TRACE-ELEMENTS IN CANVASBACKS (AYTHYA-VALISINERIA) WINTERING IN LOUISIANA, USA, 1987-1988

We determined trace element concentrations in livers of canvasbacks (A ythya valisineria) collected at Catahoula Lake and the Mississippi Riv er Delta, Louisiana during, the winter of 1987-88. Forty percent of ca nvasbacks wintering at Lake Catahoula had elevated concentrations of l ead (>6.7 mug g-1 dry weight) in the liver; 33% had concentrations con sistent with lead intoxication (>26.7 mug g-1). Based on the number of canvasbacks that winter at Lake Catahoula and the frequency of lead e xposure there, more than 5% of the continental population of canvasbac ks may be exposed to lead at Lake Catahoula alone. Lead concentrations in livers differed among months and were higher in males than females , but were not different in adults and immatures. Concentrations of se lenium and mercury in livers of females differed among months but not by age or location. Cadmium concentrations in livers differed by age, location and month of collection, but not by sex. Frequencies and conc entrations of trace elements not commonly associated with adverse effe cts on avian species (aluminum, arsenic, copper, iron, magnesium, mang anese, nickel, silver, vanadium and zinc) are presented. Except for th e elevated concentrations of lead at Catahoula Lake, all trace element s were at background concentrations.