I have written two posts on atrazine, the common herbicide. One post  mentioned a report that atrazine affects organ development in frogs. The other refers to a study showing that frogs’ immune systems are suppressed when exposed to atrazine.  Now there is a report by the Huffington Post that atrazine levels in human drinking water exceed federal safety limits in four states.

Records that tracked the amount of the weed-killer atrazine in about 150 watersheds from 2003 through 2008 were obtained by the Huffington Post Investigative Fund under the Freedom of Information Act. An analysis found that yearly average levels of atrazine in drinking water violated the federal standard at least ten times in communities in Illinois, Indiana, Ohio, and Kansas, all states where farmers rely heavily on the herbicide.

Frogs are the canaries in the coal mine, remember? It’s best not to ignore the canaries. The frogs warned us, and those warnings are not being heeded.

Imagine if found that a chemical in our food weakened our resistance to malaria and, when it entered the sewers after we washed it off our dishes, it actually caused mosquitoes to double their egg laying.  We’d call it a perfect storm.

That’s essentially the same situation facing amphibians because of atrazine, as reported in a Scientific American story about Northern Leopard Frogs. According to the story, “the culprit appears to be the common herbicide acting as a double-edged sword: It suppresses the frogs’ immune systems while boosting the population of snails that play host to parasitic worm larvae, the latter of which infect the weakened leopard frogs.”

Another way to explain it, according to the Christian Science Monitor, it this:

Atrazine reduced phytoplankton in the water, making more food and light available for algae. It also appears to speed snail reproduction. The snails, often carrying larvae of parasites harmful to frogs, feed on the increased amounts of algae. Then frogs feast on the snails. In addition, the atrazine deadens the frogs’ immune systems, leaving them less capable of countering the parasites.

Nice to see Joe Mendelson of Zoo Atlanta quoted in the coverage.

 

ScienceDaily has summarized a new study published in Environmental Health Perspectives that shows atrazine harms the development of organs, such as the heart, in baby amphibians.  Other studies have pointed to problems that the common weed killer has caused with other stages of development, but this is the first to study the impact on organ morphogenesis, or organ development. The scientists did the experiment on Xenopus laevis, or African clawed frogs. That species is the one that was shipped around the world in the 1930s and 1940s for human pregnancy tests — and unwittingly carried with it the amphibian chytrid fungus. You decide if that’s ironical.