Purpose In order to explore and refine GIS (Geographic Information System) techniques applicable to
environmental site characterization, the Tricon American facility was selected as a test facility
for analysis with ArcView GIS and the 3-D Analyst extension software. Background "The Tricon site was occupied until the mid-80s by a metal smelting company and most
recently by a pre-fab concrete wall manufacturer. During the period when the smelter was
operational, there are reports of air releases from the facility affecting residences in the area.
Also during this time period, a large waste ash pile from the operation was initiated adjacent to
the residential area. Waste concrete from the pre-fab operation has been used to partially
cover the ash pile, however, the ash material is reportedly made up of very fine particulates
with uncovered portions subject to air migration. Recently, the EPA has capped the ash pile to
limit further migration of contaminants off-site... Lead is the metal of greatest concern because of its potential health impact on small children.
For the nine residences (see map), the lead concentration in eight of the nine was at or below
61 ppm. For the yard nearest the ash pile the lead concentration reached 218 ppm. The
Centers for Disease Control (CDC) has cautioned that concentrations of lead in residential soil
or dust greater than 500-1000 ppm could lead to elevated blood lead levels in children
inhaling or ingesting soil... Based on a review of the soil sampling data collected by EPA there is no indication that either
a short or long term public health threat exists from metals presently found in the residential
yards sampled..." Dept. of Health and Human Services Agency for Toxic Substances and
Disease Registry Region VI letter (5-24-90) "The major problem identified at the Tricon facility was gasoline leaking from the UST.
Laboratory results of air samples collected by the TACB at the adjacent homes indicated
benzene, xylene, hexanes, heptanes and octanes, which are components of unleaded gasoline.
. . The gasoline apparently originated from a leaking UST on-site, which was subsequently
removed. As part of the site clean-up, a vacuum extraction soil venting system was installed at
the affected homes." Analysis performed consisted of interpolating a topographic surface, groundwater gradient
mapping, and determining the extent of soil heavy metal contamination.