Scientists are urging officials to change the way in which certain chemicals are evaluated for safety after a series of reports, which were published last Wednesday, concluded that exposure to certain chemicals at key developmental points such as in the womb, puberty and pregnancy, can change the way that breast tissue develops and increase the risks of breast cancer or lactation problems.

The problem lies in the fact that although scientists have linked over 200 chemicals to breast cancer, many others may be being missed because current tests “look only for tumours and neglect development effects”.

In animal tests, rats exposed to certain hormonally active chemicals in the womb exhibited abnormal mammary gland development, changes to the normal rate of breast development, and cancerous tumours later in life. Although it is not known whether the same thing happens in human beings, scientists say that rodent breasts develop similarly to human breasts, and in the same stages.

The chemicals responsible for these changes can be found in common items such as pharmaceuticals, plants which are consumed as foods, and certain flame retardant compounds and pesticides. In fact, in at least one case, the chemicals can be found in drinking water!

As Scientific American reports:

In a companion report published Wednesday, scientists with three federal agencies who studied mice exposed in the womb to a chemical used to make Teflon found delayed breast development and impaired lactation. The effects were found in the mice at the concentrations detected in the water supply of an Ohio town near a DuPont Co. plant that uses the chemical, known as PFOA. Water supplies are not routinely monitored for it.

“If human exposures in distinct populations are approximating those provided in this study, concern over human breast health and lactational competency are justified,” said the authors, led by Suzanne Fenton, a mammary gland expert at the National Toxicology Program.

Source : Scientific American