Sources of Toxaphene and Other
Organochlorine Pesticides in North
America As Determined by Air
Measurements and Potential Source
Contribution Function Analyses
posted on 2004-08-01, 00:00authored byEunha Hoh, Ronald A. Hites
A previous study from our laboratory suggested that the
Gulf of Mexico might be a potential source of toxaphene to
the United States. To investigate this hypothesis, we
measured gas-phase toxaphene concentrations at sampling
sites ranging from northern Michigan to southern
Louisiana; the samples were collected every 12 days
during 2002−2003. We also measured other organochlorine
pesticides in these samples. We identified major source
regions of each pesticide group using the potential source
contribution function model with the Clausius−Clapeyron
equation defining the criterion levels. These results indicate
that southern cotton farms are major sources of both
toxaphene and p,p‘-DDE to the northern United States. In
fact, there is a very strong correlation of toxaphene
and DDE atmospheric concentrations at all sites, further
indicating a common source. On the other hand, the Gulf of
Mexico is not a major source of toxaphene or DDE.
DDE's source region is similar to that of toxaphene but
somewhat broader, reflecting DDT's historically more
diversified use. The level of endosulfan in the atmosphere
at all of the sites was similar, and PSCF modeling indicated
that its sources were all toward the east of the sampling
sites.