Silencing Spring: WWRD

First Pulished September 2008 in the Montague Reporter

In her 1962 publication, Silent Spring, Rachel Carson wrote about a spring in the near future potentially silenced by “indiscriminate use of pesticides,” with names like DDT, lindane, aldrin and mirex. What she didn’t write about back then, are the now infamous perfluorinated chemicals used in nonstick and waterproof surfaces, the polybrominated flame retardants that are infused into textiles and plastics, or the triclosan and triclocarban antibacterials in soaps, toothpastes and a range of consumer goods. Back then, no one knew that these chemicals used primarily in consumer products, would eventually find their way into not only you, but also your neighbor, and your neighbor’s neighbor, and, depending on the chemical possibly their uncle in Alaska and definitely the polar bear that just roamed through your neighbor’s neighbor’s uncle’s town.

Instead, Carson chronicled what in retrospect seems obvious now, but clearly wasn't back then. That spraying long-lasting (and by long - I mean decades) chlorinated chemicals like DDT, which accumulate in the fat and are designed to be toxic, on farms, suburbs, even cities just wasn’t smart. But if her expose seems obvious now, then why almost fifty years later are scientists finding, in addition to the remnants of chlorinated pesticides banned years ago, industrial fluorinated and brominated chemicals in water, sediments, wildlife and in humans? And why is one of the “next generation,” shorter lived, barely-bioaccumulative pesticides, atrazine, turning up in surface and groundwater supplies across the nation?

There is no doubt that the publication of Silent Spring wakened the American public to the very real consequences of “better living through chemistry.”

“I was in 8^th or 9^th grade,” recalls my neighbor Jeff, “and learned about it from the mainstream media. It had a pretty big impact – it started to frame the way you looked at things. I remember kayaking down the Connecticut. It was disgusting. But,” he conceded, “none of us were really sure what to do about these things.”

Barely a year old at the time of publication, and not cognizant of books except maybe as suitable teething material, I don’t recall its publication or the impact it had on my suburban life, although I do recall tanker trucks trundling along our road, spraying for mosquitoes and gypsy moths; the shelf in the garage full of bottles and spray cans that my father used to combat whatever ailed his beloved trees and shrubs; and, befitting my current occupation, I recall mixing up my own toxic potions – from cleaning materials stashed under the sink or in the laundry room, and testing them out on the earwigs and carpenter ants that raced along our swing set. Unlike Jeff, I was clueless.

Thankfully, there were plenty of folks who were neither clueless, nor baffled about what could be done to avert the impending environmental disaster described so elegantly by Ms. Carson. Eight years after Silent Spring, the US Environmental Protection Agency, the primary body responsible for registration, release and management of chemicals was born.

Of the December 2, 1970 launch of the agency Jack Lewis, writing for EPA Journal noted, “…Surely no factor was more pivotal in the birth of EPA than decades of rampant and highly visible pollution. But pollution alone does not an agency make. Ideas are needed--better yet a whole world view--and many environmental ideas first crystallized in 1962. That year saw the publication of Rachel Carson's Silent Spring….In fact, EPA today may be said without exaggeration to be the extended shadow of Rachel Carson. The influence of her book has brought together over 14,000 scientists, lawyers, managers, and other employees across the country to fight the good fight for "environmental protection."”

That’s an impressive legacy. But sometimes, I wonder what Ms. Carson would think of her legacy today?

Reading Silent Spring for the first time (I am ashamed to admit), it’s unsettling that nearly fifty years later, albeit on a different scale, Carson’s writing is still relevant. I don’t mean the the details – I think for anyone who didn’t live through those times – or who doesn’t live near farms where aerial spaying is still used – the events Carson described are hard to imagine. It’s been over thirty years since DDT fell from the sky like snow, and “housewives” swept pellets from their front steps or washed the stuff out of their kids’ hair, and the death of so many songbirds suggested a bleak future.

No doubt, we are all better off thanks to the EPA’s slew of chemical regulations and policies, but on a different scale, pesticides and industrial chemicals continue to contaminate water, consumer products, wildlife and us. And scientists, rather than focusing on lethality and reproductive success are now measuring more subtle changes in wildlife like altered reproductive function and development. The perfluorinated and polybrominated chemicals provide examples of history repeating itself – even with regulations in place. Sometimes chemicals slip by because scientists haven’t figured out how to measure them in the environment. Sometimes they slip by because no one expected them to be there, and sometimes they slip by because the industry that produced and released them didn’t provide all the relevant data. But thanks to greater collective environmental awareness ( by consumers, activists, scientists, policy makers and even industry), unlike DDT, it won’t take over a decade to phase-out fluorinated and brominated chemicals – phase-outs for these chemicals are already in progress.

