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Atmospheric Concentrations of PCB-11 Near the Great Lakes Have Not Decreased Since 2004
journal contribution
posted on 2018-02-20, 21:13 authored by Ronald A. Hites3,3′-Dichlorobiphenyl
(PCB-11) is thought to be a byproduct
of the production of yellow pigments, and thus, it has sources to
the environment that differ both in type and magnitude compared to
the PCBs that made up the, now banned, Aroclor commercial products.
To assess these differences, the temporal trends of atmospheric concentrations
of PCB-11 relative to those of 31 specific Aroclor-related congeners
and relative to those of total Aroclor-PCBs at six sites near the
North American Great Lakes were investigated. About 1800 atmospheric
samples were collected over the period of 2004–2015 (inclusive).
A multiple linear regression approach was used to isolate the variations
in the atmospheric concentrations due to the human population near
the sampling sites, seasonal effects, and long-term temporal changes.
The atmospheric concentrations of the Aroclor-PCBs are decreasing
with halving times of about 12 years, but the atmospheric concentrations
of PCB-11 have not changed significantly over this time period. These
results suggest that PCB-11 is still leaking into the environment,
while at the same time sources of Aroclor-PCBs are coming under control.
This effect is particularly notable at the most remote site on Lake
Superior, where PCB-11 levels are, on average, 11% of those of total
Aroclor-PCBs; this is a not insignificant abundance of a single PCB
congener.