Taking lead on lead may aid birds


June 29, 1993|By PETER BAKER

Last Wednesday, the Environmental Protection Agency and the Environmental Defense Fund came to an agreement that would ban the manufacture, processing and distribution of some types of lead fishing weights in the United States.

The EDF, a New York-based, non-profit organization, petitioned and then sued the EPA before the settlement was reached last week.

The EDF based its arguments on studies that showed common loons, trumpeter swans and a Mississippi sandhill crane, an endangered species, had been poisoned by ingesting lead fishing sinkers.

The EPA said in court papers filed Wednesday that it will "publish by Jan. 14, 1994 . . . a proposed rule to ban lead in certain fishing sinkers."

England adopted a similar measure in 1987 to protect its mute swans, and the incidence of lead poisoning has dropped dramatically, according to the EDF.

Although EDF studies dealt with only loons, trumpeters and the sandhill crane, the environmental group contends that ducks, grebes, herons, egrets, ospreys and eagles also are subject to lead poisoning if they ingest lead sinkers.

Bill Harvey of the Maryland Department of Natural Resources Migratory Bird Program said yesterday that it is possible for any waterfowl to ingest lead that exists in its environment.

To digest their food, waterfowl must take pebbles, stones or other hard objects of similar size into their gizzard, where the objects work together to grind food at the front end of the digestive system.

Eventually, the pellets grind themselves into pieces small enough to be passed completely through the digestive system.

The size of a lead pellet ingested might determine the duration of exposure to toxic lead.

Harvey said a swan certainly could eat a 1-ounce sinker, but ducks might manage a pellet the size of a kernel of corn or a small, split-shot weight and a goose an object only twice that size.

In the 1970s, during the research and discussion about the changeover from lead to steel shot for waterfowl guns, Harvey said: "We looked at more than 7,000 duck and goose gizzards and found no occurrences of lead poisoning."

Loons and swans apparently present a more weighty problem because they can ingest larger objects.

In Maryland, Harvey said, the danger to trumpeter swans is negligible, because the birds are fairly rare here.

"But we do have a lot of loons that come through here in the spring and fall," Harvey said. "In fact, they arrive in the fall during the rockfish season.

"We don't have trumpeter swans, except for one once in a while, but we do have tundra swans, which are similar in size and would be capable of ingesting pellets of similar size."

The EPA intends further study on the effects of sinkers on ducks, geese and other birds before making a recommendation that could affect 60 million fishermen in the country.

Bismuth, tin, steel and steel and plastic combinations are possible replacements for lead sinkers, and non-toxic sinkers have been available from catalog and retail outlets for some time.

The EPA also intends to test alternative sinker materials to ensure they are not toxic before making its recommendation.

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