N.M. Admin. Code § 20.5.120.2012

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

Section 20.5.120.2012 - MONITORED NATURAL ATTENUATION

A. If approved by the department, owners and operators shall submit a plan for remediation by monitored natural attenuation to the department if any of the following conditions have been identified at the site:

(1) concentrations of contaminants of concern exceed target concentrations in soil or WQCC or EIB standards in groundwater or surface water; and

(2) other conditions exist as a result of the release which threaten public health, safety and welfare or the environment, as determined by the department.

B. Owners and operators shall submit the monitored natural attenuation plan in accordance with this section and 20.5.120.2013 NMAC and in accordance with a timeline approved by the department or the timeline set forth in Subsection E of 20.5.120.2000 NMAC.

C. The intent of the monitored natural attenuation plan is to provide a written description of the methodology proposed and demonstrate how the plan will achieve target concentrations in a manner that is practicable, cost effective, and protective of public health, safety and welfare and the environment. The content of the monitored natural attenuation plan, at a minimum and as appropriate, shall include:

(1) a site plan drawn to scale of no less than one inch equals 40 feet, showing all existing buildings, structures, paved areas, utilities, buried utility trenches, former and existing storage tanks and ancillary equipment, other sources of contamination, extent and magnitude of contamination, and existing and proposed monitoring wells;

(2) cross sections showing the source contaminant mass in relation to the groundwater contamination;

(3) a topographic map of appropriate scale showing the site in relation to existing and reasonably foreseeable future receptors;

(4) concentration contour maps depicting the extent and magnitude of the contaminants of concern and the designated monitoring wells in relation to the site;

(5) a schematic drawing depicting the construction details including lithology and screen intervals for the designated monitoring wells;

(6) justification for selecting the designated monitoring wells;

(7) recommended approach to monitoring including an implementation and monitoring schedule, the analytical methods, and the justification for the recommendation;

(8) an estimation of the time necessary for achieving target concentrations, and a demonstration through calculations or other appropriate means which supports this schedule;

(9) a contingency plan in case of a change in site conditions that threatens public health, safety and welfare or the environment;

(10) public notice in conformance with the following requirements:

(a) owners and operators shall publish a legal notice of the submission or planned submission of the monitored natural attenuation plan at least twice in a paper of general circulation in the county in which soil or water has been contaminated by the release; the first notice shall appear within one week of, but not later than, the day of submission of the monitored natural attenuation plan to the department; the second publication of this notice shall occur no later than seven days after the date the monitored natural attenuation plan is submitted to the department, and owners and operators shall submit two certified affidavits of publication from the newspaper to the department within 21 days after the date the monitored natural attenuation plan is submitted;

(b) the notice shall contain the information specified in this section including the following:

(i) a statement that a monitored natural attenuation plan has been submitted to the department proposing actions to monitor natural attenuation of a release of hazardous substances;

(ii) the name and physical address of the site at which the release occurred and the names and physical addresses of properties where any part of contaminant plume is located, using adequate identification of the properties, including street addresses if applicable;

(iii) a statement that a copy of the monitored natural attenuation plan and all data and modeling related to the monitored natural attenuation plan, if applicable, can be viewed at the department's main office and at the department's field office for the area in which the release occurred; and

(iv) a statement that public comments on the plan must be delivered within 21 days of the publication of the second notice, to the owner or operator's assigned project manager at the petroleum storage tank bureau, New Mexico environment department, or a district office if approved by the department, and to the secretary of the environment department;

(c) within seven days of the date a monitored natural attenuation plan is submitted to the department, owners and operators shall also mail by certified mail a copy of the legal notice to adjacent property owners;

(d) owners and operators shall post a notice of the submission of the monitored natural attenuation plan at the release site within seven days of the submission of the monitored natural attenuation plan; the notice shall contain the information specified in this Subsection and shall be at least eight and on-half inches by 11 inches in size and prominently displayed in a location where it is likely to be seen by members of the public for a continuous period until the monitored natural attenuation plan is approved and implemented; public comments must be received by the department within 21 days of the date of the second publication of the public notice; and

(11) other requirements as directed by the department.

N.M. Admin. Code § 20.5.120.2012

Adopted by New Mexico Register, Volume XXIX, Issue 14, July 24, 2018, eff. 7/24/2018