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The Green Chemist

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The chemical industry is about 150 years old and, undeniably, it has brought the world enormous benefits. But sometimes there is a price. Unforeseen adverse health and environmental effects can show up decades after a chemical has been commercialized. Enter Carnegie Mellon's Terry Collins who is developing real-world solutions.

It's 1971 and this undergraduate chemistry student is a hardworking kid. When not in class, Terry Collins spends most of his time in labs, conducting experiments, sometimes for classes and sometimes just to satisfy his own curiosity. Once the spring term ends, there is no summer vacation for the native New Zealander. To help pay for his education at New Zealand's University of Auckland, he loads refrigerators onto trucks for a local appliance factory. At lunchtimes, he enjoys shooting the breeze with the other workers.

Like workers everywhere, they all have their gripes, especially the guys on the parts cleaning crew. This group is an important cog in the factory's routine. Before the outer and inner cabinet linings of a 1970s refrigerator can be assembled to have foam impressed between them, this crew must remove any traces of tar that was used to seal the inner lining's outer surface. They do the cleaning by wiping the inner lining's enamel surface with cloths drenched in an industrial solvent.

Collins notices that this crew's complaints go beyond the typical rumblings and that they are also eerily similar—nosebleeds, dizziness, fatigue, persistent headaches. The 19-year-old aspiring chemist is concerned. Among all his hours spent in the university teaching labs, he had been reading about the toxicity of benzene. It has dawned on him that the workers may be displaying the classic symptoms of overexposure to benzene, which can be found in industrial cleaning solvents.

He decides to dig deeper. He visits the cabinet cleaning room where the workers use the solvents, estimates the room's dimensions, notes its lack of ventilation, determines how many drums of solvent the workers go through daily. He then calls the producer, posing as a buyer, and learns how much benzene and related aromatics are in the solvent—5% aromatics of which about 1% is benzene. With all of this information, he calculates how much benzene the workers inhale at work.

Even his most conservative estimate points to what he suspected. The workers' exposure is enormous, just through inhalation (not to mention what must be passing through their hands). These workers, simply by doing their job, are being poisoned—literally, not figuratively.

Although he is just a college student on a summer job, Collins takes it upon himself to try to help the workers. He goes to the company's chief chemist and explains his findings, but he is told that if there are unhealthy exposures, it's because of the crew not following proper procedures. Collins adamantly disagrees. He is also told the company will soon move to a safer approach. Collins doesn't know whether to believe this, but summer is over, and it's time for him to return to his university studies. He doesn't forget the workers, though, and some months later, he revisits the factory hoping to find changes have been made. There were no changes. The workers are still holed up in their scrubbing room, applying the same solvent the same way. He informs a leader in the national chemistry society about what is happening at the factory. The official doesn't believe that the government will take the matter seriously. Frustrated, Collins photocopies all of the references he can find on benzene toxicity and delivers them personally to the chief chemist at the refrigerator factory.

Collins says he will always remember the look on the chief chemist's face when he handed over the documents.

Three decades later—as the Thomas Lord Professor of Chemistry and director of the Institute for Green Science at Carnegie Mellon—Collins still refuses to look the other way when it comes to the short-term and long-term adverse effects of chemistry on health and the environment. He is an advocate of what is called green chemistry, which is the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances—a definition he attributes to his friend and colleague, Paul Anastas, who is Yale's director of the Center for Green Chemistry and Green Engineering.

Through green chemistry, Collins has devoted himself to "look farther down the road" in order to stave off problems that chemical technologies can create. "We chemists have focused primarily on solving challenges of technical performance and profitability," he says, citing the demand for breakthroughs that lead to advances in consumer products such as a stronger plastic, a more pressure-sensitive ink, or a pleasing fragrance that people will buy. The solutions, though, like the process used in cleaning the refrigerators at the New Zealand factory, can have significant consequences.

"Chemists are usually not well educated in toxicity and ecotoxicity," reveals Collins, "and that area needs much more of our attention. When we put hazardous chemicals into distributive products, a payback will likely follow. And if the hazardous chemical can disrupt cellular development at environmentally relevant concentrations, as endocrine disrupting chemicals can do, then we may end up impairing our descendents."

So, when it comes to thwarting endocrine disruptors—which act like hormones and can adversely disrupt normal endocrine functions—Collins, as a green chemist, asks: "Can we find safer substitutes for hazardous chemicals? And, if we can't find safer substitutes for hazardous chemicals that we can't live without, then can we find green ways to reduce their adverse impacts?"

Collins, who has been a member of the Mellon College of Science faculty since 1987, pursues his green chemistry undertakings at the institute, which was established as a research, education, and development center to pursue "a holistic approach to sustainability science."

"Rule number one," he says, "is to finds ways to reduce and eliminate toxic elements in distributive technologies."

"We know a lot about the toxicity of the elements. Unless it is radioactive—in which case it is certainly hazardous—a toxic element will not degrade, period. The atoms of toxic elements are the prototypical persistent toxicants. Once you mine, refine, and release a toxic element so that it can move through the environment, it is going to poison whatever it encounters that has susceptibility.

"Rule number two is to find ways to reduce and eliminate persistent molecules in distributive technologies."

