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

lakes in the United Kingdom the distribution of sediment-bound trace elements (including Pb)
have been affected by forestry activities and catchment erosion (Yang and Rose, 2005). Yang
and Rose (2005) believe that more contaminated soil in-wash could increase sediment heavy
metal concentrations while less contaminated soil in-wash could dilute sediment heavy metal
levels.
Climate Change
Atmospheric Pb is not likely to contribute significantly to global climate change. Lead
compounds have relatively short residence times in the atmosphere, making it unlikely that they
will reach the stratosphere. Also, Pb compounds are not known to absorb infrared radiation and,
therefore, are unlikely to contribute to stratospheric ozone depletion or global warming.
Climate change does, however, represent a disturbance to terrestrial ecosystems.
Unfortunately, the potential linkages between climate-related stress and Pb cycling are poorly
understood. As in the previous examples, effects related to alterations in organic matter cycling
may influence Pb migration. For example, an increase in temperature leading to increased rates
of organic matter decomposition could lead to temporary increases in DOM concentrations and
smaller steady-state pools of soil organic matter. Either of these factors could result in increased
concentrations of Pb in waters draining terrestrial ecosystems.
Climate change may also affect the fluctuations of temperature and/or precipitation in
terrestrial ecosystems. For example, there is some evidence for recent increases in the frequency
of soil freezing events in the northeastern United States (Mitchell et al., 1996). Soil freezing
occurs when soils have little or no snow cover to insulate them from cold temperatures and
results in an increased release of nitrate and DOC from the O horizons of forest soils (Mitchell
et al., 1996; Fitzhugh et al., 2001). Increased DOC losses from O horizons subjected to freezing
may also increase Pb mobilization.
Increased fluctuations in precipitation may induce more frequent flooding, with
potentially significant consequences for Pb contamination of floodplain ecosystems. Soils
collected from the floodplain of the Elbe River, in Germany, contained elevated concentrations
of Pb and other trace metals (Krηger and Grongroft, 2003). Tissues of plants from floodplain
sites did not, however, contain higher Pb concentrations than control sites. More frequent
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