(A) Such determinations shall be based on sound scientific
principles including fate and transport evaluation of contaminant migration.
Procedures and conclusions shall be documented to the satisfaction of the
executive director.
(B) The executive director may require the evaluation of additional
migration pathways beyond those listed in this section if determined necessary.
Such additional pathways may include but are not limited to, food chain contamination,
impairment of soil for agricultural purposes, phytotoxicity, accumulations
of contaminants in sediment of surface water bodies, or other impairments
of natural resources, land, or water use.
(j) Other adjustments. Cleanup levels may be adjusted according
to paragraphs (1) - (3) of this subsection.
(1) If the practical quantitation limit (PQL) or the background
concentration (represented by results of analyses of samples taken from media
that are not affected by waste management or industrial activities) for a
contaminant is greater than the cleanup level determined by procedures of
this section, then the greater of the PQL or background shall become the cleanup
level.
(2) Other scientifically valid published criteria, such as,
but not limited to threshold limit values for air and secondary maximum contaminant
levels for water, shall be utilized as cleanup levels for contaminants for
which the procedures of this section are not appropriate (e.g., mixtures or
substances that do not have toxicological data) or that do not exceed standards
or criteria protective of human health as determined by the procedures of
this section but otherwise adversely impact environmental quality, or the
public welfare and safety, or present objectionable characteristics (e.g.,
taste, odor, etc.), or make a natural resource unfit for use.
(3) More stringent cleanup levels may be established for a
facility than are specified in this section if, by utilizing available guidance
or scientific literature, the executive director determines that it is necessary
to protect environmental receptors.
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