RADIOCESIUM PATTERNS IN WOOD DUCK EGGS AND NESTING FEMALES IN A CONTAMINATED RESERVOIR

Radionuclide releases from nuclear industry are an important ecologica l issue, particularly because these contaminants may directly affect a nimals and may be transferred to the hunting public through consumptio n. During 1991-92, we collected 13 clutches of wood duck (Air sponsa) eggs from nest boxes established in an abandoned reactor cooling reser voir. We examined whole-egg radiocesium (Cs-137) levels and apportionm ent within egg components (albumen, yolk, and shell). Whole-egg concen trations averaged 0.113 Becquerels (Bq)/g wet mass (SE = 0.01, n = 137 ) over 2 years. Albumen had the highest concentration of Cs-137 ((x) o ver bar = 1.096 Bq/g dry mass), followed by shell ((x) over bar = 0.13 2 Bq/g dry mass) and yolk ((x) over bar = 0.098 Bq/g dry mass). Levels of potassium (K), a chemical analog of Cs, suggested that contaminati on levels in yolk were disproportionally lower than those in albumen. Levels of Cs-137 that appeared in these components may reflect tempora l differences in the synthesis of yolk and albumen. Laying order did n ot relate to whole-egg Cs-137 concentrations within clutches, but Cs-1 37 concentrations in post-laying females were positively related to me an egg Cs-137 levels in their respective clutches (r(2) = 0.97). While female ducks and their eggs examined in this study would not have pos ed a health hazard to persons consuming them as food, we suggest that Cs-137 levels in breeding female wood ducks and their clutches may be indicators of foraging habitat selection (both contaminated and uncont aminated) during the laying cycle.