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Note: This study found no significant biological effects under its experimental conditions. We include all studies for scientific completeness.

DNA & Genetic Damage

Bacterial mutation in high magnetic fields and radiofrequency radiation

No Effects Found

Mineta M, Katada R, Yamada T, Nagasawa K, Takahashi K, Aburano T, Yoshida I · 1999

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Bacteria showed no genetic mutations when exposed to MRI-strength magnetic fields and radiofrequency radiation for up to one hour.

Plain English Summary

Summary written for general audiences

Japanese researchers exposed bacteria commonly used in genetic testing to extremely strong magnetic fields (6.3 Tesla) combined with radiofrequency radiation similar to what's found in MRI machines for up to one hour. They found no increase in genetic mutations compared to unexposed bacteria, suggesting that MRI-level electromagnetic exposures don't cause DNA damage in this bacterial model.

Why This Matters

This study addresses an important safety question about MRI exposure, which combines both static magnetic fields and radiofrequency radiation at levels far exceeding everyday consumer devices. The 6.3 Tesla magnetic field used here is roughly 126,000 times stronger than Earth's magnetic field and typical of high-end medical MRI scanners. While the Ames test using Salmonella bacteria is a well-established screening method for mutagenic substances, it's worth noting that bacterial responses don't always translate directly to human health effects. The study's negative findings align with the general scientific consensus that MRI procedures, while using intense electromagnetic fields, don't appear to cause genetic damage. However, this single study shouldn't be viewed as definitive proof of safety across all biological systems or exposure scenarios.

Exposure Details

Magnetic Field
6300 mT
Exposure Duration
15, 30, 45, and 60 minutes

Exposure Context

This study used 6300 mT for magnetic fields:

Building Biology guidelines are practitioner-based limits from real-world assessments. BioInitiative Report recommendations are based on peer-reviewed science. Check Your Exposure to compare your own measurements.

Where This Falls on the Concern Scale

Study Exposure Level in ContextStudy Exposure Level in ContextThis study: 6300 mTExtreme Concern - 5 mGFCC Limit - 2,000 mGEffects observed in the Extreme Concern range (Building Biology)This level is 31,500 times the FCC limit

Study Details

The purpose of this study was to examine the safety of magnetic resonance imaging (MRI) by observing whether bacterial mutation occurs in an approximate MRI environment.

We employed a GX-270 FT-NMR unit (JEOL, Ltd.) with a magnetic field strength of 6.3 Tesla. The Salmo...

The rates of revertant mutation in mixed strains and the TA98 strain were not statistically signific...

Therefore, it was concluded that bacterial mutation is not increased by RF radiation under a 6.3 Tesla magnetic field.

Cite This Study
Mineta M, Katada R, Yamada T, Nagasawa K, Takahashi K, Aburano T, Yoshida I (1999). Bacterial mutation in high magnetic fields and radiofrequency radiation Nippon Igaku Hoshasen Gakkai Zasshi 59(9):467-469, 1999.
Show BibTeX
@article{m_1999_bacterial_mutation_in_high_3248,
  author = {Mineta M and Katada R and Yamada T and Nagasawa K and Takahashi K and Aburano T and Yoshida I},
  title = {Bacterial mutation in high magnetic fields and radiofrequency radiation},
  year = {1999},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/10487059/},
}
PubMed: 10487059

Cited By (5 papers)

Quick Questions About This Study

Japanese researchers found that MRI-level electromagnetic exposures don't cause DNA damage in bacteria. They exposed bacteria to 6.3 Tesla magnetic fields with radiofrequency radiation for up to one hour and found no increase in genetic mutations compared to unexposed bacteria.
A 1999 study found no genetic damage from extremely strong 6.3 Tesla magnetic fields combined with radiofrequency radiation. Bacteria exposed for one hour showed no statistically significant increase in mutation rates, suggesting these MRI-strength fields don't damage DNA.
Research using bacteria commonly used in genetic testing found no increased mutation rates from 6.3 Tesla magnetic fields with radiofrequency radiation. The study exposed bacteria for up to one hour and found mutation rates were not statistically different from unexposed controls.
A Japanese study found radiofrequency radiation under 6.3 Tesla magnetic fields is not mutagenic to bacteria. Researchers tested bacterial strains commonly used in genetic testing and found no significant increase in revertant mutations after one-hour exposures to MRI-level electromagnetic fields.
Medical imaging-level magnetic fields don't appear to affect bacterial genetics. A 1999 study exposed bacteria to 6.3 Tesla magnetic fields with radiofrequency radiation for one hour and found no increase in genetic mutations, suggesting MRI exposures don't damage DNA.