Current through all regulations passed and filed through December 16, 2024
The owner or operator must comply with the following
requirements for any ground water monitoring program developed to satisfy rule
3745-54-98, 3745-54-99, or3745-54-100 of the Administrative Code.
(A) The ground water monitoring system must
consist of a sufficient number of wells, installed at appropriate locations and
depths to yield ground water samples from the uppermost aquifer that:
(1) Represent the quality of background
ground water that has not been affected by
leakage from a regulated unit;
(a) A
determination of background ground water quality
may include sampling of wells that are not hydraulically upgradient of the
waste management area where:
(i)
Hydrogeologic conditions do not allow the owner or operator to determine what
wells are hydraulically upgradient; and
(ii) Sampling at other wells will provide an
indication of background ground water quality that is representative or more
representative than that provided by the upgradient wells; and
(2) Represent the quality of ground water
passing the point of compliance; and
(3) Allow for the detection of contamination
when hazardous waste or hazardous constituents have migrated from the waste
management area to the uppermost aquifer.
(B) If a facility contains more than one
regulated unit, separate ground water monitoring systems are not required for
each regulated unit provided that provisions for sampling the ground water in
the uppermost aquifer will enable detection and measurement at the compliance
point of hazardous constituents from the regulated units that have entered the
ground water in the uppermost aquifer.
(C) All monitoring wells must be cased in a
manner that maintains the integrity of the monitoring well bore hole. This
casing must be screened or perforated and packed with gravel or sand, where
necessary, to enable collection of ground water samples. The annular space
(i.e., the space between the bore hole and well casing) above the sampling
depth must be sealed to prevent contamination of samples and the ground water.
(D) The ground water monitoring
program must include consistent sampling and analysis procedures that are
designed to ensure monitoring results that provide a reliable indication of
ground water quality below the waste management area. At a minimum the program
must include procedures and techniques for:
(2) Sample preservation and shipment;
(3) Analytical procedures; and
(4) Chain of custody control.
(E) The ground water
monitoring program must include sampling and analytical methods that are
appropriate for ground water sampling and that accurately measure hazardous
constituents in ground water samples.
(F) The ground water monitoring program must
include a determination of the ground water surface elevation each time ground
water is sampled.
(G) In detection
monitoring or where appropriate in compliance monitoring, data on each
hazardous constituent specified in the permit will be collected from background
wells and wells at the compliance point(s). The number and kinds of samples
collected to establish background must be appropriate for the form of
statistical test employed, following generally accepted statistical principles.
The sample size must be as large as necessary to ensure with reasonable
confidence that a contaminant release to ground water from a facility will be
detected. The owner or operator will determine an appropriate sampling
procedure and interval for each hazardous constituent listed in the facility
permit which must be specified in the unit permit. This sampling procedure must
be:
(1) A sequence of at least four samples,
taken at an interval that assures, to the greatest extent technically feasible,
that an independent sample is obtained, by reference to the uppermost aquifer's
effective porosity, hydraulic conductivity, and hydraulic gradient, and the
fate and transport characteristics of the potential contaminants; or
(2) An alternate sampling procedure proposed
by the owner or operator and approved in the permit.
(H) The owner or operator will specify one of
the following statistical methods to be used in evaluating ground water
monitoring data for each hazardous constituent which will be specified in the
unit permit. The statistical test chosen must be conducted separately for each
hazardous constituent in each well. Where practical quantification limits
(PQL's) are used in any of the following statistical procedures to comply with
paragraph (I)(5) of this rule, the PQL must be proposed by the owner or
operator and approved by the director. Use of any of the following statistical
methods must be protective of human health and the environment and must comply
with the performance standards outlined in paragraph (I) of this rule.
(1) A parametric analysis of variance (ANOVA)
followed by multiple comparisons procedures to identify statistically
significant evidence of contamination. The method must include estimation and
testing of the contrasts between each compliance well's mean and the background
mean levels for each constituent.
(2) An ANOVA based on ranks
followed by multiple comparisons procedures to identify statistically
significant evidence of contamination. The method must include estimation and
testing of the contrasts between each compliance well's median and the
background median levels for each constituent.
(3) A tolerance or prediction interval
procedure in which an interval for each constituent is established from the
distribution of the background data, and the level of each constituent in each
compliance well is compared to the upper tolerance or prediction limit.
(4) A control chart approach that
gives control limits for each constituent.
(5) Another statistical test method submitted
by the owner or operator and approved in the permit.
(I) Any statistical method chosen under
paragraph (H) of this rule for specification in the unit permit must comply
with the following performance standards, as appropriate:
(1) The statistical method used to evaluate
ground water monitoring data must be appropriate for the distribution of
chemical parameters or hazardous constituents. If the distribution of the
chemical parameters for hazardous constituents is shown by the owner or
operator to be inappropriate for a normal theory test, then the data should be
transformed or a distribution-free theory test should be used. If the
distributions for the constituents differ, more than one statistical method may
be needed.
(2) If an individual
well comparison procedure is used to compare an individual compliance well
constituent concentration with background constituent concentrations or ground
water protection standard, the test must be done at a "Type I" error level no
less than 0.01 for each testing period. If a multiple comparisons procedure is
used, the "Type I"
experimentwise error rate for each testing period must be no less than
0.05; however, the "Type I" error of no less than 0.01 for individual well
comparisons must be maintained. This performance standard does not apply to
tolerance intervals, prediction intervals, or control charts.
(3) If a control chart approach is used to
evaluate ground water monitoring data, the specific type of control chart and
its associated parameter values must be proposed by the owner or operator and
approved in the permit if it is found to be protective of human health and the
environment.
(4) If a tolerance
interval or a prediction interval is used to evaluate ground water monitoring
data, the levels of confidence and, for tolerance intervals, the per centage of
the population that the interval must contain, must be proposed by the owner or
operator and approved in the permit if these parameters are found to be
protective of human health and the environment. These parameters will be
determined after considering the number of samples in the background data base,
the data distribution, and the range of the concentration values for each
constituent of concern.
(5) The
statistical method must account for data below the limit of detection with one
or more statistical procedures that are protective of human health and the
environment. Any practical quantification limit (PQL) approved in the permit
under paragraph (H) of this rule that is used in the statistical method must be
the lowest concentration level that can be reliably achieved within specified
limits of precision and accuracy during routine laboratory operating conditions
that are available to the facility.
(6) If necessary, the statistical method must
include procedures to control or correct for seasonal and spatial variability
as well as temporal correlation in the data.
(J) Ground water monitoring data collected in
accordance with paragraph (G) of this rule including actual levels of
constituents must be maintained in the facility operating record. The permit
will specify when the data must be submitted for review.