A variety of environmentally persistent chemicals, including some phthalate plasticizers, are weakly estrogenic.

TLDR

Sewage is a major source of environmental pollution, and phthalate esters—common industrial chemicals that bioaccumulate in animal fat—are among the most widespread environmental estrogens, with evidence suggesting they may contribute to reproductive and cancer disorders, though further in vivo studies are required to confirm their impact. Screening of 20 industrial chemicals in effluents found that half bind the estradiol receptor, with BBP, DBP, and BHA showing weak estrogenic activity that is less potent than octylphenol and act as agonists rather than antagonists, suggesting cumulative estrogenic effects.

Abstract

Sewage, a complex mixture of organic and inorganic chemicals, is considered 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-estradiol to the fish estrogen receptor. Further studies, using mammalian estrogen screens in vitro, revealed that the two phthalate esters butylbenzyl phthalate (BBP) and di-n-butylphthalate (DBP) and a food antioxidant, butylated hydroxyanisole (BHA) were estrogenic; however, they were all less estrogenic than the environmental estrogen octylphenol. Phthalate esters, used in the production of various plastics (including PVC), are among the most common industrial chemicals. Their ubiquity in the environment and tendency to bioconcentrate in animal fat are well known. Neither BBP nor DBP were able to act as antagonists, indicating that, in the presence of endogenous estrogens, their overall effect would be cumulative. Recently, it has been suggested that environmental estrogens may be etiological agents in several human diseases, including disorders of the male reproductive tract and breast and testicular 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 conditions.