New Mexico Administrative Code › Title 20 - ENVIRONMENTAL PROTECTION › Chapter 5 - PETROLEUM STORAGE TANKS › Part 120 - CORRECTIVE ACTION FOR UST SYSTEMS CONTAINING OTHER REGULATED SUBSTANCES › Section 20.5.120.2008 - MINIMUM SITE ASSESSMENT, PRELIMINARY INVESTIGATION - REQUIREMENTS

Current through Register Vol. 35, No. 13, July 16, 2024
Owners and operators shall conduct a preliminary
				  investigation in accordance with this Subsection and under a timeline approved
				  by the department or the timeline set forth in Subsection E of 20.5.120.2000
				  NMAC. The preliminary investigation shall determine the following, unless
				  otherwise approved by the department.
A. If not previously identified and reported
				under 20.5.120.2003 NMAC, the preliminary investigation shall determine the
				regulated substance released or suspected of being released at the site, the
				media of concern, current and potential receptors, current and anticipated use
				of property, complete and incomplete exposure pathways, and routes of
				exposure.
B. The preliminary
				investigation shall also determine the horizontal and vertical extent and
				magnitude of soil contamination.
(1) Owners
				and operators shall conduct a soil boring survey by advancing a continuously
				cored soil boring at each area of release where soil contamination is most
				likely to be encountered unless otherwise directed by the department. The
				initial incident report and a soil vapor survey may be used in locating these
				areas. Owners and operators shall advance at least one of the borings into the
				groundwater saturated zone or, with approval from the department, to a depth at
				which measured levels of contaminants in soil are no longer detectable by
				laboratory analysis, and vapor concentrations, as determined with a field
				instrument, are less than 100 whole instrument units.
(2) Owners and operators shall advance at
				least four additional soil borings to characterize the release within property
				boundaries. Borings shall be completed to the depth at which contaminants in
				soil are no longer detectable by laboratory analysis, and vapor concentrations,
				as determined with a field instrument, are less than 100 whole instruments
				units. If the soil borings indicate that contaminated soil extends beyond the
				boundary of the property on which the storage tank system is located, owners
				and operators shall advance soil borings sufficient to characterize the extent
				and magnitude of contamination within site boundaries.
(3) The preliminary investigation shall
				assess, at five-foot intervals, field estimates of concentrations of
				contaminants of concern in the soil borings and select and prepare samples for
				laboratory analysis.
(4) Owners and
				operators shall gather field data for soil classification, determining and
				recording color, grain size, texture, description of lithification, plasticity
				and clay content.
(5) The
				preliminary investigation shall include derived values for soil bulk density
				(g/cc), soil moisture content (percent by mass), and effective porosity, and
				fraction organic carbon content (percent by mass) using samples taken from an
				uncontaminated area of the vadose zone.
(6) The preliminary investigation shall
				delimit the horizontal and vertical extent of contaminant saturated soil as
				defined in 20.5.101.7 NMAC.