U.S. Geological Survey Home Page USGS Patuxent Wildlife Research Center Science Meetings; dedicated to Chandler S. Robbins USGS Patuxent Wildlife Research Center; Science Meetings dedicated to Chandler S. Robbins Dedicated to Chan Robbins USGS Patuxent Wildlife Research Center; Science Meetings dedicated to Chandler S. Robbins Poster Abstracts from USGS Patuxent Wildlife Research Science Meetings, October, 2006
Patuxent Science Meeting 2006 Poster Abstract

Egg injections as a hybrid field-lab technique for assessing the

embryotoxicity of methylmercury to different birds

Heinz GH, Hoffman DJ, Klimstra JD, Schoen KR

Part of the challenge in assessing the threats of mercury pollution to vulnerable species of birds

involves field studies in contaminated areas, but another part is being able to design controlled

laboratory studies to determine how sensitive aquatic birds, particularly fish-eating species, are

to methylmercury (MeHg). Embryos are believed to be the most sensitive life stage in birds;

consequently, controlled breeding studies would be a logical laboratory approach.

Unfortunately, raising fish-eating birds in captivity is difficult and costly, and no controlled

laboratory studies with mercury have been conducted on them. We developed a hybrid field-lab

approach in which wild bird eggs are collected from the field and taken to the lab where they are

injected with various doses of MeHg. This approach bypasses the problems of breeding adults

in captivity, while allowing control over the dosing of eggs. Our protocol involves injecting various

doses of MeHg dissolved in corn oil into the air cell of the egg. We discovered that the embryos

of various species of birds differ in their sensitivity to MeHg. Some embryos are more sensitive

than the embryos of mallards, a species which to date has been used as a default species to

protect the embryos of wild birds. However, now that it is known that mallards seem to be less

sensitive than some fish-eating species, the use of the mallard data as a default must be re-

examined.

Friday, September 22, 2006



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