Global Sources of Local Pollution An Assessment of Long-Range Transport of Key Air Pollutants to and from the United States (2010) / Chapter Skim
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5 Persistent Organic Pollutants
5 Persistent Organic Pollutants
Pages 113-124
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From page 113... ...
Because of their long reaction half-lives in water, soil, and sediment, and their potential for revolatilization and atmospheric transport, some POPs cycle in the global environment for many decades, similar to mercury. In this chapter, we focus on the POPs identified in the United Nations Economic Commission of Europe's Convention on Long-range Transboundary Air Pollution (UNECE LRTAP)
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From page 114... ...
. It is noted that while the use of the synthetic organic POPs such as pesticides and industrial chemicals was banned in the United States several decades ago, they continue to volatilize from historically-contaminated soils and cycle in the environment.
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From page 115... ...
. Although persistent organic pesticides are banned or restricted in most developed countries throughout the world, they continue to cycle in the global environment due to revolatilization from historically contaminated soils, vegetation, and water bodies.
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From page 116... ...
The task force also performed a short hazard assessment for polychlorinated terphenyls, polybrominated diphenylethers, polybrominated dibenzo-p-dioxins and dibenzofurans, and short-chain chlorinated paraffins to identify the main gaps in information necessary for risk assessment. ATMOSPHERIC FATE AND INTERMEDIA TRANSPORT The more volatile POPs (such as HCB and HCHs)
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From page 117... ...
In particular, elevated concentrations of aerosol-phase PAHs, HCB, and alpha-HCH have been measured in transpacific air masses relative to regional North American air masses at remote sites in the Pacific Northwestern United States (Killin et al., 2004; Primbs et al., 2008a,b; Zhang et al., 2008a; Genualdi et al., 2009)
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From page 118... ...
national parks, by correlating their measured concentrations with the cropland intensity within 150 km of the park. They estimated that 100 percent of the POP concentrations measured in Alaskan parks were due to long-range transport, while 30 to 70 percent of the concentrations of these POPs measured in the most westerly continental U.S.
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From page 119... ...
EXISTING POP MODELING CAPABILITIES Because of their global atmospheric transport potential, distribution between the atmospheric gas and aerosol phases, and potential to partition to and from various environmental media, global atmospheric transport models for POPs are not as refined as the global transport models for PM species or volatile compounds. Modeling the long-range transport of POPs
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From page 120... ...
Intercontinental transport of α-HCH is more significant than PCB-153 because it is present in the atmospheric gas phase rather than the aerosol phase. For example, a 20 percent reduction in α-HCH emissions from East Asia results in a 3 percent reduction in deposition in North America.
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From page 121... ...
CLIMATE CHANGE AND POPS Because the global environmental fate of POPs (including their degradation and intermedia transport) is highly temperature dependent, global climate change has the potential to significantly change the current global
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From page 122... ...
Changes in the North Atlantic Oscillation, the El Niño-Southern Oscillation, the Arctic Oscillation, and the Pacific North American pattern could all affect the re-release and global redisribution of POPs currently stored in ocean water (Macdonald et al., 2003, 2005; Macdonald, 2005; Ma and Li, 2006)
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From page 123... ...
to be exposed to increasing concentrations of certain POPs that have increasing emissions outside the United States (for instance, inha lation exposure to carcinogenic PAHs and food web exposure to bioaccumulated PCDD/Fs)
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From page 124... ...
inflow and outflow of POPs through measurements and modeling. This includes the continu ation of long-term atmospheric monitoring programs, which can aid our ability to track how POPs are redistributed due to climatic and global emission changes.
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