Consumers Have No Cause To Be Alarmed By Report
Consumers Have No Cause To Be Alarmed By Report - Experts
Auckland, May 27, 2003 - Consumers have been unnecessarily concerned by recent reports, Plastics NZ Environmental Affairs Manager Carolyn Cox says.
Contrary to some recent reported comments polycarbonate is totally safe in its common applications as a versatile engineering and packaging material, even when these uses involve long-term food contact, she says.
And experts say that contrary to reported comments, polycarbonate is not the most commonly used polymer for food and beverage containers.
Polycarbonate is extensively used for a wide range of applications, and the grades used for food contact have been specifically and scientifically approved by authorities such as the US Food and Drug Administration (FDA).
Ms Cox was commenting on some recent overseas media reports into the Hunt study, published here, which reported toxic effects on mice from exposure to bisphenol A (BPA).
BPA is a building block (monomer) that is transformed through the polymerisation process to make polycarbonate. Because of its durability, transparency and its high resistance to heat, the polycarbonate polymer has many uses including CDs, protective equipment and food and beverage containers. The Hunt study is based on the findings of Patricia Hunt and colleagues from Case Western Reserve University in Ohio who found during the course of experiments BPA caused chromosomal abnormalities in female mice. Ms Hunt traced the exposure to their plastic cages, which were "worse for wear" from use of a harsh detergent, and had released BPA. She followed up by directly exposing mice to bisphenol A, with similar results.
Report Creates Confusion and Misinformation Crown Research Institute, Industrial Research Ltd, Material Engineer specialising in polymer technology and metallurgy, Dr Neville Miller, says he has grave reservations about some media reports of the study, which have been speculative about the study's findings and BPA's safety for human health.
Dr Miller notes that unfortunately a Reuters report published in some local media outlets, lacked information about the stringent testing required for polycarbonate food handling products and failed to provide such key details as the level of BPA the mice were exposed to or the plastic material the cages were made off to determine conclusively where the BPA came from.
Such failure to report the strict regulatory framework for BPA and other relevant details would only have the effect of creating confusion and misinformation in the minds of consumers. Dr Miller also expressed concern that of the two scientists quoted in the Reuters article, Patricia Hunt, a geneticist, and Fred vom Saal, an expert on the effects of toxins on reproduction - neither are polymer chemistry experts. In particular, Dr Miller takes issue with Fred vom Saal's reported statements that: "Bisphenol A is one of the most commonly used plastic materials in food containers, in beverage containers" and that "this is a ubiquitous chemical ... at least in the developed world".
In fact, Dr Miller says, Bisphenol A is not a plastic material in its own right, rather it is an intermediate used in the production of polycarbonate, and by far the greatest bulk of plastic consumer products used in New Zealand and worldwide are made from polyethylene, polypropylene, PVC, polystyrene and PET - none of which contain BPA.
In New Zealand, the commonest beverage containers (such as carbonated soft drink bottles) are made from PET, while the plastic milk containers commonly found in supermarkets are high-density polyethylene. Tupperware and similar type containers are usually polyethylene or polypropylene and other food containers can be made of polystyrene and PVC.
"Given all this, then vom Saal's statements are, to say the least, misleading and could even be considered to be untrue," Dr Miller says.
Expert puts report in factual context New Zealand-based internationally recognised polymer chemist Dr Peter Plimmer says the study's findings should be seen in the context of well-established facts about BPA and polycarbonate:
* Polycarbonate has been successfully used for rigid 'see-through' drinking water containers for years without any reports of any toxicity from extracted BPA.
* Manufacturers of polycarbonate must test potential toxic effects (extraction studies) in order to meet FDA and European safety criteria for food handling safety. The toxicity of BPA must also be well documented in the technical literature. This ensures that the residual level of monomer in the end product - is negligible.
In light of all this, Dr Plimmer says he fails to see any toxic hazard arising from the proper use of a product moulded properly from polycarbonate polymer.
He also says it should be pointed out that the Hunt study appears to have ignored that there are chemical and thermal limitations set by polycarbonate producers. "The study offers no details of the type of "harsh" detergent used, nor is there any indication of the temperature during this cleaning operation (possibly hot detergent). When polymers are abused, thermally or chemically, they can break down into their 'building blocks' - and become brittle, and discolour. "I believe that the Hunt group saw this type of behaviour and, in the case of polycarbonate, this could generate BPA.
"The maximum upper end use temperature, as well as chemical (detergent) resistance, is usually well defined by the polymer producer's "safety in handling" literature - to provide a safety warning to end-users, and avoid mishandling that could lead to polymer degradation." Dr Plimmer concludes: "In my opinion polycarbonate is an excellent polymer for use as a transparent container for food and liquid packaging, as long as it isn't abused to the point of degradation - to break down and evolve BPA."
Crown Research Institute, Environmental Science and Research Ltd, Food Scientist specialising in safety aspects of polymers, Dr Jim Mitchell, says the Hunt study is one of several recent studies that have suggested BPA may have a toxic effect on animals at lower levels than previously thought. "I think this is interesting but it doesn't yet tell us anything about whether this has any implications for humans. If there were any obvious health effects we would have been aware of these by now. However we cannot discount any subtle effects - these are likely to be hard to detect and have yet to be fully investigated."
Though the Hunt report did not examine any human health effects from BPA, a large volume of scientific work has previously investigated these. Independent scientific institutes and regulatory authorities in both the US and Europe have thoroughly tested BPA for any reproductive and cancer-causing effects and have found no links, according to a Bayer information sheet.
In addition, a review of all scientific literature conducted by Bayer, one of the world's major suppliers of polycarbonate, concludes that polycarbonate is safe for its intended uses.
The review notes that consumers' contact with polycarbonate is confined to packaging products, which are subject to detailed statutory regulations. Bayer notes that BPA has statutory approval in Europe for the production of plastics, such as polycarbonate, that come into contact with food. Polycarbonate also meets FDA regulations for indirect food contact.
NZ manufacturers comply with stringent regulations Ms Cox adds that the FDA is known to have possibly some of the most stringent regulations in force, and all New Zealand manufacturers of polycarbonate food and beverage products comply with these.
She says the industry has decided to take this step to provide information about BPA and polycarbonate products as part of Plastics New Zealand's recently launched Plastics Sustainability Initiative.
"One of the aspects of this initiative is to better inform our stakeholders - including the public - so they are well-advised and informed about plastics and the environment, and this includes better understanding of hazardous substances," Ms Cox says.
industry is concerned that consumers should have access to
full information so they don't automatically jump to the
conclusion that plastic is bad for you, and bad for the
environment, without knowledge of the relevant facts."
Sources: Bayer Whitebook, Makrolon (BPA) F.W. Jakat and W.
Pump, Bayer A.G., Statement on bisphenol A and