Current through Register Vol. 63, No. 3, March 1, 2024
(1)
Subject to section (12) of this rule, a responsible person proposing to
remediate a site to risk-based remediation levels must submit a corrective
action plan for responding to contaminated soil and groundwater.
(2) A remediation level must be proposed for
each contaminant of concern in soil and groundwater based on:
(a) Site-specific risk-based concentrations
calculated according to OAR
340-122-0244,
or generic risk-based concentrations developed under OAR
340-122-0252;
(b) Current or future reasonably likely
significant adverse effects to beneficial uses of groundwater or surface water
not addressed by risk-based concentrations under subsection (a) of this
section; and
(c) Proposed
institutional and engineering controls, if any.
(3) The corrective action plan must be
submitted to the Department within 45 days of completing field work necessary
for its development, or within a longer period of time approved by the
Department, and must contain sufficient information to support the proposed
remedial measures including, at a minimum:
(a) The site history and a summary of all
previous actions taken in response to the release;
(b) A summary and analysis of all sampling
data, including site maps, drawn to scale, showing the magnitude and extent of
contamination;
(c) The conceptual
site model and an explanation for each remediation level proposed under section
(2) of this rule;
(d) Land and
water use information necessary to support the conceptual site model, including
current uses, and comprehensive plan and zoning designations for adjacent
properties, and all properties potentially affected by the release;
and
(e) A discussion of all
remedial measures including institutional and engineering controls, addressing
any contamination exceeding acceptable risk levels and non-risk
impacts.
(4) A
corrective action plan which contains a proposal for groundwater monitoring or
remediation must include:
(a) A
recommendation for which monitoring well or wells will serve as compliance
points for the site based on the following minimum requirements:
(A) Compliance monitoring points must define
an area surrounding the source of contamination, outside of which remediation
levels must be attained and maintained.
(B) The compliance monitoring points shall
establish a vertical boundary extending from the uppermost level of the
saturated zone to the lowest depth which could potentially be affected by the
release;
(C) Compliance monitoring
points must be located close enough to the source of contamination so that they
reasonably detect contamination, if present; and
(D) Compliance monitoring points may not be
located beyond the source property boundary except as approved by the
Department.
(b) At least
one monitoring point which measures contaminant concentrations in the source
area.
(c) A discussion of all
actions being proposed to monitor or remediate the groundwater contamination.
These actions might not require sampling from all wells or monitoring for all
contaminants detected during the investigation, provided:
(A) Hydrogeological and contamination data,
as well as compliance point requirements, support the wells proposed for
monitoring;
(B) Appropriate
indicator compounds are analyzed at regular intervals during remediation and
monitoring;
(C) Analytical
parameters are consistent with remediation levels; and
(D) All contaminants of concern detected
during the investigation are sampled and analyzed to confirm preliminary and
final compliance.
(5) The Department shall approve the
corrective action plan only after ensuring that implementation of the plan,
including any applicable remediation levels, will adequately protect human
health, safety, and welfare and the environment, and after providing any public
notice consistent with the requirements of OAR
340-122-0260.
(6) Upon approval of the corrective action
plan by the Department, a responsible person must implement the plan, including
any modifications to the plan made by the Department. The responsible person
must monitor, evaluate, and report the results of implementing the plan in
accordance with a schedule and in a format established by the
Department.
(7) For remediation of
groundwater contamination:
(a) Preliminary
compliance is attained when the first sampling event following the installation
of all required monitoring wells shows that all samples collected from all
compliance monitoring points and out to the edge of the contaminant plume meet
the remediation levels for all contaminants of concern. When preliminary
compliance has been attained, the responsible person may suspend groundwater
treatment system operation at any time. The Department may require that a
suspended groundwater treatment system be reactivated if any of the water
samples collected at or beyond the compliance monitoring points during the
required period of monitoring are found to contain any contaminant
concentrations in excess of remediation levels. If the treatment system is
reactivated, treatment must be continued until preliminary compliance is again
attained.
(b) Final compliance is
attained when:
(A) A minimum of four
consecutive quarterly groundwater monitoring events has been completed
following shutdown of the treatment system, and all samples collected from all
compliance monitoring points and out to the edge of the contaminant plume meet
the remediation levels for all contaminants of concern. The four consecutive
sampling events may include the sampling event at which preliminary compliance
is achieved, provided that all contaminants of concern are included in the
sampling and analysis;
(B)
Site-specific hydrogeologic and contaminant level data are presented in a
written report to the Department demonstrating that any remaining contaminants
will not migrate beyond the compliance monitoring points at levels exceeding
remediation levels; and
(C) A final
report containing a summary of all groundwater data collected at the site, an
analysis of the data demonstrating that the final compliance requirements have
been met, and any other relevant information deemed necessary by the Department
to demonstrate that all of the requirements of this rule have been met is
submitted to and approved by the Department.
(c) Notwithstanding final compliance, the
Department may require continued monitoring of groundwater in situations where
site-specific conditions warrant such measures.
(8) The responsible person must submit
additional information or develop and submit a modified correction action plan
at the Department's request if the Department determines that remedial
activities must be modified or that treatment system performance (e.g., rate of
cleanup) is not achieving results as projected in the approved corrective
action plan.
(9) When all
requirements of an approved corrective action plan have been met to the
Department's satisfaction, the Department shall issue a no further action
letter to the responsible person.
(10) In the event that contamination
exceeding risk-based concentrations remains, the Department may require the
implementation of institutional or engineering controls necessary to ensure
protection of public health, safety, and welfare and the environment.
(11) A responsible person may, in the
interest of minimizing environmental contamination and promoting more effective
remediation, begin remediation of soil and groundwater before the corrective
action plan is approved provided that the responsible person:
(a) Notifies the Department of its intention
to begin remediation;
(b) Complies
with any conditions imposed by the Department including halting remediation or
mitigating adverse consequences from remedial activities; and
(c) Incorporates the self-initiated remedial
measures in the corrective action plan that is submitted to the Department for
approval.
(12) The
requirement that a corrective action plan be used does not apply to low-impact
site closures, or to generic remedies unless specified by the Department in
generic remedy guidance. However, the Department may require that a corrective
action plan be developed and implemented for sites being considered for
remediation under the soil matrix cleanup options (OAR
340-122-0320
), as low-impact sites (340-122-0243 ),
or under generic remedies (340-122-0252 )
if, upon review of available information, the Department determines that
conditions at the site are not appropriate for the initial proposed remedial
option or the proposal does not provide adequate protection to human health,
safety, and welfare and the environment.
Stat. Auth.: ORS 465.400 & ORS 466.746
Stats. Implemented: ORS 465.200 - ORS 465.455 & ORS
466.706 - ORS 466.835
