Evaluating the efficiency of the 2020 ban of BPA and BPS in thermal papers in Switzerland

Thermal printing technology requires a color developer to activate the dye under the action of heat. Bisphenol A (BPA) has traditionally been used for this purpose, although it has increasingly been replaced by bisphenol S (BPS) in recent years. Due to concerns regarding their toxicity, the Swiss authorities have banned both BPA and BPS from thermal papers since 2020. The impact of this regulatory decision was evaluated during 3 monitoring campaigns: in 2013-2014, 2019 and 2021. They were used to describe the starting point, the transition phase, and the status after entry into force of the ban, respectively. Whereas the use of BPA as color developer dropped from 82.2% in 2013/14 to 10.8% in 2021, the fraction of BPS-based thermal paper rose from 3.1% to 19.1% during the same period, despite being banned. However, Pergafast® 201 (PF201) is now the main color developer in thermal paper in Switzerland, with an occurrence of 60.3%. Other alternatives such as D-8, TGSA, PPSMU, NKK-1304, BPS-MAE, D-90 and Blue4est® have only been marginally detected. This study demonstrates the efficiency of the regulatory measure and the feasibility to substitute BPA in thermal papers with less-toxic alternatives.

market assessed by Fourier transform infrared spectroscopy

Cash register receipts made of thermal paper expose workers and shoppers to endocrine-disrupting chemicals and contaminate paper recycling streams. In 2022, 571 receipts were collected from retail stores in the United States and tested for developer chemicals using attenuated total reflection infrared spectroscopy. The results were compared to a 2017 study of 167 receipts to determine changes in color developer use over time. Receipts were tested as-is and a subset were additionally subjected to a simple extraction that improved detection of receipt chemicals. Bisphenol S was the most frequently detected developer (85% of tested receipts), followed by Pergafast 201 (12%), bisphenol A (1%); and Appvion Alpha Free, D-8, and NKK-1304 (each below 1%). NKK-1304 is reported here for the first time in a scientific journal. The frequency of bisphenol A usage in receipts decreased and the frequency of bisphenol S and Pergafast 201 increased between 2017 and 2022, particularly among large companies. National retailers were more likely than regional or local retailers to have adopted non-bisphenol alternatives. Potential health and environmental hazards of the detected developer chemicals and strategies for reduction are discussed.

Screening bisphenols in complex samples via a planar Arxula adeninivorans bioluminescence bioassay

The Arxula yeast bisphenol screen (A-YBS) utilizes the bioluminescent Arxula adeninivorans yeast-based reporter cells for tailored analysis of bisphenols, one of the major endocrine-disrupting compound groups. For the first time, this bioreporter has been applied on the high-performance thin-layer chromatography (HPTLC) adsorbent surface to develop a respective planar bioluminescence bioassay (pA-YBS). The goal was to combine the advantages of HPTLC with a more selective bioassay detection for bisphenols. The performance of this pA-YBS bioluminescence bioassay was demonstrated by calculating the half-maximal effective concentration (EC50) of bisphenols compared to references. The EC50 ranged from 267 pg/band for bisphenol Z and 322 pg/band for bisphenol A (BPA) to > 1 ng/band for other bisphenols (BPC, BPE, BPF, and BPS) and references (17β-estradiol and 17α-ethinylestradiol). The EC50 value of BPA was three times more sensitive in signal detection than that of 17β-estradiol. The visual or videodensitometric limit of detection of BPA was about 200 pg/zone. The higher signal intensity and sensitivity for BPA confirmed the tailored bioassay selectivity compared to the existing estrogen screen bioassay. It worked on different types of HPTLC silica gel plates. This HPTLC-UV/Vis/FLD-pA-YBS bioluminescence bioassay method was used to analyze complex mixtures such as six tin can migrates, five thermal papers, and eleven botanicals. The detected estrogenic compound zones in the tin can migrates were successfully verified via the duplex planar yeast antagonist estrogen screen (pYAES) bioassay. The two bisphenols A and S were identified in one out of five thermal papers and confirmed with high-resolution mass spectrometry. No bisphenols were detected in the botanicals investigated via the pA-YBS bioluminescence bioassay. However, the botanicals proved to contain phytoestrogens as detected via the pYAES bioassay, which confirmed the tailored bioassay selectivity. This HPTLC-UV/Vis/FLD-pA-YBS bioluminescence bioassay is suited for cost-efficient analysis of BPA in complex samples, with no need for sterile conditions due to the fast workflow.

