Xenoestrogen

A xenoestrogen is a synthetic compound that mimics the hormone estrogen by binding estrogen receptors, a subclass of endocrine disruptor. Marine-relevant xenoestrogens include nonylphenol and octylphenol (alkylphenol surfactant breakdown products), bisphenol A, certain phthalates, and the pesticide o,p’-DDT. They feminize male fish: exposure induces vitellogenin, the egg-yolk protein normally made only by females, which is the standard biomarker of estrogenic exposure. Effects appear at nanogram-per-liter concentrations in wastewater-influenced coastal water, skewing sex ratios and reducing reproductive success in exposed populations.