sunday times: worse living through chemicals

When I was growing up, the world was still on the post-World War II binge of using chemicals to "improve" our lives on all fronts. We are certainly paying the price.  Even the cleanest-living among us cannot escape exposure.

We now begin our lives full of chemicals. Chemicals are so pervasive in the environment, that a study has found 287 different contaminants in human umbilical cord blood, which means toxins are being delivered to fetuses while in the womb.  These contaminants included pesticides, fire retardants, and mercury.

Even if we don't consume drugs, we may ingest them in our drinking water. A Washington Post article reports on the alarming amount of pharmaceuticals in our nation's waterways, the result of drugs being tossed down the drain and flushed down the toilet (both in original and, I presume, processed form). These chemicals, including hormones found in birth control pills, may have human health risks, since water treatment plants only remove a fraction of pharmaceutically-active compounds).  Nobody is sure what the effects are, how these substances interact, or the full seriousness of their impacts on wildlife.  Nonetheless, most government officials don't seem particularly interested in the issue. (More info here). 

Nor can we escape, even in the far corners of the world.  Toxins are not local, but far reaching, carried from source areas to far away places by wind, ocean currents, and, as has been recently reported in the journal Science, in the feces of roaming seabirds. A study found lakes in the Canadian Arctic

"...that are frequented by northern fulmars (Fulmarus glacialis) can harbour 10-60 times more pollutants than neighbouring, birdless lakes. These pollutants include persistent, toxic compounds such as mercury, DDT and hexachlorobenzene (HCB), which were once common ingredients in pesticides and fungicides."

The fulmars acquire the contaminants in their diets of fish, squid, and carrion.

***Update on deer overpopulation:  A paper in the new issue of Biological Conservation, "A natural experiment on the impact of overabundant deer on songbird populations," studied a British Columbia archipelago, comparing forest bird populations on islands without deer, those that have had deer <20 years, and those with deer >50 years.  Not surprisingly,the authors found that bird abundance on islands browsed for >50 years was 55–70% lower than on deer-free islands. Bird species that rely on forest understory were most effected, decreasing 93%. These species include Fox Sparrow (Passerella iliaca), Rufous Hummingbird (Selasphorus rufus), Song Sparrow (Melospiza melodia), Orange-crowned Warbler (Vermivora celata), Winter Wren (Troglodytes troglodytes), and Golden-crowned Kinglet (Regulus satrapa).

---

Allombert, S., A. J. Gaston, and J.-L. Martin.  2005. A natural experiment on the impact of overabundant deer on songbird populations. Biological Conservation 126: 1-13.

Blais, J.M., L.E. Kimpe, D. McMahon, B.E. Keatley, M. L. Mallory, M.S.V. Douglas, and J.P. Smol. 2005. Arctic seabirds transport marine-derived contaminants. Science 309: 445.

Comments

[Clare]

Okay, now I'm just plain depressed. There has been a lot of studies lately on organic contaminents in Arctic wildlife. Seems there is no where to escape them.

However on a happier note, doesn't the Winter Wren have the greatest specific name? Troglodytes troglodytes. Just makes you want to say it over and over.

[John]

The Winter Wren has one of my favorite songs - it is so complex and ethereal. I would hate to see that species disappear because of over-browsing.

[Nuthatch]

I don't like to publish depressing posts; at least I like to include action items. But sometimes I feel like I need to put out some sort of heads-up, even if I don't know what the hell to do about it.

As for Winter Wrens: also one of my favorite birds. I guarantee there's a post in the future about them.

[Lene]

I hadn't seen the study on bird feces contaminating water. When I read your post, I was reminded of a study I read a few years back about the biotransport issues related to fish that migrate thousands of miles. It was a study in Alaska comparing land locked fish with a lake in a similar environment that had migrating fish. I can't remember all of the details, but it was startling to hear how fish that migrated and then died in more pristine environments were contaminating the area with their deteriorating flesh. If you're interested, I would be happy to look up the study for you.