Environmental Engineering Reference
In-Depth Information
PCB levels in white perch from the Chesapeake Bay area
were found by King and colleagues to be strongly related
to the percentage of suburban and urban development in
the local watershed. They considered the intensity of devel-
opment in watersheds using four measures of developed
land-use (%  impervious surface, % total developed land, %
high-intensity residential + commercial, and % commercial)
to represent potential source areas of PCBs to the subestuar-
ies. When development of the land in the watershed reached
about 20% of the total area (which is not particularly dense
for our coastal states), PCBs in the fish begin to exceed recom-
mended limits for consumption. PCBs historically produced
or used in commercial and residential areas are apparently
persisting in the environment and the amount of developed
land close to the subestuary had the greatest effect on PCB
levels in the fish.
PCBs have been banned in the United States since the 1970s,
but continue to be redistributed and dispersed. More than
30 years after their prohibition, they are still accumulating in
fish tissue to such an extent that state agencies recommend that
people do not eat striped bass or blue crabs from the Newark
Bay area, and eat no more than one meal a week of seafood
from other areas in the New York Harbor estuary.
Another PCB-contaminated site is an 18,000 acre tidal estu-
ary in New Bedford, Massachusetts, where manufacturers of
electric devices used PCBs and discharged wastes into the
harbor directly as well as through the city's sewage system.
PCB levels in fish and lobsters exceed the Food and Drug
Administration's limit for PCBs in edible seafood. There is
an increased risk of cancer and other diseases for people who
regularly eat seafood from the area. While some species have
disappeared, Diane Nacci and colleagues at EPA found that
the killifish at the site have become very tolerant to the PCBs.
The fish adapted to the high levels of PCBs through genetic
changes by developing an abnormal biochemical pathway.
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