Novel ‘Green’ Chemical Endocrine Screening Protocol Looks Beyond EPA’s

Inside EPA: Risk Policy Report – 07/12/2011
By Jenny Hopkinson

A group of private and government scientists is moving closer to completing a testing protocol for determining whether new “green” chemicals entering the market are safer than those they are intended to replace and do not pose endocrine disruption risks, an effort that extends beyond EPA’s screening program, which focuses on existing chemicals.

Advancing Green Chemistry (AGC), the non-profit group leading the efforts, has joined with National Institute of Environmental Health Sciences (NIEHS), Environmental Health Sciences, Inc and other private sector groups, to develop a five-tiered testing protocol that will eventually be available free to chemical producers to determine whether their products may disrupt human endocrine systems, an outcome that has been linked to a slew of health problems including obesity and breast cancer.

An AGC source says the protocol is close to being submitted for peer review and developers hope it will be completed in about another year.

The protocol is designed to address concerns that newly developed green chemicals — which are intended to be safer alternatives than existing substances — may not be much better for the endocrine system, which regulates the body’s hormones, than the existing chemicals they are being created to replace.

While EPA is required by law to test a slew of existing chemicals under its endocrine disruptor screening program (EDSP), so far the agency has been “stuck” in what it can get done and has been struggling for almost two decades, the AGC source says.

Delays with the EPA program have long been a concern. For example, former House Rules Committee Chairman Louise Slaughter (D-NY) last year pushed legislation that would have created a new endocrine screening program at NIEHS, in part because EPA had been slow to establish its program. “While EPA does have the EDSP they’ve been more focused on toxics and only in the past few years focused on endocrine disruption,” her spokeswoman said (Risk Policy Report, Dec. 22, 2009).

Similarly, the AGC source says EPA is “snarled up in the morass of trying to regulate existing chemicals, and that hamstrings people.” Testing for endocrine disrupting effects “is something the government should be doing, but it just doesn’t seem to be something that’s happening,” the source says.

The source puts the blame on industry for the delays in EPA’s program. “There’s a lot of vested interest in the chemicals on the market” by their manufacturers, and that is slowing down the process, the source says. So far the agency “hasn’t been able to sort that out.” Rather than get bogged down in attempts for regulation of the chemicals, “we are trying to just look forward,” the source says.

But that is not to say that EPA hasn’t shown interest in the protocol. Paul Anastas, head of the Office of Research and Development, has been involved with developing the system, although the source says while he has been “constructive and supportive,” there has been no indication that EPA will adopt the methods. “But if they want to take over our project, great I think that would be better for all of us,” the source adds. “This should just be the way we test chemicals, period.”

A second source, however, argues that EPA’s programs aren’t capable of looking at such sensitive effects of chemicals. “Unfortunately there are people still working in the lab in EPA . . . who will say none of this work has any value,” the source continues. “They are stuck with toxicologists who are still doing old school toxicology.”

As a result, AGC, about a year ago, brought together a group of chemists, toxicologists and other government and private scientists to examine what the source describes as a “burgeoning wave” of new science on endocrine disruption with the goal of developing a tool for chemical makers to ensure in the development process that a chemical will not have effects on hormones.

The result is a five-tiered protocol that begins with what the source described as “quick and easy” Quantitative structure-activity relationship (QSAR) modeling and looking at a chemical’s structure, followed by in vitro high-throughput screening assays, validated and specialized cell-based assays, amphibian and fish tests, with the final tier being mammalian testing.

While chemical producers can run a new substance through as many or as few tiers as they choose, if a chemical passes through all the tiers, then it is quite likely to be safe, said Thaddeus Schung, a postdoctoral research fellow with NIEHS, speaking at the American Chemistry Society’s 15th Annual Green Chemistry and Engineering Conference in Washington, DC, June 22.

Schung said that the system aims to be a logical, consensus based tool to determine endocrine activity based on sound science. “Were trying to use this brain power here to come up with a sensible effort to . . . predict chemical toxicity.” Our hope, Schung said, is to “kick some of these chemicals out of production and make way for some new chemicals that are being developed by green chemistry.”

The AGC source echoes this, saying the protocol will provide an important new tool for chemical producers. As chemists develop these new materials “it’s really hard for them to know whether or not what they’ve designed has the potential to be an endocrine disruptor.”

“Green chemists are being asked to design the next generation of benign chemicals and they don’t have the tools to do it,” the source continues, adding that chemists are not toxicologists. “This is the new design criteria — you want to make chemicals that don’t act like hormones and don’t rewire people’s systems.”

And another source says that given the public backlash on products containing such endocrine disrupting chemicals such as bisphenol A (BPA), “industry is staying ahead of this now,” the source says. “They realize that this is the way we have to go.” — Jenny Hopkinson