Air Quality Criteria for Lead Volume II of II - (NEPIS)(EPA) - US ...

Very little research has been done to expand the knowledge of the toxicity of Pb to birds
since the Eco-SSL work was done. However, several studies have been conducted on waterfowl.
Toxicity data for waterfowl (in particular, mallards) were included in the soil Eco-SSL
development process (Table AX7-1.3.3), although mallards may be more exposed to
contaminants in sediment than soil. Effects on waterfowl may vary depending on the form of Pb,
characteristics of the sediment, the foraging strategy of the species (which may vary during
reproduction), and the nutritional status of the animal. Sediment is recognized as an important
route of exposure for waterfowl, particularly those species that dabble (i.e., forage on
invertebrates in the sediment) (Beyer et al., 2000; Douglas-Stroebel et al., 2005). Douglas-
Stroebel et al. (2005) found that mallard ducklings exposed to Pb-contaminated sediment and a
low nutrition diet exhibited more changes in behavior (as measured by time bathing, resting, and
feeding) than Pb exposure or low nutrition exposure alone. These effects may be due to the low
nutrition diet being deficient in levels of protein, amino acids, calcium, zinc, and other nutrients.
Beyer et al. (2000) related blood Pb to sublethal effects in waterfowl along the Coeur
d=Alene River near a mining site in Idaho. The authors suggested that 0.20 mg/kg ww blood Pb
represents the no-effect level. This no-effect blood concentration corresponds to a sediment Pb
concentration of 24 mg/kg. A sediment concentration of 530 mg/kg, associated with a blood Pb
concentration of 0.68 mg/kg ww, is suggested to be the lowest-effect concentration. These
results are consistent with those of Scheuhammer (1989) who found blood Pb concentrations of
0.18 µg/mL to 0.65 µg/mL in mallards corresponded to conditions associated with greater than
normal exposure to Pb, but that that should not be considered Pb poisoning. The study by Beyer
et al. (2000) related blood Pb to waterfowl mortality and concluded that some swan mortality
may occur at blood Pb levels of 1.9 mg/kg ww, corresponding to a sediment Pb concentration of
1800 mg/kg. Using the mean blood level of 3.6 mg/kg ww from all moribund swans in the
study, it was predicted that half of the swans consuming sediment at the 90th percentile rate
would die with chronic exposure to sediment concentrations of 3600 mg/kg.
Mammalian Consumers
Effects on mammals observed in studies conducted since the 1986 Lead AQCD (U.S.
Environmental Protection Agency, 1986a) are similar to those reported previously: mortality,
effects on reproduction, developmental effects, and changes in growth (U.S. Environmental
AX7-70