LAKE OUACHITA — Park rangers at Lake Ouachita have been busy this week informing visitors about a warning regarding the possibility of high mercury levels in some fish caught in the lake that lies in Garland and Montgomery counties, according to Park Superintendent Lee Howard.
The superintendent said Monday that rangers are posting signs and handing out fliers to visitors about the mercury advisory that was issued earlier in the day.
Howard said the mercury warning, issued by the Arkansas Department of Health, came as a surprise.
“It’s too early to know just how we may be affected,” Howard said. “For now, our priority is getting the word out and letting people know. This is a sign of the times as we all struggle with pollution issues.”
The state health department issued the fish-consumption advisory concerning Lake Ouachita after fish were collected by the Arkansas Game and Fish Commission from the lake and tested for mercury content by the Arkansas Department of Environmental Quality. Those fish were found “to contain levels of mercury that had a potential to put human health at risk.” The three state agencies form the Mercury in Fish Taskforce to check the levels in larger fish.
When a fish species is found to have more than one part per million of mercury, then the potential risk is calculated, and an advisory is issued.
The fish consumption advisory is very specific about who is at risk and the amount of fish that can be consumed:
High-risk groups (women of childbearing age, pregnant women, breastfeeding women and children younger than 7:
• Should not eat largemouth bass (13 inches or longer), white bass (13 inches or longer) or striped bass (25 inches or longer) from this lake.
General public (men, women and children 7 and older):
• Eat no more than two meals per month of largemouth bass (13 inches or longer), white bass (13 inches or longer) or striped bass (25 inches or longer) from this lake.
• Eating fish with mercury will not make people sick right away, but as they eat more and more, it can build up in the body and, over time, potentially cause adverse health effects.
The limited nature of the advisory for Lake Ouachita fish is explained in a question -and-answer memo issued by the Arkansas Department of Health.
The memo states that people who have eaten fish from Lake Ouachita are likely OK if the fish were eaten in moderation.
“Risks associated with eating fish from the areas listed in a fish-consumption advisory are based on long-term consumption and are not tied to eating fish occasionally.”
The Q&A goes on to say that it is safe to fish in Lake Ouachita. Recreational fishing is safe for the general population, as is the consumption of the fish species involved at the posted rates. It is also safe to handle these fish for catch-and-release. The memo also says occasional fish consumers such as vacationers and sport anglers are at little risk.
“This advisory is specific for mercury in fish and not in the water,” according to the Q&A statement. “This advisory does not limit the recreational use of Lake Ouachita for fishing, bird watching, swimming, boating or other types of recreational uses or as a drinking-water source.”
ADH said the agency was unaware of any mercury poisonings due to fish consumption.
The source of mercury can be natural. Cinnabar, a natural solid form of mercury, is found in the area around the lake and has been mined in the region, according to information from the Department of Health.
“Once mercury has entered the lake or a stream feeding the lake, it is taken up by bacteria in the water that is eaten by insects,” said a statement from the health department. “The insects are eaten by smaller fish, and those fish are eaten by larger predators, and the mercury concentration increases with every step all the way up the food chain to top predators such as largemouth bass and striped bass.”
The health department suggests eating more of the smaller fish from species such as bluegill, buffalo and crappie, as well as farm-raised catfish and fish from more than one source.
Lake Ouachita is not the only body of water in Arkansas with a consumption advisory. There are now more than 20 bodies of water under a mercury-in-fish advisory in the state. Among those listed are the Saline and Ouachita rivers in southern Arkansas from Cleveland County downriver to near the border with Louisiana.
There is also an advisory for black bass, 16 inches or more, taken from Lake Winona in Saline County.
Nationally, there are lakes and rivers in all 50 states with fish-consumption advisories having to do with mercury amounts in the fish.
A U.S. Army Corps of Engineers lake, the 40,000-acre, 40-mile long Lake Ouachita was built for recreation and flood control. There is very limited commercial development of the lake, which is formed by Blakley Mountain Dam near Mountain Pine.
Staff writer Wayne Bryan can be reached at (501) 244-4460 or wbryan@arkansasonline.com.