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Speculation in the guise of science was again recently featured in the pages of Environmental Health Perspectives, where Andrea Schwartz and Philip Landrigan (researchers at the Mount Sinai School of Medicine in New York) and Julia Taylor, Frederick vom Saal and others at the University of Missouri, published letters that expand on an earlier study by Taylor.

Taylor et al.’s initial study had discussed human exposure to BPA. In their letter, Schwartz and Landrigan endorse and discuss Taylor’s paper – then go even further, claiming that a potentially important non-food source of exposure to BPA may be the thermal paper used in cash register receipts. Despite these alarming claims, Schwartz and Landrigan provide no new data in support of this speculation.

Then, in their own letter, Taylor and her colleagues dismiss out of hand the detailed safety assessments conducted by expert committees of the world’s most scientifically respected advisory groups and regulatory agencies (European Food Safety Authority, U.S. Food and Drug Administration, the German Society of Toxicology, and others) that establish a safe dose level for BPA, and find current exposure levels from all sources are well below the safety level, indicating no reason for concern.

These latest letters may be from scientists, but their publication continues a concerted effort by activists to claim health effects from thermal paper using BPA technology.

However, there is no evidence of any potential threat to anyone who uses thermal paper, even those workers, such as cashiers, who are exposed to the paper over long periods of time.

The American Chemical Society (ACS) inexplicably launched a podcast last week suggesting that handling of paper products, including thermal receipts, may pose a risk of harmful health effects. The podcast reports that “bisphenol A (BPA) – a substance that may have harmful health effects –occurs in 94 percent of thermal cash register receipts” and that “handling of paper products can contribute up to 2 percent of the total daily BPA exposure in the general population.” However, the study itself (Liao & Kannan, Widespread Occurrence of Bisphenol A in Paper and Paper Products: Implications for Human Exposure, Environ. Sci. Technol. 45:9372-79, 2011) characterizes these values as “minor” compared to exposure through diet.

Further, the study notes that estimated daily intake (EDI) values calculated for BPA from paper products were “several orders of magnitude” lower than the oral Reference Dose (RfD) or the Tolerable Daily Intake (TDI) value of 50 micrograms per kilogram body weight per day established by the U.S. Environmental Protection Agency and the European Food Safety Authority. Both the RfD and TDI have similar definitions – the amount of a substance that can be taken in daily over a lifetime without appreciable health risk. Because median EDI values from thermal paper receipts, even from occupational exposure (worst case), were in fact over 1500 times lower than the RfD and TDI, the findings of the paper do not support the insinuations of the podcast of health risk from BPA in thermal paper.

In short, ACS should have done more research on thermal paper – a product with a long history of proven safety – before launching its podcast.

A recent investigation of the safety of thermal paper receipts containing bisphenol A by the Danish Environmental Protection Agency concluded that these products are safe for consumers.

According to the Danish agency, “the receipts do not pose a risk to consumers or cashiers who handle the receipts. Even if they are pregnant, and even when taking into account the amount of bisphenol A that also comes from food.”

However, the Danish report’s claim that receipts are a “significant source” of exposure is contradicted by two previous studies that note that receipts are at most a secondary source of exposure, with food the main source of exposure. Indeed, the Danish EPA report indicates that its exposure estimates are based on “worst case” estimates and “the actual exposure of the general consumer in most cases will be considerably lower.” Nonetheless, the Danish report demonstrates the safety of the products even based on worst case exposure estimates.

A link to the Danish EPA study is available here.

Links to the two previous reports showing receipts are secondary sources of exposure:

http://www.xerr.uzh.ch/news/bisphenol01.html

 

The Environmental Health Research Foundation recently released an update on BPA, highlighting the fact that US agencies responsible for protecting human health – after numerous updates and multiple reviews of the science during both Democrat and Republican administrations – regard BPA as a negligible risk.

Joshua Sharfstein, then Deputy Commissioner of US Food and Drug Administration, in a 2010 press conference said, “If we thought it [BPA] was unsafe, we would be taking strong regulatory action.”  In addition a recent paper analyzed the risk associated with potential dermal absorption of BPA.  The data indicate that skin exposure to BPA does not pose any special risk to human health.  The low levels that people are exposed to –whether through their skin, through their food, or both combined – do not raise concerns for human health.

Furthermore, the Foundation’s update reports on Coca-Cola’s recent decision to continue the use of BPA in their can linings.  Muhtar Kent, chairman and chief executive officer of The Coca-Cola Company, assured shareholders at the company annual meeting, “If we had any sliver of doubt about the safety of our packaging, we would not continue to use [BPA]”.  The Coke website continues,

“In the past couple of years, BPA has become controversial, even though reliable scientific evidence repeatedly reviewed by regulatory authorities indicates that the levels of BPA associated with can linings are safe.  While we are very aware of the highly publicized concerns and viewpoints that have been expressed about BPA, our point of view is that the scientific consensus on this issue is most accurately reflected in the opinions expressed by those regulatory agencies whose missions and responsibilities are to protect the public’s health.”

The Coke shareholders agreed that regulatory authorities – experts in science, toxicology, and health – know best and 75% voted to continue to use BPA.  Food accounts for roughly 95% of human exposure to BPA.   The tiny amount of BPA that could result handling thermal paper is much smaller than levels people are exposed to from food packaging – and those levels have been deemed safe by the US FDA, the US EPA, and the European Food Safety Administration (EFSA).

The publication also notes the growing chorus of pro-science critics of coverage of BPA in the media.   Several science writers including, Jon Entine and Trevor Butterworth, have noted the importance of properly evaluating the scientific robustness of large studies compared to small studies that lack statistical power and/or studies that cannot be replicated.  Their comments echo the results of a review by the independent German Society of Toxicology.  Their analysis of over 5000 studies points out a number of flaws in small-scale exploratory studies and concludes that BPA at current exposure levels does not pose a risk to human health.

