As the use of polycarbonates in food contact substances increases, it has become necessary to study the effect of the polymer on human health. The main concern is Bisphenol A (BPA); the polycarbonate polymer's building block. Results from BPA studies have been contradictory; dividing opinions, especially in the different United States government agencies that oversee public safety, namely the Food and Drug Agency (FDA), the Centers of Disease Control and Prevention (CDC), the Consumer Product Safety Commission (CPSC) and the United States Environmental Protection Agency (USEPA).
Acceptable Amount of Bisphenol A in Our Diet
In 1993 the USEPA set the maximum acceptable dose for BPA at 0.05 milligrams per kilogram of body weight and this number is what most agencies use as the human consumption safety standard. Some agencies feel that the current amount of BPA exposure from the leaching of bottles and epoxy resins in cans is extremely low (450 times below the USEPA standard); therefore it is not possible for the BPA to impart noticeable effects on human health. The opposing view focuses on the results of lab tests that show negative development and estrogenic effects in lab animals exposed to BPA at concentrations equivalent to the low doses humans are exposed to daily.
The Centers of Disease Control and Prevention (CDC) and the bioavailability of BPA
According to a CDC November 2007 Biomonitoring Study, 93 percent of the study group had BPA in their urine. The high number was attributed to the increasing amount of BPA being used in the population. BPA concerns were further exacerbated when in January 2008 another BPA study appeared in the journal Toxicology Letters. The study reported that when polycarbonate bottles were placed in boiling water (as in sterilizing the baby bottles) BPA was released at a higher rate (55 percent higher than normal use) into the contents of the container. Based on the data available to the CDC, the agency maintains that more research and epidemiological studies are needed to determine the long term health effects of BPA at these low concentrations.
National Toxicology Program’s (NTP) Statement on Bisphenol A
In the latter part of 2008, the NTP, an interagency scientific panel of the different United States government agencies reviewed BPA studies and issued a document outlining their findings. Different health concerns were classified using a five tier system; where “serious concern” represented the highest level of concern, through “concern”, “some concern”, and “minimal concern”, to the lowest; “negligible concern”. The NTP had “some concern” for Bisphenol A’s effect in fetuses, infants and children’s brain, behavior, and prostate gland development. The panel listed "minimal concern" on BPAs effect on mammary gland development and effect on causing early puberty in females exposed in utero, as babies and as children. The document lists "negligible concern" for BPA exposure resulting in miscarriages, birth defects, exposed pregnant women delivering smaller babies and reproductive problems for non-occupationally exposed workers.
FDA and Bisphenol A
FDA approved the use of Bisphenol A for the intended use in food storage containers and food preparation in April 2002 based on the USEPA acceptable maximum dose. In September 2008 amidst growing pressure, FDA issued a draft statement on BPA’s safety. Citing over 100 different studies the federal agency concluded that BPA was still safe as a food contact substance. The agency also reported that the leached BPA concentrations were low enough to be considered harmless. Later in November 2008, the FDA revisited their position in the wake of the NTP’s document and findings by the Environmental Working Group (EWG). As the FDA continues to review more BPA studies, it still maintains the safety of BPA but is urging concerned citizens to consider alternatives to polycarbonates. As a result many manufacturers are producing BPA-Free water bottles.
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