title: Hormesis associated with a low dose of methylmercury injected into mallard eggs.
abstract: We injected mallard (Anas platyrhynchos) eggs with methylmercury chloride at doses of 0, 0.05, 0.1, 0.2, 0.4, 0.8, 1.6, 3.2, and 6.4 μg mercury/g egg contents on a wet-weight basis. A case of hormesis seemed to occur because hatching success of eggs injected with 0.05 μg/g mercury (the lowest dose) was significantly greater (93.3%) than that of controls (72.6%), whereas hatching success decreased at progressively greater doses of mercury. Our finding of hormesis when a low dose of methylmercury was injected into eggs agrees with a similar observation in a study in which a group of female mallards was fed a low dietary concentration of methylmercury and hatching of their eggs was significantly better than that of controls. If methylmercury has a hormetic effect at low concentrations in avian eggs, these low concentrations may be important in a regulatory sense in that they may represent a no-observed adverse effect level (NOAEL).
authors: United States Geological Survey, Patuxent Wildlife Research Center, BARC-East, Building 308, 10300 Baltimore Avenue, Beltsville, MD 20705, USA. gheinz@usgs.gov
authors: Gary H
authors: GH
authors: Heinz
authors: David J
authors: DJ
authors: Hoffman
authors: Jon D
authors: JD
authors: Klimstra
authors: Katherine R
authors: KR
authors: Stebbins
authors: Shannon L
authors: SL
authors: Kondrad
authors: Carol A
authors: CA
authors: Erwin