AUG 23, 2020 6:02 AM PDT

How Microbes Can Help Clean a Toxic River

WRITTEN BY: Carmen Leitch

Some places in the United States have become dangerously polluted with hazardous waste. The EPA oversees a program that aims to clean up these so-called Superfund sites; there are about 40,000 of them and 1,600 are considered to be priorities.

A view of the dioxin-contaminated Passaic River in Newark, New Jersey. Credit  Donna E. Fennell

One Superfund site is the Passaic River in New Jersey, where very toxic chemicals called dioxins have built up in the sediment. The pollution there dates to manufacturing in the 1940s, but it seems to have become especially bad when a company called Diamond Alkali began manufacturing Agent Orange, a defoliant and herbicide, for use in the Vietnam War. Chemicals used or produced in the manufacturing process, of which the toxic carcinogen 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is one, and Agent Orange itself ended up in the river. That clearly caused serious damage to the environment.

The half-life of TCDD can also be very long. In river sediments, the half-life of TCDD is thought to be 100 years. So it hangs out there and poses a threat to the environment and local food production for ages.

Scientists at Rutgers University may have some good news for this Superfund site, however. They learned that bacteria can help defuse the dioxin in the Passaic River sediments. The findings, which were reported in Environmental Science & Technology, may also aid in the cleanup of other sites, though more research will be needed to make that determination.

"The bacteria-driven process we observed greatly decreases the toxicity of dioxin," said the senior study author Donna E. Fennell, a professor who chairs the Department of Environmental Sciences in the School of Environmental and Biological Sciences at Rutgers University-New Brunswick.

In this work, the researchers obtained samples from the bottom of the river and used it to create mud in the lab. They added the TCDD, and a chemical that encourages bacteria to dechlorinate called dichlorobenzene.

Bacteria were found to dechlorinate the TCDD; they take chlorine atoms away from the chemical. After sequencing the genetic material in the mud, the researchers suggested that a novel Dehalococcoidia bacterium is responsible for the dechlorination.

"Our results showed that although the process is quite slow, it can be enhanced and may even have the potential to remove all toxic chlorines from the compound," said lead author Rachel K. Dean, a graduate student at Rutgers.

Dredging will still be necessary to remove the sediments in the Passaic River that are thoroughly contaminated. Some chemicals will remain in the estuary where it has spread. The bacteria could be helpful in removing it.

The scientists want to find the bacterial enzyme or enzymes that are involved in dioxin dechlorination so that it can be studied and potentially applied elsewhere.


Sources: AAAS/Eurekalert! via Rutgers University, Environmental Science & Technology

About the Author
  • Experienced research scientist and technical expert with authorships on 28 peer-reviewed publications, traveler to over 60 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
JUL 22, 2020
Infographics
The Science of Sourdough
JUL 22, 2020
The Science of Sourdough
During the coronavirus stay-at-home order, many people have taken up the art of making sourdough bread and have learned ...
AUG 02, 2020
Microbiology
Examining the Existence of Organelles in Bacteria
AUG 02, 2020
Examining the Existence of Organelles in Bacteria
Cells can be grouped into two general categories: prokaryotic, which make up microbes like bacteria and archaea, or euka ...
AUG 25, 2020
Drug Discovery & Development
The Potential of Antivitamins
AUG 25, 2020
The Potential of Antivitamins
What exactly are antivitamins? They are substances no less that have the power to target the biological function of a ge ...
SEP 01, 2020
Cell & Molecular Biology
Smell Cells Are Especially Good at Fighting the Flu
SEP 01, 2020
Smell Cells Are Especially Good at Fighting the Flu
All over the body, cells line organs and vessels, forming protective barriers. But pathogens like the flu have gained th ...
SEP 09, 2020
Clinical & Molecular DX
Swallow the Pill, Discover the Bugs Within
SEP 09, 2020
Swallow the Pill, Discover the Bugs Within
The 30-foot long human gastrointestinal tract consists of tissues and organs that work in concert to digest our food. Th ...
OCT 06, 2020
Microbiology
Scarlet Fever 'Superclones' Pose Rising Public Health Threat
OCT 06, 2020
Scarlet Fever 'Superclones' Pose Rising Public Health Threat
More than 100 years ago, the world faced waves of scarlet fever epidemics; between around 1820 and 1880 there were sever ...
Loading Comments...