Last month a fish-consumption advisory was issued for mercury involving several bodies of water just north of the state line. The issue was not unlike a state-wide alert released by the Oklahoma Department of Environmental Quality, involving all bodies of water - including farm ponds.
Environmentalist want to know just how much mercury is in fish in the Grand Lake area residents are consuming and how it is affecting them.
“We know there is mercury in the water and we know there is mercury in the fish,” said Earl Hatley, an environmental activist with the LEAD Agency in Miami and a member of the study team. “What we don’t know is how that is affecting the people who eat the fish.”
Mercury is a neurotoxin that can damage the brain, spinal cord, kidneys, lungs and liver. It is especially dangerous to fetal development.
Scientist have begun a $1 million study to determine how safe it is to consume fish in Grand Lake and its watershed - including Spring, Elk and Neosho rivers.Mercury is a heavy, silvery metal which is liquid at room temperature. It's one of six elements that have the liquid characteristic at or near room temperature and pressure. Mercury is a rare element in the earth’s crust. It occurs naturally only rarely.
Usually it's found in cinnabar, livingstonite, corderoite and other metals.
Mercury is harmless as mercuric sulfide, its insoluble form. However, it's poisonous in its soluble forms like methyl mercury or mercuric chloride.
When mercury moves through the environment, it goes through a series of changes.
“It’s the conversion of mercury into methyl mercury - the organic form of mercury,” said Hatley. “For that to happen, you have to have nutrients and bacteria.”
Tar Creek, a source of heavy metals from the Picher mining field, is part of the watershed too. The water column in the lake is affected by nutrient runnoff and bacterial loading.
Methyl mercury enters the food chain and accumulates most readily in fish at the top of the food chain - bass, walleye, saugeye and flathead catfish. It enters the food chain via algae, which is consumed by small fish, which, in turn, are eaten by bigger fish.
“We might find out that you can eat fish and be just fine,” said Bob Lynch, University of Oklahoma Health and Sciences Center and a member of the study team. “But, it might not be fine. We already know that certain fish consumed in certain quantities can be a problem.”
The plan is to find 150 volunteers who eat fish from the lake and have them fill out food frequency questionnaires four times per year. The questions will be about the types and frequency of fish eaten.
The participants also will provide a hair sample, which will be measured for mercury by researchers at Harvard School of Public Health.
“Hair is often used as a biomarker of mercury exposure,” said Hatley. “Analyzing the amount of mercury in a person’s hair will provide an indication of the amount of mercury in his or her diet.”
Participants will receive the results of their mercury measurements, along with general information about mercury to help interpret the results.
The research team is being funded by a grant of $250,000 annually over four years by the National Institute of Environmental Health Sciences.
“What we want is a more specific idea about the situation here,” said Lynch. “After we have done this, people in other places with similar conditions can compare. We will know more about how mercury moves in the atmosphere and is transformed in the environment.”