But then there’s Atrazine. The top selling herbicide in the United States, banned by the European Union in 2003, atrazine is an example of a “new and improved” pesticide gone awry. Applied primarily to corn, with minor uses including lawns and golf courses, the EPA estimates that roughly 73 million of pounds of atrazine are applied to crops each year. Compared with the longevity of the chlorinated pesticides like DDT atrazine lasts for merely a blink in time with a half-life 146 days or so (although in these more enlightened days even that’s considered long-lived.) Unfortunately once Atrazine works its way into ground water it may last for years. The result? In the midwest, Atrazine is one of the most commonly detected contaminants in surface and groundwater, additionally it’s been detected although to a lesser extent in groundwater in the Northeast, including Massachusetts. Though detected concentrations often fall well below EPA’s 3 part-per-billion drinking water standards, there are a growing number of studies suggesting that other species, particularly amphibians may be susceptible to much lower concentrations.

University of California, Berkely researcher Tyrone Hayes reported back in 2003 that exquisitely low concentrations of atrazine, as low as 0.1 ppb, altered the steroid hormone balance in frogs, feminizing male frogs and resulting in hermaphrodism and demasculization of the vocal cords. And just recently, Krista McCoy and others, publishing in Environmental Health Perspectives, reported a link between hectares of farmland and feminization in local frogs. Although the authors didn’t measure specific pesticides, among the suspects is atrazine. All this got me wondering – where’s our EPA? Atrazine was recently up for reregistration, an opportunity for EPA to review data accrued over the years since a pesticide is first registered. For atrazine that was 1958. This was well before scientists were clued in to subtle reproductive and developmental impacts caused by small concentrations of chemicals. Nor was consideration given back then, and only rarely now, to the reality that seldom are individuals or wildlife exposed to single chemicals. We are all exposed to complex mixtures of contaminants released by industry, agriculture and from consumer products like soaps, sunscreens and pharmaceuticals.

Surely, I thought, given the pervasive groundwater contamination and the recent data on frogs, atrazine’s registration if not revoked would at least be restricted. At the very least maybe the allowable environmental concentrations (the “chronic criterion”) would be reduced below those found to impact amphibians? Unable to find the appropriate numbers on EPA’s website, I emailed EPA. “We anticipate this chronic criterion, when finalized later next year, will fall within the range of 10 to 20 ug/l [ppb]” wrote Frank Gostomski of EPA’s Health and Ecological Criteria Division. I asked if Hayes’ studies had been included. Yes, was the answer. But if Hayes’ studies hold up to scientific scrutiny –and there seems to be a growing body of literature that suggests that they do - then EPA’s concentrations are way higher than those found to feminize male frogs.

Though hard to imagine in our own backyard where spring peepers and cluckers keep us awake, is it possible that some day thanks once again to “indiscriminate use of pesticides” spring could still be silenced?

Making Lists: Dr. Cal's thoughts on priortizing chemicals

Guest blogger, Dr. Cal Baier-Anderson, a toxicologist at the University of Maryland, Baltimore; and Environmental Defense, adds her own thoughts about prioritizing chemicals (also check out the list created by J. Lowe from Impact Analysis in the comments section of Fav Five.)

A few years ago at a professional meeting I participated in a panel on the chemical perchlorate, which was receiving a lot of attention as an emerging drinking water contaminant. Perchlorate, an oxidizing agent that is used in rocket fuel, can block the uptake of iodide in the thyroid. One member of the audience suggested that focusing attention on perchlorate was a waste of time and money, that there are other chemicals that are more important. Make a list, I challenged the group; professional organizations and industry should step up to the plate and identify the top 10 chemicals of concern, from an industry perspective. It is certainly not an easy task, as Emily pointed out, many different lists can be made, depending on what features are most important.

With tens of thousands of chemicals in commerce, chemical prioritization is a hot topic. The traditional risk assessment process focusing on one chemical at a time requires a lot of data collection: the identification of the most important hazard endpoints (a prioritization process in and of itself); determination of dose-response for the priority endpoint, the characterization of exposure; and the assessment of risks. Chemical prioritization can be based on hazard, it can be based on likelihood of exposure, or it could be based on risk, incorporating both hazard and exposure. Many environmental groups argue that there is so much uncertainty in the risk assessment process that it is better to focus on hazard, emphasizing carcinogens, mutagens, reproductive toxicants, and endocrine disruptors. This has lead to the creation of lists, such as California’s Proposition 65 list of carcinogens, mutagens and reproductive toxicants (CMR), which requires that products containing a chemical on this label their products with a special notice.

Chemicals that can be classified as persistent, bioaccumulative and toxic (PBT) are also considered to be high priority chemicals. EPA initially devised a list of PBT chemicals, but then developed a computer program that evaluates individual chemicals to score them as to PBT properties. Persistence and bioaccumulation are determined by basic chemical properties, whereas toxicity is based on aquatic toxicity data.

With public attention focused on chemicals in consumer products, many companies are critically evaluating their products’ ingredients to determine if they are made with chemicals of concern. But how can we define chemicals of concern? Based on hazard, or based on risk? Some companies have developed their own restricted substances list that contains chemicals that the companies believe to pose some unacceptable risk to their workers and/or consumers. REI has a list, but a simple Google search of “restricted substance list” will uncover many more.

