Tony Lambert delphine1939@videotron.ca
2 février 2008-02-02
Heating Plastic Bottles Releases Potentially Harmful Chemical
U.S. NEWS & WORLD REPORT
Saturday, February 2, 2008
http://health.usnews.com/usnews/health/healthday/080130/heating-plastic-bottles-releases-potentially-harmful-chemical.htm
_____________________________________________
Study found exposure to boiling water released environmental estrogen 55 times faster
By Amanda Gardner
Posted 1/30/08
WEDNESDAY, Jan. 30 (HealthDay News) -- Exposing plastic bottles to boiling water can release a potentially harmful chemical 55 times faster than normal, new research suggests.
Bisphenol A (BPA) is found in the plastics that make up water bottles, baby bottles, and otherfood and drink packaging. It acts as an environmental estrogen and can disrupt the function of the endocrine system.
In 2007, an expert panel convened by the U.S. Center for the Evaluation of Risks to Human
Reproduction (CERHR) concluded that exposure to BPA presents some risk to development and reproduction, although it's unclear at what level that harm begins to occur.
"There isn't a real answer," said study senior author Scott Belcher, an associate professor of pharmacology at the University of Cincinnati. "There seems to be a current difference of opinion between the scientific research field and the folks doing risk assessment. If you were to sum it up in an easy, relatively conservative way, the scientific data points to some reason for caution at low concentrations. There really isn't much information regarding the effects on human populations directly." Belcher's findings appear in the Jan. 30 issue of the journal Toxicology Letters. (see below abstract)
Animal experiments have suggested that BPA may mimic the female sex hormone estradiol.
The fear has been that exposure to BPA can cause birth defects and developmental problems.
In addition, exposure to BPA has been blamed for a variety of other problems, including cancer, diabetes, obesity and attention-deficit disorder.
Exposure to BPA can occur through direct contact or by exposure to food or drink that has been in contact with material containing BPA.
Previous studies had found that repeatedly scrubbing, washing and boiling polycarbonate baby bottles could cause them to release BPA.
"It was migrating from the bottle into the water," Belcher explained.
This latest study tried to assess the effect from "normal" use, looking at both "old" polycarbonate water bottles from a local climbing gym as well as new bottles of the same brand.
The age of the bottle made no difference in the amount of BPA released.
However, if the bottles were briefly exposed to boiling water, they released BPA 55 times more rapidly than before being dunked in the hot water, the study said.
"There's nothing new in this paper," said Steven Hentges, executive director of the polycarbonate business unit of the American Plastics Council. "Migration has been studied many times before. In a sense, this is good news because it confirms what we already know."
Kirby Donnelly, department head of environmental and occupational health at the Texas A&M School of Rural Public Health, said the new finding was "not surprising" because it is a basic principle of chemistry that if a solvent is heated up, it will form a liquid solution.
"With BPA there are such contradictions as to whether it is toxic or nontoxic; a lot of times, it comes down to dose and duration," he added.
What does this mean to the average consumer?
According to Belcher, dishwashing temperatures might be OK but he stressed that even without the boiling water, such bottles do release small amounts of BPA. For his part, Belcher avoids polycarbonate plastic. "That's been my personal choice," he said.
More information
Abstract
19 November 2007.
Abstract
The impact of endocrine disrupting chemical (EDC) exposure on human health is receiving increasingly focused attention. The prototypical EDC bisphenol A (BPA) is an estrogenic high-production chemical used primarily as a monomer for the production of polycarbonate and epoxy resins. It is now well established that there is ubiquitous human exposure to BPA. In the general population, exposure to BPA occurs mainly by consumption of contaminated foods and beverages that have contacted epoxy resins or polycarbonate plastics. To test the hypothesis that bioactive BPA was released from polycarbonate bottles used for consumption of water and other beverages, we evaluated whether BPA migrated into water stored in new or used high-quality polycarbonate bottles used by consumers. Using a sensitive and quantitative competitive enzyme-linked immunosorbent assay, BPA was found to migrate from polycarbonate water bottles at rates ranging from 0.20 ng/hto 0.79 ng/h. At room temperature the migration of BPA was independent of whether or not the bottle had been previously used. Exposure to boiling water (100 °C) increased the rate of BPA migration by up to 55-fold. The estrogenic bioactivity of the BPA-like immunoreactivity released into the water samples was confirmed using an in vitro assay of rapid estrogen signaling and neurotoxicity in developing cerebellar neurons. The amounts of BPA found to migrate from polycarbonate drinking bottles should be considered as a contributing source to the total "EDC-burden" to which some individuals are exposed.
Keywords: BPA Endocrine disruption; Estrogen; Neurotoxicity; Non-genomic Abbreviations: BPA, 2,2-bis (4-hydroxyphenyl) propane; EDC, endocrine disrupting chemical; ELISA, enzyme-linked immunosorbent assay; HDPE, high-density polyethylene; HPLC, high-performance liquid chromatography; LDH, lactate dehydrogenase; PC, polycarbonate these studies were supported by NIH grant R01-ES015145 awarded to SMB; Emily Carlson, and Jason Chua were fellows of the University of Cincinnati College of Medicine's Summer Undergraduate esearch Program. The study sponsors had no involvement in the design of this study, the collection, analysis or interpretation of data, the writing of this report, nor the decision to submit this manuscript for publication.
Corresponding author at: Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, 231 Albert Sabin Way, PO Box 670575, Cincinnati, OH 45267-0575, United States. Tel.: +1 513 558 1721; fax: +1 513 558 4329.
Toxicology Letters
Volume 176, Issue 2, 30 January 2008, Pages 149-156
