Current through August 26, 2024
The owner or operator shall comply with the following
requirements for any groundwater monitoring program developed to satisfy s.
NR 664.0098, 664.0099 or 664.0100:
(1) The groundwater monitoring system shall
consist of a sufficient number of wells, installed at appropriate locations and
depths to yield groundwater samples from the uppermost aquifer that do all of
the following:
(a) Represent the quality of
background water that has not been affected by leakage from a regulated unit. A
determination of background quality may include sampling of wells that are not
hydraulically upgradient of the waste management area where all of the
following conditions are met:
1.
Hydrogeologic conditions do not allow the owner or operator to determine what
wells are hydraulically upgradient.
2. Sampling at other wells shall provide an
indication of background groundwater quality that is representative or more
representative than that provided by the upgradient wells.
(b) Represent the quality of groundwater
passing the point of standards application.
(c) Allow for the detection of contamination
when hazardous waste or hazardous constituents have migrated from the waste
management area to the uppermost aquifer.
(2) If a facility contains more than one
regulated unit, separate groundwater monitoring systems are not required for
each regulated unit provided that provisions for sampling the groundwater in
the uppermost aquifer will enable detection and measurement at the point of
standards application of hazardous constituents from the regulated units that
have entered the groundwater in the uppermost aquifer.
(3) All monitoring wells shall be cased in a
manner that maintains the integrity of the monitoring-well bore hole. This
casing shall 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 shall be sealed to prevent contamination of samples and the
groundwater.
(4) The groundwater
monitoring program shall 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 shall include procedures and techniques for all of the following:
(a) Sample collection.
(b) Sample preservation and
shipment.
(c) Analytical
procedures.
(d) Chain of custody
control.
(5) The
groundwater monitoring program shall include sampling and analytical methods
that are appropriate for groundwater sampling and that accurately measure
hazardous constituents in groundwater samples.
(6) The groundwater monitoring program shall
include a determination of the groundwater surface elevation each time
groundwater is sampled.
(7) In
detection monitoring or where appropriate in compliance monitoring, data on
each hazardous constituent specified in the license shall be collected from
background wells and wells at the points of standards applications. 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 shall determine an appropriate sampling
procedure and interval for each hazardous constituent listed in the facility
license which shall be specified in the unit license upon approval by the
department. This sampling procedure shall be any of the following:
(a) A sequence of at least 4 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.
(b) An alternate sampling procedure proposed
by the owner or operator and approved by the department.
(8) The owner or operator shall specify one
of the following statistical methods to be used in evaluating groundwater
monitoring data for each hazardous constituent which, upon approval by the
department, shall be specified in the unit license. The statistical test chosen
shall 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 sub. (9) (e), the pql shall be proposed
by the owner or operator and approved by the department. Use of any of the
following statistical methods shall be protective of human health and the
environment and shall comply with the performance standards outlined in sub.
(9).
(a) A parametric analysis of variance
(ANOVA) followed by multiple comparisons 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.
(b) An analysis of variance (ANOVA) based on
ranks followed by multiple comparisons 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.
(c) 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.
(d) A control chart approach
that gives control limits for each constituent.
(e) Another statistical test method submitted
by the owner or operator and approved by the department.
(9) Any statistical method chosen under sub.
(8) for specification in the unit license shall comply with all of the
following performance standards, as appropriate:
(a) 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.
(b) 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 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.
(c) 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 department if it finds them to be
protective of human health and the environment.
(d) 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 department if it finds these parameters to be protective of
human health and the environment. These parameters shall be determined after
considering the number of samples in the background database, the data
distribution and the range of the concentration values for each constituent of
concern.
(e) 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 department under sub.
(8) 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.
(f) 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.
(10) Groundwater monitoring data
collected in accordance with sub. (7) including actual levels of constituents
shall be maintained in the facility operating record. The department shall
specify in the license when the data must be submitted for review.
