A VARIETY OF ENVIRONMENTALLY PERSISTENT CHEMICALS, INCLUDING SOME PHTHALATE PLASTICIZERS, ARE WEAKLY ESTROGENIC

Sewage, a complex mixture of organic and inorganic chemicals, is consi dered to be a major source of environmental pollution. A random screen of 20 organic man-made chemicals present in liquid effluents revealed that half appeared able to interact with the estradiol receptor. This was demonstrated by their ability to inhibit binding of 17 beta-estra diol to the fish estrogen receptor. Further studies, using mammalian e strogen screens in vitro, revealed that the two phthalate esters butyl benzyl phthalate (BBP) and di-n-butylphthalate (DBP) and a food antiox idant, butylated hydroxyanisole (BHA) were estrogenic; however, they w ere all less estrogenic than the environmental estrogen octylphenol Ph thalate eaters, used in the production of various plastics (including PVC), are among the most common industrial chemicals. Their ubiquity i n the environment and tendency to bioconcentrace in anima fat are well known. Neither BBP nor DBP Were able to act as antagonists, indicatin g that, in the presence of endogenous estrogens, their overall effect would be cumulative. Recently, it has been suggested thar environmenta l estrogens may be etiological agents in several human diseases, inclu ding disorders of the male reproductive tract and breast and testicula r cancers . The current finding that some phthalate compounds and some food additives are weakly estrogenic in vitro, needs to be supported by further studies on their effects in vivo before any conclusions can be made regarding their possible role in the development of these con ditions.