Dissertation/Thesis Abstract

Lithological Influences on the Synthetic Precipitation Leaching Procedure Test and Implications to Assessment and Remediation at the Southwest Foods Site in Lafayette, Louisiana (LDEQ Agency Interest No. 69569)
by Allen, Carson B., M.S., University of Louisiana at Lafayette, 2018, 176; 10816803
Abstract (Summary)

Southwest Foods in Lafayette, Louisiana has multiple underground storage tanks that leaked petroleum products over a period of time, releasing numerous toxic constituents of concern into the surrounding soil and groundwater. During the assessment phase of risk evaluation, the Synthetic Precipitation Leaching Procedure (SPLP) test was used to measure the leaching potential of possibly contaminated soils and lithologies when exposed to acidic rainfall. However, during the site investigation, SPLP data produced erratic results that apparently are related to the type of geologic material (“soil”) involved. These erratic results could have major implications for assessment, remediation, and the establishment of Risk Evaluation/Corrective Action Program (RECAP) standards in the state of Louisiana. Incorrectly applied RECAP standards could ultimately mean contaminants of concern could reach points of exposure (POEs), and potentially harm nearby residents and the environment. Previously, lithological composition had not been considered when evaluating the environmental impact of the test.

At the site, numerous geotechnical soil boring logs were completed, and soil samples were sent to analytical laboratories for analysis of contamination. Soil analytical data compiled by the laboratories along with samples acquired from multiple groundwater monitoring wells at the site provided an in-depth view into the degree of contamination at Southwest Foods and produced the first signs of erratic SPLP test results. Contour maps of contamination and groundwater potentiometric levels were created to show both the level of contaminants in soil and the possible migration paths of affected groundwater. The SPLP sample data were evaluated and categorized into lithological subgroups for further examination. The lithologies, or soil types (with USCS symbols), that produced erratic results (i.e., some “passed” and some “failed”) for the SPLP analyses included “clay, high plasticity” (CH) and “clayey silt/sandy silt/silt” (ML). The results for “silty clay/sandy clay” (CL) were more consistent. The inconsistent SPLP data could result in incorrect application of site-specific RECAP standards and the subsequent cleanup at Southwest Foods and conceivably at other contaminated sites as well.

Indexing (document details)
Advisor: Duex, Timothy W.
Commitee: Hillman, Aubrey, Poudel, Durga, Sinitiere, Stephen M.
School: University of Louisiana at Lafayette
Department: Geology
School Location: United States -- Louisiana
Source: MAI 58/05M(E), Masters Abstracts International
Subjects: Hydrologic sciences, Environmental Geology, Soil sciences
Keywords: Contamination, Leaching, Lithology, Remediation, SPLP, Soil
Publication Number: 10816803
ISBN: 9781392041543
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