Design Out Endocrine Disruptors

Endocrine disruptors, chemicals that interfere with the body's endocrine system, can cause adverse developmental, reproductive, neurological and immunological effects in humans and other animals.
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Many, but not all, are manmade and the list is already long: pharmaceuticals, dioxins, polychlorinated biphenyls and pesticides have all been in the spotlight at various times. Indeed, the book that many credit with creating the modern environmental movement, "Silent Spring," targeted the risks of the pesticide DDT ("A Milestone Book Turns 50"). In recent years, the focus has been on plasticizers such as bisphenol A (BPA). Already banned in some baby products by the U.S. Environmental Protection Agency (EPA), new research by the NYU School of Medicine, New York City, has linked the chemical with childhood obesity.

So, one of the major challenges for chemical companies is how to design out such hazards from their products.

Help is now at hand from a group of scientists from North America and Europe who believe such hazards have, to date, been inadequately addressed both by the industry and regulatory science.

In response, they've developed a five-tiered testing system that manufacturers can use to ensure that the chemicals and consumer products they produce are free of harmful endocrine-disrupting chemicals (EDCs).

Their study, "Designing Endocrine Disruption Out of the Next Generation of Chemicals," was published in the January issue of the Royal Society of Chemistry journal Green Chemistry.

In it, the scientists describe the Tiered Protocol for Endocrine Disruption (TiPED). It's been created under the oversight of a scientific advisory committee composed of leading representatives from both green chemistry and the environmental health sciences.

TiPED is conceived as a tool for new chemical design and so starts with a chemist theoretically at "the drawing board." The five testing tiers range from broad in silico evaluation up through specific cell-based and whole-organism-based assays.

To be effective at detecting endocrine disruption, a testing protocol must be able to measure potential hormone-like or hormone-inhibiting effects of chemicals, as well as the many possible interactions such chemicals may have with cell-based receptors. Accordingly, the scientists have designed this protocol to broadly interrogate the endocrine system.

The proposed protocol won't detect all possible mechanisms of endocrine disruption because scientific understanding of these phenomena is advancing rapidly. As new research on endocrine disruptors becomes available, the tests will be updated.

In the paper, the 23 authors — who are all chemists, biologists and environmental scientists — present the principles that should guide the science of testing new chemicals for endocrine disruption, as well as principles by which to evaluate individual assays for applicability, and laboratories for reliability.

In a proof-of-principle test, six EDCs that act via different endocrinological mechanisms were run through the protocol using published literature. The test identified each as endocrine active by one or more tiers.

"We believe that this voluntary testing protocol will be a dynamic tool to facilitate efficient and early identification of potentially problematic chemicals, while ultimately reducing the risks to public health," they write.

"Endocrine-disrupting chemicals are a clear and present danger to the welfare of all living species," notes Terry Collins, the Teresa Heinz Professor in Green Chemistry and director of the Institute for Green Science at Carnegie Mellon University, Pittsburgh, Pa. "It is important for people everywhere and especially for future generations that we strive to design chemicals that are not endocrine disruptors themselves and materials that are inherently free of endocrine disruptors," adds Collins, who also is one of the authors of the study.

The researchers conclude the need for an effective testing strategy for EDCs is now imperative. By using these tests, they say, manufacturers can create safer products and provide their consumers with peace of mind in knowing the products tested are safe from endocrine disruption to the highest standards of science at any given time.

In another move aimed at eliminating risks consumers face from chemicals,  the Biz-NGO Working Group recently issued a 64-page guide aimed at helping companies implement its "Four Principles for Safer Chemicals" ("'How To' Book Targets Chemical Substitution").