from the source of the contamination.

(a) The location of the temporary point of compliance shall be based on the individual site characteristics listed in subsection 62-780.690(1), F.A.C.

(b) The point of compliance may be temporarily moved to the property boundary, or to the edge of the plume when the plume is within the property boundary, while cleanup, including cleanup through natural attenuation processes in conjunction with appropriate monitoring, is proceeding.

(c) The temporary point of compliance may extend beyond the property boundary when accompanied by monitoring, if such extension is needed to facilitate monitoring of natural attenuation or to address the current conditions of the plume, provided human health, public safety, and the environment are protected. If the point of compliance is proposed to be temporarily extended beyond the property boundary, it cannot be extended further than the lateral extent of the plume at the time of execution of a CAD, if known, or the lateral extent of the plume as defined at the time of the approved site assessment. Prior to the Department authorizing a temporary extension of the point of compliance beyond the property boundary, the PRSR shall provide notice and an opportunity to comment pursuant to subsection 62-780.220(3), F.A.C.

(d) Pursuant to subsection 62-780.220(4), F.A.C., additional notice concerning the status of the natural attenuation processes shall be similarly provided every five years to persons receiving notice pursuant to paragraph 62-780.690(2)(c), F.A.C.

(3) Where surface water is or may be exposed to contaminated groundwater (based on monitoring well data, groundwater flow rate and direction, or fate and transport modeling), the point of measuring compliance with the surface water standards shall be in the groundwater from the landward side immediately adjacent to the surface water body. For cleanups being conducted pursuant to section 376.30701(2), F.S., (including petroleum contamination sites being addressed pursuant to section 376.3071, F.S., that are not eligible for state-funded site rehabilitation, if the PRSR elects) or section 376.81(1), F.S., such measurement is not necessary if it has been demonstrated, based on site assessment data provided in accordance with rule 62-780.600, F.A.C., that the contaminants do not cause or contribute to the exceedance of applicable surface water quality criteria.

(4) If the criteria of subsection 62-780.690(1), F.A.C., are met, a Natural Attenuation with Monitoring Plan, prepared pursuant to subsection 62-780.690(8), F.A.C., may be submitted. Unless the Natural Attenuation with Monitoring Plan is included in a Site Assessment Report pursuant to subparagraph 62-780.600(8)(b) 2., F.A.C., or in a Risk Assessment Report pursuant to paragraph 62-780.650(4)(b), F.A.C., the PRSR shall submit to the Department for review an electronic or paper copy of the Natural Attenuation Monitoring Plan.

(5) The Department shall:

(a) Provide the PRSR with written approval of the Natural Attenuation Monitoring Plan, or

(b) Notify the PRSR in writing, stating the reason(s) why the Natural Attenuation Monitoring Plan does not contain information adequate to support the conclusion that the applicable Natural Attenuation Monitoring criteria of rule 62-780.690, F.A.C., have been met.

(6) If the Natural Attenuation Monitoring Plan is incomplete in any respect, or is insufficient to satisfy the criteria of subsection 62-780.690(1), F.A.C., the Department shall inform the PRSR pursuant to paragraph 62-780.690(5)(b), F.A.C., and the PRSR shall submit to the Department for review an electronic or paper copy of a revised Natural Attenuation Monitoring Plan that addresses the deficiencies within 30 days after receipt of the notice. If the deficiencies are not timely corrected, or cannot be corrected, the PRSR shall, as appropriate, continue the implementation of the approved Remedial Action Plan or submit to the Department for review an electronic or paper copy of a Remedial Action Plan pursuant to rule 62-780.700, F.A.C., within 60 days after receipt of the notice.

(7) If the Natural Attenuation Monitoring Plan meets the criteria of subsection 62-780.690(1), F.A.C., a Natural Attenuation Monitoring Plan approval shall be issued. The objective of the monitoring program shall be to meet the applicable No Further Action criteria of rule 62-780.680, F.A.C.

(8) The monitoring program shall be performed as specified in the Natural Attenuation Monitoring Plan approval, as follows:

(a) A minimum of two monitoring wells is required:

1. At least one well shall be located at the downgradient edge of the plume; and,

2. At least one well shall be located in the area(s) of highest groundwater contamination or directly adjacent to it if the area of highest groundwater contamination is inaccessible (for example, under a structure).

(b) The designated monitoring wells shall be sampled for analyses of applicable contaminants as specified in the Natural Attenuation Monitoring Plan approval but no more frequent than quarterly;

(c) Water-level measurements in all designated wells and piezometers shall be made within 24 hours of initiating each sampling event;

(d) Within the time frames specified in Table A or the CAD, the PRSR shall submit to the Department for review an electronic or paper copy of a Natural Attenuation Monitoring Report. The report shall include the analytical results (laboratory report), chain of custody record form [Form 62-780.900(2) or an equivalent chain of custody form that includes all the items required by Form 62-780.900(2)], the tables required pursuant to subparagraph 62-780.600(8)(a) 27., F.A.C., updated as applicable, site maps that illustrate the analytical results, and the water-level elevation information (summary table and flow map);

(e) If analyses of groundwater samples indicate that concentrations of applicable contaminants exceed any action levels specified in the Natural Attenuation Monitoring Plan approval, then the monitoring report referenced in paragraph 62-780.690(8)(d), F.A.C., shall be signed and sealed by an appropriate registered professional pursuant to rule 62-780.400, F.A.C., and shall include a proposal to:

