Foreign biological substances such as pesticides, heavy metals (cadmium, lead, mercury), organ chlorines (dioxin, PBBs, PCBs), and petrochemical residue from plastic ingredients and surfactants (polycarbons, styrene used in detergents, paper, paints). Some of the 100,000 registered chemicals for use in the world have hormonal effects in addition to toxic and carcinogenic effects. These chemicals are ubiquitous in the environment and food supply, persisting in the cells and tissues of the body years after exposure. Xenoestrogens can cross the placenta and disrupt the hormone-regulating endocrine system by mimicking estrogen. This reproductive system activity has been linked to abnormalities and cancers of hormone sensitive human tissues, including breast, cervical, endometrial and prostate.