CE 599 DP1 (Spring 2021) - 1 of 4
This design project involves the use of publicly available tools developed by USEPA to design “screening”
assessment plan in a community where vapor intrusion exposure risks may be a concern.
The site is shown below and will target three buildings: A, B and C. The groundwater concentrations included in
Table 1 are actual concentrations detected at the site.
Although these concentrations were detected
several years ago, it is common for vapor intrusion professionals to evaluate historical groundwater
concentration trends as part of vapor intrusion screening assessments to determine if additional evaluation is
Building A includes a three-story multi-family home (basement depth approximately 5.5 feet bgs) with
a paved patio (approximately 32 ft by 23 ft) and a grassy area (42 ft by 29 ft) northwest of the home.
Building B includes an open space grassy field (approximately 50 ft by 50 ft) with a three-story
multifamily home (basement depth approximately 5.5 feet bgs) is located in the southwest corner.
Building C is a slab-on-grade building that was used for commercial purposes (assume the building slab
is 6 inches thick). The entire surface area for Property C was asphalt paved (maximum dimensions were
approximately 58 ft by 93 ft).
The contaminant source is located to the west of these properties. The depth to groundwater fluctuated
from 10 ft bgs to 13 ft bgs depending on the season.
The soil geology was surprisingly consistent across
the site, including two primary soil types: an upper unit (0-6 ft bgs) consisting of urban fill (assume: sandy
loam); and, a lower unit (6- 12 ft bgs) consisting a dense, stiff, sandy clay loam. Near the water-bearing
unit, a sandy loam was detected in some soil borings.