Wednesday, March 28, 2007

Waterproofing the Ocean: the consequence of keeping dry

“Must keep water out” was my mantra. The old red backpack, my faithful traveling companion for over twenty years, cross country, up mountains, at sea, and across the ocean had sprung a leak. Wet through completely when a drenching rain followed my husband and I down the Madison Gulf trail. Socks, underwear, warm clothes – sopping. But rather than purchase a new frame pack, I reached for the Scotchgard™, and methodically sprayed each crack, crevice and seam, confident in that by “renewing” my old pack, I was doing the right thing.

What I didn’t know then, shames me now. What I didn’t know then, apparently the 3M Company and the Dupont Corpration had known for years. That the use of, and manufacturing process for products like Scotchgard™, my Gore-Tex Coat, and the surface on my favorite fry-pan, leave behind more than just consumer goods. What we know now, according to a review recently published by Magali Houde and others from the Unversity of Guelph in the journal Environmental Science and Technology (ES&T), is that the perfluorinated polymers, the most notorious being PFOA and PFOS, used to resist, protect, and repel, have infiltrated almost every living system on earth, from Great Lakes algae to polar bears in Svalbard, from the green-lipped mussel to Kemp’s ridley sea turtle, the bald eagle and the common loon. And, unless you consider yourself separate from life on earth, these chemicals have infiltrated you, me and your next-door neighbor.

By now, this is old news. Many of us are familiar with the stories. Parrots dropping dead, 3M voluntarily “outing” PFOS, reports of PFOA and PFOS in our blood. It is old news that these chemicals persist in the environment and are found from the North Pole to the South Pole and everywhere in-between.

But how did this happen? These chemicals have been around for over fifty years. Where was the US EPA? Where were our environmental protections? Turns out, that these chemicals slipped through, legally, at least one process that would have identified their current role as the environmental contaminants de jour. That is, the Premanufacture Notification process.

Ever since Congress passed the Toxic Substances Control Act back in 1976, the EPA has had the authority to review and regulate each new chemical based on its potential threat to us, and the environment prior its use in commerce. But there’s a catch. According to the EPA, “chemicals in commerce prior to the effective date of the Toxic Substances Control Act were placed on the inventory without going through the premanufacture notice.” And, some classes of chemicals were specifically granted exemptions. These included some of the perfluorinated chemicals involved in the production of PFOA and PFOS. The idea being, according to the agency, that “certain chemical health and safety information [would] be submitted to the Agency…when companies learn of it.”

But in 2004, the US EPA charged that Dupont had violated that bit about providing “certain health and safety” information. Apparently they forgot to report that not only was PFOA persistent, but that it might be toxic to humans and the environment. Oops.

Dupont settled for over $10 million, EPA initiated a voluntary phase-out of the chemical by 2015 (a program in which Dupont along with several other manufacturers, is a participant) and back in 2000, the 3M Company voluntarily phased their use of PFOA, PFOS and related chemicals.

Phew. Glad that’s over.

Or is it?

What about those polar bears, eagles, and loons? What about the starfish, green-lipped mussels, tuna, sea-turtles and otters? Konstantinos Prevedouros and others from Stockholm UniversityE. I. duPont de Nemours, in a study published in ES&T, estimated that over the years, thousands of tons of PFOA or PFOA precursors were released to the environment, with much of it discharged into our waters. and In one case, 61% of the chemical used was released to the environment, most going right into the water, without violating a single law. Well, excepting those companies that knew, but didn’t tell. And this is only part of the legacy bequeathed upon us not just by industry but by our own desire for eggs to slide, fabric to repel, and carpets to gleam. There is no accounting of the tons of PFOS used or released over the years.

“Water is the main vector for exposure in wildlife,” says Frank Gobas, a researcher at Simon Fraser University who studies chemicals that accumulate in wildlife. In the environment, according to Gobas, perfluorinated chemicals exist in a relatively water soluble form. “Marine mammals are likely the most exposed, due to water to fish to mammal transport, which the perfluorinated chemicals tend to favor.”

