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Environmental Threat: Lead Sinkers
by Leif Enger
May 9, 2000
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Research from Tufts University School of Veterinary Medicine has revealed that lead poisoning in loons in New Hampshire is a direct result of ingesting a lead object, almost always a lead sinker or jig. In total,13 studies have confirmed a direct link between the ingestion of lead sinkers and jigs and mortality of Common Loons from lead poisoning. Once swallowed, lead sinkers and jigs are dissolved by stomach acids and the grinding action of the gizzard. Lead is absorbed into the blood and body tissues, causing lead poisoning. Lead poisoning from the ingestion of lead sinkers and jigs has been documented in 27 species of birds to date.

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Minnesotans are hitting the sporting-goods shops this week, gearing up for Saturday's walleye opener. Among the most-common fishing accouterments is the humble sinker: a tiny weight used to lower the hook into the fish's purview. For many anglers, going fishing without lead sinkers, makes as much sense as going out without hooks. But hundreds of Minnesota's favorite birds - loons and bald eagles - are turning up with lead poisoning, and researchers say sinkers are part of the reason.

WHEN IT COMES TO SINKERS, nothing beats lead; it's heavy, cheap, and soft enough to squeeze onto monofilament fishing line with a pair of pliers, or molars. So perfect is the lead sinker, you can go into most bait shops and find no other kind. Every spring, thousands of fishing folk buy a new bag or two, because last year's supply is running short. But here's something to muse over: where did last year's supply go?

"There's a saying in ecology: Everything goes somewhere," says Pam Perry, the Department of Natural Resources' non-game wildlife specialist in the Brainerd-lakes area. "If you dump something into the environment, it doesn't just go away. It'll show up again some other time, or some other place."

"How much of a percentage is tolerable for us to lose, in loons? Ten percent? Twenty percent? Some would say any percentage of losing our state bird may be too much, over the long term."

And it's not just loons; bald eagles are especially vulnerable to lead. Eagles eat fish, including the bottom-feeding varieties most likely to scoop sinkers from the sediments. Director Pat Reddig of the U of M's Raptor Rehabilitation Center says of the 120 or so bald eagles brought in yearly, about a quarter have severe lead poisoning.

"They're very, very sick birds," Reddig says. "They're not able to stand, they're having great difficulty breathing. Their livers are badly damaged, and they are passing bile in their urine and feces. They're unable to eat, they vomit their food if you force feed them. In some cases they are blind or partially so. They're suffering terribly, no question about it."

The center successfully treats about half the poisoned eagles; if a bird has ingested too much lead, it can't be saved. Reddig says sinkers are only part of the lead problem; raptors also pick up bullet fragments from deer carcasses, or the shot showered over fields and wetlands by generations of hunters. But lead shot has been illegal in the state for years, and Reddig has joined a number of conservationists calling on anglers to buy alternatives to lead.

"I think hunters and fishermen are conservationists at heart, and if they understood what the problem was, they'd feel that a little more expense for tackle would be a small price to pay compared to our eagles and loons that become poisoned."

Similar problems have already led to bans of small lead sinkers in Maine and New Hampshire. They're prohibited in all Canadian national parks. In the early '90s, the U.S. Senate held hearings on a possible nationwide ban, but anglers and manufacturers mounted such strong opposition the idea was dropped.

"We don't feel there's much demand for an environmental sinker whatever, because we've been offering them side by side with our lead products for years, and they have not grabbed very much of a market," says Geoff Ratte, the spokesman for the Minnesota-based Water Gremlin Company, which makes lead sinkers.

In 1994, Water Gremlin - which sells more than 500 tons of lead sinkers annually - started offering a sinker of tin, which is harmless to wildlife. The company was angling for what it saw as a potentially huge market of green-minded anglers. But the tin sinkers cost ten-time more to make; and they're so light, it takes twice as many to get the worm down where the fish can see it.

Ratte says in time the market may dictate otherwise; but for now, lead is where it's at. "We've looked up and down the periodic chart from every angle possible, and we haven't found anything that's even close to lead in terms of density, in terms of ease of manufacture, in terms of softness, in terms of availability, and in terms of cost."

A few manufacturers have focused harder on alternatives; the Nebraska-based Bullet Weights Inc., specializes in steel sinkers - though around here you can walk into most bait shops and draw vacant stares by asking for them.

The Gopher Tackle Company, across from the Woodtick Inn in rural Crow Wing County, has perfected the manufacture of the bismuth sinker. Bismuth? What's bismuth you ask? Conrad Peterson, who started Gopher Tackle, is delighted to explain "Bismuth, if you look in the dictionary, is actually a stomach medicine," says Conrad Peterson, who started Gopher Tackle. "They use the same thing, except they grind it into a powder."

Bismuth is an element almost as heavy as lead, which won't surprise users of Pepto Bismol, and in the early '90s, when it looked like lead might be exiting, Peterson made thousands of bismuth sinkers for national tackle distributors.

Like tin, though, bismuth is expensive, and like most of his competitors, Peterson is back to mostly lead. But he's watching the future. He's kept all his bismuth-alloy formulas; and in a back room lie boxes of the metal itself, purchased years ago from the Chinese army. Come a lead ban, Peterson says, or come a deep surge of conscience from the nation's anglers, he'll have all the bismuth he can handle.