Assessing Environmental
Fate of β‑HCH
in Asian Soil and Association with Environmental Factors
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Abstract
Chinese Gridded Pesticide Emission and Residue Model
was applied
to simulate long-term environmental fate of β-HCH in Asia spanning
1948–2009. The model captured well the spatiotemporal variation
of β-HCH soil concentrations across the model domain. β-HCH
use in different areas within the model domain was simulated respectively
to assess the influence of the different sources of β-HCH on
its environment fate. A mass center of soil residue (MCSR) was introduced
and used to explore environmental factors contributing to the spatiotemporal
variation of β-HCH soil residue. Results demonstrate that the
primary emission dominates β-HCH soil residues during the use
of this pesticide. After phase-out of the pesticide in 1999, the change
in β-HCH soil residues has been associated with the Asian summer
monsoon, featured by northward displacement of the MCSR. The displacement
from several major sources in China and northeastern Asia shows a
downward trend at a 95% confidence level, largely caused by environmental
degradation and northward delivery of β-HCH under cold condition
in northern area. The MCSRs away from the India and southern and southeastern
Asia sources show a rapid northward displacement at a 99% confidence
level, featuring the cold trapping effect of the Tibetan Plateau