The big “so what” comes from my son. Each time I begin to write, he knows it’s bad news.

“So what do those kill?” he asks peering over my shoulder.

I explain that aside from killing the occasional parrot - though Dupont and others suggest that birds are sensitive not only to fumes from overheated Teflon but from overheated butter and oils - the effects on wildlife are unknown

And although there may be ample evidence of a chemical’s toxicity in the laboratory (one form of PFOA causes neurotoxicity, liver toxicity, immuno toxicity and developmental toxicity), and ample evidence of the chemicals presence in the tissues of wild animals, one of the more challenging problems in environmental toxicology is linking the presence of that chemical in the environment with harmful effects on wildlife.

For example, Kurunthachalam Kannan, of the New York State Department of Heath, and SUNY Albany, and others, recently reported on the relationship between PFOA and PFOS concentrations in sea otters found dead or dying along the California coast and disease status. The group found more PFOA and PFOS in sea otters determined to be diseased at the time of their death, compared with those classified as non-diseased, However, according to their study, reported in ES&T, they were unable to determine if the higher levels of perfluorinated chemicals were “a cause of the disease, a consequence,or coincidental.”

Kannan’s group also reported a decline in PFOS in the otters over time, following 3M’s phase-out. Was that a surprise? “I expect that it would take much longer for the environment to respond,” says Kannan. “Maybe what we found was circumstantial, but a few other researchers have found a similar decline in seals from the Arctic.”

James Armitage, a PhD candidate at Stockholm University, studies the fate of PFOA in the environment. He agrees that once the release of these chemicals and their precursors is halted, depending on the location, environmental concentrations may decline quite swiftly.

“Given the lifespan of most creatures in the environment,” says Armitage, “I would expect to see a response to declining environmental concentrations fairly rapidly.”

“But,” he adds referring to a modeling study soon to be published, “we observed that concentrations in the North Temperate Zone, the source area, decline almost immediately, while concentrations in the North Polar Zone continue to increase.” The declines he notes are due mainly to redistribution to other ocean areas. In other words, even if phased out, the perfluorinated chemicals aren’t likely to go away soon, they’ll just go somewhere else.

According to those in the industry, there really is no replacement for perfluorinated chemicals. It is the combination of fluoride and carbon that provides the repellent properties that make these chemicals so useful and durable. The 3M Company has already developed a new polyfluorinated chemical to replace PFOA, PFOS and PFOS-related products. Their website, asserts that the reformulated products have been tested for toxicity and bioaccumulation, and have apparently passed with flying colors. But, what the site doesn’t say is that they are persistent in the environment. And though no one expects them to accumulate in the sediments, they are expected to hang around in water.

When asked about the replacement products Enesta Jones of the EPA, says “The new chemical replacements have been subject to considerable scrutiny. The Agency is requiring robust fate and toxicity testing, and will retain regulatory authority over these chemicals until we can be assured they do not present unreasonable risk.”

I hover over my daughter’s leather boots, and ponder my desire to keep her feet dry, a can of Sno-Seal silicon (non-polyfluorinated) water-guard in my hand, and begin to spray.

Tuesday, March 27, 2007

Monopoly Boards and Polar Fleece, Mysteries of Curbside Recycling Revealed

I shouldn’t admit this, but I get an odd thrill on trash collection day. Maybe it’s because our two trashcans are packed so full that it’s a relief to have the stuff carted away. Or maybe it’s because waking up to empty barrels means I’ve actually remembered to pick up some stickers from the Mini-Mart and put them on the barrels. I don’t mind paying the $2.50 a barrel, in fact, I think it’s more than fair. After all, thanks to the incredible recycling program in town, it’s only once or twice a month we even drag the barrels to the curb.

For years I’ve ignored that nagging question, does recycling really reduce the amount of waste we toss from our homes? Am I justified in bragging to friends and family that we generate only two barrels or so of trash a month? Years ago (in another town) there were rumors that our carefully sorted bottles and paper ended up with the rest of the trash – in the landfill. Some part of me wanted to be content in my ignorance, in my faith that unethical recyclers were a thing of the past or something that only happened in big cities.

