Beata Urbaniak
Abstract
Evaluation of potential on-site human health risks to future indoor workers associated with vapor
intrusion at the Koppers site
The Koppers site, located in the Northern part of Gainesville and covering almost 90
acres is one of the two sites that make up the Cabot Koppers Superfund Site. Wood treatment
operations began at the site in 1916 and ended up in 2009 along with the use of different wood
preservatives were used such as chromated copper arsenate, pentachlorophenol and creosote. The
site was placed on the National Priorities List in 1983 due to soil and groundwater
contamination.
Issue / Problem
In 2007, forty-six surficial aquifer monitoring wells were sampled and analyzed for
different contaminants. Results show elevated concentrations of several Volatile Organic
Compounds (VOCs) and Semi-Volatile Organic Compounds (SVOCs) throughout the site. Some
of these contaminants are sufficiently toxic and volatile to result in a serious threat to human
health through a pathway known as vapor intrusion. The United States Environmental Protection
Agency (US EPA) defines vapor intrusion as the “transport of vapors from volatile organic
compounds or other contaminants of interest from the subsurface into the buildings” (EPA).
The objective of my study is to determine if sufficiently toxic and volatile SVOCs and
VOCs are present at sufficient concentrations to suggest an unacceptable risk to future indoor
workers. My research project focuses on the worker population because the US EPA plans to
clean up the site to industrial / commercial use.
Methods
I developed a spreadsheet based on the model and site-specific parameters to determine
the likelihood of cancer and non-cancer adverse health effects.
Results
The Hazard Index is 26 and therefore is greater than 1, which suggests that noncancer
adverse human health effects are possible. The total cancer risk is 9.76 in ten thousand exceeding
the US EPA’s allowable risk range of one in a million to one in ten thousand and FDEP’s risk
benchmark of one in a million. Without further study, it appears that future
commercial/industrial workers at the Koppers site may be at risk from vapor intrusion.
Implications
The results advocate the need to acquire up-to-date surficial aquifer samples to get more
representative conditions of the site since the most recent data are from 2007. Moreover, the US
EPA should perform additional sampling of the surficial aquifer offsite. Finally, the US EPA
should perform soil-gas sampling which is a measurement of the concentration of contaminants
in the air in the soil.