科研之友
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摘要
A Canadian ban on lindane for agricultural use came into effect on December 31, 2004. In the years leading up to this ban, air concentrations of gamma-HCH, the active ingredient of lindane, decreased gradually over the Great Lakes region. Typical mean concentrations were about 5 and 10 pg m(-3) for Lakes Huron and Ontario, respectively, during the summer of 2005. However, during the period June 27-28, 2005, a gamma-HCH air pollution episode was captured in Toronto by three independent sampling programs [Episodic Pesticide Transport (EPT) Study, Integrated Atmospheric Deposition Network (IADN) and Canadian Atmospheric Network for Currently Used Pesticides (CANCUP)], with concentrations of 586 and 3 070 pg m(-3) measured in north and downtown Toronto, respectively - an increase of about two orders of magnitude above typical levels. This episode was not observed at any of the regional IADN sites on the same day, suggesting a localized emission in the city from an unknown and episodic source. This study demonstrates the value in continued monitoring of persistent organic pollutants (POPs) beyond their phase-out period and highlights the importance of combining information from different projects to discover environmental pollution events.
- 出版日期2010-7