But, one afternoon while listening to an National Public Radio story on recycling those new compact fluorescent bulbs, the spiral energy saving bulbs you have to wrestle from all that energy intensive plastic packaging, the commentator noted how few consumers are even aware the new bulbs contain mercury, although each package clearly states that: LAMP CONTAINS MERCURY; Manage in Accord with Disposal Laws; See

Listening to the story and aware that I limit her tuna fish consumption to a can a week because of my concern about mercury, my daughter Sophie asked, “What do they do with the mercury, and how do they get it out?”

Good question. In fact, what happens to all the stuff we leave curbside? The yogurt containers, juice cartons, milk jugs, tin cans, and cereal boxes. And why can’t we leave eggs cartons, pizza boxes and plant pots?

According to our local expert, Jan Ameen, Executive Director of the Franklin County Solid Waste Management District, there truly is an afterlife for our milk jugs, soda bottles and computer paper, though disposal is the end of the road for the lowly egg carton.

“Egg cartons use the shortest paper fiber,” Ameen explained. “Basically, they are the end of the paper recycling line. The fiber cannot be used again, so when they go to the paper mill for recycling, they dissolve and end up in the wastewater.

“Pizza boxes can be recycled if they’re not greasy. Most recycling paper mills don’t use chemicals, just warm water to dissolve the paper. There isn’t a good way to get rid of the grease from this process.”

In contrast, all the used and reused printing and computer paper, all the old bills, envelopes, and technical reports on obscure topics I finally cleared from my filing cabinet fared better than the egg cartons and pizza boxes.

“All of the paper from western Massachusetts,” said Ameen, “ends up at a paper recycling mill in Fitchburg, North Shore Fibers. They make Monopoly boards and book covers, mostly, and other paper products.”

It was good news to find my old paper might be hosting games of Monopoly, or protecting someone’s storybook, but I wasn’t really worried about paper recycling. It’s been around for decades, and it seems these days all sorts of paper products are recycled including my Seventh Generation toilet paper, which proudly proclaims the “post-consumer” content (post-consumer meaning made from the stuff we leave curbside) as 80%. Not bad. Neither did I worry about recycling cans. Tin and steel are valuable, so it makes sense we’ve been recycling them for years.

But what about plastics and their array of letters and symbols: PETE, HDPE, LDPE, PP, PS? Why do we no longer sort them, and why can’t we recycle all those plastic plant pots?

It’s a big world, and there’s lots of plastic. The American Chemistry Council reports that in 2005, 922 million pounds of HDPE bottles (those thick plastic bottles like milk jugs and laundry detergent bottles) were recycled, as were over 2 billion pounds of PET and PP bottles (PET are things like coke and juice bottles, and PP are polypropylene – those “next generation” bottles that don’t add a plastic taste to your drinking water.) This represents only about 25 - 30% of all recyclable bottles out there. Sadly, many still end up in the trash. Still, that’s a lot of recycled plastic. And those plastic plant pots? Says Ameen, “Plant pots aren't recyclable because of the dirt and because they are often black (no black plastic is recyclable.)” Though a web search led me to a couple of programs specifically for plant pot recycling, one in New Jersey and one in Missouri, it seems that gardeners nationwide are stymied by the inability to recycle these items locally!

In our town, the first stop for all of our bottles, boxes and papers is the Springfield Materials Recycling Facility, where plastic recyclables are sorted according to type and then sent off for further processing, depending on the item. For plastics, that means recycling them into anything from fiberfill to polyester-like fibers, to those blue recycling bins, to plastic lumber furniture. Ever have a cinder land on your new fleece jacket and watch it melt its way through the fabric? That’s because fleece is plastic! And while some companies still rely on “virgin” polyester to produce fleece, there is now EcoSpun, ECO-Fleece, and EcoPile products made primarily or entirely from our recycled bottles. Even large corporations like Malden Mills, which produces Polartec, are touting their recycled fleece products.

