Mercury alert: 2 duck species too toxic to eat
Two days before the opening day of the duck hunting season, state officials warned Utah hunters not to eat northern shovelers or common goldeneyes that feed on Great Salt Lake marshes because tests of their flesh show toxic levels of mercury.
The health advisory appears to be the first of its kind in the nation, said state Health Department toxicologist Wayne Ball, who analyzed Utah State University laboratory results of samples state scientists took from seven different duck species on the south end of the lake last year and during the past two months.
All but three of the species in the sample had at least one duck with mercury levels higher than what the U.S. Environmental Protection Agency considers safe to eat. Ten goldeneyes were tested and showed results ranging from below the EPA standard of .3 milligrams of mercury per kilogram of edible tissue to 14 times the standard. Of the 20 shovelers sampled, only one was below the standard, while the rest ranged from about twice the standard to 39 times the safety point.
The EPA standard for edible tissue is the same for fish as for ducks. Ball said toxicologists normally try to calculate what amount of fish is safe to consume because eating fish is healthy. But with the ducks, "these levels were high enough that there's really no safe level of consumption," he said.
That likely will disappoint 11-year-old Justin Summers, who shot a shoveler last weekend during the state-sponsored youth waterfowl hunt. Justin's father, Troy Summers, says he told the young hunter "we eat what we kill."
The duck feast was planned for Thursday night.
"Not now," Summers said on hearing of the advisory. "I'll just have to explain it to him. We do eat what we shoot, but this warning wasn't out there when he took this bird. It is not worth risking somebody's health."
The state Health Department, Department of Environmental Quality, Division of Wildlife Resources and the U.S. Fish and Wildlife Service jointly issued the no-consumption advisory after meeting Thursday morning. The agencies knew it was vital to get the information out before the hunt's opening day, which they did with just 40 hours to spare.
Testing waterfowl is an offshoot of the state's new mercury-related fish-testing program, began this summer. Last month, the state Division of Water Quality and the Health Department issued Utah's first-ever advisories for mercury in fish taken from Mill Creek near Moab and Gunlock Reservoir near St. George.
Utah Waterfowl Association Vice President Jack Ray was one of the prime movers behind waterfowl testing. He says he became concerned after reading a Salt Lake Tribune article in February about a federal study of the Great Salt Lake that found some of the highest levels of mercury ever recorded in the nation.
Ray said he was glad the agencies moved quickly because hunters will be able to make good decisions on what they shoot and eat.
"This suggests there's an awful lot of mercury here in Utah along the Wasatch Front and someone needs to take the issue seriously," he said.
Mercury is a highly toxic element that occurs naturally in the environment but also has been introduced through human activity. Coal-burning power plants are the largest human-caused source of mercury pollution in the world and continue to spread mercury through the atmosphere.
Utah's industrial and mining past has exposed the Great Salt Lake and other waterways to mercury pollution. Gold mines in northeastern Nevada, upwind of Salt Lake City, have reported releasing large amounts of mercury into the atmosphere.
Mercury evaporates easily. Rain redeposits it on land and in water bodies, where it is changed to its organic form, methylmercury, which in turn "bioaccumulates" in animals and humans. Methylmercury affects the human nervous system, and is most harmful to fetuses and young children because it can cause developmental and neurological problems. Recent studies also have linked mercury exposure to autism, Alzheimer's disease and increased risk of heart disease in men.
In February, scientists with the U.S. Geological Survey and Fish and Wildlife Service reported finding in the Great Salt Lake some of the highest levels of methlymercury ever recorded in the United States. The study focused on eared grebes, migratory birds that feed heavily on brine shrimp from May to December. The researchers found mercury levels in the birds' livers more than doubled during their months on the lake.
Grebes aren't eaten. Some hunters also spurn northern shovelers, also known as spoonbills, and goldeneyes, claiming they don't like their taste. But Tom Aldrich, waterfowl program coordinator for Wildlife Resources and a wildfowl hunter who eats everything he takes, disagrees.
"The early season fat shovelers are actually very good roasted. I defy the people who think shovelers aren't good to eat," he said. Goldeneyes, however, "are strong-flavored and difficult to pick. But a nice big drake goldeneye is a pretty bird, and some folks prefer to add them to their taxidermy collection."
The other duck species USU and the toxicologists tested were mallard, cinnamon teal, green wing teal, redhead and gadwall. Samples from the latter three were all below the mercury standard. While some mallards and a cinnamon teal showed elevated levels, they aren't a worry, Aldrich said.
Since shovelers and goldeneyes both eat brine shrimp, brine shrimp eggs and larvae, the reasons why shovelers had mercury levels so much higher are a mystery.
"It's got to be that those shovelers are selectively picking something up that most of the species aren't," Aldrich said. "As we learn more, we will refine the questions and eventually really zero in on what they're eating and what the source of the mercury is."
It is unlikely that hunters will bag any goldeneye early in the season because they usually do not arrive on the Great Salt Lake marshes on their southern migration until the middle of November. But shovelers make up about 10 percent of the current waterfowl population and have accounted for 13 to 14 percent of the overall ducks taken by hunters mid-October through mid-November over the last three seasons, Aldrich said.
This weekend, wildlife law enforcement officers, biologists and even parking lot personnel will be part of a massive campaign to alert hunters about the advisory, Aldrich said. "But I have to tell you, we've got guys out camping on Farmington Bay today so they get their spot. I don't think we will go out there to hand them notices."
For duck hunters
* What is the advisory?
The State Department of Health advises hunters to not eat northern shovelers and common goldeneye ducks taken from Great Salt Lake marshes because of high levels of mercury in their meat.
* How do I identify the two species?
Check out the 2005 Waterfowl Proclamation for an illustration of a shoveler. A photo of a common goldeneye is on the Web at http://www.dwrcdc.nr.utah.gov/ucdc.
* Can I still shoot those species?
Yes, but laws require hunters to retrieve any shot ducks, and shovelers or goldeneye killed this season will count in the daily bag limit.
* What about eating other duck species?
None of the other five species tested averaged high enough levels of mercury for an advisory, though some individual ducks were above the recommended levels.