| 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 |