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New Bacterium Removes Two Harmful Contaminants from Groundwater Hidden

Researchers at the New Jersey Institute of Technology recently discovered the bacterium Azoarcus sp. DD4 (DD4) and its ability to remove two co-existing contaminants from groundwater. 80% of groundwater sites contaminated with 1, 4-Dioxane also contain 1,1-Dichlorethylene (1,1-DCE). Both contaminants are toxic and difficult to treat in water using traditional methods. The discovery of Azoarcus sp. DD4 creates new possibilities for future water treatment.

What is 1, 4-Dioxane?

1, 4-Dioxane is an emerging contaminant, meaning little is known about the behavior and risks which makes treatment difficult. A maximum contaminant level for water has yet to be established by the EPA.

What we know about 1,4-Dioxane

  • Likely carcinogen
  • Found in thousands of groundwater sites in the U.S.
  • Moves rapidly in water
  • Industrial chemical from paint strippers, greases, waxes, shampoos, and cosmetics
  • Enters the body through ingestion, inhalation, and skin contact

Side effects of 1, 4-Dioxane exposure

  • Short-term exposure may cause nausea, drowsiness, and irritation to the eyes, nose, and throat.
  • Long-term exposure may cause liver and kidney damage.

What is 1, 1-Dichlorethylene (1, 1-DCE)?

1,1-DCE is rarely detected in surface water but can spill into groundwater via industrial discharge and spread. According to the EPA drinking water regulations, the public health goal for 1,1-DCE in water is .007 (mg/L)2. Rapid separation makes this contaminant difficult to identify in water.

What we know about 1, 1-DCE

  • Sweet odor like chloroform
  • Colorless
  • Used in cleaning solvents and plastic manufacturing
  • Enters body through inhalation, skin contact, and administration of drugs

Side effects of 1, 1-DCE exposure

  • Liver problems
  • Kidney damage
  • Central nervous system depression

Water treatment with Azoarcus sp. DD4 (DD4)

Biodegradation, the breakdown of substances into smaller particles, removes leftover contaminants after physical and chemical water treatment. 1, 4-Dioxane generally resists these remediation methods. Adding 1, 1-DCE in conjunction with 1, 4-Dioxane makes treatment even more difficult. Together, these two contaminants cause serious damage.

After applying the new microbe DD4, however, both contaminants decreased significantly. 1, 4-Dioxane decreased from 10 parts-per-million (ppm) to .38 parts-per-billion (ppb), and 1, 1-DCE decreased from 3 ppm to .02 ppm.

After 3 days of refrigeration, 80% of the bacterium survived, making it possible to deliver these microbes to infected water sites in the future.

Benefits water treatment with DD4

  • Eco-friendly
  • Cost-efficient
  • Spreads easily in water

Researchers plan to conduct further study to understand how DD4 reduces contaminants. Using the bacterium in water treatment could begin within a year.

 

Source:

New Jersey Institute of Technology. "Newly discovered bacterium rids problematic pair of toxic groundwater contaminants." ScienceDaily. www.sciencedaily.com/releases/2018/10/181009115019.htm (accessed October 16, 2018).


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