Current through Register Vol. 35, No. 18, September 24, 2024
A. The
owner or operator shall conduct detection monitoring at all ground water
detection monitoring wells unless such monitoring has been suspended in
accordance with Subsection C of 20.9.9.8 NMAC. The detection monitoring program
shall include the monitoring for constituents and parameters listed and
referenced in Subsection A of 20.9.9.20 NMAC, and shall be conducted at least
semiannually during the active life and post-closure care period of the
facility. After background concentrations have been approved as required in
Subsection E of 20.9.9.10 NMAC for all constituents in Subsection A of
20.9.9.20 NMAC, the owner or operator may request a specific approval that the
ground water detection monitoring program description be amended to:
(1) not require testing for particular
constituents in Subsection A of 20.9.9.20 NMAC for a municipal landfill if it
can be shown that the particular constituents are not reasonably expected to be
in or derived from the waste contained in the landfill; and
(2) establish an alternate list of inorganic
indicator parameters constituents for a landfill in lieu of some or all of the
heavy metals listed or referenced in Subsection A of 20.9.9.20 NMAC if the
alternative constituents provide a reliable indication of inorganic releases
from the landfill to the ground water; in determining alternative constituents,
the department shall consider the following factors:
(a) the types, quantities, and concentrations
of constituents in wastes managed at the landfill;
(b) the mobility, stability, and persistence
of constituents or their reaction products in the unsaturated earth zone
beneath the landfill;
(c) the
detectability of the constituents, and reaction products in the ground water;
and
(d) the concentrations or
values and coefficients of variation of levels of the constituents in the
ground water;
(3) allow
annual sampling of the approved alternate list after the first year based on
the following factors:
(a) lithology of the
aquifer and unsaturated zone;
(b)
hydraulic conductivity of the aquifer and unsaturated zone;
(c) ground water flow rates;
(d) minimum distance between upgradient edge
of the landfill and downgradient monitoring well screen (minimum distance of
travel); and
(e) resource value of
the aquifer.
B. Regardless of approval by the department
of an alternate constituent list under Subsection A of this section, the
minimum frequency for testing for all the constituents in Subsection A of
20.9.9.20 NMAC shall be at least once every five years in addition to the
required frequencies for the alternate list.
C. If the owner or operator determines, as
evidenced in the ground water monitoring data, that the AML has been exceeded
for one or more of the constituents or parameters referenced in Subsection A of
20.9.9.20 NMAC or approved alternate constituent list at any monitoring well,
the owner or operator:
(1) shall, within 14
days of this finding, notify the department of the exceedance and place a
notice in the operating record indicating which constituents or values have
exceeded approved AMLs; and
(2)
shall submit, within 60 days of the finding, an assessment monitoring plan that
meets the requirements of 20.9.9.13 NMAC;
(3) in addition, the owner or operator may
submit, within 60 days after the finding, a demonstration that a source other
than a landfill caused the contamination or that the AML exceedance resulted
from an error in sampling, analysis, statistical evaluation, or natural
variation in ground water quality; a report documenting this demonstration
shall be certified by a qualified ground water scientist, shall be placed in
the operating record, and shall be submitted to the department for specific
approval; the department shall issue a specific approval or denial within 90
days approving or denying the demonstration; if the demonstration is denied,
the assessment monitoring shall proceed according to the submitted plan within
90 days after the denial.