"While toxic elements are toxic at the level of the individual atoms, there is another type of persistent species that arises when atoms are tied together to produce molecules that do not break down easily in the environment. Persistent molecules are free to wander the environment. And some of them find ways to cause trouble."

Collins can rattle off some for-instances that don't take a chemistry background to consider:

What should we do when a plastic breaks down in a landfill to release an endocrine disruptor to water? Should we develop a replacement plastic? Should we develop better treatments for landfill runoff? Should we ban the plastic outright?

How should we react when a medicine's resiliency means that the active ingredient passes through people, through the sewage system, through water treatment plants, into our environmental waters to adversely affect aquatic life, and even into our tap water? Are there ways to retain the vital benefits of pharmaceuticals, but avoid the perplexing problems associated with their persistence?

Collins has championed the need to develop greener technologies in his writings and in nearly 500 public lectures. Recently, he gave the conference summary lecture for a group of international environmental health scientists and green chemists who are working to unite the fields to better deal with endocrine disruptors.

In addition to calling for "green chemistry" among his colleagues, he says he is committed to training the next generation of scientists to always keep environmental considerations in mind, something he believes needs to be better emphasized in chemistry curricula: "From the day they enter undergraduate chemistry, to 10 years or more later when they get their PhD, unless students make a special effort, they will have no training in toxicity or ethics. It kind of defies common sense." Collins began teaching the first course in green chemistry at Carnegie Mellon in 1992. Since then, his green chemistry research team has included around 20 graduate students and 50 undergraduate students.

But he is more than an advocate for change, more than a mentor. He is a scientist with a lab.

Beginning in 1980, he set out to find a safer way to disinfect and purify drinking water. The major chlorination process in use today produces carcinogenic by-products. He and his team hoped to develop a catalyst to activate hydrogen peroxide to destroy the persistent molecular pollutants and pathogens in water, literally oxidizing them into non-toxic components. But the sought-after catalyst and its processes also had to produce no toxic by-products.

Fifteen years later, Colin Horwitz, a member of Collins' research group, gives a demonstration of the team's progress. He places into a beaker of water a speck of powder, the catalyst Iron-TAML (short for tetramido macrocyclic ligand). Then he adds a squirt of an industrial dye to color the solution a vibrant orange. Finally, he adds a dash of hydrogen peroxide. Within a few seconds, the solution in the beaker turns clear again. Horwitz adds another squirt of dye, and as soon as it hits the solution it also disappears. He does it again, and again, and each time the dye bleaches nearly instantaneously. For as many times as he adds dye, the hydrogen peroxide and the iron-TAML catalyst make it vanish.

To the untrained eye, Collins realizes this simple experiment might not seem groundbreaking. But he points out the amount of catalyst used. All that was needed to strip the water of its colored pollutant was about four parts per million. And for many applications a hundred parts per billion may be sufficient. Then imagine, for a moment, that instead of being colored water, the solution is an industrial wastewater containing persistent organic compounds. Or obsolete pesticides. Or legacy wood preservatives. Or the colored and smelly pollutants of wood pulp bleaching. Or anthrax-like microbes. Collins and his team members discovered that their Iron-TAML catalysts with hydrogen peroxide can quickly decompose or kill these and many other pollutants.

In the years following their discovery, the Institute for Green Science has developed over 20 variations of the prototype TAML activator. They can be tweaked and repurposed to target a variety of different pollutants. "Now we need to make TAML processes cost-effective for industry and other uses," Collins says.

Enter GreenOx Catalysts, Inc., a company Collins cofounded with Horwitz and others, which seeks to investigate the technical feasibility of commercializing TAML activators to provide environmentally friendly oxidation catalysts for numerous fields of use. Tim Hall, a venture capitalist with more than 20 years of experience in developing startup technology companies, came in as the company's CEO.

"The commercial applications are endless," says Hall, "but in a nutshell what we intend to do with GreenOx is to provide industry with new, cost-efficient ways to get lean, mean, and green."

As GreenOx gets off the ground, positioning itself as a potent force for dealing with hazardous oxidizable chemicals in water, Collins and his team realize the work has really just begun. Their patented technology may well be something close to a silver bullet for degrading oxidizable pollutants in water, but there are so many targets to study. And, as he travels the world lecturing about green chemistry, he continues to be reminded of the price people pay when the adverse effects of hazardous chemicals are ignored. At one of his recent lectures before a collegiate audience, he spoke about the toxicity of chlorine-containing plastics which produce dioxins upon combustion. After the lecture, as he was gathering his notes, a student came up to him and asked:

"What would happen if you spent two months at a construction site burning PVC offcuts?"

"Nobody would do that—you and the surrounding environment would be contaminated with dioxins," Collins responded.

"But that's been my summer job for the last several years," the student replied somberly.

Bradley A. Porter is a freelance writer living in Chicago. He is a regular contributor to this magazine.

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egmeyer@uwyo.edu

I know and admire Terry Collins. The story is vintage Collins. Best regards Terry. Gerry Meyer Univ. Wyoming

M. J. Keenan, Ph.D. CMU Chemistry 1974

This is great and useful work. Could the oxidation be made selective, such as converting primary alcohols to acids?

Thomas gates

Useful