Health Advisory - Mercury

Mercury poisoning can cause some major health issues, so the EPA is working to boost signage and knowledge about the high mercury levels in Carson River.

Depending on how long you've lived in Northern Nevada, or maybe how much fishing you do, you might already know that fish from the Carson River and its reservoirs could make you sick.

The fish, some of the water fowl-- like ducks-- and the plants along the banks are all unsafe to eat. And the Environmental Protection Agency is trying to make sure everyone knows it.

The problem has a long history, spanning more than 160 years and 330 square miles. To understand it, we have to go all the way back to the Comstock.

The Mercury Problem

On a sunny day in March, two fishermen stand on the banks of the Lahontan Reservoir; casting, reeling, and hoping for a good catch. It's a beautiful spot for a day of fishing. But they won't want to eat what they bring in. Lahontan Reservoir is home to some of the most toxic fish in the world.

The problem is mercury. High levels of the heavy metal that over time have built up in the fish, the water fowl, and the plants, all throughout the Carson River Watershed.

"Mercury is a serious neurotoxin. It affects the nervous system, especially in children," Andrew Bain, Remedial Project Manager for the EPA, said. "We're concerned about people that eat a lot of fish or other animals or plants that might have picked up the mercury through the environment."

The EPA has had their eye on the Carson River problem since 1980. In 1990, the whole area was put on the National Priorities List as a "Superfund" site: a designation for some of the most polluted, potentially dangerous, parts of the country. In the 90s, the EPA did some work to clear out some of the most contaminated soil, but the site spans 330 square miles. It covers the land and water east from Carson City to the Lahontan Valley past Fallon, including the Big and Little Washoe Lakes.

"Because it's so extensive, because mercury is so ubiquitous, it's challenging to try to locate it all and address it," Bain said.

So, unable to fix the problem, Bain says the best they can do is tell people about it.

"It's safe to swim, it's safe to recreate," Bain said. "Catch and release fishing is fine. But we don't want people eating the fish."

And for good reason.

When it comes to mercury, the EPA and Food and Drug Administration consider .46 parts per million in fish to be the limit for safe eating. For example, in tuna, a higher mercury fish, there's a median amount of .34 parts per million. In 1981, researchers found a striped bass in the Lahontan Reservoir with a whopping 23.65 parts per million. That's more than 50 times the amount of mercury already considered unsafe.

40 years later, the mercury problem is still very much an issue. But to understand how we got here, you have to go much farther back than the 80s; all the way back to the Comstock Lode.

The History

Visiting the Donovan Mill in Silver City, Nevada is like taking a step back to the mid-1800s, when gold and silver mills dotted the hills around a booming Virginia City.

"Most of the mills around this area were stamp mills, very similar to this one," Comstock Foundation Director Don Bergstrom explained during a tour of the Donovan Mill. His organization has been working to restore and preserve the site for future visitors.

From 1860 to about 1890, there were 236 mills in that area that crushed the ore from the mines and then processed it using mercury.

"There was usually a copper plate that was laid on the bottom of the table, and they would smear mercury on top of that copper plate," Bergstrom said. "The ore would come out of the stamps, which was ground really fine, and the gold and the silver would stick to the mercury. And that would be called an amalgam."

The mercury was expensive, and had to be shipped in from mines in California. So, the mills recaptured and reused it, but a lot of it escaped.

"There's tailing piles, as you can see, all over the place," Bergstrom said, "where there's some mercury that got away."

Over the years, an estimated 14 million pounds of mercury ended up in the Carson River and the surrounding watershed.

Most of it is still there today, settling along the riverbanks and reservoirs all the way to the end of the system at the Stillwater Wildlife Refuge, and  passing right through reservation lands of the Fallon Paiute Shoshone Tribe.

The Cultural Impact

"It knows no boundaries. Where it goes, it affects everybody," Richard Black, Environmental Manager for the Fallon Paiute Shoshone Tribe said. "It's a health concern for all of us here."

For the members of the tribes, the mercury means a further departure from their ancestral way of life; of hunting, fishing, and using water plants for food and materials.

"These are constructed completely out of tule and cattail," Fallon Paiute Shoshone Tribe Member Joey Allen said, showing a handmade duck decoy used in traditional native duck hunting. "The cattail itself, and the tule, were used to eat, as a sustainable food source, like infinitely sustainable."

Now, knowing about the mercury, the risks are too great.

"I'm not going to go to the Carson River and any of those main sources to get this, because I have to handle it," Allen said. "I have to go re-wet it. I have to put it in my mouth."

"We reflect with the land and water, the animals and the environment," Black said. "It's Mother Earth, and you're polluting it, so that affects us. Everyone, it affects, but to us, you know, we hold the earth sacred."

Looking to the Future

The EPA officials in charge of managing the Carson River Superfund Site say eating one high-mercury fish isn't likely to hurt you, but eating the fish regularly or during childhood or pregnancy could cause major health problems. Mercury poisoning can cause vision problems, muscle weakness and tremors, speech impairment, and major birth defects involving the brain.

The EPA is working to boost signage and education, but with such a large area to cover, there are long stretches of shoreline with no signs. Bain says there are currently fewer than 20 locations with signs along the full 130 miles of shoreline. And he says at this point, there's no budget to do mass soil removal.

But the EPA does have an updated proposal for monitoring the site and expanding awareness. To see that proposal, click here.