Evaluation of an inkless method for fingerprint recordings using hand sanitizer gel on thermal paper (Part II): Effect of time, temperature, and biological sex

This article further investigates the suitability of an inkless method to obtain and maintain exemplar fingerprint recordings on thermal paper; in this case, stored for 1.5 years at different temperatures. Inkless impressions were (re-)examined by optical means via two independent methods. First, an automated metric from the FBI's Universal Latent Workstation (ULW) was adapted (i.e., BlueGreen color-coded maps) to evaluate visual differences among inkless fingerprint sets with respect to storage time, temperature, relative humidity, and biological sex. Additionally, a conventional assessment system was applied, a categorical quality score (QS) metric that ranges on a grading scale from 1 to 4. Results revealed that storage time (72 weeks), as well as a colder temperature (~ 3 ºC) and lower relative humidity (~ 12 %), had little impact on the preservation of ridge clarity when compared to freshly deposited counterparts. A biological sex effect was again detected, but its influence was not significant under certain conditions. Despite minor visual differences, the ridge clarity of the inkless impressions remained stable for the duration of the experiment. The stability and durability of the proposed inkless method were proven, becoming a potential alternative to the conventional black ink method.

Thermal paper as a potential source of bisphenol A for humans and the environment: migration and ecotoxicological impact

The objective of this work was to evaluate thermal paper (TP) tickets used in Argentina as a potential source of bisphenol A (BPA) that could impact humans and the environment. BPA in TP was measured by HPLC ranging from 11.1 to 30.5 mg BPAg^-1. In order to estimate the impact on humans, dermal BPA estimated daily intake was calculated as being 79.3 ± 19.5 μgd^-1 for workers and 1.6 ± 0.4 μgd^-1 for the general population. To evaluate TP's impact on the environment, BPA migration from TP to water and soil was studied. In the case of water, 99.6% of the BPA tickets content migrated in 30 h, while 78.0% moved into the soil in 96 h. BPA degradation kinetics in soil and water were also carried out; while in soil 61.9% of BPA degraded in 120 h, no degradation was observed up to 120 h in tap or river water.Additionally, ecotoxicological effects of BPA on the earthworm Eisenia andrei, a representative terrestrial indicator, were studied performing bioassays on lethality, avoidance, and reproductive and enzymatic activity. BPA showed to be very toxic to E. andrei (LC₅₀ value in contact paper test of 17 μgcm^-2, 95% confidence interval 6-46 μgcm^-2, 24 h exposure) and also caused an increase of total cocoons for earthworms exposed to 10 and 50 mg BPA kg^-1 soil. Evasion response was observed at a concentration of 50 mg BPA kg^-1 soil, while no effect was observed on cholinesterases, carboxylesterases, and glutathione S-transferases activities (1, 10, and 50 mg BPA kg^-1 soil). Finally, a simple BPA degradation technology using water peroxide and radish (Raphanus sativus) tissue as catalyst was explored as a simple and domestic potential treatment to avoid BPA migration to the environment.

Supramolecular solvent-based microextraction probe for fast detection of bisphenols by ambient mass spectrometry

In this study, we investigated for the first time the suitability of supramolecular solvent (SUPRAS)-based microextraction probe for the development of generic and fast sample treatment prior to qualitative analysis by ambient mass spectrometry (AMS) based on ASAP (atmospheric solids analysis probe). SUPRAS are nanostructured liquids formed by the self-assembly of amphiphilic aggregates with multiple binding sites and microenvironments of different polarity for the efficient extraction of multiple compounds. Different types of SUPRAS were evaluated as a simple and single step sample treatment for ASAP. The method was applied to the screening of bisphenol A and structural analogues in thermal paper. Optimal results were achieved with SUPRAS synthesized with 1-decanol in mixtures of ethanol:water. SUPRAS (1.1-2 μL) were loaded onto glass probes and placed in contact with samples for 10 s before ASAP analysis. AMS signal peaks (width: 0.2-0.5 min) were easily integrated and normalized with internal standards (RSD: 2-25%). The method was applied to 62 samples of thermal paper. BPA and BPS were the most widely used, this highlighting the progressive industrial replacement of BPA by BPS.

