Developmental toxicity of lead-contaminated sediment to mallard ducklings

Sediment ingestion has been identified as an important exposure route for t oxicants in waterfowl. The toxicity of lead-contaminated sediment from the Coeur d'Alene River Basin (CDARB) in Idaho was examined on posthatching dev elopment of mallard (Anas platyrhynchos) ducklings for 6 weeks. Day-old duc klings received either untreated control diet, clean sediment (24%) supplem ented control diet, CDARB sediment (3,449 mu g/g lead) supplemented diets a t 12% or 24%, or a positive control diet containing lead acetate equivalent to that found in 24% CDARB. The 12% CDARB diet resulted in a geometric mea n blood lead concentration of 1.41 ppm (WW) with over 90% depression of red blood cell ALAD activity and over threefold elevation of free erythrocyte protoporphyrin concentration. The 24% CDARB diet resulted in blood lead of 2.56 ppm with over sixfold elevation of protoporphyrin and lower brain weig ht. In this group the liver lead concentration was 7.92 ppm (WW), and there was a 40% increase in hepatic reduced glutathione concentration. The kidne y lead concentration in this group was 7.97 ppm, and acid-fast inclusion bo dies were present in the kidneys of four of nine ducklings. The lead acetat e positive control group was more adversely affected in most respects than the 24% CDARB group. With a less optimal diet (mixture of two thirds corn a nd one third standard diet), CDARB sediment was more toxic; blood lead leve ls were higher, body growth and liver biochemistry (TBARS) were more affect ed, and prevalence of acid-fast inclusion bodies increased. Lead from CDARB sediment accumulated more readily in duckling blood and liver than reporte d in goslings, but at given concentrations was generally less toxic to duck lings. Many of these effects are similar to ones reported in wild mallards and geese within the CDARB.