Current through Register Vol. 49, No. 13, September 23, 2024
Subpart 1.
Program outline.
The owner or operator shall prepare an outline of a ground
water quality assessment program. The outline must describe a more
comprehensive ground water monitoring program than that described in part
7045.0590, subparts
4,
5, and
6. The program must be
capable of determining:
A. whether
hazardous waste or hazardous waste constituents have entered the ground
water;
B. the rate and extent of
migration of hazardous waste or hazardous waste constituents in the ground
water; and
C. the concentrations of
hazardous waste or hazardous waste constituents in the ground water.
Subp. 2.
Comparison of
analysis results.
For each indicator parameter specified in part
7045.0590, subpart
6, item B, subitem (3), and
determined pursuant to part
7045.0590, subpart
6, item B, subitem (4), the
owner or operator shall calculate the arithmetic mean and variance, based on at
least four replicate measurements on each sample, for each well monitored in
accordance with part
7045.0590, subpart
6, item D, and compare these
results with its initial background arithmetic mean. The comparison must
consider individually each of the wells in the monitoring system, and must use
the Student's t-test at the 0.01 level of significance as described in Code of
Federal Regulations, title 40, part 265, appendix IV, as amended, to determine
statistically significant increases and, in the case of pH, decreases from
initial background.
Subp.
3.
Additional sampling.
If the comparisons for the upgradient wells made under
subpart
2 show a significant increase
or pH decrease, the owner or operator shall submit this information in
accordance with part
7045.0590, subpart 8, item A,
subitem (2).
If the comparisons for downgradient wells made under subpart
2 show a significant increase
or pH decrease, the owner or operator shall then immediately obtain additional
ground water samples from those downgradient wells where a significant
difference was detected, split the samples in two, and obtain analyses of all
additional samples to determine whether the significant difference was a result
of laboratory error.
Subp.
4.
Notification.
Notification requirements are as follows:
A. If the analyses performed under subpart
3 confirm the significant
increase or pH decrease, the owner or operator shall provide written notice to
the commissioner, within seven days of the date of such confirmation, that the
facility may be affecting ground water quality.
B. Within 15 days after the notification
under item A, the owner or operator shall develop and submit to the
commissioner a specific plan, based on the outline required under subpart
1 and certified by a
qualified geologist or geotechnical engineer, for a ground water quality
assessment program at the facility.
C. The plan to be submitted under item B or
part
7045.0590, subpart
5, item A must specify:
(1) the number, location, and depth of
wells;
(2) sampling and analytical
methods for those hazardous wastes or hazardous waste constituents in the
facility;
(3) evaluation
procedures, including any use of previously gathered ground water quality
information; and
(4) a schedule of
implementation.
D. The
owner or operator shall implement the ground water quality assessment plan
which satisfies the requirements of item C and determine:
(1) the rate and extent of migration of the
hazardous waste or hazardous waste constituents in the ground water;
and
(2) the concentrations of the
hazardous waste or hazardous waste constituents in the ground water.
E. The owner or operator shall
make the first determination under item D as soon as technically feasible, and,
within 15 days after determination, submit to the commissioner a written report
containing an assessment of the ground water quality.
F. If the owner or operator determines, based
on the results of the first determination under item D, that no hazardous waste
or hazardous waste constituents from the facility have entered the ground
water, then he or she may reinstate the indicator evaluation program described
in part
7045.0590, subpart
6, item B, subitems (1) and
(2). If the owner or operator reinstates the indicator evaluation program, he
or she shall so notify the commissioner in the report submitted under item
E.
G. If the owner or operator
determines, based on the first determination under item D, that hazardous waste
or hazardous waste constituents from the facility have entered the ground
water, then he or she:
(1) shall continue to
make the determinations required under item D, on a quarterly basis until final
closure of the facility, if the ground water quality assessment plan was
implemented prior to final closure of the facility; or
(2) may cease to make the determinations
required under item D, if the ground water quality assessment plan was
implemented during the postclosure care period.
Subp. 5.
Completion requirement.
Notwithstanding any other provision of this part, any ground
water quality assessment to satisfy the requirements of subpart
4, item D, which is initiated
prior to final closure of the facility must be completed and reported in
accordance with subpart
4, item E.
Subp. 6.
Annual evaluation.
Unless the ground water is monitored to satisfy the
requirements of subpart
4, item D, the owner or
operator shall evaluate at least annually the data on ground water surface
elevations obtained under part
7045.0590, subpart
6, item E, to determine
whether the requirements under part
7045.0590, subpart
4, for locating the
monitoring wells continues to be satisfied. If the evaluation shows that part
7045.0590, subpart
4, is no longer satisfied,
the owner or operator shall immediately modify the number, location, or depth
of the monitoring wells to bring the ground water monitoring system into
compliance with this requirement.
Subp.
7.
Record keeping and reporting.
If the ground water is monitored to satisfy the requirements
of subpart
4, item D, the owner or
operator shall:
A. keep records of the
analyses and evaluations specified in the plan, which satisfies the
requirements of subpart
4, item C, throughout the
active life of the facility, and for disposal facilities, throughout the
postclosure care period as well; and
B. annually, until final closure of the
facility, submit to the commissioner a report containing the results of the
ground water quality assessment program which includes, but is not limited to,
the calculated or measured rate of migration of hazardous waste or hazardous
waste constituents in the ground water during the reporting period. This report
must be submitted as part of the annual report.
Statutory Authority: MS s
116.07