Bisphenol A and its alternatives in Austrian thermal paper receipts, and the migration from reusable plastic drinking bottles into water and artificial saliva using UHPLC-MS/MS

Bisphenol A (BPA) a synthetic, high production volume chemical identified as endocrine disruptor and toxic to reproduction is mainly used in the production of polycarbonate plastics, in epoxy resins, polyvinylchloride, thermal papers as color developer, and is present in a wide range of consumer goods such as food packaging materials, storage containers, and cash receipts. Due to its effects on health and legal restrictions, BPA is increasingly replaced by other bisphenols. In this study, BPA and 13 alternatives including BPS, Bisphenol F (BPF), Bisphenol B (BPB), Bisphenol C (BPC), Bisphenol Z (BPZ), Bisphenol M (BPM), Bisphenol P (BPP), Bisphenol AF (BPAF), Bisphenol FL (BPFL), Bisphenol C12 (BPC12), Tetramethylbisphenol A (tmBPA), 4,4-bisphenol (BP-4,4), and p,p-oxybisphenol were analyzed in thermal paper cash receipts (content) and migration studies were carried out in BPA-free labelled reusable plastic drinking bottles using a sensitive UHPLC-MS/MS method. The receipts contained almost only BPA and BPS, whereas BPS was found in all samples ranging at levels up to 38 μg/g. BPA was detected at low concentrations, only in one sample 11,000 μg/g were found, exceeding the EU limit of BPA in thermal paper of 0.02% per weight. In leaching solutions from the drinking bottles BPA, BPS and BPF were found at concentrations up to 0.047 μg/L BPA, 0.043 μg/L BPS, and <0.01 μg/L BPF. No other analogues were detected. However, these levels identified are far below the legal limits. In addition, a theoretical exposure assessment was conducted indicating that exposures were within the current regulatory guidelines.

Forensic examination of thermal papers using Video Spectral Comparator (VSC) and ATR-FTIR spectroscopy coupled with chemometrics: Non-destructive approach

Thermal papers are replacing the conventional form of printing and are being extensively used across the globe. This study encompasses a non-destructive approach to examine thermal papers by using ATR-FTIR spectroscopy and Video Spectral Comparator (VSC), where the former technique helps in characterizing and discriminating different samples and the latter helps in deciphering the faded prints on thermal paper. The qualitative analysis of the spectroscopic data based on peak to peak comparison and quantitative analysis using chemometrics has been done to obtain high discriminating power. Multivariate analysis using HCA gave a discriminating power of 83.82% and PCA showed a variance of 95.64%. The strength of the study is portrayed through the decipherment of artificially and naturally faded thermal papers using VSC and analyzing the effect of different storing conditions on their rate of fading.

A fast and direct determination of bisphenol S in thermal paper samples using paper spray ionization mass spectrometry

Concerns about human health regarding the large use of bisphenol A in thermal papers have led to its replacement by bisphenol S. Analyses of bisphenols require several sample pretreatment steps, which are laborious, expensive, and time-consuming. A paper spray ionization mass spectrometry (PSI-MS) was developed to detect and quantify bisphenol S in three different brands of thermal papers commercially available. Parameters such as paper size, and paper position relative to the mass spectrometer inlet were evaluated. The analyses were performed in selected ion monitoring mode on a linear ion trap mass spectrometer. The developed method presented absolute recovery values ranging from 92.2 to 109.04%, accuracy values from -1.2 to 9.0%, and inter assay precision from 1.8 to 5.6% and enabled LOD as low as 5 ng g^-1. The concentration of bisphenol S in all of the three brands of BPA-free thermal papers evaluated ranged from 1.36 to 6.77 μg g^-1, and the concentrarion of BPA ranged from 6.56 to 16.4 μg g^-1 in all samples of thermal paper evaluated. The PSI-MS method described here was comparable to the conventional ones, such as liquid chromatography coupled with mass spectrometry and gas chromatography coupled with mass spectrometry described in the literature. The present study proved to be practical, fast, and efficient for the direct determination of bisphenol S in thermal papers. Furthermore, the methodology here described showed to be a promising alternative to replace the classical methods for determination of bisphenol S, due to its simplicity, and no needing of any sample pretreatment.

