Current through Register Vol. 48, No. 38, September 20, 2024
a) The owner or operator must prepare an
outline of a groundwater quality assessment program. The outline must describe
a more comprehensive groundwater monitoring program (than that described in
Sections
725.191
and
725.192)
capable of determining each of the following:
1) Whether hazardous waste or hazardous waste
constituents have entered the groundwater;
2) The rate and extent of migration of
hazardous waste or hazardous waste constituents in the groundwater;
and
3) The concentrations of
hazardous waste or hazardous waste constituents in the groundwater.
b) For each indicator parameter
specified in Section
725.192(b)(3),
the owner or operator must calculate the arithmetic mean and variance, based on
at least four replicate measurements on each sample, for each well monitored in
accordance with Section
725.192(d)(2)
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 (see
Appendix D) to determine statistically significant increases (and decreases, in
the case of pH) over initial background.
c) Well Comparisons
1) If the comparisons for the upgradient
wells made under subsection (b) show a significant increase (or pH decrease)
the owner or operator must submit this information in accordance with Section
725.194(a)(2)(B).
2) If the comparisons for downgradient wells
made under subsection (b) show a significant increase (or pH decrease) the
owner or operator must then immediately obtain additional groundwater samples
for 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.
d) Notice to the Agency
1) If the analyses performed under subsection
(c)(2) confirm the significant increase (or pH decrease) the owner or operator
must provide written notice to the Agency - within seven days after the date of
such confirmation - that the facility may be affecting groundwater
quality.
2) Within 15 days after
the notification under subsection (d)(1), the owner or operator must develop a
specific plan, based on the outline required under subsection (a) and certified
by a qualified geologist or geotechnical engineer for a groundwater quality
assessment at the facility. This plan must be placed in the facility operating
record and be maintained until closure of the facility.
3) The plan to be submitted under Section
725.190(d)(1)
or subsection (d)(2) must specify all of the following:
A) The number, location, and depth of
wells;
B) Sampling and analytical
methods for those hazardous wastes or hazardous waste constituents in the
facility;
C) Evaluation procedures,
including any use of previously gathered groundwater quality information;
and
D) A schedule of
implementation.
4) The
owner or operator must implement the groundwater quality assessment plan that
satisfies the requirements of subsection (d)(3) and, at a minimum, determine
each of the following:
A) The rate and extent
of migration of the hazardous waste or hazardous waste constituents in the
groundwater; and
B) The
concentrations of the hazardous waste or hazardous waste constituents in the
groundwater.
5) The
owner or operator must make his first determination under subsection (d)(4), as
soon as technically feasible, and prepare a report containing an assessment of
the groundwater quality. This report must be placed in the facility operating
record and be maintained until closure of the facility.
6) If the owner or operator determines, based
on the results of the first determination under subsection (d)(4), that no
hazardous waste or hazardous waste constituents from the facility have entered
the groundwater, then he may reinstate the indicator evaluation program
described in Section
725.192 and
subsection (b). If the owner or operator reinstates the indicator evaluation
program, he must so notify the Agency in the report submitted under subsection
(d)(5).
7) If the owner or operator
determines, based on the first determination under subsection (d)(4), that
hazardous waste or hazardous waste constituents from the facility have entered
the groundwater, then the owner or operator must do either of the following:
A) It must continue to make the
determinations required under subsection (d)(4) on a quarterly basis until
final closure of the facility if the groundwater quality assessment plan was
implemented prior to final closure of the facility; or
B) It may cease to make the determinations
required under subsection (d)(4) if the groundwater quality assessment plan was
implemented during the post-closure care period.
e) Notwithstanding any other
provision of this Subpart F, any groundwater quality assessment to satisfy the
requirements of subsection (d)(4) that is initiated prior to final closure of
the facility must be completed and reported in accordance with subsection
(d)(5).
f) Unless the groundwater
is monitored to satisfy the requirements of subsection (d)(4) at least annually
the owner or operator must evaluate the data on groundwater surface elevations
obtained under Section
725.192(e)
to determine whether the requirements under Section
725.191(a)
for locating the monitoring wells continues
to be satisfied. If the evaluation shows that Section
725.191(a)
is no longer satisfied, the owner or operator must immediately modify the
number, location, or depth of the monitoring wells to bring the groundwater
monitoring system into compliance with this requirement.
