Current through Register Vol. 39, No. 6, September 16, 2024
(a) If the level of
contamination of any chemical of concern exceeds risk-based screening levels or
site-specific target levels, a remedial action plan shall be developed and
implemented at the site.
(b) A
remedial action plan shall be sufficient to meet the risk-based screening
levels or site-specific target levels established for the site and shall
include, if applicable:
(1) a summary of the
results of all assessment and interim remedial activities conducted at the
site;
(2) justification for the
remediation method selected based on an analysis of each of the following
factors:
(A) results from any pilot studies
or bench tests;
(B) the remediation
methods considered and why other alternatives were rejected;
(C) practical considerations in implementing
the remediation, including ease of construction, site access, and required
permits;
(D) operation and
maintenance requirements;
(E) the
risks and effectiveness of the proposed remediation including an evaluation of
the type, degree, frequency, and duration of any post-remediation activity that
may be required, including operation and maintenance, monitoring, inspection,
reporting, and other activities necessary to protect public health or the
environment;
(F) long-term
reliability and feasibility of engineering and institutional
controls;
(G) technical feasibility
of the proposed method to reduce the concentrations of chemicals of concern at
the site;
(H) estimated time
required to achieve risk-based screening levels or site-specific target
levels;
(I) cost-effectiveness of
installation, operation and maintenance, when compared to other remediation
alternatives; and
(J) community
acceptance;
(3) an
evaluation of the expected breakdown chemicals or by-products resulting from
natural processes;
(4) a discussion
of the proposed treatment or disposition of contaminated media that may be
produced by the remediation system;
(5) an operation and maintenance plan and
schedule for the remediation system;
(6) design drawings of the proposed
remediation system;
(7) a
groundwater monitoring plan to monitor plume stability and effectiveness of the
remediation;
(8) a plan to evaluate
the effectiveness of the remedial efforts and the achievement of risk-based
screening levels or site-specific target levels;
(9) a plan that addresses the health and
safety of nearby residential and business communities;
(10) a discussion of how the remedial action
plan will protect ecological receptors;
(11) all required land-use restrictions and
notices prepared in accordance with
G.S.
143-215.104M and
15A NCAC
02S. 0508; and
(12) measures necessary to protect plant and
animal receptors and habitats.
(c) Monitored natural attenuation of
chemicals of concern may be approved as an acceptable remediation method,
provided:
(1) all free product has been
removed or controlled to the maximum extent practicable;
(2) contaminated soil is not present in the
unsaturated zone above risk-based screening levels or site-specific target
levels for the soil-to-groundwater pathway for the site unless it is
demonstrated that the soil does not constitute a continuing source of
contamination to groundwater at concentrations that pose a threat to human
health, safety or the environment, and it is demonstrated that the rate of
natural attenuation of chemicals of concern in groundwater exceeds the rate at
which the chemicals of concern are leaching from the soil;
(3) the physical, chemical and biological
characteristics of each chemical of concern and its by-products are conducive
to degradation or attenuation under the site-specific conditions;
(4) the travel time and direction of
migration of chemicals of concern can be predicted with reasonable
certainty;
(5) available data shows
an apparent or potential decrease in concentrations of chemicals of
concern;
(6) the chemicals of
concern will not migrate onto adjacent properties that are not served by an
existing public water supply system, unless the owners have consented to the
migration of chemicals of concern onto their property;
(7) if any of the chemicals of concern are
expected to intercept surface waters, the groundwater discharge will not exceed
the standards for surface water contained in
15A NCAC
02B .0200;
(8) all necessary access agreements needed to
monitor groundwater quality have been or can be obtained; and
(9) a monitoring program, sufficient to track
the degradation and attenuation of chemicals of concern and by-products within
and down-gradient of the plume and detect chemicals of concern and by-products
at least one year's travel time prior to their reaching any existing or
foreseeable receptor, is developed and implemented. Analytical data collected
during monitored natural attenuation shall be evaluated on an annual basis to
determine if the annual rate of expected progress is being achieved.
(d) If the Division determines
that it is technically impracticable to achieve a risk-based screening level or
site-specific target level for a specific chemical of concern due to geological
conditions, remediation technology limitations, site conditions, physical
limitations, or other factors, the Division shall approve or modify the
remedial action plan to provide for the use of institutional controls,
engineering controls, and long-term monitoring until the risk-based screening
levels or site-specific target levels are met. Methods that may be used to
demonstrate that remediation is technically impracticable include the
following:
(1) a full-scale field
demonstration consisting of an operating remediation system;
(2) a pilot study applying a remediation
technology on a small portion of the contaminated site;
(3) predictive analyses or modeling that
shows the potential for the migration and remediation of chemicals of concern
to occur at the site;
(4)
comparison of specific conditions at the subject site to those of similar sites
in case studies or peer-reviewed and published research papers;
(5) a combination of the above methods;
or
(6) other equivalent methods
that demonstrate that remediation is technically impracticable.
Authority
G.S.
143-215.104D;
Eff. September 1,
2007;
Readopted Eff. September 1,
2018.
