Response to the Comments of Delclos et al Free

Drs Delclos, Camacho, and Gamboa da Costa (2019) emphasize that the NTP CLARITY-BPA core report has been reviewed by a panel of scientists. We acknowledge the review that occurred, but emphasize that the process is significantly different from peer review experienced by scientists upon submission of a manuscript to a scientific journal. Notably, the NTP panel specifically excluded any researcher who has published on BPA (NTP, 2018a). As BPA is one of the most widely studied environmental chemicals, with over 30 000 publications (identified by Web of Science), this severely limits the reviewer pool.

We followed the review process, but it is important to note that the final report was not yet released when our publication was submitted. Now that the final report has been released, we can say that we had hoped to see greater changes in response to comments from various groups on the draft report. We also would like to indicate that we disagree with the statement that effects of BPA in the study below the highest dose (25 000 μg/kg bw/day) are not biologically plausible. Further, we think that use of historical controls is problematic, especially because the controls were exposed to BPA through polycarbonate housing (NTP, 2018b), which is known to leach BPA under normal use (Howdeshell et al., 2003; Hunt et al., 2003).

Our reference to the half-lives of BPA and phthalates as “on the order of days” was to emphasize their short lifetimes in relation to other environmental pollutants such as PCBs (t_1/2 = 36 500–54 750 days) (Ritter et al., 2011). Although studies do show that BPA and its metabolites, as well as many phthalates and phthalate metabolites, are eliminated in less than 1 day, phthalate metabolites such as monobutyl phthalate (t_1/2 = 2.7 days in rats) can remain for much longer (Frederiksen et al., 2007). We acknowledge that our description of the toxicity of phthalate metabolites was unclear; we intended to note that phthalate metabolites are bioactive toxicants, not BPA metabolites.

DECLARATION OF CONFLICTING INTERESTS

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

REFERENCES

Available as a Supplementary File.