At the recent SOT meeting in Seattle, there was a session on hazard vs. risk-based approaches. Many state governments and large companies are defaulting to hazard-based approaches as a simpler approach to removing chemicals of concern from consumer products. Several prominent toxicologists opined that focusing on hazard without considering exposure will result in time and money wasted on chemicals posing very little risk. But as my colleague noted during the discussion, there are many folks in the environmental community that are wary of our capacity to predict exposure, citing numerous examples where it was initially predicted that there would be no exposure, and the experts were wrong: PCBs, Bisphenol A, phthalates, PFOA, PBDEs…If we can’t correctly predict exposure, then confidence in the risk assessment plummets, shifting focus to hazard.

A new approach is being promoted by some very smart people: alternatives assessment. Rather than making simple restricted substances lists, focus on what are the alternatives and compare using a suite of criteria. These assessments can be used to drive continual improvement in materials safety – protecting workers, the environment and consumers. Makes sense to me!

From Our Town Dump to.....The fate of high tech waste, the journey begins

Crossposted from Earth Forum:

Sidney's post on Waste Management, prompted me to add this post. When I read his title, my own thoughts jumped to management of e-waste (and wondered if this would be covered at that meeting.)

From my impression, this one of those waste issues where growing awareness is making a difference. In my own town, for example, you can rid yourself of computers, televisions and any electronic waste for something like five dollars. But the question is - then what? Turns out it "used" to go into a box car and then apparently on to China. I emphasize "used to" because that's only what I am told. The change, presumably, occurred because of environmental and health concerns. But at the moment no one can tell me if they've really changed their practices (it's something I'm looking into for a future article on the stuff.)

Two articles recently published in Environmental Science and Technology reveal the high risk to residents and workers caused by the dismantling of e-waste in regions where environmental laws are lax or nonexistent. The first article, by Huiru Li and others, is entitled " Severe PCDD/F and PBDD/F Pollution in Air around an Electronic Waste Dismantling Area in China " and the other by Xinhui Bi and others "Exposure of Electronics Dismantling Workers to Polybrominated Diphenyl Ethers, Polychlorinated Biphenyls and Organochlorine Pesticides in South China," describe the exceedingly high concentrations of these toxic chemicals to which not only workers but local residents are exposed during the dismantling processes.

For those interested in further reading on the subject, check out "High Tech Trash," written by Elizabeth Grossman, published by Island Press. An informative and sobering book, through which I'm slowing making my way.

Doh! There's more to bioaccumulation than we thought!

Here’s one for the “why didn’t we figure this out sooner” file, or maybe the “gee – those of us air-breathers really are different from our gilled cousins!” You see, for years one of the primary methods of determining the ability of a chemical to accumulate in living creatures was to study the accumulation (or bioaccumulation) of the chemical in fish. The model is based on the idea that fat-loving chemicals, which includes most bioaccumulative chemicals, are essentially absorbed from the surrounding water by fish, or, more or less technically, by “swimming bags of lipid.” Those that are not rapidly metabolized are retained in the fat, allowing not only for accumulation in our little fish, but also for the proverbial big fish that eats the little fish all the way up the food chain to polar bears, bald eagles and homo sapiens. Some infamous lipid-loving chemicals that we all know and fear include certain PCBs, dioxins, and DDTs.

Most governments, including the U.S., have thankfully learned (after…umm decades) to consider carefully a chemical’s potential for persistence, or ability to hang around the environment, and bioaccumulation when evaluating and regulate commercial chemicals.

Great! No more bioaccumlative chemicals climbing up the food chain. Problem solved. Or is it? A recent report by Barry Kelly, Frank Gobas and others, published in Science (Volume 317, pages 236-239) suggests that our current method for evaluating bioaccumulation may miss – and in a big way. According the study, some chemicals that don’t accumulate in fish, or chemicals that might pass the “swimming lipid bag” test with flying colors, can accumulate land mammals and marine mammals.

What’s the difference? After all fat is fat – be it a swimming or walking bag of lipid (which I must admit sometimes I’ve felt myself as I struggle to squeeze into my favorite jeans at the end of the summer.) Turns out, as with anything, there’s more to bioaccumulation than hanging out in fat. Living organisms are dynamic creatures, and most things that enter the body have the potential to be metabolized and/or excreted. Even chemicals that hide out in fat can be eliminated given enough time. But what’s different between fish and polar bears or fish and humans (among other things) is that according to Kelly and others, “…air-breathing organisms in this analysis exhibit higher [biomagnification factors] than those in water-respiring organisms because of their greater ability to absorb and digest their diet, which is related to differences in digestive tract physiology and body temperature.” Additionally, note the author, air-breathers may be less efficient when it comes to eliminating certain chemicals from their bodies than water-respirers.

Go figure. This is where, as a toxicologist who bought into the “bag of lipid” model years ago without question, now wonders – what was I thinking? Chemicals that might pass (and have passed) the fish bioaccumulation test, wouldn't pass a mammalian test, according to the authors who note that these chemicals, “representing a third of organic chemicals in commercial use, constitute an unidentified class of potentially bioaccumulative substances that require regulatory assessment to prevent possible ecosystem and human-health consequences.”

Time once again, to reconsider how we evaluate and regulate, and release chemicals into our environment.