But, I wondered what happens then, when the fleece eventually becomes too ratty to donate to the Salvation Army? Patagonia, the mega-outdoor retail store now recycles old fleece into new products, though they note that their process is currently limited to Polartec, and their own capilene and cotton products from Patagonia. On their website, they say they hope other companies begin taking advantage of old fleece as well.

Ah, but what about those mercury containing fluorescent bulbs? The good news is, according to the EPA, the new bulbs help decrease mercury emissions by reducing the demand for electricity. Primary sources of electricity are coal-fired plants, which still routinely emit mercury into the atmosphere.

The bad news is there is no curbside service for the bulbs, and many distributors don’t have a program in place to recycle the bulbs. Fortunately, this shouldn’t be too much of a problem, since the new bulbs are supposed to last for five years, or 8,000 hours. That’s right - five years, and if they don’t last that long, all you have to do is send in your receipt and UPC (hah!) and get a refund. But when the time does come, and it certainly came sooner than five years for a few of our bulbs (unfortunately, those UPCs were recycled long ago), we can take them to the Montague Transfer Station where they are sent off to Veolia Environmental Services in Stoughton, MA, for recycling. Although at the moment it costs fifty cents a bulb, maybe in five years when we all recycle our bulbs en masse, there will be more recycling options.

Veolia specializes in recycling lighting and electronic wastes. On their website they note that an “estimated 600 million fluorescent lamps are disposed of in U.S. landfills, amounting to 30,000 pounds of mercury waste.” That’s a lot of mercury.

Using an enclosed process Veolia crushes the bulbs, and then extracts mercury and other components. In the end, the company’s website declares that all parts, including glass, metal end-caps, powder, and mercury, can be reused.

So next time you flip on your compact fluorescent, and pull on your favorite fleece for a game of Monopoly, who knows, you could be enjoying the fruits of your recycling efforts!

For more information on recycling in your county check out:

Earth 911: A site that provides you with disposal and recycling information for any zip code in the country.

Wednesday, March 21, 2007

Ingesting, digesting, and egesting oh my: nanoparticles and water fleas

Years ago when I first met my husband, I am ashamed to say, I may have belittled the importance of his research project. He was studying larval fish, and observing what they ate, how much they pooped and how quickly they grew. Who cared I wondered? I was a toxicologist I’d thought at least my work was somewhat applicable to….to something! That was almost twenty years ago and now he’s out saving wild fish populations, and I’m here typing at my desk! But recently I came across an article entitled In Vivo Biomodification of Lipid Coated Carbon Nanotubes by Daphnia Magnia” by Aaron Roberts, et al., published in Environmental Science and Technology, which highlights the importance of ingesting and egesting (or eating and pooping) in an environmental context that even a toxicologist can appreciate.

Turns out that what little critters eat, digest and poop may have some important implications for nanomaterials. Roberts et al. reports on the fate (and to some extent toxicity) of single-walled carbon nanotubes or, SWNTs, in aquatic creatures known as Daphnia magnia, or better known as water fleas.

Alone, SWNTs are not water soluble, which apparently limits their utility. In this case, the authors first combined SWNTs with an amphiphilic coating, (that means it goes both way water loving and fat loving,) to render them soluble in water. Rendering SWNTs more water soluble, according to the authors will:

“..not only enable biological studies of cellular responses but also empower the development of next generation single-molucule chemical and biosensors and self-assembled nanodevices,.”

But, they noted, this new and improved water soluble nanomaterial comes with a caveat,

“Because of the large number of applications there may be great potential for discharge of coated, solubilized nanomaterials into the environment.”

Enter, the fleas.

