Pesticide DDT Found In Escambia River, Adjacent Wetlands

January 4, 2017

The pesticide DDT has been found in sediment samples from the Escambia River and its adjacent wetlands, a post-doctoral research associate at the University of West Florida has discovered.

Dr. Geoffrey Marchal, who was hired in April to begin the research, is now testing those sediment samples to see how readily available the pollutant is to the many diverse species that inhabit the bay.

“That’s the big concern,” Marchal said. “If the DDT in the sediment is bioavailable and can go through the food chain, then we have an issue.”

Since DDT and other pollutants can be held very tightly by the sediments, the optimal finding would be that the pollutant is stable in the sediment and out of the reach of wildlife, said Dr. Johan Liebens, a professor in the Department of Earth and Environmental Sciences.

“That’s not good, but it’s the best we can hope for in the current situation,” Liebens said of the possibility of that finding.

Marchal’s research is a follow-up to a study performed in 2009 by Liebens and Dr. Carl Mohrherr, who is now a retired professor from UWF. That study showed elevated levels of DDT in the sediments of the Escambia River wetlands that exceeded a Florida government guideline known as the probable effects level.

“We got the results back and they were really very high, at least in the wetlands, in the north end of the bay, not in the bay itself,” Liebens said. “In the bay itself, there was no DDT.”

However, some details of that initial study were difficult to explain, Liebens said

DDT that has been present for a long time typically breaks down into its metabolites – DDD and DDE. But none of those breakdown products were present, Liebens said.

“It’s very, very unusual,” he said. “But one potential explanation was that the DDT was so recent, it didn’t have time to break down.”

And if the DDT has been used recently, it would be illegal. The U.S Environmental Protection Agency banned DDT in 1972 based on its potential hazardous environmental effects, including to wildlife as well as risks to humans.

The sediment samples from the study done by Liebens and Mohrherr, which was funded by the EPA, were taken to a private lab. Another possibility for the 2009 findings was that the lab was not able to detect the DDD and DDE breakdown products in the samples, Liebens said.

“Because it was very hard to explain the numbers that we got back from the lab, we wanted to go back and check and do the analysis in house,” Liebens said.

Marchal’s latest research, which was funded by a Scholarly and Creative Activities Committee grant from the UWF Office of Undergraduate Research, found that fewer sites contained DDT and the levels are lower than originally found in the 2009 study.

“The most important point is we found less sites with DDT,” Marchal said. “Originally, nearly all the wetlands were contaminated.”

Marchal is still testing samples in the wetlands research laboratory at UWF. Liebens said he hopes that the findings of the study will be published in a scientific journal, possibly as soon as April.

Whether the researchers make any recommendations to government agencies depends on the results of Marchal’s testing, Liebens said.

“It depends on what we find with the bioavailability,” Liebens said. “If we would find really high levels of bioavailability then we could advise government agencies and draw their attention to what we have found.”

Pictured top: Post doctoral research associate Geoffrey Marchal performs a soxhlet extraction in the lab. Courtesy photo. Pictured inset: The Escambia River at Molino. file photo, click to enlarge.


14 Responses to “Pesticide DDT Found In Escambia River, Adjacent Wetlands”

  1. MargieLu on January 7th, 2017 6:53 am

    Of course, our public hunting lands are all along these wetlands, so the taxpayer who hunts for subsistence or recreation is put at the highest risk of exposure.

    Maybe now our state wildlife commission will bring the public area onto dry land so that equal access is granted, reducing toxic exposures to folks who shouldn’t have to pay twice (taxes + hunt club fees) to hunt in their own home state.

  2. Facetious Bob on January 5th, 2017 11:10 pm


    From what I have read, the animal most responsible for more human deaths over this planet is the mosquito. DDT was used to kill this pest, until Rachael Carlson wrote “Silent Spring.” The cessation of this chemicals use resulted in the safe propagation of many animals such as eagles. ” Sorta like Danged if you duz, danged if you duzzent.”

  3. mike on January 5th, 2017 3:33 pm

    @chris: okay, point taken. maybe we can all get the government to dig up all the wetlands, put it thru a leaching process & pump all the water in the area thru massive filters to purify it. They cleaned up that dioxin site in town, right? Mayhap they can do the same for the several square miles of wetlands referred to in the article. Should only cost billions, but hey, the feds give that much away every year to foreign countries, right? :)

  4. chris on January 5th, 2017 1:30 pm

    No dig intended. But the impact on wildlife, some of which is consumed by humans, cannot be discounted.

  5. mike on January 5th, 2017 8:09 am

    @chris: good thing you can post a chris instead of chris in Molino, so you can get a dig in at me, eh? :)

  6. Larry on January 4th, 2017 4:05 pm

    And to think some newly elected politicians believe the E.P.A should be done away with and let the “Free Market” decide. Just about the only good thing Nixon honestly recognized was the need for the EPA sense the 50s and 60s. Google India or China or Brazil Air and Water pollution and be amazed how bad others have made it for themselves. DDT is a highly toxic carcinogen and no one in there right mind would be using it…

  7. lone chief on January 4th, 2017 3:24 pm

    We humans are pretty gross when it comes down to it. We’ve been poisoning ourselves (and the earth) for a long time and it will not stop. Oh yeah, we’re more aware nowadays but it really hasn’t changed things much. We just change the formulas….more plastics please, throw those batteries away anywhere you like, more weed killer in the yard honey, disposible electronics, and on and on and on (that was sarcasm if ya didn’t get it).

  8. David Huie Green on January 4th, 2017 2:51 pm

    The Case of The Missing Compound

  9. CW on January 4th, 2017 2:24 pm

    No telling how many chemicals come floating down river from the Midwest.

  10. chris on January 4th, 2017 1:28 pm

    @mike: Good thing fish and deer don’t live in wetlands. Otherwise somebody might catch and eat them.

  11. nod on January 4th, 2017 11:56 am

    Big todo over nothing. We get all kinds of stuff from Mexico that hasDDT on ot.

  12. jeeperman on January 4th, 2017 9:30 am

    So if the second round of testing comes up a certain amount different than the first round, would not a third and forth round be required to get an valid conclusion?
    And each round would have to be by another testing lab.

  13. mike on January 4th, 2017 8:02 am

    Disturbing. 20 year old cement water mains had asbestos mixed in with the cement, too. Check it out. Curiously little about it online. As far as the DDT, the damage done. Good thing most of us don’t live in the wetlands.

  14. Pop on January 4th, 2017 7:17 am

    Wel!! Isn’t that just great!!!!

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