Published: March 23, 2011

r 2011 American Chemical Society 3814 dx.doi.org/10.1021/es200613m | Environ. Sci. Technol. 2011, 45, 3814–3815

CORRESPONDENCE/REBUTTAL

pubs.acs.org/est

Reply to Comments on “Bisphenol A (BPA) in U.S. Food”

We respond to the letter submitted by Ackerman andNoonan 1 concerning our article, ”Bisphenol A (BPA) in

U.S. Food”.2 The article described our study of BPA levels in amarket basket survey of U.S. fresh, canned, and plastic containedfood. We thank the authors for their comments, but we feel theirletter fails to note that we stated our manuscript is the first peerreviewed publication measuring BPA levels in a single study inU.S. food for all three types of wrapping material or containers.The 11 articles cited by Ackerman and Noonan reflect literaturewhere either one or two types of the food containers of interesthave beenmeasured for BPA levels in various countries, but thesearticles do not present data from U.S. food for BPA levels in foodthat is fresh, canned, and in plastic containers.

The purpose of our market basket survey, one in a series ofrelated studies,3�6 was to describe the levels of BPA found in asample of commonU.S. foods that can be purchased bymembersof the general public at common distribution sites (super-markets). We realize that cans and other types of containersmay vary in composition which may, at times, result in contam-ination. It was not our goal to evaluate technical details of foodpreparation or packaging in cans prepared in different ways andhow this may affect BPA contamination of food. The idea that theconcentrations of BPA in food may not be the same fromdifferent manufacturers or at different times is perfectly reason-able given the changing market conditions in the U.S. andvariations in BPA levels that can occur over time and in differentcountries.

Eurofins GfA GmbH is an accredited laboratory working inthe field of environmental contaminants and human exposure formore than 25 years. All analyses performed need to fulfill specificQC/QA measures. For the determination of BPA, QC/QAincluded a multi point calibration curve, recalibration withineach sequence of analysis with a minimum of one blank in eachbatch of a maximum of 10 samples, and duplicate analyses of>50% of positive samples. Nearly all positive samples wereanalyzed in triplicate. The percent CV indicates percent coeffi-cient of variation; for the replicate/duplicate analysis of BPA infood samples, the CV percents were between 1.1 and 11.4% withan average of 6.01%.

The laboratory blank level for BPA is 0.43 ng absolute (totalamount of BPA per blank sample). (mean; n = 15) with SD: 0.12ng abs and BPA: 0.05 ng/g ww (LOD) with 0.11 ng/g ww(LOQ) based on 15 g ww (sample intake).The limits of detectionwere 0.20 ng/g wet weight (ww). Accuracy of laboratory proto-col and ability to reproduce results were determined by analyzingfortified (spiked) samples and included the freeze-drying pro-cess. The ratio between the assigned value and the determinedvalue was in the range of 86% and 102% (average 92.1%;reproducibility variation coefficient of 9.59%; n = 6).

Our report of correlation with pH and some BPA concentra-tion in our article was simply a means of characterizing ourfindings.We did not suggest that this implied causality. In fact, weexpressed considerable skepticism about the generalizability ofthis finding, including that it was unexpected, “may be due tochance or artifact,” and may reflect container types. Our use of

the word “curvilinear” does not refer to a quadratic model, butrather the results of our ANOVA, which we took to be aconservative way to test the pattern evident in the data, ofincreasing and then decreasing BPA levels as pH increased.The “single difference between the two most populous pHgroups” to which the comment refers was the result of a posthoccomparison after this ANOVA, using the standard, conservativeBonferroni method of adjusting for multiple comparisons. Bynone of the possible interpretations of “non-detect frequency”that we considered was this equal to 44%. The “triplicatesamples” were in fact three distinct samples of the same kindof food. We did not assert that it would not be appropriate toconduct another analysis including a random effect for food typein addition to the fixed effect of pH.

Our goal was to present the first findings of BPA in U.S. foodthat is fresh, canned, and in plastic containers from a marketbasket survey. Studies by others on chemical composition of cansand changes in pH or BPA levels by preparation of the productfor sale would make an interesting manuscript. However, thatwas not a goal of our research. We noted the percent of samplesshowingmeasurable levels of BPA and the types of food involved.These represent food purchased from U.S. stores at the time ofcollection.

Arnold Schecter, Noor Malik, Darrah Haffner, Sarah Smith,and T. Robert Harris

University of Texas School of Public Health, Dallas, Texas,United States

Olaf Paepke

Eurofins GfA GmbH Laboratory, Hamburg, Germany

Linda Birnbaum

National Cancer Institute, Bethesda, Maryland, United States,NIH, Research Park Triangle, North Carolina, United States

’REFERENCES

(1) Ackerman, L. K.; Noonan, G. O. Comment on “Bisphenol A(BPA) in U.S. Food. Environ. Sci. Technol. 2011, DOI: 10.1021/es2002869.

(2) Schecter, A.; Malik, N.; Haffner, D.; Smith, S.; Harris, T. R.;Paepke, O.; Birnbaum, L.; Bisphenol, A. (BPA) in U.S. Food. Environ.Sci. Technol. 2010, 44 (24), 9425–9430.

(3) Schecter, A.; Colacino, J.; Patel, K.; Kannan, K.; Yun, S. H.;Haffner, D.; Harris, T. R.; Birnbaum, L. Polybrominated diphenyl etherlevels in foodstuffs collected from three locations from theUnited States.Toxicol. Appl. Pharmacol. 2010, 243 (2), 217–224.

(4) Schecter, A.; Colacino, J.; Haffner, D.; Patel, K.; Opel, M.; P€apke,O.; Birnbaum, L., Perfluorinated compounds, polychlorinated biphe-nyls, and organochlorine pesticide contamination in composite foodsamples from Dallas, Texas, USA. Environ. Health Perspect. 2010,118 (6).

3815 dx.doi.org/10.1021/es200613m |Environ. Sci. Technol. 2011, 45, 3814–3815

Environmental Science & Technology CORRESPONDENCE/REBUTTAL

(5) Schecter, A.; Haffner, D.; Colacino, J.; Patel, K.; P€apke, O.; Opel,M.; Birnbaum, L., Polybrominated Diphenyl Ethers (PBDEs) andHexabromocyclodecane (HBCD) in Composite U.S. Food Samples.Environ. Health Perspect. 2009, 118 (3).(6) Schecter, A.; P€apke, O.; Harris, T. R.; Tung, K. C.; Musumba, A.;

Olson, J.; Birnbaum, L., Polybrominated diphenyl ether (PBDE) levelsin an expanded market basket survey of U.S. food and estimated PBDEdietary intake by age and sex. Environ. Health Perspect. 2006, 114 (10).