New Mexico Administrative Code › Title 20 - ENVIRONMENTAL PROTECTION › Chapter 5 - PETROLEUM STORAGE TANKS › Part 119 - CORRECTIVE ACTION FOR STORAGE TANK SYSTEMS CONTAINING PETROLEUM PRODUCTS › Section 20.5.119.1908 - 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 20.5.119.1900
				  NMAC. The preliminary investigation shall determine the following, unless
				  otherwise approved by the department.
A. If not previously identified and reported
				under 20.5.119.1903 NMAC, the preliminary investigation shall determine the
				source of contamination, 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
				hydrocarbon 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 hydrocarbon 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) Owners and
				operators shall assess at five-foot intervals, field estimates of
				concentrations of petroleum hydrocarbons 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 determinations of 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) Owners and operators shall delimit the
				horizontal and vertical extent of contaminant saturated soil as defined in
				20.5.101.7 NMAC.