N.M. Admin. Code § 20.9.9.11

Current through Register Vol. 35, No. 23, December 10, 2024

Section 20.9.9.11 - DETECTION MONITORING PLAN

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.

N.M. Admin. Code § 20.9.9.11

20.9.9.11 NMAC - Rp, 20 NMAC 9.1.VIII.804, 8/2/2007