Since solubilized nanomaterials might end up in watery environments, the authors exposed Daphnia to concentrations of coated SWNTs. They reported that up to a point, the Daphnia not only tolerated but (under conditions of starvation) may have even benefited from the coated materials. Daphia ingested the materials, stripped the coatings, and apparently used them as a food source (those in SWNT water survived to a greater extent than those without), and egested (pooped out) uncoated and now insoluble SWNTs. But we all know what happens when we over indulge. When exposed to higher concentrations, the Daphnia didn’t fare so well, and survival was reduced. Additionally the authors noted that coated SWNTs also accumulated on the outer surfaces of Daphnia (also not good.) I would also suggest that all food sources are not created equal. For example what keeps one generation going, might not be sufficient for producing the next, so that further studies of such materials might include life-cycle tests and more intensive investigation into the quality of "food" provided by similarly coated nanomaterials.

In conclusion, the authors note that:

“Our data show that biomodification of lysophospholipid-coated carbon nanotubes in vivo can occur and have dramatic effects on the physical properties of the nanomaterial. These modifications may result in unanticipated effects both on the materials properties as well as the organisms exposed to the nanomaterial. Biomodification is an important phenomenon that should be considered in studies on the biological applications, environmental fate, and toxicity of convalently and noncovalently functionalized nanomaterials.”

You can find the full article, by Aaron P. Roberts, et al., In Vivo Biomodification of Lipid Coated Carbon Nanotubes by Daphnia Magnia in Environmental Science and Technology, ASAP Articles, March 7, 2007.

Wednesday, March 14, 2007

More on Sunscreens

This morning I finally came across the science article I’d been dreading. With the kids off to school and the dog walked, I settled in to my morning routine, coffee, bagel and Science Magazine. After skimming articles on ancient towers marking the solar calendar in Peru, brain evolution, and African penguins, I came across a News Focus article entitled “A Healthy Tan?” written by Ingrid Wickelgren. Over the past ten years as I’ve coated the kids with sunscreen I’ve been waiting for the inevitable. As a scientist I know that science is always on the move, particularly when it comes to understanding how the body responds to chemical or physical (as in the sun’s ultraviolet rays) insults. As scientists learn more, things change. So I’ve been waiting for the down side of sunscreens. The, “If we only knew then, what we know now.”

Though the news isn’t all that bad, it is worth considering that scientists and those in the health fields are still figuring out the best way to protect those of us who insist on playing in the sun (besides the obvious – just cover up!)

According to Wickelgren:

Anyone who relies on sunscreen knows it is sticky, inconvenient, and easy to forget. But sunscreen has a lesser known, and more serious, downside: It doesn't adequately protect against the deadliest form of skin cancer.

Although ultraviolet (UV)-blocking sprays and creams protect people against sunburn and the milder forms of skin cancer--squamous cell and basal cell carcinoma--they do not form an effective shield against melanoma, which doctors diagnose in 132,000 people worldwide each year. Ironically, says a growing cadre of skin biologists, what seems to protect best against melanoma is something that sunscreens efficiently thwart: a deep, dark tan.

Dark-skinned people, who also tend to tan well, are up to 500 times less likely to get melanoma and other skin cancers than are fair-skinned individuals. The ability to tan confers protection, researchers say, regardless of the skin's background level of pigmentation. This is due in part to the UV-shielding effect of melanin, the pigment that makes skin cells dark, and perhaps in part to an acceleration of DNA repair that some believe accompanies tanning. But tanning in the sun is a fool's wager, dermatologists say, because it causes dangerous DNA damage, which may lead to cancer before it can be fixed. To provide a sun-independent alternative, scientists are now developing compounds that trigger tanning and DNA repair by acting on molecules that control the melanin production pathway.”

The complete story can be found in Science, March 2, Vol 315 pages 1214-12166.

Tuesday, March 13, 2007

So, should I order the fish?

Much to my embarrassment, shortly after graduating with my Ph.D. and directing my attention to PCBs and other toxics in fish, whenever we stood by the fish counter at the local seafood restaurant, my father would announce that I was an expert on contaminants in fish. “So, should I get the fish?” he’d ask.

I’d turn red and shrug my shoulders, muttering something like, “I don’t know, depends where it comes from, I guess.” Truth was that I studied the impacts of chemicals on reproduction in fish not humans, so really, I could only answer as an expert for fish concerned about their reproductive health.

