Bisphenol A (BPA) is back in the news but no concrete conclusions of its safety have yet been established.  The latest evidence feeding the BPA safety controversy is a study that suggests BPA lingers in the human body longer than had been previously expected and may come from sources other than plastic food and beverage containers.

Dr. Richard Stahlhut and his colleagues at the University of Rochester tested the urine of 1,469 American adults for levels of BPA.  Urine levels were tested only after the study participants fasted, some for as short a time as eight hours but some fasted for an entire day.

Operating under the commonly shared assumption that BPA leaves the body quickly once ingested, the findings indicate otherwise.  BPA was found in significant measure in all study participants and the BPA level did not vary, as was expected, based upon how long a person fasted before testing.

The shorter the amount of time a toxic substance spends in the body, the less damage it does.  According to Stahlhut, knowing the plastic chemical stays in the body longer than previously expected “changes the game.”

The American Chemistry Council, an industry trade group representing manufacturers of BPA-based products, has no faith in the Stahlhut study.  A council spokesperson, Steven Hentges, called the study’s conclusions “speculative at best” and held fast to the industry’s opinion that BPA is safe as it is currently being used in the American food supply.

The chemical is commonly used in food and beverage containers, including plastic water bottles and baby bottles, but it also lines canned goods to keep the can’s metal components from leaching into the food and imparting an ‘off’ taste.  BPA leaches into the foods it contains, too, and it’s this leaching that causes alarm.

Last year, toxicologists at the National Institutes of Health raised concerns over the potential for harm when BPA is ingested.  The chemical mimics estrogen and may cause behavioral changes in infants and children and perhaps at even the fetal stage.  It is thought to induce early puberty and hinder development of the brain and prostate.

A 2008 British study links BPA to diabetes, heart disease, and abnormalities of liver enzymes.  Products containing BPA have been banned in many countries, including Canada.

BPA is used in many food and beverage containers but it’s also used to make medical devices, too.  The lingering effect witnessed by Stahlhut’s study suggests it may come from other sources besides food containers or medical devices, with tap water and house dust being possibilities.

Stahlhut also speculates the chemical may be stored in fat tissue once consumed, where it would be metabolized much more slowly.  The slower metabolic rate would produce a more steady level of the chemical in the urine, as was the case with the fasting participants in his study.

The Stahlhut study has been published in the journal, ‘Environmental Health Perspectives.’