Drs. Thomas W. and Christine M. Custer, USGS, Dr. Bruce Eichhorst, University of Nebraska, Kearney, NB and Dave Warburton, Biologist USFWS authored the paper, 14 p, which was printed in the Archives of Environmental Contamination and Toxicology;   published online.

Exceptionally high cadmium (Cd) and chromium (Cr) concentrations were reported in eggs. feathers, or livers of selected waterbird species nesting at Agassiz NWR in 1994.   Because of the high levels and potential for adverse effects a cooperative investigation was intitiated in 1998 to reevaluate Selenium (Se) and metal contamination in Franklin's gulls, black-crowned night herons, eared grebes, and pied-billed grebes nesting at Agassiz with emphasis on Cd and Cr.  A concurrent study on tree swallows was initiated to determine whether metal exposure to birds was associated with specific drainages into Agassiz. 

Frankling gull, eared grebe, and black crowned night heron chicks (10-15 days old) were collected in 1998, 1999, and 2001.  Freshly laid eggs were collected in 2001 from all 3 species and pied billed grebe nests.  Based on a multivairate analysis, the pattern of Se and metal concentrations differed among species for eggs, chick feathers and chick livers.  Low Cd and Cr concentrations were measured in eggs, livers, and feathers of all 4 species.  Mercury concentrations in black crowned night heron and eared grebe eggs collected in 2001 were lower than concentrations reported in 1994.  Se and metal concentrations, including Cd and Cr, in waterbird eggs and chicks at Agassiz (1998, 1999, 2001) were not at toxic levels.

Dave Warburton, Ecological Services, Twin Cities Field Office, secured funding for the study through the USFWS Contaminants Program, managed the contract with USGS and coordinated field efforts with Agassiz refuge.