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Tuesday, August 11, 2015

"Chasing Molecules" Has a Green Message for Chemists and Consumers

I have synthesized over 2,500 compounds! I have never been taught what makes a chemical toxic! I have no idea what makes a chemical an environmental hazard! I have synthesized over 2,500 compounds! I have no idea what makes a chemical toxic!
Chasing Molecules, xxiii

Elizabeth Grossman, the author of Chasing Molecules: Poisonous Products, Human Health, and the Promise of Green Chemistry (Island Press, 2011), quotes the above from Dr. John Warner, who is the co-founder of the Warner Babcock Institute for Green Chemistry.

Hearing that quote for the first time, and throughout the first pages of the book, my reaction was initially hostile. Of course I know what makes a molecule toxic, I thought to myself. I'm an expert chemist. People literally pay me money to do this. So I picked my favorite example of a toxic molecule: benzene. Every chemist knows benzene is toxic. Its toxicity is obvious. It's toxic because... well, um... it's benzene?

And carbon tetrachloride? Toxic. Duh. That one's got a halogen. Halogens are toxic, right? Ooh, and lead, of course, which is bad for you because it gets in there somewhere and does... something.

The more I read forward from Warner's quote, the more I realized that he was absolutely right. As a chemist, I have been given the tools to understand how to make a narrow subset of molecules and solids, carry out some physical characterization, and dispose of waste according to environmental standards. I hope that some day, my research might find an industrial application and improve somebody's life, but I have no perspective on any of the myriad ways in which my activities could inadvertently harm lives or on how to engineer them to avoid doing so.

Chasing Molecules: you'll devour it.
In Chasing Molecules, Grossman takes this idea as one of her central theses. I have no perspective on the harm done by my chemistry because bestowing that perspective has not ever been a priority in chemistry education. Toxicology and ecology have been the territory of public health and biology students rather than the chemists designing potentially toxic molecules. Part of green chemistry involves educating chemists on those disciplines. The book begins with an introduction to green chemistry and some of its key players in academia. In the opening chapter, she describes precisely what is meant by green chemistry and makes a case that chemists in all disciplines and in all areas of the industry should practice it.

In 2015, the word "green" conjures images of expensive off-brand cleaners, your smug Prius-driving friend, and the vegan at your party going on about the clean water cost of large-scale meat production. But for researchers like Warner and Paul Anastas, the director of Yale's Center for Green Chemistry and Green Engineering, green chemistry boils down to one simple concept: understanding the full toxicity profile of a chemical product before it gets put into lucrative, high-volume production is the best way to minimize cost. Here, cost includes the traditional expenses of capital, raw materials, labor, etc., but is expanded to include the costs of environmental contamination and human exposure. "Benign by design," if you will

From those beginnings, the book picks up quickly. Grossman takes us on a long tour of the scientific evidence for environmental contamination by chemicals from consumer products. We meet researchers on an Arctic ice ship who are finding industrial pollutants in the most remote and pristine environments on our planet. We learn that babies in every part of the world are being born with plasticizers like bisphenol A and flame retardants like polybrominated diphenyl ethers already in their bloodstream. Grossman shows us that some of these compounds can chemically alter DNA and RNA, leading to diseases and disorders that can show up in your children years after you've been exposed. The discussion progresses through polymers that are used in your non-stick cookware all the way to the nanomaterial frontier. The principles of green chemistry, discussed somewhat dryly in the opening chapters, immediately take full form when held up next to data from environmental monitoring and endocrine toxicology studies. Grossman does an excellent job of juxtaposing the two and letting the science speak on behalf of the science policy.

In all of these cases, the story remains the same. The manufacturing sector, ever-focused on the bottom line, has studied acute toxicity - in short, whether or not you'll get sick if you're exposed to lots of a substance all at one time. If a product's acute toxicity is acceptably low, or maybe even if it isn't, it gets put into production and money gets made. When new information surfaces about how the material behaves in the environment or may affect populations exposed to small amounts over a long period of time, bringing about change means fighting against companies entrenched by the fact that they are making money. It also means fighting against their money.

Chasing Molecules is at its strongest when it takes the system to task. Are chemical companies releasing these pollutants into the environment because they're bad people? Are they putting products that they know to be potentially hazardous into large-scale production because they're evil? No. They're doing these things because they're good businesspeople. Research is expensive, and it should come as no surprise that the bulk of a chemical company's research dollars go towards maximizing the performance and cost-efficiency of a given product. The companies focus on crafting the best product possible, then selling it to the public at a price that allows for profit from their "cradle-to-gate" expenses. Whether or not that product breaks down into a harmful chemical once it's in the hands of the consumer just does not factor into the company's bottom line. It's the system, which has historically placed human and environmental costs at a stark minimum compared to material capital, which has endorsed a manufacturing ethic that places profits above all other considerations, that has given rise to the problems. The system continues to prosper in part due to lax regulation from government agencies, particularly in the United States.

