EMERGING CONCERNS - Marine Pollution: What Everyone Needs to Know - page 123

“usual suspects,” the chlorinated hydrocarbons (which do
have endocrine effects). Later it was noticed that actual hor-
mones themselves were in the water, coming out from sew-
age treatment plants, and scientists realized that estrogens
from birth control pills were playing a major role. Waters
contain pharmaceuticals, such as metabolized birth control
pills, that people excrete and which can affect fish and other
animals. Currently, there is considerable interest in investi-
gating the pharmaceuticals and personal care products that
end up in aquatic ecosystems, and numerous studies have
found endocrine effects in aquatic organisms. Altered sex
ratios and abnormal female fish have been seen downstream
of treatment plants, as well as intersex fish with both male
and female reproductive tissue. It would not be at all sur-
prising if pharmaceutical pollution produces greater endo-
crine effects than the usual suspect pollutant chemicals,
because the biology of humans is very similar to that of fish
in this regard. When impacts of CECs from wastewater were
investigated in Southern California by Steven Bay from the
Southern California Coastal Water Research Project and col-
leagues, CECs were found in effluents from the major munici-
pal wastewater dischargers, as well as in seawater, sediments,
and fish near the outfalls. Fish hormones were altered; they
had reduced stress response, altered estrogen, and reduced
thyroid hormone, but responses could not be definitively
linked to the discharges. However, thyroxine was lower in
fish from all discharge sites, and estradiol was lower at three
of the four outfall sites. The physiological changes, however,
did not apparently lead to decreased reproduction.
Glucocorticoids (adrenal hormones) are also found in the
environment at concentrations that may be high enough to
affect aquatic life. A team of scientists that reviewed hun-
dreds of studies concluded that there are no safe doses for
hormone-altering chemicals. Such chemicals have effects at
low levels, which are often completely different than effects at
high concentrations.