Swimmers, Hoppers and Fliers: How Do Toxic Chemicals Move around the Planet?

Toxic chemicals created by human activity reach unusual concentrations in the Arctic, among other places















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CONTAMINATED ICE: The Arctic bears unusually high levels of various man-made chemicals. Image: NOAA Office of Ocean Exploration

Editor's Note: The following is an excerpt from Elizabeth Grossman's  book Chasing Molecules.

Even hundreds of miles from the nearest industrial or agricultural activity, the sea ice, ocean, and Arctic plants and animals regularly yield evidence of elemental and synthetic chemical contamination. This contamination includes not only herbicides, fungicides, and pesticides—chemicals that are used in open air, may have washed directly into rivers or are released from factories—but also metals, among them mercury as well as flame retardants and water repellants, among other substances that are, at least in theory, incorporated into the materials of the products they’re designed to enhance.

Among the errant compounds now found regularly in the Arctic, for example, are brominated flame retardants, including those known as PBDEs (polybrominated diphenyl ethers) used widely in upholstery foam, textiles, and plastics. Also routinely recorded in the far north—some at remarkably high levels—are perfluorinated compounds (PFCs) used as stain repellants, waterproofing agents, and industrial surfactants (think Scotch-guard, Teflon, Gore-Tex, and the slick coating on paper used in food packaging such as pizza boxes, candy wrappers, and microwave popcorn bags).

These same compounds are now being detected in animals and people all over the world. A network of more than forty sampling sites has found evidence of synthetic chemicals that do not break down into nontoxic components—a mix of pesticides, fossil-fuel emissions, and industrial compounds—virtually everywhere it looked, from Antarctica, North America, Australia, and Africa to Iceland. A recent five-year study conducted in U.S. national parks across the American West and Alaska found these same contaminants in the majority of its snow, soil, water, plant, and fish samples.

It’s not known when the first persistent synthetic chemical contaminants arrived in the Arctic, but this kind of pollution has been detected there on a regular basis since the 1960s. “Everyone thought the Arctic was pristine, so we were taken aback to find such high contaminant levels in top predators,” says Gary Stern, a senior scientist with Canada’s Department of Fisheries and Oceans. But “anything released in the mid-latitudes travels rapidly north.”

Long-lasting synthetic chemicals are often referred to as “persistent organic pollutants,” or POPs for short. Used in this way, “organic” means that the chemical compound contains one or more carbon atoms and not all organic compounds are toxic or persistent.

Public awareness of POPs such as DDT, PCBs, and dioxins has been growing. By 2001 concern about the environmental and health impacts of POPs had risen sufficiently to prompt the United Nations Environment Programme to formulate a treaty called the Stockholm Convention aimed at curtailing the use and release of these chemicals. “Exposure to Persistent Organic Pollutants (POPs) can lead to serious health effects,” writes the organization that administers the Stockholm Convention, “including certain cancers, birth defects, dysfunctional immune and reproductive systems, greater susceptibility to disease, and even diminished intelligence.” (The United States has signed, but as of 2009 had not yet ratified, the Stockholm Convention—so it has not been a full participant in its meetings and decision making, and its use of chemicals is not yet formally bound by the Convention’s regulations.)

By taking samples at numerous study sites over extended periods of time, scientists have discovered that some contaminants travel entirely by air—these are what Frank Wania of the University of Toronto calls fliers. Some—the swimmers—stay in the water, circulating with ocean currents. Most are hoppers, though; they make their way north in what’s been dubbed the grasshopper effect, a series of air- and waterborne hops, moving toward the Arctic with cyclical and seasonal patterns of evaporation and condensation.



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  1. 1. eco-steve 06:34 PM 11/23/09

    For decades legally acceptable levels of discharged pollutants in air and water have relied on the notion that as they go downstream they will become diluted to ever safer levels. This is to ignore that once in the oceans, these pollutants will be concentrated back up through the food chain to toxic levels. Therefore the only acceptable dilution is zero discharged pollutants. Waste effluents should logically be dried and deposited in safe landfill sites where like naturally occurring toxic mineral ores they can do little harm.

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  2. 2. Bops 08:08 PM 11/23/09

    eco-steve
    All your ideas that I've read so far are really good.
    Could you e-mail your idea... maybe someone, in the right place, will think, Better idea... and put your thoughts in practice. Can't hurt to try.

    Great things are not done by impulse,
    but by a series of small things brought together.
    By Vincent Van Gogh

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  3. 3. Sybil 04:39 AM 11/24/09

    eco-steve
    Sorry to tell you that, it is not so simple. Drying waste use huge amount of energy and will vaporise what can be vaporise. Then you have to find apropriate landfill that will not leachate, without worried neighbours...
    People fixing legally acceptable levels of pollutant know that no level is guarantee to be safe. It is just the best we can get. No government can ask the industries not to pollute. Its only a balance between what price you are willing to pay and what risk you can accept. A lot is being done with waste treatment and I think green design is the next step.
    Zero discharge is a good dream. Keep dreaming, good changes begynn with good dreams.

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  4. 4. eco-steve 09:25 AM 11/24/09

    Sybil : Drying waste certainly can be energy-hungry. Yet a lot can be done simply. First of all ensure no rain falls on effluents, and that waste is properly held in flood-free tanks and reservoirs. For example, the china clay industry in England was forced, (Yes, by massive fines), to build settling beds downstream of their quarries. Overnight pollution stopped. The settling beds were built so wind dried them. Industrial wastes are often potential raw materials for other uses. Think about sewerage sludge which can be used as fuel by cement ovens, which can also incorporate toxic wastes to seal them virtually forever.
    The problem of lixiviation will be cracked when once properly conceived landfill sites are optimised. The main problem is that many firms find it cheaper to dump waste rather than to treat it legally.

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