Analytical Toxicology

Measurement of Bisphenols in Thermal Paper

Bisphenol A (BPA) is a high volume chemical with over six billion pounds produced annually and over 100 tons released into the global environment. BPA is used to make polycarbonate plastic and epoxy resins commonly found as internal coating for food and beverage cans. A 2008 monograph by the National Toxicology Program, Center for the Evaluation of Risks to Human Reproduction (NTP-CERH) concluded that BPA causes developmental toxicity and in 2016 the California Office of Environmental Health Hazard Assessment (OEHHA) has added BPA to the list of chemicals known to cause female reproductive toxicity.  BPA is often used as a color developer in receipts relying on the thermal transfer technology.  Recently, there is an increased concern of exposure to BPA through contact with BPA-containing paper, particularly thermal receipt paper (cash register receipts, credit card terminals) as well as recycled paper used in food and beverage containers. In addition to cashiers, most people come in contact with thermal paper on a daily basis which has prompted concern for dermal exposure routes for BPA.  With increasing legislation against BPA, new unregulated bisphenols (BPS, BPF, BPB, BPZ, BPSIP, etc.) are being used as replacements for BPA in thermal paper.  This research project has developed new, highly-sensitive analytical methods to universally detect bisphenols in thermal receipts and recycled paper in order to assess the use and human exposure potential of this class of compounds in paper products.

Measurement of Polybrominated Diphenyl Ethers in Indoor Environments

PBDEs are a class of brominated flame-retardants that are added to commercial textiles and plastics in order to reduce fires.  In 2002, the main producer of PBDEs in the U.S. voluntarily discontinued production of select PBDE mixtures.  The fully brominated PBDE (BDE-209) remains the most widely used PBDE globally (56,100 tons in 2001) with equal use in North America and Asia.   As of July 2008, BDE-209 is banned in Europe and is under intense scrutiny in the media for its links to neurodevelopmental disorders in children.  Since introduction to the marketplace in the late 1970s, PBDE levels have increased in human blood and breast milk and human exposure data indicates that North American PBDE body burdens remain in excess of European and Asian body burdens. In addition to PBDE intake through diet, studies have examined the inhalation, ingestion, or dermal contact of household dust as an alternate route of human exposure.  While less brominated PBDEs are readily measured by gas chromatography/electron capture negative ion mass spectrometry (GC/ECNI-MS), BDE-209 analysis is unreliable in the literature due to decomposition at the excessive temperatures required for volatilization.  Our laboratory has analyzed PBDEs by on-column modified GC/ECNI-MS methods but has also developed a new liquid chromatography, negative ion atmospheric pressure photoionization tandem mass spectrometry (LC/NI-APPI/MS/MS) method to reliably quantify BDE-209 without the need for elevated temperature and thus avoiding decomposition.  Following validation of this method, we have quantified BDE-209 and other PBDEs in the dust sampled from 60 automobiles that were available for resale at U.S. dealerships and an equal number of personal vehicles.  BDE-209 comprised 95% of the total PBDE levels in automobile interior dust and these levels are approximately 50 times greater than the levels in household dust.  While DecaBDE use is banned in Maine and Washington and is targeted for restriction in the near future by six U.S. states, vehicles and airplanes are exempt from the ban.  Considering the average vehicle lifetime in the U.S. is 16.9 years, it is anticipated that the human exposure potential to PBDEs from automobile dust ingestion will continue for an indefinite future period in the U.S. population.  Our findings have influenced national and international reform on this class of chemicals and recent studies have indicated that this class of chemicals has begun to decrease in women’s bodies. 

Funding Source: NSF-CHE-RUI award 0718530, “RUI: Development of alternative solvent extraction methods and tandem mass spectrometric analysis of polybrominated diphenyl ethers in automobile interior dust”, Funding period: 9/2007 to 9/2011, Amount: $191,000.