For a popular update on the impact of anthropogenic estrogenic chemicals
on marine and terrestrial animals have a look at "Hormone Hell" by
Catherine Dold, Discover September 1996, pg 53. A broad class of chemicals
that includes the polychloro-dioxins are produced by incineration of
chlorinated organic polymers like polyvinyl chloride (PVC) or "Saran"
(plastic food wrap). These chemicals bind estrogen (female hormone)
receptors and decrease fertility for both males and females. Ms. Dold
recounts the evidence regarding the decrease in size of Columbia River
otter bacalums, penis bones. The walrus penis bone is called an oosik by
Inuits. It might be informative about estrogenic chemical contamination of
the Bering Sea to evaluate the time progression in the size of oosiks.
There are 72 fresh ones at Cape Peirce right now just waiting to be
measured.