Can you provide a link to that study? Not that I don't believe you but I'd like to see it as it seems to clash with one in New York that found,
"To date, cases of lead toxicity have accounted for 20-50% of loon mortalities analyzed by the NYS Wildlife Pathology Laboratory and the Wildlife Clinic at the Tufts Univ. School of Veterinary Medicine (excluding catastrophic events, such as the botulism outbreak in Lake Erie)."One thing you mind want to keep in mind is loons are not as common as other waterfowl and they are not the only waterfowl suffering from lead poisoning.
http://www.adkscience.org/loons/lead.htm
