Mining

Mercury in Waterways

Mercury warnings for area waterways

Grass Valley Union — 12/17/03
By Dave Moller, staff writer

You can still eat the fish out of area streams and lakes, but state officials Tuesday said people should limit their consumption because of Gold Rush-legacy mercury levels that could harm human nervous systems.

California Environmental Protection Agency spokesman Allan Hirsch said no one has been known to die or suffer from any disease after eating Nevada County fish and that physical contact with mercury in watersheds is not a concern.

Although state and local officials have been sending out consumption warnings for mid-Sierra fish for three years, "this is final," Hirsch said. The warning was issued at various levels for:

• The South Yuba and Bear rivers
• Deer Creek
• Scotts Flat Reservoir
• Lake Englebright
• Lake Combie
• Rollins Reservoir
• Camp Far West Reservoir

The agency is especially concerned about pregnant women, who could pass mercury levels on to children, and those 17 or younger.

Affected infants could have short attention spans, language-skill deficiencies and learning disabilities, he said.

All other people with mercury poisoning from fish could get tingling in their hands, feet or mouths, Hirsch said. Higher levels could affect vision or coordination.

The official state fish advisory said children and women of childbearing age should not eat any bass at all from Camp Far West Reservoir. They should also limit their bass and channel catfish meals to one or two a month from all other bodies of water in Nevada, Placer and Yuba counties.

The at-risk group should limit meals of trout from Deer Creek to twice a month and from the Bear and Yuba rivers to four times a month, the advisory said.

All other females and adult males should limit their bass and channel catfish meals to two to four meals a month and Deer Creek trout to eight a month, the state said.

The advisory lumped Lake Englebright, Scotts Flat Reservoir, Rollins Reservoir and Lake Combie fish under general mercury guidelines of no more than 12 meals per month for adults and only four per month for children and women of childbearing age.

Hirsch said higher levels of mercury found in Deer Creek fish during a federal study in 2000 caused the tougher consumption recommendation levels for that stream. He also said trout in area streams had higher levels in most cases than lakes because stream trout tend to be natives that can soak up more mercury over time compared to lake trout, most of which are young planters.

In 2000, the federal study caused county health officials to recommend limiting their bass meal intake to only one a month and once a week for trout, blue gill, sunfish, crappie and catfish. Those officials were unavailable to reconfirm those recommendations late Tuesday.

Gold miners used mercury to separate gold from sand and gravel. The toxic mercury was allowed to flow into rivers and streams, where it accumulated in the soil.

Over the generations, bacteria convert the inorganic mercury to more dangerous methylmercury, which fish then eat. The state EPA warns that methylmercury can accumulate in fish in concentrations thousands of times greater than in the surrounding water.

The Associated Press contributed to this story.