JUN 18, 2020 8:51 AM PDT

Resistant Weeds Killer Risks Water Contamination

WRITTEN BY: Daniel Duan

(Pixabay)

It's a story that sounds way too familiar: scientists find a chemical to kill weeds and increase crop production, the chemical pollutes the environment and causes health concerns. Chemists go back to the drawing board and develop a new compound, but the product boomerangs with new problems.

Isoxaflutole is a highly selective herbicide that was developed to fight resistant weeds on maize farms. The compound competitively inhibits an enzyme called 4-hydroxyphenylpyruvate dioxygenase (HPPD), stripping the targeted plants off their ability to make carotenoids. (These organic pigment molecules are essential for absorbing light energy in photosynthesis and providing photoprotection.) The bleaching effect of isoxaflutole-containing herbicides suppresses the growth of weeds and eventually kill them off.

Like many herbicides, isoxaflutole has its own caveat. The EPA-categorized "probable carcinogen", as well as its breakdown products isoxaflutole diketonitrile and isoxaflutole benzoic acid, appear to be good at finding their way to groundwater and then major water bodies. 

A 2004 US Geological Survey report revealed that isoxaflutole and its degradation products were found in ten major rivers in Iowa, despite the compound's rare usage in the state farming practice. Its persistent environmental presence is compared to atrazine, a controversial herbicide that is notorious for contaminating groundwater.

Popular Weed Killer Stirs Health, Environmental Concerns (VOA News)

Against the warning from many environmental organizations, the US Environmental Protection Agency gave the official approval for the use of isoxaflutole on new varieties of soybeans this April, broadening its traditional field of application. Since these genetically modified crops cannot be affected by the herbicide, as long as the use of isoxaflutole was restricted to areas that have little access to groundwater, everything would be a-okay, or so it seems. 

Many are concerned that widening the use of the HPPD-inhibiting herbicide, which is toxic to non-engineered plants, mammals, and other components in the ecosystem, will quickly add to the environmental burden in regions that are already polluted by other agricultural chemicals. 

Aside from its ecological impact, some in the farming community also cast doubts on the longevity of isoxaflutole as a herbicide, due to the increasing presence of multi-resistant weeds that can survive over many different herbicides. The continuous push for applying new compounds turns the battle against weeds (and pests) into a vicious cycle, just like the one between medical antibiotics and bacteria. Others suggest adopting non-herbicidal approaches could be a better alternative, eliminating the risk of contaminations and stopping the evolution of resistant strains.

Source: C&EN

About the Author
  • Graduated with a bachelor degree in Pharmaceutical Science and a master degree in neuropharmacology, Daniel is a radiopharmaceutical and radiobiology expert based in Ottawa, Canada. With years of experience in biomedical R&D, Daniel is very into writing. He is constantly fascinated by what's happening in the world of science. He hopes to capture the public's interest and promote scientific literacy with his trending news articles. The recurring topics in his Chemistry & Physics trending news section include alternative energy, material science, theoretical physics, medical imaging, and green chemistry.
You May Also Like
MAY 26, 2021
Chemistry & Physics
Turning bullfrog skin into human bones - as easy as....?
MAY 26, 2021
Turning bullfrog skin into human bones - as easy as....?
In an effort to support the growth of the circular economy, researchers from Nanyang Technological University, Singapore ...
JUN 01, 2021
Chemistry & Physics
"Candy" models allow the visually impaired to visualize complex 3D images with tongue
JUN 01, 2021
"Candy" models allow the visually impaired to visualize complex 3D images with tongue
New research hopes to improve accessibility to science for people who are blind or visually impaired. Approximately 36 m ...
AUG 01, 2021
Drug Discovery & Development
New Compound Halts Neurodegeneration in Alzheimer's
AUG 01, 2021
New Compound Halts Neurodegeneration in Alzheimer's
Chemists have synthesized new compounds that can halt neurodegeneration linked to Alzheimer’s and other neurologic ...
AUG 17, 2021
Chemistry & Physics
Physicists Transform Pure Energy into Matter and Antimatter
AUG 17, 2021
Physicists Transform Pure Energy into Matter and Antimatter
A new study published in Physical Review Letters presents evidence for the creation of matter and antimatter from energy ...
AUG 26, 2021
Immunology
Sugar-Coating Organs Stops Them From Getting Rejected
AUG 26, 2021
Sugar-Coating Organs Stops Them From Getting Rejected
Once organ failure patients receive the gift of a transplant, they face a life-long threat of immune rejection. Their im ...
SEP 14, 2021
Chemistry & Physics
The World's Most Accurate Clock
SEP 14, 2021
The World's Most Accurate Clock
The world’s most accurate clock has taken the 2022 Breakthrough Prize in Fundamental Physics. Jun Ye, a physicist ...
Loading Comments...