Patterns in science; goals in policy
J.P. Myers, Ph.D.
American Association for the Advancement of Science
16 February 1998
The evolution of endocrine disruption as a scientific issue manifests six broad trends:
Is there scientific certainty about cause and effect in these cases? No. But Occams Razor positions endocrine disruption as one of the prime explanatory hypotheses: We know that in laboratory animals these same patterns can be reproduced by fetal exposure. We know that the developmental control of sperm count and genital formation in lab animals is highly similar to humans. We know that some percentage of the human population is exposed to the relevant range of contamination. It is not unreasonable to posit endocrine disruption as a possible cause. If fact, what is unreasonable is to dismiss it.
In response to these trends and the underlying science, Congress and the Administration have responded with several policy initiatives which I would regard as constructive first steps but incomplete.
Significant increases in the amount of money available for research, particularly at EPA and NIH. This is crucial and welcome. This work should help resolve which of the currently identified risks represent substantial threats to human and ecosystem health, and which can be rejected.
The administration, in part because of concern about this issue, has moved to reorient federal contamination standards to protect the most vulnerable in the populationthe developing fetus and young children. This step would have been justified even without concern for endocrine disruption.
Congress passed the Food Quality Protection Act of 1996. Again, most of this would have been justified without endocrine disruption. One of the most important aspects of that legislation is the Endocrine Disruption Screening and Testing Advisory Committee, or EDSTAC. The work that committee is undertaking is fundamentally important. It has been hard work, and we owe them a great deal for having been willing to participate, especially the academic and not-for-profit scientists whose participation is an add-on to their main employment.
I am concerned, however, that the results of EDSTAC and related efforts to apply traditional risk assessment procedures to signal disrupting chemicals will most likely fail to protect public health, for two reasons.
First, the numbers of chemicals to be assessedboth those already in widespread use as well as the many new ones that enter commerce each yearis daunting.
We have a lot of experience in a chemical-by-chemical approach to contaminant regulation, and one of the principal impacts is often to enshrine ignorance because of the laborious nature of the process we know almost nothing about most of the chemicals in widespread use, not just with respect to endocrine disruption but also about other more classic health endpoints. For example, the Environmental Defense Fund released a report last year finding that nearly three quarters (71%) of sampled high-volume chemicals do not meet the minimum data requirements for health hazard screening set by international standards.
As EDF pointed out in their study: "Absence of data is not the same as proof of harm, of course. It is only proof of ignorance." But ignorance means that any conclusion about safety is unfounded.
Second, if there is a general message to the emergence of endocrine disruption as a policy issue, it isnt just that we havent been able to catch up with all the chemicals in use and the new ones coming on the market, it is also that we are caught with a scientific and regulatory structure that for decades was ignorant of what questions to ask. Experience tells us that we do not do very well at anticipating unexpected forms of toxicity, and that commerce proceeds to ramp up production and dispersion of new compounds far more rapidly than the sciences of toxicology and epidemiology can advance. The pace at which these two sciences move forward is not commensurate with the pace of commercialization of new products. The result is that we wind up performing decades long experiments on the public and we do so even lacking adequate monitoring systems to alert us to problems.
There is an alternative approach, one that is being developed by the Chemicals Policy Committee of the Swedish government, established in 1996 in Sweden to evaluate approaches to achieving an environmentally sustainable chemical industry.
The CPC begin by observing, as I just mentioned, that we do not do very well at anticipating unexpected forms of toxicity. They go on to observe that substances that are persistent and bioaccumulative create widespread exposure, both through atmospheric and water transport as well as through trade, and that when problems are finally identified the exposures cannot easily be reduced simply by discontinuing production. They conclude that for substances that are persistent and bioaccumulative, we are virtually guaranteed to find that knowledge of adverse impacts will come to late to avoid widespread damage.
For these reasons, the Swedish Chemicals Policy Committee has proposed a series of targets for the governments chemical policies:
Specifically with respect to endocrine disrupters, the Chemical Policy Committee has proposed that substances that meet criteria established for endocrine disrupters be phased out, without the need to achieve scientific certainty in demonstrating harm. Period. Even more dramatically, the Committee recommends that polyvinyl chloride plastic materials be phased out from commerce no later than 2007.
This approach is radically different from that being used in the United States, because it begins with the premise that precautionary measures should be taken in the face of significant potential harm even without scientific certainty. They go farther, however, than the most timid applications of precautionary measures, by acknowledging that if our centurys experience with chemical safety issues has demonstrated anything, it is that we do very poorly at anticipating deleterious effects mediated by unanticipated mechanisms of toxicity.
The SPCs targets are directed toward industry. They are ambitious. They are intended to generate driving forces for change in the choice of chemicals and products and in requirements for products.
They have chosen a long time frame for change, out to the year 2012. They judge that ten to 15 years is a reasonable lead time for targets related to restrictions and phase-outs. Were the timetable longer, then motivation to implement new design criteria would be insufficient. Were it shorter, the targets would be viewed as unrealistic.
The targets focus on sending market signals with enough lead time to allow manufacturers to develop and implement new design criteria. The fact is thatwith the significant exception of pesticidesrarely do products of the modern chemical industry require biological activity, environmental persistence or bioaccumulation as a design objective of products. By being explicit about the need to employ design criteria that explicitly eliminate these characteristics, we are more likely to encourage the development of a sustainable chemical industry which can continue delivering the benefits of modern chemical synthesis with much less risk.