So what does all this information about BPA mean for thermal paper?  In short, it means that BPA in thermal paper does not raise concern for human health.   Exposure to BPA from thermal paper is very low – much lower than exposure from our food – and even when combined, those levels fall far below the levels that could trigger concern, according to the world’s leading health authorities.  The US FDA, the US EPA and EFSA all agree that the low levels of BPA that people are exposed to pose no risk to human health.

A new scientific study adds to the large and growing body of evidence that BPA in thermal paper does not pose any concern for human health.

The study by Mielke and colleagues models how BPA gets processed in the body, how efficiently it is metabolized, and the internal dose that is experienced by various organs (the pharmacokinetics) of ingested and dermally absorbed BPA.   They show that neither BPA absorbed through the skin nor ingested BPA presents a risk to human health.

For their model, Mielke et al., use the worst case scenario of a person with their hands and entire forearms in contact with thermal paper for 8 hours, without washing.  Their model indicates that the maximum concentration of BPA that could get into the body is 700 times lower than the concentration that may pose concern for the liver – the organ that is most sensitive to the effects of BPA.  Furthermore, the authors model the combined effects of dermal absorption and oral intake; their model predicts that even when combined, the two sources of exposure will not reach the levels that would trigger concern for human health.

Recent articles have been sounding the alarm with assertions that US citizens have two times more BPA in their urine than Canadians.  In an article that compared the national studies, the author cited a number of possible differences between Americans and Canadians that she believed could account for the difference.   One factor mentioned was thermal paper.  However, thermal paper is unlikely to play a role in the differences observed between Americans and Canadians.

Could thermal paper account for the difference?

First, there is no indication that the use of thermal paper is substantially different in the US and Canada.  BPA has been used in thermal paper since the 1960’s, though it came into more common use in the 1990s – so it is not a new phenomenon that has occurred exclusively in the US.

Second, health agencies in the US, Europe, Canada and the World Health Organization have determined that most of BPA exposure is from food sources; therefore BPA in thermal paper could not possibly result in doubling exposures.  In fact, absorption through the skin is thought to account for only 1 percent of total BPA exposure.

Additionally, studies have demonstrated that the small amount of BPA that is absorbed through the skin is rapidly metabolized, similar to its metabolism for oral doses.  So, dermal exposure poses no greater health concern nor results extended exposures.

What may account for the difference between Americans and Canadians

The Canadian Health Measures Survey (CHMS) and the US National Health and Nutrition Examination Survey (NHANES) have different methods for tracking and controlling for fasting, last urinary void, and the time of day of specimen collection.  Since exposure to BPA is almost exclusively from food and BPA is rapidly excreted in the urine, differences in the methodology to account for these factors is likely to skew the data and make the variation between US and Canada seem more extreme.

In addition, the timeframe of the studies was different.  US NHANES data was collected in 2003-2004.  The Canadian Health Measures Survey data was collected in 2007-2009.  The use of reusable polycarbonate water bottles declined over this period and could account for the lower levels of BPA in the later study.

What does this difference mean?

Even if you take the differences at face value, the difference is between 1.4 µg BPA/g creatinine (1.16µg/L urine) in Canadians to 2.6 µg/g creatinine (2.6µg/L urine) in Americans [a microgram (µg) is 0.000001g].  This different is incredibly small.

For comparison, the United States and Europe have adopted the standard that consumption of 50 µg/kg body weight/day is safe.  That’s 300ug/day for someone who weighs 132 pounds and regulators have built in margins of safety to this figure.

A good effort putting this data into perspective can be found at the Huffington Post.

A new study by researchers at the Institut National de Recherche et de Se´curite´ in France (Marquet et al., Arch Toxicol2011) confirms that thermal paper receipts do not pose a safety risk to workers.

The paper supports the conclusion of previous research by Biedermann et al., which found that even “worst case” exposures to thermal paper receipts – exposures by cashiers to the material for 10 hours or more a day – are lower than international safety estimates (Total Dietary Intake, or TDI) for high exposures.

According to the new study, maximal exposure to BPA from one hour of exposure to the entire hands and forearms would be 4 µg/kg/day, or 12.5-fold lower than the daily safe exposure level (TDI) of 50 µg/kg/day.

Since exposure to thermal paper is unlikely to include so much surface area (hand and forearms)the conclusion indicates that normal handling of thermal paper is indeed quite safe for consumers and workers.

The paper further corrects a concern expressed in the Biedermannpaper that moisture or greasy conditions on the skin could increase the rate of BPA dermal penetration.  According to Marquet et al., their results indicated no significant differences in the presence or absence of occlusion, which would be expected to increase moisture on the skin.

For further information:

Marquet at al.:http://www.springerlink.com/content/t779340680t016t8/
Biederman et al.:http://www.springerlink.com/content/d5j507113141120h

There is no evidence that thermal paper containing BPA poses any health or safety risk to the public or to workers who handle it on a frequent basis, according to the most recent review of all relevant studies by the nonprofit Environmental Health Research Foundation.  Specifically, the Foundation “found no evidence to suggest adverse health effects from the small amounts of BPA that may migrate from thermal paper to human skin.”   It also found no evidence to support commercial advertising claims suggesting that the use of “BPA-free” thermal paper presents any health or safety benefit to cashiers or other workers handling such paper.   The fully documented report can be found here.

 

Thermal paper is not a significant source of BPA, according to an international panel of experts convened by the World Health Organization, which announced that food is “by far the main source of BPA exposure and other sources are of minor relevance.” It also noted that BPA “is not accumulated in the body and is rapidly eliminated through urine.”