Green Chemistry: Real world solutions for real environmental problems.

By Terry Collins, Thomas Lord Professor of Chemistry and Director, Institute for Green Science, Carnegie Mellon University, Pittsburgh, Pa. Imagine if water could be free from chemical pollutants. You could eat fish, drink a glass of water, or gaze upon the beauty of an ocean without fretting over toxic contaminants. Given the global dimensions of water pollution today, this might seem like an impossible dream. But through green chemistry, we are making progress toward cleaner water. Nevertheless, substantial barriers exist to creating a world with safer, sustainable chemicals. Industry sometimes follows the money more single-mindedly than the science. And our regulatory system is so anemic that even when toxicity to children has been scientifically certain for decades, it requires an act of Congress to get a potent neurotoxin, lead, out of children’s toys.

In the world today, environmental problems arise across all sectors of the chemical enterprise. Water contamination by persistent drugs is an example. Traces of ethinylestradiol, an active ingredient in most birth control pills, can devastate fish populations. So should we restrict or ban its use? If so, should we do the same with other eco-toxic drugs? My research group at Carnegie Mellon is working on another solution: a more effective, environmentally compatible technology for degrading not only drugs, but all persistent organic pollutants in water. In the real world, the idea is to clean waste streams in a green way before they are released to the environment.

The pharmaceutical industry usually designs active pharmaceutical ingredients to resist degradation, which makes them effective at low doses. But the downside is that they are excreted by people and flushed into sewage systems. From there, they may escape destruction in water treatment plants and pass on to environmental waters. Some even boomerang back to us in drinking water.

My research group’s work derives its inspiration from studies of biological catalysts called peroxidase enzymes. They activate hydrogen peroxide in living things to oxidize organic compounds in ways that are reminiscent of combustion. Our systems are miniature replicas of peroxidase enzymes. They cannot eliminate toxic elements like lead or mercury, but they can attack and destroy many if not most water contaminants. At miniscule concentrations, they accelerate peroxide chemistry to degrade a wide range of pervasive and recalcitrant chemicals in water, including ethinylestradiol and other estrogenic compounds. The list includes drugs, pesticides, dyes, aromatic gasoline components, organochlorines, organosulfur compounds, the colored and smelly contaminants associated with pulp and paper mill effluents, and more. They also rapidly kill bacterial spores, the hardiest of pathogens.

The take-home scientific message is simple. Green chemistry holds real promise for improving our water quality. Now we are expanding our efforts to show that these technologies can be commercially successful. Because we are green chemists, we are focused on reducing hazardous chemicals. Clearly, we want to avoid introducing any of our own. Toxicity studies to date contain no bad news. Our approach looks to be more effective and environmentally friendly than current technologies.

The modern chemical enterprise began 150 years ago. Experience since has taught us that we cannot have certainty that any chemical in use today will not elicit an unknown toxicity. Green chemistry seeks to develop real world solutions to the problems of hazardous substances through a new design approach based upon our considerable existing understanding of hazards. But the proclivity of industry trade associations to spin important matters of toxicity is a huge burden on our health and a giant obstacle to sustainability. Acknowledging rather than camouflaging the science of toxic chemicals is key to creating green chemistry solutions that will bring long-term financial stability to industry and sustainability to the chemical dimension of our civilization. As odd as it may seem, it is rare for professional chemists to have any training in toxicology. So there is a lot of catch-up needed to bring rigor to the field. Some of the worst chemical risks we face are large production volume chemicals that we now understand are endocrine disruptors. Dioxins (which arise from the burning of the ubiquitous vinyl or PVC), phthalates, bisphenol A, nonylphenols, and various pesticides disrupt cellular development to impair living things at ultra-low, environmentally relevant concentrations. Clear scientific evidence indicates humans are not immune. Endocrine disruptors put the welfare of our children on the chopping block, making them a top priority challenge for green chemistry.

As a chemist, I know science can’t fix all pollution problems. Government has a major role, too. The federal government has been sweeping legitimate tensions between the human benefits and the environmental negatives of chemicals under the rug. Regulatory agencies may claim to be resolving conflicting economic, societal and environmental factors through risk analysis. But when commercial chemicals are discovered to have environmental problems, the U.S. regulatory record can be summarized simply enough:  If a chemical delivers a desirable performance, is economically important, and has no proven link to human toxicity, it is staying on the market.

In a world where industry unwittingly produces endocrine disruptors and other health threats from time to time, regulatory agencies need to be much more effective. Lead was first restricted in household paint in Austria, France and Belgium in 1909. Because of the work of the Lead Industries Association and support from a few compliant, imperious academics, the U.S. federal government took until 1977 to get most lead out of household paint. Those years of procrastination have meant the intellectual impairment of many Americans. We simply cannot play deadly spin games for decades before dealing with endocrine disruptors which, because of ultra-low dose effects, might be even more hazardous than lead. Our political leaders need to support the regulatory agencies financially, spiritually and intellectually. They need to permit the agencies to do top quality work by overcoming the temptations that lead to politics trumping science.

In the United States, federal funding for green chemistry has been essentially nonexistent.  Carnegie Mellon University is not alone in struggling to build an authentic green chemistry program. If the field is supported, America will assuredly contribute to building green chemistry solutions to some of society’s most urgent environmental problems.