Ariz. Admin. Code § R18-16-407 - Feasibility Study

A. The feasibility study is a process to identify a reference remedy and alternative remedies that appear to be capable of achieving remedial objectives and to evaluate them based on the comparison criteria to select a remedy that complies with A.R.S. § 49-282.06.

B. The Department or any person may perform all or any portion of a feasibility study, except that once the Department has issued a notice under A.R.S. § 49-287.03 for a site, a person may perform such work only under a written agreement with the Department. The feasibility study process shall include community involvement procedures in compliance with R18-16-404 and may be reported concurrently with the remedial investigation. A work plan shall be developed and implemented for all or any portion of a feasibility study for a site or a portion of a site, as follows:

1. The work plan shall demonstrate that the work performed will meet the requirements of this Section.

2. A work plan may be modified as appropriate.

3. Any person proposing to implement a work plan for all or a portion of a feasibility study shall, before implementing the work plan, notify the Department in writing of the name and address of the working party and a general description of the work being performed. This notice is for the Department's information only and receipt of the notice shall not constitute approval of the work plan. A person seeking approval of a work plan by the Department shall proceed under R18-16-413.

C. For remedies addressing only soils, an analysis of alternative remedies is not required. A feasibility study report shall be prepared that demonstrates:

1. That the proposed remedy addresses the contaminated soil in a manner that achieves compliance with A.R.S. § 49-152 and 18 A.A.C. 7, Article 2 and will achieve the remedial objectives for the use of the property.

2. That the proposed remedy was selected based upon best engineering, geological, or hydrogeological judgment following engineering, geological, or hydrogeological standards of practice, considering the following information:

a. The remedial investigation;

b. Best available scientific information concerning available remedial methods and technologies;

c. A written analysis explaining how the remedy is consistent with A.R.S. § 49-282.06, including a brief explanation of the comparison criteria as applied to the remedy.

D. For remedies addressing only landfills that have not and will not impact groundwater or similar sites or portions of sites that have not and will not impact groundwater, and that contain material not subject to A.R.S. § 49-152 and 18 A.A.C. 7, Article 2, an analysis of alternative remedies is not required. A feasibility study report shall be prepared that demonstrates:

1. That the proposed remedy is designed to prevent human exposure to hazardous substances through the achievement of:

a. Soil remediation levels established under 18 A.A.C. 7, Article 2, or

b. Site-specific remediation levels based on a site-specific human health risk assessment, meeting a cumulative excess lifetime cancer risk between 1 x 10-4 and 1 x 10-6 and a hazard index no greater than 1. The excess lifetime cancer risk shall be selected by the Department based upon site specific factors including the presence of multiple contaminants, the existence of multiple pathways of exposure, the uncertainty of exposure, and the sensitivity of the exposed population. With prior approval of the Department, a person may achieve a site specific remediation level based on the use of institutional and engineering controls. The approval shall be based in part on the demonstration that the institutional and engineering controls will be maintained.

2. That the proposed remedy was selected based upon best engineering, geological, or hydrogeological judgment following engineering, geological, or hydrogeological standards of practice, considering the following information:

a. The remedial investigation;

b. Best available scientific information concerning available remedial methods and technologies;

c. A written analysis explaining how the remedy is consistent with A.R.S. § 49-282.06, including a brief explanation of the comparison criteria as applied to the remedy.

3. That the proposed remedy will achieve all of the remedial objectives.

E. For remedies other than provided in subsections (C) and (D), the feasibility study shall provide for the development of a reference remedy and at least two alternative remedies as follows:

1. The reference remedy and alternative remedies shall be capable of achieving all of the remedial objectives. The reference remedy and each alternative remedy shall consist of a remedial strategy under subsection (F) and all remedial measures to be employed. The combination of the remedial strategy and the remedial measures for each alternative remedy shall achieve the remedial objectives. The reference remedy and any alternative remedy also may include contingent remedial strategies or remedial measures to address reasonable uncertainties regarding the achievement of remedial objectives or uncertain time-frames in which remedial objectives will be achieved. The reference remedy and other alternative remedies shall be developed and described in the feasibility study report in sufficient detail to allow evaluation using the comparison criteria, but plans at construction level detail are not required. The units of measure set forth in Appendix A may be used, as applicable, for comparison of the relevant factors. Where appropriate, the reference remedy and an alternative remedy may incorporate different strategies for different aquifers or portions of aquifers.

2. The reference remedy shall be developed based upon best engineering, geological, or hydrogeological judgment following engineering, geological, or hydrogeological standards of practice, considering the following:

a. The information in the remedial investigation;

b. The best available scientific information concerning available remedial technologies; and

c. Preliminary analysis of the comparison criteria and the ability of the reference remedy to comply with A.R.S. § 49-282.06.

3. At a minimum, at least two alternative remedies shall be developed for comparison with the reference remedy. At least one of the alternative remedies must employ a remedial strategy or combination of strategies that is more aggressive than the reference remedy, and at least one of the alternative remedies must employ a remedial strategy or combination of strategies that is less aggressive than the reference remedy. For the purposes of this Section, a more aggressive strategy is a strategy that requires fewer remedial measures to achieve remedial objectives, a strategy that achieves remedial objectives in a shorter period of time, or a strategy that is more certain in the long term and requires fewer contingencies. With the Department's approval, one of the minimum required alternative remedies may use the same strategy as the reference remedy but use different viable technologies or a more intensive use of the same technology utilized in the reference remedy.

