How safe is Lexan? It was an article titled, "Hazards of Hydration -- Choose your plastic water bottles carefully" in the November/December 2003 issue of Sierra magazine that started the emails and calls to SNEWSÂ® central. That article also caused folks at Nalgene and GSI to begin scrambling to formulate an appropriate response.
The flashpoint for this sudden concern surrounding the safety of drinking water out of bottles made of Lexan is a published report in the April 2003 issue of Current Biology by Dr. Patricia Hunt, a geneticist at Case Western Reserve University in Cleveland. As a result of a worker accidentally washing polycarbonate mouse cages with a very harsh detergent, chromosomal abnormalities that were normally found in only 1 percent to 2 percent of mouse eggs prior to the washing spiked to 40 percent. The cause was Bisphenol-A (BPA) which is a known endocrine disruptor that mimics the hormone estrogen. The BPA leached from the polycarbonate. For humans not living in mouse cages, food-grade polycarbonate is what those clear and sometimes now colorful water bottles are made of that are widely sold these days not just at outdoor shops, but also at health clubs and at chic coffee houses.
Sierra magazine used the article (on pages 16 and 18) to then make the leap, led by several experts including Hunt, that Lexan bottlesÂ might not be safe for human use. Hunt even stated that washing polycarbonate water bottles in a dishwasher could cause the chemical to leach. Hunt is also quoted as saying that "the amount of leaching increases as the plastic ages and is degraded by use." Also cited, in the same paragraph, is a study published in the July issue of Environmental Health Perspectives (EHP) that the Sierra magazine article alleged confirmed the finding. In taking our own look at the study, we found it does no such thing; what is does confirm is only that BPA leached into water from polycarbonate mouse cages, just as Hunt's study found.
The fact is neither Hunt's study (click here to read ) nor the EHP published study tested or evaluated food-grade Lexan â€“ a slightly different form of the polycarbonate. In other words, according to Jim Burkhart, science editor at Environmental Perspectives: "You cannot generalize results of one study across all types of plastics."
Robert Hess, communications director for GE Plastics added that, "There are many, many grades and many manufacturers of polycarbonate. Grades are developed specific to applications, including FDA approved grades such as those used in personal water bottles."
When asked by SNEWSÂ®, Dr. Hunt agreed that you cannotÂ reach aÂ conclusion regarding the safety of Lexan bottles, like those Nalgene manufactures, based on the test results from her study. However, she also asserts that she firmly believes that what her study does indicate is a need for much more testing and evaluation.
"I think that what really needs to happen nowÂ is for tests to be conducted on polycarbonate sport bottles to determine how much BPA can be detected in water when the bottles are new and then how much the BPA levels change through extended use and by subjecting the bottles to harsh cleaning conditions," says Dr. Hunt.
SNEWSÂ® checked with the U.S. Food and Drug Administration (FDA), and while FDA reports said the agency is evaluating BPA risks in the food and medical areas, no conclusions have been reached and aren't expected for some time since it too believes more research is needed.
The one published paper that appears to carry the most weight is one from the Scientific Committee on Food from the Health and Consumer Protection Directorate of the European Commission (we know, quite a mouthful). In the paper titled, "Opinion of the Scientific Committee on Food on Bisphenol A," published May 3, 2002, the following paragraph sums up the current position that there is no known risk.
"BPA is widely used as a monomer for polycarbonate plastics. Polycarbonates are used to make baby feeding bottles, water bottles, jugs, beakers and microwave ovenware. Many migration studies have been conducted worldwide. There is no significant effect from repeated-use, abrasion, heating, or chemical sterilisation of these plastic articles. The general findings are that migration is low or not detectable, typically in the range <10 to 20 Âµg/kg for water, fruit juices and infant formulae. In tests using simulants, the migration of BPA can be higher than into foodstuffs. In a European-wide survey, migration from bottles into food simulants was not detectable at <3 Âµg/kg. Applying aggressive extraction conditions using 95% ethanol with shaking at 60ÂºC for 24 hours, the migration was generally not detectable (<10 Âµg/kg) and only a few of the 163 bottles tested released BPA at over 20 Âµg/kg; the highest release was 110 Âµg/kg. However these extraction conditions are considered unrepresentative of actual use, since no migration was detected when simulants representative of the normal bottle contents (water or 3% acetic acid) were used. Taking a more realistic worst-case migration level of 10 Âµg/kg and the highest ratio of food intake to body weight for infants (a 4.5 kg infant consuming 0.7 litre of formula each day), an intake of 1.6 Âµg/kg bw/day can be estimated. A number of studies on polycarbonate tableware and food storage containers have shown some migration up to 5 Âµg/kg into food simulants, but no detectable migration into actual foods or beverages."
"Âµg" is a scientific term that means a mass of one microgram â€“ that's really really small.
To read the complete report, click here
The European Commission is widely considered to be very conservative and more restrictive than most when it comes to concerns about health and safety, so its findings are often cited as reliable and often considered a gold standard.
Nalge Nunc International, makers of Nalgene water bottles, issued the following in a statement released Nov. 11, "â€¦many of the stories regarding the Hunt study contain speculation on health effects that reach far beyond the actual findings of the study. Contrary to what has been reported about the results of the Hunt Study, the weight of scientific evidence shows there is no basis for health concerns from exposure to low levels of BPA."
SNEWSÂ® contacted Joan Hamilton, editor-in-chief of Sierra magazine, who told us that the magazine stands by its story and has seen no scientific data yet that would make the editors believe the story needs updating or correcting.
SNEWSÂ® View: Clearly this is a controversial issue with numerous scientific studies and data from both sides of the spectrum each supporting ardent beliefs of safety or risk. Knowing that, and with all due respect to Joan Hamilton, we would expect MUCH better reporting from a magazine of Sierra's reputation. Only two scientists are quoted, one with a known anti-plastics bias and the other one citing a study that dealt only with animal cages and water bottles, not food-grade polycarbonate. Didn't Sierra think to look at other studies to present more balanced findings? Trying to make the leap to correlate test results found with plastics used in animal cages and animal water bottles to those used for food-grade packaging is scientifically invalid, according to the scientists with whom we spoke.Â As Dr. Hunt toldÂ us, it is notÂ appropriate toÂ reach a conclusion about sport bottle safety based on her study. It didn't take SNEWSÂ® much time at all to uncover numerous international papers all dealing with food-grade plastics testing. The fact is, the studies that have specifically tested food-grade plastics, including polycarbonate (Lexan), in Europe, Japan, and the United States, have been unable to establish any evidence of sufficient risks to human health including carcinogenic, prenatal, or reproductive systems to warrant any kind of warning. In paging through all the reams of paper (thank goodness SNEWSÂ® staffers have degrees in biology and kinesiology, and can read this stuff) there is one underlying message throughout: More study is needed to determine if even the POTENTIAL of risk to the human reproductive system exists. So far what we do know is that high heat and detergents with high alkalinity (conditions you would find in a dishwasher for example) as well as cleaning with bleach can accelerate the deterioration of polycarbonate. And since GSI has, in order to address a spider cracking issue in wine and other plastic glasses, been advising consumers to hand wash and use mild detergent only, SNEWSÂ® would still feel it prudent to begin advising consumers to do the same for all polycarbonate bottles and food containers -- hand wash, mild detergent. If for no other reason than to extend the life of what thus far has proven to be a fantastic, taste-free, durable product. As a final aside, help your customers to understand too that plastic is not forever. It does break down and does need to be replaced over time. If Lexan bottles start to appear cloudy, or if spider cracking starts to appear in Lexan containers, it's time to toss them into the recycling bin and buy new ones.
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