A study headed by researchers at the University of Granada (UGR) in Spain found that the vast majority of thermal paper-type shop receipts tested in Spain and Brazil and half of a sample of French receipts contained BPA Bisphenol A (BPA), a mass-produced chemical that has well-recognized endocrine-disrupting properties.

The researchers warn that tickets should not get in contact with food—for example, meat or fish—while unpacking it in the kitchen. [University of Granada]
The researchers, reporting in Environmental Research, say most of the samples tested also demonstrated estrogenic and anti-androgenic activity. They are urging consumers to be careful how they handle this type of receipt, which can easily be recognized because it turns black when placed near a heat source such as a lighted match. “For example, tickets should not get in contact with food—for instance, meat or fish—while unpacking it in the kitchen,” commented research lead Nicolás Olea, professor of medicine at UGR. “Moreover, we should not crumple the tickets to throw them in the trash, play with them, write notes on them, or store them in cars, purses, or handbags. In short, we should manipulate these kind of tickets as little as possible.”


Olea and colleagues noted that while governments and regulators are mandating less use of BPA, one alternative, bisphenol S (BPS), which they found in some of the French receipts tested, is also an endocrine disruptor. “What’s bad about the French alternative is that it seems to use BPS, since we have found it mostly in samples from that country and seldom have we found it in Brazilian or Spanish samples,” Olea suggested. “Unfortunately, BPS is also an endocrine disruptor, and its environmental persistence is greater than that of BPA, so it’s not a valid option.”

The researchers reported their findings in a paper titled, “Determination of bisphenol A and bisphenol S concentrations and assessment of estrogen- and anti-androgen-like activities in thermal paper receipts from Brazil, France, and Spain.” Co-authors alongside the UGR team included researchers at Instituto de Investigación Biosanitaria research institute (ibs.Granada), the Hospital Universitario San Cecilio (Granada), the National School of Public Health (Rio de Janeiro, Brazil), the Université Paris Descartes, and the Hôpital Necker Enfants Malades (Paris, France).

BPA is a high-production volume chemical that is commonly used as a color developer in thermal paper, but which studies have linked with a wide range of adverse health outcomes in humans and animals, the authors wrote. The chemical is an endocrine disruptor that binds to the nuclear estrogen receptor and can modify oestrogen-controlled gene expression. It has also been found to induce anti-androgenic activity, and alter the expression of steroidogenic enzymes, as well as modify a range of signaling pathways. BPA has been associated with hormone-related disorders including genitourinary malformation, infertility, obesity, and cancers, such as breast cancer, in hormone-dependent organs. The chemical is a key component in the production of plastics and is used to produce epoxy resins that coat the insides of food and drink cans. As a result, our exposure to BPA is mostly dietary, but its use as a color developer in thermal paper that is used for cash register and credit card receipts, for example, is also of increasing concern, the team noted.

The potential health risks associated with exposure to BPA have resulted in regulatory restrictions on its use, and the industry has turned to alternatives including BPS and bisphenol F (BPF). BPS is the most commonly used alternative to BPA that is used in thermal paper, but tests have shown that BPS also bind to the estrogen receptor and elicits estrogen-induced gene transcription, as well as affecting androgen production. BPF similarly has estrogenic and anti-estrogen effects similar to those of BPA, although the chemical is not commonly used as an alternative to BPA in thermal paper. Nevertheless, as the authors commented, “ … it is suspected that these alternatives may have similar toxicological properties to those of BPA.”

Olea and colleagues set out to evaluate the concentrations and hormonal activity of BPA, BPS, and BPF in extracts from 112 thermal paper receipts collected in 2017 in Brazil, Spain, and France. The tickets included bank card receipts and public transport tickets, as well as receipts from different stores, restaurants, and gas stations. This type of thermal paper receipt is easily identified by customers, Olea noted, “… since they are those receipts that, after some time, lose what they have printed on them and, when you are going to return the trousers you bought, the cashiers tell you that they cannot see anything. Very often, the only thing you find is a fine white powder that comes off when taking them out of the handbag or purse. BPA is, precisely, that white powder that sticks to your fingers.”

The team’s analyses found that BPA was present in 95.3% of receipts from Spain, 90.9% of those from Brazil, and 51.1% of those from France. The finding that only half the French receipts contained BPA may reflect the French government’s drive to reduce the use of the chemical in thermal paper since 2014, the authors noted. Even so, many of the French samples still displayed endocrine-disrupting activity. “Estrogenic activity was observed in all samples from Brazil and Spain and in 74.5% of those from France,” they reported. Anti-androgenic activity was observed in >90% of samples from Brazil and Spain and in 53.2% of those from France.” Just 25.5% of the French samples were negative for both estrogenic and anti-androgenic activity.

The researchers noted with concern that the BPA levels measured in the study were up to 30–100 times higher than the recommended levels set by the European Commission from January 2020. “These are worrying findings, given the potential health risks that may be posed by long-term and low-level exposure to BPA, especially for pregnant women and children.” And with the EU estimating that 30% of thermal paper used in point-of-sale receipts in Europe is recycled to produce other paper products, its no surprise that BPA and/or BPS have been detected in a wide range of recycled materials ranging from toilet paper and napkins to food-packaging materials.

The overall results suggested that the estrogenic and antiandrogenic activities of thermal paper receipts were influenced by their BPA content, the team concluded. “… however, we cannot rule out the presence of other hormonally active compounds in the thermal paper extracts … Further studies are needed to better characterize the contribution of thermal paper to human exposure to bisphenols and to assess the safety of the proposed alternatives to BPA as a developer in thermal printing.”

The team is, in addition, calling into question the safety of BPA alternatives. “There is an urgent need to evaluate the safety of alternatives proposed to replace BPA as developer in thermal printing,” they wrote. “The large proportion of samples with hormonal activity calls for the adoption of preventive measures.”

“It’s another evidence that something is failing in toxicity controls for chemical compounds in our environment,” Olea stated. “It seems like regulatory policies are established a posteriori, when human exposure is evident. In fact, the protection of hundreds of thousands of young people working as cashiers in supermarkets and other stores is not as strictly implemented as it should.”

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