Researchers are measuring mercury concentrations in and around the historic Alcoa Superfund site at Lavaca Bay.
Jessica Dutton, an associate professor in the Department of Biology at Texas State University in San Marcos, is conducting the study with graduate students Liam McInerney and Dillan Wulf. The team is monitoring trout, blue crabs, red and black drum and other species that have entered the site’s boundaries. Dutton and her students will also study the mercury concentrations in the surrounding bays as well.
The project is funded by the Matagorda Bay Mitigation Trust.
Results of the research may be finalized by next summer, Dutton said.
A Superfund is a contaminated area deemed by the Environmental Protection Agency to be a site that should be cleaned and frequently monitored.
The region in Lavaca Bay designated as a Superfund was once nearby Alcoa Corporation’s chlor-alkali plant in Point Comfort, which was in use during the 1960s and 1970s. Wastewater from the plant had been delivered to an offshore lagoon and the overflow from the lagoon was discharged into Lavaca Bay.
In the late 1980s, the Texas state health department closed a section of Lavaca Bay to the public because fish and crabs were found to have been poisoned by mercury. The EPA signed a plan to clean up the hazardous waste in 2001 and nearly six years later the agency marked the completion of clean up activities with a “Preliminary Close Out Report.”
Today the area remains closed to fishing, as the EPA called for continued monitoring of mercury concentrations inside the closed area and in nearby areas open to recreational and commercial activities.
An ongoing plan to widen and deepen the Matagorda Shipping Channel could impact the Superfund, Dutton said.
“The concern now is that the dredging proposal, which includes the 1,200-foot turning basin, could resuspend mercury within the closed area,” Dutton said. “The mercury could enter the food web.”
The EPA analyzed mercury levels in red drum in 2018 and found the average concentration had steadily declined for three years.
Dutton’s team is currently collecting mercury samples inside the Superfund, as well as in Matagorda and San Antonio bays. Comparing mercury concentrations in the open and closed areas is necessary because fish can travel between both locations, Dutton said.
“We have a quota of 50 for each species we are studying,” Dutton said. “The hard part is getting the data.”
To study particular mercury samples, the researchers will use a machine known as a direct mercury analyzer. Dutton said the group will prepare samples by freeze drying and powderizing them.
The analyzer can run one sample through its system in six minutes, Dutton said. Around 50 samples are analyzed in one day.
“One of our goals is to get the baseline data on our study before the dredging happens,” Dutton said. “That way people understand the impacts and risks dredging would have on the Lavaca Bay ecosystem.”