But even for those who study the human health impacts of chemicals, the issue of evaluating the risk associated with contaminants in seafood has always been tricky. Risk from contaminant exposure depends on the contaminant, the particular health effects associated with the contaminant, the species of fish (some fattier than others), the age of the fish, where it was caught (if wild), if farmed, what it was fed, how much one eats fish how often, and even on who’s eating the fish!

An recent analysis by Sam Luoma and Ragnar Lofstedt titled "Contaminated Salmon and the Public's Trust" published in Environmental Science and Technology addressed the complexity of that simple question “Should I get the fish?” and “If so, what kind?” They refer to a study published in Science several years back, which reported on concentrations of PCBs and similar chemicals in farmed and wild salmon, and which reported that farmed salmon were, in general, more highly contaminated than wild-caught salmon.

According to Luoma and Ragnar, this set off a “contentious dialogue….mostly because the risk analysis for salmon did not consider a balance of risks,” the end result (at least for a time) was a drop in consumer confidence for farmed salmon resulting in a heavy burden on wild salmon populations.

While the authors don't answer the question "to eat or not to eat", they do provide an interesting discussion about communicating and evaluating risk for complex scientific issues, even ones that seem simple, check out it.

Monday, March 05, 2007

More on Nanotech

Nanotechnology is an interesting field for a toxicologist because of the very public discussion about toxicity, regulation and the future of nanotechnology. Unlike other major technological advances in the past with the potential for health and environmental impacts, nanotechnology is developing under the virtual microscope of the internet – where citizens, researchers, regulators are able to access a great deal of information and can organize via the internet.

Below are a few new articles on the toxicology of nanomaterials and a link to a podcast "The Implications for Health, Safety and the Environment of the Nanotech Revolution."

This interesting and informative podcast sponsored by Nanotechnology Victoria (Austrailia), considers the ethics, toxicology, risk assessment, worker heath and safety. While those interviewed agree that there are data gaps in the toxicology and potential for environmental impacts of nanotechnology, they also note the potential benefits of future nanotechnology products. Views range from a moratorium on nanotechnology development, to greater government and industry resources to improve worker standards to avoid another potential “asbestos-like” disaster for workers in the field, to a call for all involved to recognize the broad range of materials to which the term nanotechnology refers.

For those interested in more technical articles on nanomaterials, below are three articles recently published in Environmental Health Perspectives describing recent toxicological research on nanoparticles.

Cardiovascular Effects of Pulmonary Exposure to Single-Wall Carbon Nanotubes by Zheng Li,1 Tracy Hulderman,1 Rebecca Salmen,1 Rebecca Chapman,1 Stephen S. Leonard,2 Shih-Houng Young,2 Anna Shvedova,2 Michael I. Luster,1 and Petia P. Simeonova concludes:

“Taken together, the findings are of sufficient significance to warrant further studies to evaluate the systemic effects of SWCNTs [Single-Wall Carbon Nanotubes] under inhalation exposure paradigms more likely to occur in the workplace or environment, such as low-level chronic inhalation exposure.”

Inhalation Exposure Study of Titanium Dioxide Nanoparticles with a Primary Particle Size of 2 to 5 nm by Vicki H. Grassian,1,2,3, Patrick T. O'Shaughnessy,3 Andrea Adamcakova-Dodd,3 John M. Pettibone,2 and Peter S. Thorne concludes:

“Mice subacutely exposed to 2–5 nm TiO2 nanoparticles showed a significant but moderate inflammatory response among animals at week 0, 1, or 2 after exposure that resolved by week 3 postexposure.”

Finally, an interesting article entitled Effects of Aqueous C60 Nano-Aggregates to Tetrahydrofuran Decomposition Products in Larval Zebrafish by Assessment of Gene Expression by Theodore B. Henry, Fu-Min Menn, James T. Fleming, John Wilgus, Robert N. Compton and Gary S. Sayler suggests that toxicity in this case was caused by chemicals used in the preparation of the nanomaterials, rather than the nanomaterials themselves.