Environmental Engineering Reference
In-Depth Information
Fig. 1
Qualitative
diagrammatic representation
of the sequence of processes
influencing the fate of CPY
in various environmental
compartments after release
and their influence on
exposures to biota
potential exposures to CPY that were presented previously (Giesy et al.
1999
;
Solomon et al.
2001
) and includes additional information on environmental chemo-
dynamics of CPY that have become available subsequent to those earlier publica-
tions. There have been and continue to be extensive studies on the presence of CPY
and CPYO in environmental media near to and remote from sites of application.
Many are prompted by concerns that these substances may have effects on distant
sensitive organisms, such as amphibians and in remote food webs as have occurred
with organo-chlorine pesticides.
2
Fate in the Atmosphere and Long-Range Transport
The potential for long-range transport (LRT) is a concern for synthetic chemicals
of commerce, including pesticides. Concentrations of synthetic chemicals mea-
sured at locations distant from sources, in conjunction with mass-balance model-
ing, have combined to provide information on key contributing processes involved
in LRT, especially for persistent organic pollutants (POPs) that have relatively
long residence times in the atmosphere. A quantitative predictive capability has
emerged in the form of simple mass-balance models such as TAPL3 and the
OECD Tool (Beyer et al.
2000
; Wegmann et al.
2009
). These models have been
used in regulatory contexts and characterize LRT as a Characteristic Travel
Distance (CTD) over which some two-thirds of the mass of chemical transported
from source regions is deposited or transformed to other chemicals, while the
remaining third is transported greater distances through the atmosphere. The
focus here is the organophosphate insecticide, CPY and its transformation
product CPYO, in which the sulfur atom is replaced by oxygen (Giesy et al.
1999
; Racke
1993
).
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