Geologist fights for mercury awareness

September 15, 2000

Heather Heilman

Barry Kohl is a geologist who has spent his career studying the Gulf of Mexico, reconstructing paleoenvironments and climates that existed millions of years ago. He is also responsible for talking Louisiana politicians into spending an extra $200,000 a year on a public health initiative that may help prevent babies from being born with brain damage.

Geology and public health seem to be disparate fields with little relevance to each other. But Kohl, an adjunct professor at Tulane, found at least one link between the two in a hazardous substance that was not supposed to be a problem in Louisiana.

An outdoorsman fond of boating on the Pearl River, Kohl was asked in 1994 to review a section of the environmental impact statement for a proposed U.S. Army Corps of Engineers dredging project along the river. In reading the data, he noticed there were high levels of heavy metals in the sediment of the Pearl River.

"I started wondering where it was coming from," Kohl said. "I called up the state and federal agencies to find out what information was available, and I was able to collect some research and studies from the U.S. Fish and Wildlife Service and other sources that showed that there were not only high levels in the sediment, there were high levels of methyl mercury in the fish."

Mercury in the environment builds up in fish. Methyl mercury is poisonous to the people who eat the fish, particularly to unborn babies and children under 7, who may suffer permanent brain damage from exposure to the metal. The mercury levels at Pearl River were close to the limits the Food and Drug Administration had set for safe fish consumption.

What had been an intellectual question for Kohl now became a public health issue. The river was a popular spot for fishing. Commercial fishermen trapped catfish there. Sportsmen trolled for bass. Many low-income people in the area depended on the rivers fish for their main source of protein. But there was no fish advisory for the river. And to dredge the river would resuspend mercury-laden sediments, which would further contaminate the food chain.

In 1995, Kohl testified at a hearing on mercury contamination conducted by the Louisiana House of Representatives committee on natural resources. At the hearing, he was astonished to hear an official from the state Department of Environmental Quality tell the committee that mercury was not a significant problem in the state and that there were no sources of mercury pollution in Louisiana. He said it all comes from air pollution from Texas, Kohl said.

Kohl responded by informing the committee there were plenty of sources of mercury pollution in Louisiana. In the 1960s, tons of mercury were used as a fungicide in the rice fields around Lafayette and Eunice. It was used as a slimicide in every paper mill in the state, including one in Bogalusa that contaminated the Pearl River. It was used in the oil industry and on golf courses. Chlorine plants still release more than a ton of mercury into the air each year.

"There was a time when nobody realized mercury was a significant poison," Kohl said. "They didn't understand what happens when you just dump it into the environment. The use of mercury has been restricted since the 1970s, but the damage has been done. Elemental mercury never disappears," Kohl said. "You just move it from one place to another."

Thanks to Kohl's 1995 testimony, state legislators appropriated an additional $200,000 that year and every year since to the Mercury in Fish Project. The total annual budget is approximately $500,000. Things have slowly begun to improve.

In 1995, only one stream in Louisiana was under a mercury advisory. State agencies insisted the Bogue Chitto and Pearl rivers were not contaminated, even though the state of Mississippi's Department of Environmental Quality had posted an advisory on the Bogue Chitto River and also reported high levels of mercury on the Pearl River.

"I thought to myself, thats strange," Kohl said. It seems that Mississippi fish don't swim downstream into Louisiana. Thanks to the additional funding that has resulted in increased sampling, a total of 18 advisories have been posted for Louisiana streams identified as having high levels of mercury, including the Pearl, Bogue Chitto, Bayou Liberty and the Blind rivers. Notices have been posted at public boat launches on contaminated streams. Public education efforts are under way, as are research efforts to discover which fish at which sizes are safe and which are not.

Starting next month, blood mercury screenings will be conducted on subsistence fishermen and their families in Orleans, St. Tammany, Washington, Jefferson and St. John the Baptist parishes. William R. Hartley, associate professor of environmental health sciences at Tulane's School of Public Health and Tropical Medicine, directs that project.

Kohl says his experience shows that scientists need to involve themselves in policy-making. "A single professor can do a lot of good by providing advice to decision-makers," he said. "It may take five years, but one can have a positive impact on policy. We all have to give something back."

Tulane University, New Orleans, LA 70118 504-865-5000