Current through Register Vol. 50, No. 9, September 20, 2024
The owner or operator must comply with the following
requirements for any groundwater monitoring program developed to satisfy LAC
33:V.3317, 3319, or 3321.
A. The
groundwater monitoring system must consist of a sufficient number of wells,
installed at appropriate locations and depths, to yield groundwater samples
from the uppermost aquifer that fulfill the following requirements.
1. The samples must represent the quality of
background groundwater that has not been affected by leakage from a regulated
unit. A determination of background groundwater quality may include sampling of
wells that are not hydraulically upgradient of the waste management area where:
a. hydrogeologic conditions do not allow the
owner or operator to determine which wells are hydraulically upgradient;
and
b. sampling at other wells will
provide an indication of background groundwater quality that is representative
or more representative than that provided by the upgradient wells.
2. The samples must represent the
quality of water passing the point of compliance.
3. The samples must allow for the detection
(as defined in LAC 33:V.3303.A.1) 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 groundwater
monitoring systems are not required for each regulated unit, if provisions for
sampling the groundwater in the uppermost aquifer will enable detection and
measurement at the compliance point for hazardous constituents for the
regulated units.
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
groundwater 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 groundwater.
D. The groundwater monitoring program must
include consistent sampling and analysis procedures that are designed to ensure
monitoring results that provide a reliable indication of groundwater quality
below the waste management area. At a minimum, the program must include
procedures and techniques for:
1. sample
collection;
2. sample preservation
and shipment;
3. analytical
procedures; and
4. chain of custody
control.
E. The
groundwater monitoring program must include sampling and analytical methods
that are appropriate for groundwater sampling, and that accurately measure
hazardous constituents in groundwater samples.
F. The groundwater monitoring program must
include a determination of the groundwater surface elevation each time
groundwater is sampled.
G. In
detection monitoring or where appropriate in compliance monitoring, data on
each indicator parameter and 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
shall be appropriate for the form of statistical test employed, following
generally accepted statistical principles. The sample size shall be as large as
necessary to ensure with reasonable confidence that a contaminant release to
groundwater 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 shall be specified in the unit
permit upon approval by the administrative authority. This sampling procedure
shall 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 by the administrative
authority.
H. The owner
or operator will specify one of the following statistical methods to be used in
evaluating groundwater monitoring data for each indicator parameter and
hazardous constituent that, upon approval by the administrative authority, will
be specified in the unit permit. The statistical test chosen shall be conducted
separately for each indicator parameter and hazardous constituent in each well.
Where practical quantification limits (PQLs) are used in any of the following
statistical procedures to comply with LAC 33:V.3315.I.5, the PQL must be
proposed by the owner or operator and approved by the administrative authority.
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 LAC 33:V.3315.I.
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 analysis of variance (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 by the administrative
authority.
I. Any
statistical method chosen under LAC 33:V.3315.H for specification in the unit
permit shall comply with the following performance standards, as appropriate.
1. The statistical method used to evaluate
groundwater monitoring data shall be appropriate for the distribution of
chemical parameters or hazardous constituents. If the distribution of the
chemical parameters or 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 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 comparisons procedure
is used, the Type I experimentwise 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 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 groundwater monitoring data, the specific type of
control chart and its associated parameter values shall be proposed by the
owner or operator and approved by the administrative authority if he or she
finds it to be protective of human health and the environment.
4. If a tolerance interval or a prediction
interval is used to evaluate groundwater monitoring data, the levels of
confidence and, for tolerance intervals, the percentage of the population that
the interval must contain, shall be proposed by the owner or operator and
approved by the administrative authority if he or she finds these parameters 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 shall 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 by the
administrative authority under LAC 33:V.3315.H 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.
J. Groundwater monitoring data collected in
accordance with LAC 33:V.3315.G including actual levels of constituents must be
maintained in the facility operating record. The administrative authority will
specify in the permit when the data must be submitted for review.
K. The groundwater monitoring program must
ensure that the permittee maintains records from all required groundwater
monitoring wells and associated groundwater surface elevations for the active
life of the facility, including the operating, closure, and post-closure care
periods.
AUTHORITY NOTE:
Promulgated in accordance with
R.S.
30:2180 et
seq.
