Enviro health scientists, chemists join forces to promote safe chemicals
published 12 November 2008
In an effort to match problems with solutions, environmental health scientists and chemists convened this week to chart a path to promoting development of safe, sustainable chemicals.
Leaders in environmental health and green chemistry met at University of California, Irvine to draft a consensus statement designed to offer advice and overcome obstacles to creating new industrial compounds that won’t endanger public health or the environment.
|“Our understanding of toxicity has gone through a transformational evolution in the last decades. Everyday chemicals that once looked benign no longer do,” said Lynn Goldman, a professor of environmental health sciences at Johns Hopkins University’s Bloomberg School of Public Health.|
The goal of the collaboration is to merge the knowledge and ideas of toxicologists and others who specialize in the dangers posed by chemicals with experts in green chemistry, who design nontoxic, environmentally benign materials.
Most industries remain dependent on hazardous substances.
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Monday’s session at the National Academies’ Beckman Conference Center was open to the public, drawing an audience of about 200. But the scientists on Tuesday and Wednesday met behind closed doors to craft a consensus statement they plan to deliver in a few weeks to the public, particularly policymakers.
Facing scientific uncertainty, controversy generated by industry and ever-increasing complexity of issues, many environmental scientists in recent years have turned to consensus statements, which summarize the state of the science and recommend steps to address problems.
Pete Myers, chief executive officer of Environmental Health Sciences, which organized the conference with the nonprofit group Advancing Green Chemistry, said the group’s mission is to avoid “yet another generation of problematic chemicals.” The central theme, he said, is that new chemical compounds can be both profitable and safe.
The scientists involved in this week’s meetings expressed a sense of urgency, a desire to ensure that green chemistry becomes a priority. They are particularly concerned about hundreds of industrial compounds that can disrupt hormones at low levels. Animal studies, as well as some human data, suggest that exposure to many chemicals, particularly in the womb, can alter reproduction, immune systems, brain development and other vital functions.
Dr. Terry Collins, Carnegie Mellon
Endocrine disruptors are to the chemical industry what sub-prime mortgages are to the banking industry, said Terry Collins, Thomas Lord Professor of Chemistry at Carnegie Mellon University and director of its Institute for Green Science.
As with the mortgage crisis, he said, “it’s important not to drag our feet.”
However, many obstacles remain to promoting development of safer chemicals.
Lack of regulation, insufficient investment and inadequate training keep many chemists from embracing green chemistry. Of the estimated 83,000 chemicals in commerce, only a few hundred are “green.” For the vast majority of the others, the risks are unknown.
Dr. Joe Thornton, Univ. of Oregon
“The current regulatory strategy of testing chemicals one by one cannot possibly identify all of the substances that threaten health,” said Joe Thornton, an associate professor in the Center for Ecology and Evolutionary Biology at the University of Oregon.
Thornton recommended three changes:
Goldman said one major barrier is that chemicals are regulated one at a time, while in human bodies, they always occur in mixtures. She said the current U.S. law, the Toxic Substances Control Act, “will never be effective unless the burden can be shifted to industry to prove a product is safe.”
Under the law, enacted in 1976, the Environmental Protection Agency can only ban or restrict an industrial chemical if it poses an “unreasonable” risk to humans or the environment. In addition, the EPA is required to choose the “least burdensome” approach to regulate the chemicals.
As a result, the environmental agency has not banned any existing industrial chemical since 1989, when it tried to phase out asbestos. The asbestos ban was overturned in 1991 when a federal appeals court ruled that the EPA had not proven it was necessary. Since then, the agency has relied mostly on voluntary efforts by chemical companies.
The European Union already reformed its policies. Two years ago, the EU enacted the world’s most stringent law aimed at toxic chemicals, and it already is having global effects on the chemical industry, which must test and register thousands of compounds.
In September, California launched its own program, the nation’s most comprehensive reform of chemicals policy. The new law requires the state to evaluate, identify and perhaps ban industrial chemicals that are linked to health effects.
The group’s consensus statement is likely to tackle one of the newest environmental health issues--epigenetics. Some scientists believe that exposure to many chemicals can trigger heritable changes in how genes express themselves, making a person more susceptible to disease. Those changes might remain in place not just for the exposed fetus, but for all future generations.
Dr. Jerrold Heindel, NIEHS
|Jerrold Heindel, scientific program administrator at the National Institute of Environmental Health Sciences, said many diseases and disorders, including asthma, obesity, attention deficit disorder and heart disease, may be triggered when fetuses, babies or young children are exposed to chemicals in plastics, cosmetics, pesticides and other consumer products.|
By changing chemical policy, we can “shift the focus from curing disease to prevention and intervention," Heindel said.
When pregnant rats are exposed for a few days to a mix of two pesticides, 90% of their offspring have reduced sperm counts and 10% are infertile. And those effects lasted for at least four generations of the rats.
“If it’s true” for humans, Heindel said, “imagine the implications.” What that means, he said, is that your great-grandmother’s chemical exposure could be harming your own health and fertility.
Nevertheless, the number of students studying to become chemists is declining right at the time that innovation is desperately needed, said John Warner, president of the Warner Babcock Institute for Green Chemistry.
“The large army of practicing scientists worldwide investigating the next generation of materials has no training or skills necessary to meet these challenges,” Warner said.
Some industries are slow in following the tenets of green chemistry.
EPA officials say many high-tech industries, including the pharmaceuticals industry, are among the most wasteful in terms of the chemicals they use and the hazardous waste they create. For every kilogram of a drug they make, pharmaceutical companies use more than 100 kilograms of chlorinated compounds and other solvents that are thrown away. In comparison, the oil industry wastes a much smaller amount of solvents: 0.1 kilogram for every kilogram of product.
Many pharmaceuticals wind up in surface waters and drinking water after they are excreted. Berkeley Cue, formerly an executive at Pfizer Global Research and Development, said the biggest challenge is that a drug needs to be stable in manufacturing and in shelf life, so it is difficult to make ones that degrade to something benign in the environment.
Making environmentally benign active ingredients for drugs “is beyond our scientific understanding today,” Cue said.
Currently, drugs are screened for environmental toxicity late in the development process. Cue recommends that such screening come early in the drug discovery stage.
Chemists attending the conference said industries need incentives, sometimes regulations, to switch to environmentally benign chemicals.
Donald Blake, chair of UCI’s chemistry department who works with Nobel Laureate F. Sherwood Rowland, said the aerospace industry was resistant to eliminate metal-cleaning solvents that deplete the ozone layer. But when the Montreal Protocol phased out such substances in the 1990s, the industry discovered that a citrus-based cleaner worked just as well.
Sometimes the pursuit of profits isn’t enough to persuade companies to replace risky compounds, Warner said. For many chemicals, substitutes already have been invented, but they are not manufactured because they are big, risky investments.
Collins recommended multiple changes in policies to transform industrial chemicals, including a way to prioritize chemicals that should be replaced and elimination of all compounds that are persistent in the environment or are transported globally via the air or oceans.
“We have no choice but to embark on a course to adapt the economy to these realities,” he said.
Otherwise, chemicals invented today could harm people’s descendants hundreds of years from now.
“Trans-generational justice is really the critical thing for our civilization in the next century,” Collins said.