As of this writing, the cause of the birds' death is disputed. The Atlantic Richfield Company (ARCO), a former owner of the Berkeley Pit and currently jointly liable for its remediation, contends the artificial lake did not kill the geese. ARCO cites necropsy findings from a lab at Colorado State University. The CSU lab determined that the two geese it tested died from an acute aspergillosis infection, caused by a fungus often found on grain.
The state of Montana reports that its labs ruled out aspergillosis as a cause of death. Only one of five birds tested revealed signs of aspergillosis, according to Candace West, an attorney with Montana's Natural Resource Litigation Program.
"We don't know yet what caused their deaths," said West. "We just know that for the birds we tested, aspergillosis fungus was not the cause of death."
New results from toxicity testing of tissue are expected from ARCO's lab, from the state's labs, and from the U.S. Fish and Wildlife Service. Although West would not speculate about what those tests might reveal, she acknowledged a suspicion that the pit was in some way culpable.
"It's difficult to think about 340 dead birds in the Berkeley Pit and not suspect the pit's toxicity as a cause," she said. "Any reasonable person would suspect it."
The pit, which is approximately a mile wide, a mile-and-a-half long, and 1,200 feet deep, contains roughly 25 billion gallons of contaminated water. Every day an additional 5 million gallons flow into the pit. EPA project manager Russ Forba said he believes elevated copper levels in pit water could have affected the geese.
"We've seen in the literature where Canada geese were killed by high copper concentrations," he said.
Bill Olsen, an environmental contaminant specialist with the U.S. Fish and Wildlife Service, noted that the Berkeley Pit contains a cocktail of heavy metals. "You could almost take your pick. The concentrations of copper, cadmium, lead, zinc and arsenic are all elevated," Olsen said.
Meanwhile, ARCO spokeswoman Sandy Stash said her company "stands firm on the analyses we've done at CSU."
The EPA issued a clean-up plan for the Berkeley Pit in 1994, but the agency remains in negotiation with ARCO and another "potentially responsible party," Montana Resources, to forge a "consent decree" that will allow work to begin in 1996. Forba said he expects that decree will provide for interventions such as propane cannons to scare waterfowl away from the pit.
If federal officials ultimately attribute the birds' death to pit contamination, fines may be levied for the illegal "taking" of a migratory bird.
* Duncan Adams
The writer works in Anaconda, Montana.