Evaluation of an inkless method for fingerprint recordings using hand sanitizer gel on thermal paper

The main objective of this project was to assess an inkless method to collect reference (exemplar) fingerprints as a low-cost, portable, and hygienic technique; for temporary storage and as an alternative to the conventional black ink method. The tested inkless approach requires alcohol-based hand sanitizer gel as the medium and thermal paper as the substrate. The final quality and clarity of fingerprints were examined and compared between the two methods, especially on the basis of medium/substrate and biological sex effects. Two different evaluation systems of visual quality (clarity) were conducted to provide more reliable results: a quality score scheme (QS) and metrics from the FBI's Universal Latent Workstation (ULW). Fingerprints were obtained from 20 individuals (11 males and 9 females) between the ages of 20 and 40; a total of 240 impressions were evaluated. The results provide evidence that the inkless method produces identifiable fingerprints of equivalent quality to the standard ink method, although significantly better for males. The potential of the proposed technique as an alternative to the conventional ink method is proven and corroborated by the two independent systems of visual quality assessments.

Multilayered iron oxide/reduced graphene oxide nanocomposite electrode for voltammetric sensing of bisphenol-A in lake water and thermal paper samples

A multilayered iron oxide/reduced graphene oxide (ION-RGO) nanocomposite electrode is reported for the voltammetric sensing of bisphenol-A (BPA). Structural characterizations reveal the nanocomposite features RGO sheets decorated with nanometric spherical ION in a mixture of maghemite and magnetite phases. ITO substrate modified with the ION-RGO multilayered film exhibits strong electrocatalytic effect toward BPA oxidation, which is made possible by Fe(III) catalysts generated at the ION's surface after scanning the electrode potential from below 0 V (vs Ag/AgCl) and followed by the RGO phase conducting the transferred electrons. Under optimized differential pulse voltammetry conditions, the proposed sensor shows three linear working ranges 0.09-1.17 (r² = 0.999), 1.17-3.81 (r² = 0.995) and 3.81-8.20 (r² = 0.998), with the highest sensitivity equaling 7.76 μA cm^-2/μmol L^-1 and the lowest limit of detection of 15 nmol L^-1. A single electrode can be used for at least twenty consecutive runs loosing less than 15% of sensitivity, whereas electrodes fabricated in different bacthes exhibit almost identical perfomances. Determination of BPA in a thermal paper sample shows no difference (at 95% confidence level) between the proposed sensor and HPLC/UV. The sensor is neither influenced by the matrix composition nor by other emerging contaminants.

The presence of bisphenol A in the thermal paper in the face of changing European regulations - A comparative global research

Bisphenol A (BPA) is used as a color developer in a thermal paper that after a heating process reacts with a leuco dye and changes it to a colored form. Receipts from cash registers are considered as the main source of consumer exposure to bisphenols together with polycarbonates and epoxy resins. Levels of BPA and its possible alternatives were determined in thermal paper samples collected between May 2018 and May 2019 in 22 European and 17 non-European countries on all inhabited continents (220 samples in total, 133 of which were from Europe and 87 from other countries). These measurements were intended to check the level of BPA presence in receipts originating from different countries, especially from Europe in the light of changing regulations restricting its use. The effect of thermal printing on developer content was also analyzed, but no major changes in concentrations of bisphenols were observed during the process. Thus, printed receipts could be used for the determination of bisphenol content. Analysis of receipts from 39 countries has shown that BPA is still the most common compound used around the world with 69% samples containing this color developer. Among other tested bisphenols, BPS was used as a color developer in 20% samples, but it was noted that all samples collected from Japan and the United States of America were found to contain only BPS. Other bisphenols (F, AF, E, and B) considered as possible alternatives for BPA were detected only at trace levels or not detected at all, which showed that they were not used as color developers. The relatively large use of BPS as a BPA substitute is worrying because this compound not only has similar endocrine properties but is also poorly biodegradable. Besides, its relatively high polarity facilitates spreading in the environment.

