Current through Bulletin 2024-06, March 15, 2024
(a) The
groundwater monitoring program shall include consistent sampling and analysis
procedures designed to ensure monitoring results that provide an accurate
representation of groundwater quality at the background and downgradient wells
required by Subsection R315-319-91. The owner or operator of the CCR unit shall
develop and receive approval from the Director for a sampling and analysis
program that includes procedures and techniques for:
(1) Sample collection;
(2) Sample preservation and
shipment;
(3) Analytical
procedures;
(4) Chain of custody
control; and
(5) Quality assurance
and quality control.
(b)
The groundwater monitoring program shall include sampling and analytical
methods that are appropriate for groundwater sampling and that accurately
measure hazardous constituents and other monitoring parameters in groundwater
samples. For purposes of Subsections R315-319-90 through 98, the term
constituent refers to both hazardous constituents and other monitoring
parameters listed in either appendix III or IV of Rule R315-319.
(c) Groundwater elevations shall be measured
in each well immediately prior to purging, each time groundwater is sampled.
The owner or operator of the CCR unit shall determine the rate and direction of
groundwater flow each time groundwater is sampled. Groundwater elevations in
wells which monitor the same CCR management area shall be measured within a
period of time short enough to avoid temporal variations in groundwater flow
which could preclude accurate determination of groundwater flow rate and
direction.
(d) The owner or
operator of the CCR unit shall establish background groundwater quality in a
hydraulically upgradient or background well(s) for each of the constituents
required in the particular groundwater monitoring program that applies to the
CCR unit as determined under Subsection R315-319-94(a) or Subsection
R315-319-95(a). Background groundwater quality may be established at wells that
are not located hydraulically upgradient from the CCR unit if it meets the
requirements of Subsection R315-319-91(a)(1).
(e) The number of samples collected when
conducting detection monitoring and assessment monitoring, for both
downgradient and background wells, shall be consistent with the statistical
procedures chosen under Subsection R315-319-93(f) and the performance standards
under Subsection R315-319-93(g). The sampling procedures shall be those
specified under Subsections R315-319-94(b) through (d) for detection
monitoring, Subsection R315-319-95(b) through (d) for assessment monitoring,
and Subsection R315-319-96(b) for corrective action.
(f) The owner or operator of the CCR unit
shall select one of the statistical methods specified in Subsections
R315-319-93(f)(1) through (5) to be used in evaluating groundwater monitoring
data for each specified constituent. The statistical test chosen shall be
conducted separately for each constituent in each monitoring well.
(1) A parametric analysis of variance
followed by multiple comparison procedures to identify statistically
significant evidence of contamination. The method shall include estimation and
testing of the contrasts between each compliance well's mean and the background
mean levels for each constituent.
(2) An analysis of variance based on ranks
followed by multiple comparison procedures to identify statistically
significant evidence of contamination. The method shall 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 that
meets the performance standards of Subsection R315-319-93(g) and has been
approved by the Director.
(6) The
owner or operator of the CCR unit shall obtain a certification from a qualified
professional engineer stating that the selected statistical method is
appropriate for evaluating the groundwater monitoring data for the CCR
management area. The certification shall include a narrative description of the
statistical method selected to evaluate the groundwater monitoring
data.
(g) Any
statistical method chosen under Subsection R315-319-93(f) shall comply with the
following performance standards, as appropriate, based on the statistical test
method used:
(1) The statistical method used
to evaluate groundwater monitoring data shall be appropriate for the
distribution of constituents. Normal distributions of data values shall use
parametric methods. Non-normal distributions shall use non-parametric methods.
If the distribution of the constituents is shown by the owner or operator of
the CCR unit to be inappropriate for a normal theory test, then the data shall
be transformed or a distribution-free, non-parametric, theory test shall 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 a groundwater
protection standard, the test shall be done at a Type I error level no less
than 0.01 for each testing period. If a multiple comparison procedure is used,
the Type I experiment wise error rate for each testing period shall be no less
than 0.05; however, the Type I error of no less than 0.01 for individual well
comparisons shall 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 groundwater monitoring data, the specific type of control chart and
its associated parameter values shall be such that this approach is at least as
effective as any other approach in Section R315-319-93 for evaluating
groundwater data. The parameter values shall 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.
(4) If a tolerance
interval or a predictional interval is used to evaluate groundwater monitoring
data, the levels of confidence and, for tolerance intervals, the percentage of
the population that the interval shall contain, shall be such that this
approach is at least as effective as any other approach in Section R315-319-93
for evaluating groundwater data. These parameters shall 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
shall account for data below the limit of detection with one or more
statistical procedures that shall at least as effective as any other approach
in Section R315-319-93 for evaluating groundwater data. Any practical
quantitation limit that is used in the statistical method shall 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 shall include procedures to control or
correct for seasonal and spatial variability as well as temporal correlation in
the data.
(h) The owner
or operator of the CCR unit shall determine whether or not there is a
statistically significant increase over background values for each constituent
required in the particular groundwater monitoring program that applies to the
CCR unit, as determined under Subsection R315-319-94(a) or Subsection
R315-319-95(a).
(1) In determining whether a
statistically significant increase has occurred, the owner or operator shall
compare the groundwater quality of each constituent at each monitoring well
designated pursuant to Subsection R315-319-91(a)(2) or (d)(1) to the background
value of that constituent, according to the statistical procedures and
performance standards specified under Subsections R315-319-93(f) and
(g).
(2) Within 90 days after
completing sampling and analysis, the owner or operator shall determine whether
there has been a statistically significant increase over background for any
constituent at each monitoring well.
(i) The owner or operator shall measure
"total recoverable metals" concentrations in measuring groundwater quality.
Measurement of total recoverable metals captures both the particulate fraction
and dissolved fraction of metals in natural waters. Groundwater samples shall
not be field-filtered prior to analysis.
(j) The owner or operator of the CCR unit
shall comply with the recordkeeping requirements specified in Subsection
R315-319-105(h), the notification requirements specified in Subsection
R315-319-106(h), and the Internet requirements specified in Subsection
R315-319-107(h).