of Arnold et al. 1996
SF, DM Klotz, BM Collins, PM Vonier, LJ Guillette, Jr., and JA McLachlan.
1996. Synergistic activation of estrogen receptor with combinations
of environmental chemicals. Science 272:1489-1492
was extraordinary about the original study by Arnold et al. was
not synergy, as many examples of synergistic interactions among
chemicals have been discovered . The extraordinary dimension
of the withdrawn results was the magnitude of synergy, up to 1600-fold.
Synergy exists. It just may not be that strong.
Even with the withdrawal of this paper, synergy remains a
huge challenge to risk assessment because synergy makes it
very difficult to anticipate the health consequences of pesticides
as most people experience them, which is in mixtures. Testing
rarely looks at interactions among chemicals and almost never
in the complex soup that characterizes most people's exposures.
disruption was an issue long before McLachlan's study was even
begun and its importance does not rest on one study.
Indeed, we completed the original Our
Stolen Future manuscript before McLachlan started this
study, and the book reached print (March 1996) before the study
was published (June 1996). In the scientific epilogue of
Our Stolen Future (sent to
print in September 1996) we observe that McLachlan's results,
"if they can be replicated," heighten further
the concern about interactions among chemicals because they indicate
that interactions are even less predictable than had been understood.
Synergy was an important issue before McLachlan's study was
published and remains one since it has been withdrawn.
critics present the McLachlan case an example of bad science.
They miss the point, indeed they distort it, attempting to use
it to deflect attention from the seriousness of the underlying
This pattern--important results published, results challenged,
non-replicability confirmed, results withdrawn, is not unique
in science even if this specific case is unfortunate. Science
proceeds by people performing their experiments, publishing them,
and having other scientists challenge them. McLachlan, while
highly criticized by some industry critics, in fact behaved in
the withdrawal in the best traditions of science. As signals
came back from other laboratories that the results could not be
obtained, he turned his own laboratory back to the question and
applied serious resources over many months to attempt to understand
why this was happening. Ultimately, when the nonreplicability
was clear, he contacted Science and withdrew the
independent scientists commended McLachlan for the way he
conducted himself in this case, and Tulane University conducted
an independent review which confirmed McLachlan's integrity.