Mercury Contamination

Elevated mercury levels found in largemouth bass.

The U.S. Fish and Wildlife Service has found elevated mercury levels in largemouth bass during routine testing of lakes on the Wichita Mountains Wildlife Refuge. The refuge has issued an advisory which warns people to limit their consumption of bass from these lakes.

The advisory recommends that people over the age of seven should limit their consumption of largemouth bass from the refuge to two meals a month with serving portions not to exceed 8 ounces. Pregnant women and young children should not eat the bass.

Tissue samples from largemouth bass taken from lakes on the refuge indicated that the mercury level exceeds recommended levels for human health consumption. Warnings are posted at the lakes and additional detailed information is being distributed at the refuge's Visitor Center.

According to the Environmental Protection Agency, almost all fish contain some levels of mercury. Fish absorb mercury when they feed on aquatic organisms. The mercury in the bass causes no problem with safety of the water for drinking or contact with skin.

The Wichita Mountains Wildlife Refuge has thirteen lakes open for public fishing. At this time, Service scientists do not know the source of the mercury. However, it may be from gold mining operations conducted in the late 1800's, natural levels in the geological formations at the refuge, or from atmospheric contamination.