1. Perform a supplemental site assessment and submit a supplemental Site Assessment Report pursuant to rule 62-780.600, F.A.C.,

2. Continue the implementation of the approved Natural Attenuation Monitoring Plan,

3. Prepare and submit a Remedial Action Plan pursuant to rule 62-780.700, F.A.C., or

4. Other proposal as authorized by this rule chapter.

(f) As specified in the approved Natural Attenuation Monitoring Plan, the analytical data shall be evaluated in reference to the expected reductions in contaminant concentrations in monitoring wells pursuant to subparagraph 62-780.690(1)(f) 1., F.A.C., or sub-subparagraph 62-780.690(1)(f) 2.b., F.A.C., as applicable, to verify progress of site rehabilitation by natural attenuation. If the rate of expected cleanup progress is not achieved, then the monitoring report referenced in paragraph 62-780.690(8)(d), F.A.C., shall be signed and sealed by an appropriate registered professional pursuant to rule 62-780.400, F.A.C., and shall include a proposal to:

1. Perform a supplemental site assessment and submit a supplemental Site Assessment Report pursuant to rule 62-780.600, F.A.C.,

2. Continue the implementation of the approved Natural Attenuation Monitoring Plan,

3. Prepare and submit a Remedial Action Plan pursuant to rule 62-780.700, F.A.C., or

4. Other proposal as authorized by this rule chapter; and,

(g) If natural attenuation monitoring follows site assessment, a minimum of two sampling events is required and site rehabilitation shall be considered complete when the No Further Action criteria of subsection 62-780.680(1), 62-780.680(2), or 62-780.680(3), F.A.C., have been met for two consecutive sampling events. If natural attenuation monitoring follows active remediation, a minimum of four sampling events is required and site rehabilitation shall be considered complete when the No Further Action criteria of subsection 62-780.680(1), 62-780.680(2), or 62-780.680(3), F.A.C., have been met for at least the last two sampling events. If soil contamination was present at the beginning of the monitoring program, prior to submitting the Site Rehabilitation Completion Report soil samples shall be collected at appropriate locations and depths and analyzed for the applicable contaminants to demonstrate to the Department that applicable soil CTLs are met.

(9) If during implementation of the Natural Attenuation Monitoring Plan the PRSR submits to the Department for review a Remedial Action Plan pursuant to subsection 62-780.700(6), F.A.C., to enhance natural attenuation processes, and the Remedial Action Plan is approved, natural attenuation monitoring shall be suspended during the implementation of the enhancement and the PRSR shall perform active remediation monitoring pursuant to the approved Remedial Action Plan.

(10) When Natural Attenuation Monitoring is considered complete pursuant to paragraph 62-780.690(8)(g), F.A.C., within the time frames specified in Table A or the CAD the PRSR shall submit to the Department for review an electronic or paper copy of a Site Rehabilitation Completion Report with a No Further Action Proposal. The Site Rehabilitation Completion Report shall include the documentation required in paragraph 62-780.690(8)(d), F.A.C., to support the opinion that site cleanup objectives have been achieved.

(11) The Department shall:

(a) Provide the PRSR with a Site Rehabilitation Completion Order as referenced in subsection 62-780.680(7), F.A.C., that approves the Site Rehabilitation Completion Report with the No Further Action Proposal, or

(b) Notify the PRSR in writing, stating the reason(s) why the Site Rehabilitation Completion Report does not contain information adequate to support the opinion that cleanup objectives have been achieved. Site rehabilitation activities shall not be deemed complete until such time as a Site Rehabilitation Completion Report with a No Further Action Proposal is approved.

(12) If the Site Rehabilitation Completion Report is incomplete in any respect, or is insufficient to satisfy the objectives of subsection 62-780.690(10), F.A.C., the Department shall inform the PRSR pursuant to paragraph 62-780.690(11)(b), F.A.C., and the PRSR shall submit to the Department for review an electronic or paper copy of a revised Site Rehabilitation Completion Report that addresses the deficiencies within 30 days after receipt of the notice. If the deficiencies are not timely corrected, or cannot be corrected, the PRSR shall resume the implementation of the approved Natural Attenuation Monitoring Plan within 30 days after receipt of the notice.

(13) For brownfield sites, the Site Rehabilitation Completion Order shall contain the following statement, as applicable: "Based upon the information provided by (real property owner) concerning property located at (insert address), it is the opinion of the Florida Department of Environmental Protection that (party) has successfully and satisfactorily implemented the approved brownfield site rehabilitation agreement schedule and, accordingly, no further action is required to assure that any land use identified in the brownfield site rehabilitation agreement is consistent with existing and proposed uses. If the real property owner proposes to remove the institutional or engineering controls, the real property owner shall obtain prior approval from the Department. The removal of the controls shall be accompanied by the immediate resumption of site rehabilitation, or implementation of other approved controls, unless the criteria of subsection 62-780.680(1), F.A.C., are met."

(14) The Site Rehabilitation Completion Order shall constitute final agency action regarding cleanup activities at the site.

Notes

Fla. Admin. Code Ann. R. 62-780.690

Rulemaking Authority 376.303, 376.3071, 376.30701, 376.3078(4), 376.81, 403.061, 403.0877 FS. Law Implemented 376.3071, 376.30701, 376.3078(4), 376.81, 403.0877 FS.

New 4-17-05, Amended 6-12-13, 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 62-770.690; 62-782.690; and 62-785.690, F.A.C.

Portions of this rule were copied from rule 62-770.690; 62-782.690; and 62-785.690, F.A.C.

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