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Laišką gavau.

Ar kada pagalvojote, kodėl parduotuvėje gautas čekis toks 'malonus rankoms',šiek tiek tarsi kažkuo padengtas?


Taip yra dėl to, kad čekiai yra spausdinami ant terminio popieriaus, kuris keičia savo spalvą pašildytas. Plonas miltelių sluoksnis padeda išryškėti dažams. Paaiškėjo, kad būtent tuose milteliuose, kuriais yra dengiamas popierius yra endokrininę sistemą ardančių cheminių medžiagų – bisfenolių, kurie absorbuojasi mūsų organizme per pirštų odą.

Amerikos Medikų asociacijos žurnale (ang. Journal ot the Ameican Medical Association) vasario mėnesį paskelbtoje publikacijoje, buvo įrodyta, kad bisfenolis – A (BPA) patenka į organizmą per odą. Tyrimo metu grupė savanorių dvi valandas savo rankose laikė čekius be pirštinių. Po dviejų valandų buvo ištirtas BPA kiekis šlapime, kuris vidutiniškai padidėjo nuo 1,8 BPA mikrogramų litre iki 5.8 mikrogramų litre.

Po savaitės tyrimas buvo pakartotas, tačiau pusė savanorių čekius laikė mūvėdami pirštines. Po aštuonių valandų išmatavus savanorių, kurie nemūvėjo pirštinių BPA kiekį šlapime jis buvo padidėjęs iki 11,1 mikrogramų litre. Tai nėra labai didelis kiekis (pvz. skardinėje esančioje sriuboje gali būti apie 22 mikrogramus BPA viename litre), tačiau verta susimąstyti, kaip pavojingos cheminės medžiagos patenka į mūsų organizmus.

BPA yra naudojamas nuo 1960-ųjų. Dažniausiai – kaip antibakterinė medžiaga dengiant aliumininių konservų dėžučių vidų. Taip pat BPA plačiai naudojams plastikinių butelių ir indų gamyboje. BPA yra priskiriams endokrininę sistemą veikiančioms medžiagoms, kurios imituoja hormonus taip išbalansuodamas žmogaus organizmą. BPA yra siejamas su krūties ir kitais vėžiniais susirgimais, nevaisingumu, nutukimu, anstyvu lytiniu brendimu ir širdies ligomis. Tai nėra labai didelis kiekis (pvz. skardinėje esančioje sriuboje gali būti apie 22 mikrogramus BPA viename litre), tačiau verta susimąstyti, kaip pavojingos cheminės medžiagos patenka į mūsų organizmus.

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Handling of Thermal Receipts as a Source of Exposure to Bisphenol A

Shelley Ehrlich, MD, ScD, MPH1,4; Antonia M. Calafat, PhD2; Olivier Humblet, ScD3; Thomas Smith, PhD1; Russ Hauser, MD, ScD, MPH1

JAMA. 2014;311(8):859-860. doi:10.1001/jama.2013.283735.

Human exposure to bisphenol A (BPA) has been associated with adverse health outcomes, including reproductive function in adults1 and neurodevelopment in children exposed perinatally.2 Exposure to BPA is primarily through dietary ingestion, including consumption of canned foods.3 A less-studied source of exposure is thermal receipt paper,4 handled daily by many people at supermarkets, ATM machines, gas stations, and other settings. We hypothesized that handling of thermal receipts significantly increases BPA exposure, but use of gloves during handling minimizes exposure.


In 2010-2011, after obtaining written informed consent, we recruited Harvard School of Public Health students and staff (aged >18 years, nonpregnant) via informational fliers and e-mail. No sample size calculation was performed for this pilot study, which was approved by the Harvard University institutional review board.

We used a simulation cross-over study design. At the first simulation, participants printed and handled receipts continuously for 2 hours without gloves. After a washout period of at least 1 week, a second simulation was conducted in which participants repeated handling of receipts wearing nitrile gloves. The option to participate in the second simulation or to provide sequential urine samples following the first simulation was offered to all participants at study entry.

All participants provided a spot urine sample, collected in a sterile BPA-free polypropylene specimen cup, immediately before handling of receipts and 4 hours later. Volunteers provided additional sequential urine samples at 8, 12, and 24 hours after handling of receipts without gloves. Urinary-specific gravity was measured using a handheld refractometer. Urine was stored in polypropylene cryogenic vials at or below −20°C until analysis. Total (free plus conjugated species) urinary BPA concentration was measured at the US Centers for Disease Control and Prevention using published methods.1 Concentrations of BPA were adjusted for specific gravity to account for urine dilution.

Using SAS version 9.3 (SAS Institute Inc), mixed regression models were used to examine associations between log-transformed specific gravity–adjusted urinary BPA concentrations for prehandling and posthandling samples and across time points for those who provided sequential urine samples. Statistical significance was set at a P ≤ .05 (2-sided test).

Twenty-four volunteers (mean age [SD], 35 [12] years) provided at least 2 urine samples for the simulation without gloves; 12 volunteers provided additional sequential samples and 12 also completed the simulation with gloves (Table). We excluded 1 participant for reporting consumption of 4 cans of beverage prior to the simulation (baseline urinary BPA concentration of 49.3 μg/L vs <2 12.0="" decreasing="" for="" g="" participants="" postsimulation="" remaining="" span="" the="" to="">
We detected BPA in 83% (n = 20) of samples at baseline and in 100% of samples after handling receipts without gloves. The geometric mean urinary BPA concentration was 1.8 μg/L (95% CI, 1.3-2.4 μg/L) before simulation and 5.8 μg/L (95% CI, 4.0-8.4 μg/L) postsimulation (P = .005 for interaction between presimulation and postsimulation BPA and glove status). The geometric mean BPA urinary concentrations from 12 participants who provided sequential samples following receipt handling without gloves were 2.1 μg/L (95% CI, 1.4-3.3 μg/L) at baseline, 6.0 μg/L (95% CI, 3.4-10.7 μg/L) at 4 hours, 11.1 μg/L (95% CI, 5.5-22.8 μg/L) at 8 hours, 10.5 μg/L (95% CI, 4.9-22.6 μg/L) at 12 hours, and 4.7 μg/L (95% CI, 2.4-9.1 μg/L) at 24 hours. Each measure was significantly different from baseline (P < .001 for 4-hour, 8-hour, and 12-hour urine samples and P = .04 for 24-hour samples). We observed no significant increase in urinary BPA after handling receipts with gloves (Figure) Figure. Geometric Mean–Specific Gravity-Adjusted Urinary Bisphenol A (BPA) Concentration Error bars indicate 95% confidence intervals. NHANES indicates National Health and Nutrition Examination Survey.aAdjusted BPA at 0 hours (baseline).bAdjusted BPA at 4 hours (handled receipts for 2 hours).

In this pilot study, we observed an increase in urinary BPA concentrations after continuously handling receipts for 2 hours without gloves, but no significant increase when using gloves. The peak level (5.8 μg/L) was lower than that observed after canned soup consumption (20.8 μg/L).3 The clinical implications of the height of the peak level and the chronicity of exposure are unknown, but may be particularly relevant to occupationally exposed populations such as cashiers,5 who handle receipts 40 or more hours per week.

Limitations include the small volunteer sample and loss of participants in the second simulation. However, urinary BPA concentrations at baseline were similar in the full and smaller groups and similar to the US population (1.83 μg/L).6 A larger study is needed to confirm our findings and evaluate the clinical implications.