Fingermark visualisation on thermal paper - A comparison among different procedures as an outcome of the 2018 collaborative exercise of the ENFSI Fingerprint Working Group

In 2018 the Fingerprint Working Group (EFP-WG) of the European Network of Forensic Science Institutes (ENFSI) undertook a collaborative exercise (CE) with the aim of assessing the ability in developing fingermarks on an item constituted of a thermal layer. The test was prepared and managed by the officially established advisory group. The characteristics of the CE are summarised. Different approaches emerged from the outcomes showing on average valid results. What is evident from data is that the preliminary inspection is highly advisable especially for the thermal side exploiting specific combinations of wavelengths and filters. In general, better performances were achieved by laboratories using multiple processing techniques. Conversely, few laboratories were capable to reach the expected results with only one step process. Finally, data does not support the use of cyanoacrylate, powders, and iodine on this specific substrate.

Non-targeted detection and differentiation of agonists versus antagonists, directly in bioprofiles of everyday products

Xenoestrogens exert antiandrogenic effects on the human androgen receptor. In the analytical field, such antagonists block the detection of testosterone and falsify results obtained by sum parameter assays. Currently, such agonistic versus antagonistic effects are not differentiated in complex mixtures. Oppositely acting hormonal effects present in products of everyday use can only be differentiated after tedious fractionation and isolation of the individual compounds along with subjection of each fraction/compound to the status quo bioassay testing. However, such long-lasting procedures are not suited for routine. Hence, we developed a fast bioanalytical tool that figures out agonists versus antagonists directly in complex mixtures. Exemplarily, 8 cosmetics and 15 thermal papers were analyzed. The determined antagonistic potentials of active compounds found were comparable to the ones of known antagonists (in reference shown for bisphenol A, 4-n-nonylphenol and four parabens). Relevant biological/chromatographic parameters such as cell viability, culture conditions, dose response curves, limits of biological detection/quantification and working range (shown for testosterone, dihydrotestosterone, nandrolone and trenbolone) were investigated to obtain the best sensitivity of the biological detection. The developed and validated method was newly termed reversed phase high-performance thin-layer chromatography planar yeast ant-/agonistic androgen screen (RP-HPTLC-pYAAS bioassay). Results were also compared with the RP-HPTLC-Aliivibrio fischeri bioassay (applied on RP plates for the first time). As proof-of-concept, the transfer to another bioassay (RP-HPTLC-pYES) was successfully demonstrated, analogously termed RP-HPTLC-pYAES bioassay detecting anti-/estrogens (exemplarily shown for evaluation of 4 pharmaceuticals used in breast cancer treatment). The new imaging concept provides (1) detection and differentiation of individual agonistic versus antagonistic effects in the bioprofiles, (2) bioanalytical quantification of their activity potential by scanning densitometry and (3) characterization of unknown bioactive compound zones by hyphenation to high-resolution mass spectrometry. Depending on the hormonal bioassay, 15 samples were analyzed in parallel within 5 h or 6 h (calculated as 20 or 24 min per sample). For the first time, piezoelectric spraying of the yeast cells was successfully demonstrated for the planar yeast-based bioassays.

The optimisation of fingermark enhancement by VMD and Lumicyano™ on thermal paper

The enhancement of fingermarks on thermal paper can be challenging due to background staining caused by polar solvents used in fingermark enhancement techniques such as ninhydrin. This study explored a commercial one-step superglue fuming process, Lumicyano™, and Vacuum Metal Deposition (VMD) to develop fingermarks on this substrate and overcome this issue. Different sequential treatments involving Lumicyano™ and a combination of VMD methods were investigated with varying degrees of success with some sequences being highly sensitive. The VMD processes, however, were observed to generally be more effective at enhancing marks, whereas Lumicyano™ provided little or no benefit on this paper type. The results indicate that Lumicyano™ is only beneficial as a pre-treatment when the entire sequence of gold/zinc and silver/zinc is taken to completion. The gold/zinc and silver/zinc VMD processes were optimised on five different thermal papers, and the optimised techniques were then directly compared to determine which was more successful on each thermal paper type as a single treatment.

