|Li, Y - ENVIRONMENT CANADA|
|Bidleman, T - ENVIRONMENT CANADA|
|Barrie, L - ENVIRONMENT CANADA|
Submitted to: Geophysical Research Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 27, 1997
Publication Date: N/A
Interpretive Summary: Hexachlorocyclohexane (HCH), is an persistent chlorinated pesticide that was heavily used in the United States until the 1970's. Current HCH usage in the US is extremely limited. China was the largest global producer of HCH until 1982. India and Russia continued to use HCH until 1990. This report tracks the historical decline in atmospheric concentrations of alpha-HCH in the arctic atmosphere. Results of this study show that atmospheric concentrations have dropped after these two significant declines in usage. This suggests that the atmosphere responds relatively quickly to drops in use rates, even for persistent chlorinated compounds.
Technical Abstract: The relationship between the global technical hexachlorocyclohexane (HCH) use trends and their impact on the arctic atmospheric environment has been studied. Two significant drops in global technical HCH usage were identified. In 1983, China banned the use of technical HCH. This represented the largest drop ever in global use rates. In 1990 India stopped technical HCH usage in agriculture and the former Soviet Union banned the use of technical HCH. Since 1990, India has been the biggest user of technical HCH in the world. Significant drops in atmospheric alpha-HCH in the arctic were observed between 1982 and 1983, and again between 1990 and 1992. The rapid response in atmospheric concentrations to usage is encouraging; however, since alpha-HCH concentrations in the arctic waters have remained relatively unchanged, the decline in atmospheric alpha-HCH has reversed the net direction of air-sea gas flux. The accumulated mass in oceans and large lakes may represent a new source of HCH to the arctic atmosphere.