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

vegetable and grain crops). Few data are available for trees or native herbaceous plants,
although two of the five toxicity endpoints used to develop the Eco-SSL were for trees and two
were for clover.
Consumers
Effects of Pb on avian and mammalian consumers include decreased survival,
reproduction, and growth as well as effects on development and behavior. There remain few
field effects data for consumers, except from sites with multiple contaminants, for which it is
difficult to attribute toxicity specifically to Pb. Avian and mammalian toxicity data recently
were reviewed for the development of Eco-SSLs (U.S. Environmental Protection Agency,
2005b). Many of the toxicity data presented in the Eco-SSL document (U.S. Environmental
Protection Agency, 2005b) are lower than those discussed in the 1986 Lead AQCD, although the
EPA (U.S. Environmental Protection Agency, 2005b) recognizes that toxicity is observed over a
wide range of doses (1000 mg Pb/kg bw-day). Most toxicity data for birds have been
derived from chicken and quail studies, and most data for mammals have been derived from
laboratory rat and mouse studies. Data derived for other species would contribute to the
understanding of Pb toxicity, particularly for wildlife species with different gut physiologies.
In addition, data derived using environmentally realistic exposures, such as from Pbcontaminated
soil and food, may be recommended. Finally, data derived from inhalation
exposures, which evaluate endpoints such as survival, growth, and reproduction, would
contribute to understanding the implications of airborne releases of Pb.
Decomposers
Effects of Pb on soil invertebrates include decreased survival, growth, and reproduction.
Effects on microorganisms include changes in nitrogen mineralization and enzyme activities.
Recent data on 1986 Lead toxicity to soil invertebrates and microorganisms are consistent with
those reported in the 1986 Lead AQCD (U.S. Environmental Protection Agency, 1986a), with
toxicity generally observed at concentrations of hundreds to thousands of mg/kg soil. Studies on
microbial processes may be influenced significantly by soil parameters, and the significance of
the test results is not clear.
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