Proponents of green chemistry would hold chemists and chemical manufacturers responsible for producing and selling products in a way that does not produce persistent toxic chemicals. The green chemists Grossman interviews are quick to acknowledge that change will only come from the manufacturing sector when those changes become profitable, which involves changing manufacturing philosophy to regard environmental costs as... well, costs.

Chasing Molecules takes the principles of green chemistry from
the billboard to the laboratory and will make you think about
your research in an entirely new light.
Grossman makes the case for change with scads of scientific evidence and expert testimony, along with a healthy dose of adventure stories and personal anecdotes. Each chapter features 20-40 footnotes with sources ranging from interviews with scientists to news reports to primary scientific literature. By interviewing researchers and engaging directly with data, Grossman imbues Chasing Molecules with a high degree of credibility, as her previous publication record attests. The narrative style can be dense while the science is being traversed, but Grossman keeps readers grounded by frequently referring back to the thesis of a particular section. Despite the book's 2009 publication date (2011 republication), almost every piece of the scientific story was new to me, or was something that I had read about briefly without really delving into. I learned a great deal reading this book.

For its strengths, however, Chasing Molecules falls into some familiar traps with tone and wording. Much of the book takes on an air of "natural = good, synthetic = bad", or more specifically "natural = good, petrochemical = bad", particularly in the opening chapters. Grossman is critical of the toxic effects of synthetic polymers and adhesives, but is surprisingly less critical of their green analogues later in the book when they are introduced. For example, a particular polymer with several attractive properties is described as "thymine-based." The discussion is heavy on the potential applications of the polymer, but light on its details or toxicalogical profile. A similar story is presented on a "castor-based" polymer and  "soy-based" adhesive. These materials are certainly emerging subjects of research and perhaps these details are not yet available.

Science writers translate scientific findings between the technical and exacting language of research to language accessible to non-experts. Most of Chasing Molecules does a great job of that, but some sections are abstracted so far as to become misleading. By way of example, in writing about the toxicity of phenols, Grossman draws parallels between phenols and the broad spectrum of petrochemicals. While phenols are petrochemicals, and phenols are also toxic, their petrochemical origins are not the feature that triggers toxicity. Moments like these pass up on opportunities to arm readers with methods of critically analyzing the chemical structure of a phenol so that they can make predictions about the next suspicious molecule to cross into the spotlight.

The Low Point: The low point of Chasing Molecules, if it can be called as much, is actually the beginning. The preface, prologue, and first chapter of the book are fairly redundant. Perhaps it was my impatience to get to the scientific data, perhaps it was my left-leaning tendencies and readiness to accept measures of environmental protection, but I found myself tapping my foot and waiting for the sections to be over. Rather than a particularly dicey section of the book, however, I would label the low point as the tone with which Grossman discusses some of the green alternatives to established chemical products and the broad brush with which she paints petrochemicals, as mentioned above.

The High Point: The high point of the book was the seventh chapter, in which Grossman opens by highlighting much of the environmental policy measures already in place in the United States and elsewhere for regulating chemical manufacturing and protecting against environmental exposure. The information is fascinating, but not because the regulations are good, to put it softly. Grossman points out weaknesses and loopholes in the Toxic Substances Control Act in particular. For example, "[a]nother feature of our current chemical regulatory system [...] is that the Toxic Substances Control Act allows manufacturers to claim confidentiality and withhold full details of a material's composition." (Grossman, 138). However, Grossman is not fanatical in this indictment, or in her discussion of toxics in any point of the book. She avoids environmental scare tactics in favor of sober discussions of existing data.

Chasing Molecules is an interesting read for chemists at any station within the discipline. For me, Grossman's book transformed green chemistry from a buzzy set of guidelines posted on the wall of my laboratory breakroom to an exciting intersection of basic chemical research, science policy, public health, and manufacturing strategy. Most chemists only think about one of those things - guess which.  
Chasing Molecules is not just for chemists by any stretch of the imagination, though. The information is organized logically and clearly, and the natural science is presented at a level accessible to any reader. If you're concerned about the rumors you've heard about why your plastic water bottle is killing you or how chemical exposure affects millions of low-income workers worldwide, then this one is a great place to start.

PS. The Audiobook: I frequently drive back and forth between Michigan and Pennsylvania, which leaves me lots of golden listening time to maximize with cool books, so I listened to this book rather than reading it (Audible). The ten-hour narration was one of the more excruciating auditory experiences of my life, and I've seen Mudvayne in concert. I occasionally found myself drifting off and having to repeat sections, which has less to do with the content of the book than it does with the sing-song lullaby voice of its narrator. The narrator also mispronounces some key chemical names that are repeated often throughout the text (tributyltin, for example), which becomes grating. Grossman also uses some long and complex sentences where large amounts of information are given in appositive clauses, and the narrator's delivery often makes those moments quite difficult to understand. I would highly recommend reading this one off of the page instead.

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