Effect Measure

“Oh, what a tangled web we weave, when first we practice to deceive pollute.” I know it doesn’t rhyme. But the tangled web is real:

Songbirds feeding near the contaminated South River are showing high levels of mercury, even though they aren’t eating food from the river itself, according to a paper published by William and Mary researchers in the journal Science.

Lead author Dan Cristol said his paper has wide-ranging international environmental implications. Mercury is one of the world’s most troublesome pollutants, especially in water. The South River, a major tributary of Virginia’s Shenandoah River, has been under a fish consumption advisory for years, as are some 3,000 other bodies of water in the U.S.

The paper shows high levels of mercury in birds feeding near, but not from, the South River. Cristol and his colleagues also identify the source of the pollutant–mercury-laden spiders eaten by the birds. The Science paper is one of the first, if not the first, to offer scientific documentation of the infiltration of mercury from a contaminated body of water into a purely terrestrial ecosystem. (Science Daily)

Inorganic mercury was dumped into the river between 1930 and 1950. Bacteria then converted it to the more toxic organic methyl mercury. Aquatic animals low in the food chain were eaten by predators higher up, biomagnifying the concentrations. So any person or animal eating stuff from the river would be at risk of effects from mercury. The levels in food fish were so high that eating them is forbidden. This is quite common now in US rivers because of mercury pollution.

The songbirds studied by the William and Mary scientists weren’t eating the fish. Songbird parents feed songbird babies little spiders with high levels of mercury. The question still remains: how did the spiders get the mercury? We have yet to learn that important link in the chain.

Meanwhile, though, Darwin’s “tangled bank” has also become a tangled web of pollution.



  1. #1 Tony P
    April 21, 2008

    So we’re still dealing with the legacy of the world before air and water protections were put in place. In essence those laws prevented any more from being dumped, but they’ve done little to attempt to remedy the situation.

    Yet you have the Bush Administration who are some of the biggest supporters of dismantling the law. If anything I say we make it stronger with more and sharper teeth.

  2. #2 revere
    April 21, 2008

    Tony: It’s actually worse. We still put plenty of mercury into the environment and into rivers via coal fired power plants. And guess who supports that option?

  3. #3 Hank Roberts
    April 21, 2008

    This, then, may be good news, if it’s analogous.

    Oil drilling brings up radium which gets into ecosystems all around drill sites and downstream. Article from 1990:

    Exxon lost a Supreme Court appeal. Article today

    Exxon had argued: “Due process does not allow a jury to punish a defendant for harm or potential harm that its conduct has allegedly imposed on nonparties to the litigation ….”

    They lost on that argument.

    Bzzzt. Exxon is responsible for damage to the people who cleaned their oil drilling pipes and washed the radium off, contaminating property.

    Now, about that mercury the coal plants have been sending downwind for so long ….

  4. #4 M. Randolph Kruger
    April 21, 2008

    Spiders with mercury? Dimethyl Mercury Revere or just methyl mercury?

    Zowie… But if you live in the NE and you wont let them build nukes what are you going to use for electricity. Dont anyone say wind farms or solar panels. There aint enough hillsides for the panels in the world or hot air in Washington to make that fan blow. Maybe enough out of Al Gore though….on the way to his corporate Challenger aircraft.

    How big a spider too Revere? Spiders frequently trap small birdlets in the springtime down here. Maybe they feed over contaminated ground, get caught and sucked out, then caught themselves and fed to the birds or the young spiderlets get fed to them?

  5. #5 marquer
    April 22, 2008


    Clinton. Obama. And McCain.

    This has been another edition of simple answers to simple questions.

  6. #6 wenchacha
    April 22, 2008

    I’ve recently read some about “phytoremediation.” It sounds great: certain common plants will take up heavy metals from the soil, reducing its contamination. It doesn’t seem to do much beyond the top 2 inches of soil, and you still have to dispose of the plants, and the plants are out there in nature where all sorts of living things can nibble on them.

    It still seems like a not-bad idea. It would be great if a method could be found to dispose of the plants in some green way. There is quite a big cleanup effort needed.