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

Bisphenol A (BPA) is a high-production-volume chemical with endocrine disrupting properties commonly used as color developer in thermal paper. Concerns about the potential hazards of human BPA exposure have led to the increasing utilization of alternatives such as bisphenol S (BPS) and bisphenol F (BPF). This study was designed to assess: (i) BPA, BPS, and BPF concentrations in 112 thermal paper receipts from Brazil, France, and Spain by liquid chromatography coupled to mass spectrometry (LC-MS); and (ii) hormone-like activities of these receipts using two receptor-specific bioassays, the E-Screen for (anti-)estrogenicity and PALM luciferase assay for (anti-)androgenicity. BPA was present in 95.3% of receipts from Spain, 90.9% of those from Brazil, and 51.1% of those from France at concentrations up to 20.27 mg/g of paper. Only two samples from Brazil, two from Spain, and ten from France had a BPS concentration ranging from 6.46 to 13.29 mg/g; no BPA or BPS was detected in 27.7% of French samples. No BPF was detected in any receipt. Estrogenic activity was observed in all samples from Brazil and Spain and in 74.5% of those from France. Anti-androgenic activity was observed in > 90% of samples from Brazil and Spain and in 53.2% of those from France. Only 25.5% of French samples were negative for both estrogenic and anti-androgenic activity. Estrogenic and anti-androgenic activities per gram of paper were up to 1.411 µM estradiol (E₂) equivalent units (E₂eq) and up to 359.5 mM procymidone equivalent units (Proceq), respectively. BPA but not BPS concentrations were positively correlated with both estrogenic and anti-androgenic activities. BPA still dominates the thermal paper market in Brazil and Spain, and BPS appears to be one of the main alternatives in France. There is an urgent need to evaluate the safety of alternatives proposed to replace BPA as developer in thermal printing. The large proportion of samples with hormonal activity calls for the adoption of preventive measures.

Assessment of bisphenol A alternatives in paper products from the Chinese market and their dermal exposure in the general population

Bisphenol A (BPA), a well-known endocrine disruptor, is used as a color developer in thermal paper. More recently, some emerging structural analogues have been introduced to replace BPA due to the strengthened regulations concerning thermal paper. Nevertheless, very limited data are available regarding their occurrence and potential health risks. Here, thirteen potentially toxic compounds were investigated in paper products (120 thermal papers and 81 nonthermal papers) collected in Beijing, China. The results indicated that the replacement of BPA by alternatives such as Bisphenol S (BPS), Bis(2-chloroethyl)ether-4,4″-dihydroxydiphenyl sulfone copolymer (D-90), 4-hydroxyphenyl 4-isoprooxyphenylsulfone (D-8), Bis(4-hydroxyphenyl)sulfonylphenyl (BPS-MAE) and Bis-(3-allyl-4-hydroxyphenyl) sulfone (TGSA) has been significantly advanced in several types of thermal paper (i.e., market weight stickers, train tickets, express labels, air boarding passes and lottery tickets). The mean value for the total analyte concentrations in thermal paper was 6.06 mg/g, and the highest level found was 26.0 mg/g. In addition, the frequent detection of these chemicals in nonthermal paper (>80%, n = 81) demonstrated that the contamination in thermal paper can be spread into other recycled paper, such as corrugated boxes, newspapers, food contact papers, etc. The estimated daily intake of BPA and its alternatives through the handling of thermal paper was 0.025 μg/kg bw/day for the general population. This is the first report on the occurrence of various new BPA alternatives in paper products from China, which will be helpful for further risk assessment and making responsible replacement decisions.

Screening and potential toxicity

Thermal paper contains potentially toxic additives, such as bisphenol A (BPA), as a common color developer. Because of its known endocrine disrupting effects, structural analogues to BPA, such as bisphenol S (BPS), D-8 and Pergafast 201, have been used as alternatives, but little is known about the presence and toxicological effects of alternatives other than BPS. In this study, thermal paper is screened by direct probe ambient mass spectrometry (rapid pre-screening method not requiring sample preparation) and by liquid chromatography (LC) with high resolution time-of flight (TOF-MS) mass spectrometry. Cash receipts and other thermal paper products (cinema tickets, boarding passes and luggage tags) were analyzed. Besides BPA and BPS, other developers only recently reported (Pergafast 201, D-8) or to the best of our knowledge not reported before (D-90, TGSA, BPS-MAE) were frequently found as well as some related unreported impurities (2,4-BPS that is a BPS related impurity and a TGSA related impurity). To gain some insight into the potential estrogenicity of the detected developers, a selection of extracts was further analyzed using a LC-nanofractionation platform in combination with cell-based bioassay testing. These preliminary results seems to indicate very low or absence of estrogenic activity for Pergafast 201, D-8, D-90, TGSA and BPS-MAE in comparison to BPA and BPS, although further dose-response tests with authentic standards are required to confirm these results. Compounds for which standards were available were also tested for developmental toxicity and neurotoxicity using zebrafish (Danio rerio) embryos. TGSA and D-8 induced similar teratogenic effects as BPA in zebrafish embryos. BPS and 2,4-BPS did not induce any developmental effects but 2,4-BPS did alter the locomotor activity at the tested concentration. Our findings suggest that the alternatives used as alternatives to BPA (except BPS) might not be estrogenic. However, TGSA and D-8 showed abnormal developmental effects similar to BPA.

