Walsh, Garrett X (2021-02). The Fate and Transport of Anthropogenic Halogenated Volatile Organic Compounds (HVOCs) in Galveston Bay, TX. Master's Thesis.
Thesis
Distribution and transport of anthropogenic halogenated volatile organic carbons (HVOCs) are not well studied in estuary settings. Carbon tetrachloride (CCl4) and CFC-11 are banned substances under the Montreal Protocol, and can potentially be used as tracers for contamination sources within estuaries. Chloroform (CHCl3) and perchloroethylene (PCE) have many current sources, such as wastewater outfalls and dry cleaner waste. Loss of these HVOCs in surface waters of estuaries is presumed to be mainly through sea-to-air flux due to their volatility and long lifetimes in aerobic waters. Galveston Bay is heavily influence by anthropogenic activity and forcing events in Texas. Measurements of CCl4, CFC-11, CHCl3, and PCE were made in Galveston Bay in March, June, September, and November 2019. In March, a large chemical plant fire at the Intercontinental Terminals Company (ITC) in Deer Park, TX released an unknown quantity and composition of liquid into Galveston Bay via the Houston Ship Channel. In September, Tropical Storm Imelda released up to 39 inches of rain in the Galveston Bay watershed, potentially leading to a flushing event within the bay. Elevated concentrations of CCl4, CHCl3, CFC-11, and PCE were in the Buffalo Bayou, San Jacinto River, and Lower San Jacinto regions for all sampling months, suggesting anthropogenic sources. Within Galveston Bay, the concentrations of anthropogenic HVOCs is similar to Trinity River and Trinity Bay. Modeled loss of each compound within this region suggests that sea-to-air flux is a significant removal process but is unable to fully explain the loss of anthropogenic HVOCs in the surface water. The impacts of the ITC fire in Deer Park, TX and Tropical Storm Imelda on the concentrations of anthropogenic HVOCs in Galveston Bay and the Houston Ship Channel is unknown without a longer time series.
