Toxicity of lead-contaminated sediment to mute swans.

Most ecotoxicological risk assessments of wildlife emphasize contaminant exposure through ingestion of food and water. However, the role of incidental ingestion of sediment-bound contaminants has not been adequately appreciated in these assessments. This study evaluates the toxicological consequences of contamination of sediments with metals from hard-rock mining and smelting activities. Lead-contaminated sediments collected from the Coeur d'Alene River Basin in Idaho were combined with either a commercial avian maintenance diet or ground rice and fed to captive mute swans (Cygnus olor) for 6 weeks. Experimental treatments consisted of maintenance or rice diets containing 0, 12 (no rice group), or 24% highly contaminated (3,950 microg/g lead) sediment or 24% reference (9.7 microg/g lead) sediment. Although none of the swans died, the group fed a rice diet containing 24% lead-contaminated sediment were the most severely affected, experiencing a 24% decrease in mean body weight, including three birds that became emaciated. All birds in this treatment group had nephrosis; abnormally dark, viscous bile; and significant (p

Metal concentrations in zebra mussels and sediments from embayments and riverine environments of eastern Lake Erie, southern Lake Ontario, and the Niagara River.

Concentrations of 14 metals were studied in the soft tissues of zebra mussels ( Dreissena polymorpha) and sediments from 16 Great Lakes embayments and riverine environments. Samples were collected in 1993 and 1994 during the early and late autumn period when the body mass of mussels is least affected by reproductive activities. There was a significant difference in geometric mean concentrations of all metals except Cu in mussels sampled from different sites, and there was a significant difference in the geometric mean concentrations of all metals but Cd, Mn, and Zn between years. The higher metal concentrations in mussels from this study were generally similar to those in mussels from contaminated European and U.S. locations, and those with lower concentrations were similar to those from uncontaminated European and U.S. locations. Geometric mean sediment concentrations of all metals differed significantly among sites. Sediment concentrations of metals from some sites were above EPA guidelines for moderately polluted harbor sediments. Sites where zebra mussels had higher concentrations of Al, Cr, and V tended to be the same sites as those where sediment concentrations of these metals were also higher. However, there was not a significant statistical relationship between concentrations of metals in zebra mussels and sediments, except for Mg.

Behavioral sequelae of bracing versus surgery for Legg-Calvé-Perthes disease.

The Louisville Behavioral Checklist was administered to 23 white boys between the ages of 7 and 12 years who completed treatment for Perthes disease by bracing or surgery at the Florida Elks Children's Hospital. The groups were comparable, with 11 children in the surgery group and 12 in the bracing group. Results indicated statistically significant differences (p = 0.05) between the groups in three areas. Patients in the bracing group were more likely to demonstrate deficits in social, academic, and sexual behavior as compared with patients in the surgery group.