Bisphenol A and alternatives in thermal paper receipts - a German market analysis from 2015 to 2017

Bisphenol A (BPA) was commonly used as color developer for thermal paper such as cash register receipts, labels or tickets. Therefore, thermal paper was considered by the European Food Safety Authority (EFSA) as the main source of human exposure to BPA beside epoxy based food contact materials. In this study, a German market analysis on the use of BPA and alternative color developers in thermal paper receipts is provided for the years 2015, 2016 and 2017.114 (2015), 98 (2016) and 99 (2017) samples were randomly collected and analyzed by HPLC-DAD. In summary, BPA was still the most frequently found color developer (48.2% in 2015, 46.9% in 2016 and 52.5% in 2017). The most commonly used alternative was the phenol-free substance Pergafast^® 201 (34.2%, 33.7%, 40.4%). The bisphenol analogs bisphenol S (BPS; 11.4%, 9.2%, 6.1%) and D8 (6.1%, 7.1%, 1.0%) were less common. Another phenol-free substituent, a urea urethane compound (UU), was also detected (3.1% in 2016). Concentrations of color developers in thermal paper ranged from 1.4 to 32.4 mg/g (median values between 2.5 and 15.9 mg/g). Concentrations of BPA were found to be highest followed by BPS, UU, Pergafast^® 201 and D8. In addition, two pharmacologically active substances, dapsone (6.0 mg/g) and tolbutamide (5.5 mg/g), were detected in a non-marketed thermal paper, that was supposed to use ascorbic acid as initial color developer. Different release experiments of the detected color developers were performed. Sensitizers 1,2-diphenoxy-ethane, 1-phenylmethoxy-naphthalene and diphenylsulfone, used frequently in the thermal paper processes, were quantified.

Bisphenol A and replacements in thermal paper: A review

Thermal paper contains potentially toxic compounds such as bisphenol A (BPA), which is used as a color developer. BPA has been reported in thermal paper in concentrations up to 42,600 μg g^-1. The exposure to BPA via dermal transfer has been recently discussed as a significant contribution to the overall human exposure and the estimated daily intake (EDI) has been reported up to 218 μg d^-1. BPA has been also detected in recycled paper with concentrations up to 46 μg g^-1. Due to the fact that BPA is a known endocrine disruptor and migrates from materials, regulatory restrictions have been established to prevent risks for the human health. As a consequence, structural analogues, such as bisphenol S (BPS) have been introduced into the market. Little is known about the presence and toxicity of these emerging replacements, and concern has risen about them. The present review gives an overview of the occurrence and levels of BPA and replacements in thermal paper. BPA is still the most common color developer found in thermal paper, followed by BPS. The analytical methods used for quantification of BPA and BPA replacements in paper products are also reviewed. BPA is transferred from thermal paper products to the finger pads upon handling it. Paper-skin transfer followed by penetration of BPA depends on conditions (e.g. greasiness of fingers and use of hand cream). It is, however, still debated whether thermal paper as a source for human exposure contributes significantly to the overall internal BPA exposure.

Occupational exposure of cashiers to Bisphenol A via thermal paper: urinary biomonitoring study

Purpose

As an essential component of polycarbonate plastics and epoxy resins, Bisphenol A (BPA) is found in numerous industrial and consumer products. BPA may cause adverse health effects because of its endocrine activity. General population exposure to this compound mainly through diet is well documented. Thermal paper was also identified as a source of BPA through dermal intake. In this study, we investigated whether frequent contact with thermal paper is associated with an increase in urinary BPA excretion.

Methods

We evaluated the exposure to BPA in cashiers and in non-occupationally exposed workers from several workplaces. Urinary BPA was quantified in free (unconjugated) and total (unconjugated plus conjugated) forms in 24-h and spot urine samples using LC–MS/MS. BPA concentration in thermal paper was also measured from each workplace. In addition, participants provided information on job, food and drink, tobacco consumption and hands wash during the sampling period through a questionnaire.