F. The remedial strategies to be developed under subsection (E) are listed below. Source control shall be considered as an element of the reference remedy and all alternative remedies, if applicable, except for the monitoring and no action alternatives. A strategy may incorporate more than one remediation technology or methodology, such as a plume remediation strategy that consists of a combination of pumping and treating in portions of an aquifer and monitored natural attenuation for other portions of the aquifer. The remedial strategies are:

1. Plume remediation is a strategy to achieve water quality standards for contaminants of concern in waters of the state throughout the site.

2. Physical containment is a strategy to contain contaminants within definite boundaries.

3. Controlled migration is a strategy to control the direction or rate of migration but not necessarily to contain migration of contaminants.

4. Source control is a strategy to eliminate or mitigate a continuing source of contamination.

5. Monitoring is a strategy to observe and evaluate the contamination at the site through the collection of data.

6. No action is a strategy that consists of no action at a site.

G. Remedial measures necessary for each alternative remedy developed under subsection (E) to achieve remedial objectives or to satisfy the requirements of A.R.S. § 49-282.06(B)(4)(b) shall be identified in consultation with water providers or known well owners whose water supplies are affected by the release or threatened release of a hazardous substance. In identifying the remedial measures, the needs of the well owners and the water providers and their customers, including the quantity and quality of water, water rights and other legal constraints on water supplies, reliability of water supplies and any operational implications shall be considered. Such remedial measures may include, but are not limited to, well replacement, well modification, water treatment, provision of replacement water supplies, and engineering controls. Where remedial measures are relied upon to achieve remedial objectives, such remedial measures shall remain in effect as long as required to ensure the continued achievement of those objectives. The Department may require financial mechanisms to provide for the cost of implementation of the remedial measures.

H. The Department or any person who conducts a feasibility study by agreement with the Department shall conduct a comparative evaluation of the reference remedy and the alternative remedies developed under subsection (E). For each alternative, the evaluation shall be reported in a feasibility study report and shall include:

1. A demonstration that the remedial alternative will achieve the remedial objectives.

2. An evaluation of consistency with the water management plans of affected water providers and the general land use plans of local governments with land use jurisdiction.

3. An evaluation of the comparison criteria, including:

a. An evaluation of the practicability of the alternative, including its feasibility, short and long-term effectiveness, and reliability, considering site-specific conditions, characteristics of the contamination resulting from the release, performance capabilities of available technologies, and institutional considerations.

b. An evaluation of risk, including the overall protectiveness of public health and aquatic and terrestrial biota under reasonably foreseeable use scenarios and end uses of water. This evaluation shall address:

i. Fate and transport of contaminants and concentrations and toxicity over the life of the remediation;

ii. Current and future land and resource use;

iii. Exposure pathways, duration of exposure, and changes in risk over the life of the remediation;

iv. Protection of public health and aquatic and terrestrial biota while implementing the remedial action and after the remedial action; and

v. Residual risk in the aquifer at the end of remediation.

c. An evaluation of the cost of the remedial alternative, including the expenses and losses including capital, operating, maintenance, and life cycle costs. The cost analysis may include the analysis of uncertainties that may impact the cost of a remedial alternative, analysis of projected water uses and costs associated with use-based treatment, other use impairment costs of water not remediated to water quality standards, and the cost of measures such as alternative water supply or treatment. Transactional costs necessary to implement the remedial alternative, including the transactional costs of establishing long-term financial mechanisms, such as trust funds, for funding of an alternative remedy, shall be included in the cost estimate.

d. An evaluation of the benefit, or value, of the remediation. This analysis includes factors such as:

i. Lowered risk to human and aquatic and terrestrial biota;

ii. Reduced concentration and reduced volume of contaminated water;

iii. Decreased liability; acceptance by the public;

iv. Aesthetics; preservation of existing uses;

v. Enhancement of future uses; and

vi. Improvements to local economies.

e. A discussion of the comparison criteria, as evaluated in relation to each other.

I. Based upon the evaluation and comparison of the reference remedy and the other alternative remedies developed under subsection (E), a proposed remedy shall be developed and described in the feasibility study report. The proposed remedy may be the reference remedy, any of the other alternative remedies evaluated in the feasibility study, or a different combination of remedial strategies and remedial measures that were included in the alternative remedies evaluated in the feasibility study. The feasibility study report shall describe the reasons for selection of the proposed remedy, including all of the following:

1. How the proposed remedy will achieve the remedial objectives;

2. How the comparison criteria were considered; and

3. How the proposed remedy meets the requirements of A.R.S. § 49-282.06.

J. Any person, other than a person proposing to perform work under an agreement under A.R.S. § 49-287.03(C), may submit a request in compliance with R18-16-413 for the Department to approve a work plan or a report for all or any portion of a feasibility study. The Department shall approve a work plan for a feasibility study if the request shows that the work will comply with this Section, community involvement activities will be performed in compliance with R18-16-404, and the work plan provides for modifications to comply with this Section. The Department shall approve a feasibility study report if the feasibility study complies with this Section and community involvement activities have been conducted under this Article.

Notes

Ariz. Admin. Code § R18-16-407

New Section made by exempt rulemaking at 8 A.A.R. 1491, effective March 4, 2002 (Supp. 02-1).