Results

Urine samples were collected from 90 cashiers and 44 controls. Free and total BPA were detected in all samples. The median urinary total BPA concentration was 3.54 µg/L (2.89 µg/g creatinine) for controls and 8.92 µg/L (6.76 µg/g creatinine) for cashiers. For the free BPA, the median urinary concentration was 0.20 µg/L (0.21 µg/g creatinine) for controls and 0.28 µg/L (0.22 µg/g creatinine) for cashiers. Any correlation was found between the urinary concentration levels and the number of thermal receipts handled. Hand washes frequency, age, job length of service and tobacco consumption had also no effect on the BPA excretions.

Conclusion

A significant increase in urinary total BPA concentration was observed for cashiers handling daily thermal paper receipts. However, no significant increase was observed in urinary free BPA concentration. These findings are particularly interesting for risk assessment since all available data on occupational exposure to BPA through thermal paper were obtained from models or from simulated experiments.

Identification of characteristic organic contaminants in wastewaters from modern paper production sites and subsequent tracing in a river

The paper industry is one of the most significant industrial branches that contributes to water pollution. Recent studies regarding the chemical composition of wastewaters from modern paper production sites are sparse, and organic contaminants originating from this source may remain undetected and uncontrolled. Therefore, for this study, non-target screening analyses of wastewaters from five different paper production sites were performed, including an extended analysis of one facility, for the identification of volatile non-polar to semi-polar organic contaminants. The identified contaminants were also traced in the adjacent river. Several specific agents related to paper production, including photoinitiators, ink and thermal paper constituents, were present in most wastewaters and were therefore considered to be characteristic paper industry contaminants. A couple of contaminants identified in this study are being reported for the first time and might be toxic, but have been neglected in previous studies. Bisphenol A and 2,4,7,9-tetramethyl-5-decyne-4,7-diol were found in untreated wastewaters, treated wastewater and in river water. Bisphenol A was present in river water downstream from where the paper industry discharges at a concentration that was reported to affect the reproduction of gastropods. Thus, our findings imply that paper industry discharges pose a risk to the populations of sensitive macroinvertebrates.

NIR luminescence for the inspection of thermal paper: a novel tool for fingermarks detection

The near infrared (NIR) spectral region could offer advantages over the visible region in the detection of latent fingermarks due to the enhanced contrast between the background and the print. In this present paper, this spectral range of the electromagnetic spectrum was explored in order to study the possibility to make feasible the inspection of forensic evidences when the substrate is represented by the thermal paper, which is one of the most extensively used porous surfaces for printing receipts. We successfully applied the method to thermal paper treated with several kinds of amino acid sensitive reagents. We demonstrated that, even if the treatments could cause a dark stain over the latent fingermarks, by exploiting the luminescence of thermal paper in the NIR window we were able to create a contrast otherwise impossible in the visible region.

Bisphenol A exposure via thermal paper receipts

Bisphenol A (BPA) has one of the highest production volumes of all chemicals worldwide. It has been widely studied because of its endocrine modulating activity. In addition to dietary intake, absorption of BPA via the skin from handling thermal papers is believed to be a relevant route of exposure. We studied BPA exposure via thermal paper receipts in simulation experiments performed by three volunteers, and examined urinary excretion of BPA. We also evaluated background BPA excretion among the Finnish working-age population. The geometric mean BPA excretion among non-occupationally exposed working-age Finns (n=121) was 2.6 μg/l, the range being 0.8-18.9 μg/l. The 95th percentile of the non-occupationally exposed people was 8 μg/l, and this was set as the reference limit for the non-occupationally exposed population. In the first simulation experiment, which was conducted under conditions representing the most likely exposure, i.e., the work of a cashier in a supermarket, BPA excretion remained below the reference limit in all participants. In the second simulation experiment, with more intensive, short-time handling of thermal paper (three times 5 min), urinary excretion also remained at or below background levels (highest value being 10.3 μg/l). The calculated maximum BPA excretion per day after handling thermal paper was less than 0.2 μg/kg of body weight, suggesting a total daily intake over 25 times lower than the European Food Safety Authority's (EFSA's) proposal for a temporary tolerable daily intake (temporary TDI) (5 μg/kg/day).