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Effects of 2.45-GHz electromagnetic fields with a wide range of SARs on micronucleus formation in CHO-K1 cells.

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Koyama S, Isozumi Y, Suzuki Y, Taki M, Miyakoshi J. · 2004

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DNA damage occurred only at radiation levels 50-100 times higher than phone safety limits, primarily due to tissue heating.

Plain English Summary

Summary written for general audiences

Researchers exposed hamster cells to WiFi-frequency radiation for two hours at different power levels. DNA damage occurred only at extremely high exposures (100-200 times typical phone levels), likely from heating effects rather than radiation itself, suggesting minimal risk from normal wireless device use.

Why This Matters

This study provides important context for understanding EMF exposure thresholds and mechanisms. The 100-200 W/kg exposure levels that produced DNA damage are roughly 50-100 times higher than the 2 W/kg safety limit for mobile phones and thousands of times higher than typical WiFi exposures. What's particularly significant is that the researchers demonstrated the DNA damage was primarily thermal - caused by tissue heating rather than direct electromagnetic effects. This supports the current regulatory approach that focuses on preventing tissue heating. However, the study's limitation is that it only examined acute 2-hour exposures in isolated cells, which doesn't reflect the chronic, lower-level exposures we experience daily from multiple wireless sources.

Exposure Details

SAR
5, 10, 20, 50, 100, and 200 W/kg
Source/Device
2.45-GHz
Exposure Duration
2 hours

Exposure Context

This study used 5, 10, 20, 50, 100, and 200 W/kg for SAR (device absorption):

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 ContextA logarithmic scale showing exposure levels relative to Building Biology concern thresholds and regulatory limits.Study Exposure Level in ContextThis study: 5, 10, 20, 50, 100, and 200 W/kgExtreme Concern0.1 W/kgFCC Limit1.6 W/kgEffects observed in the Extreme Concern range (Building Biology)FCC limit is 0x higher than this exposure level

Study Details

In order to investigate the properties of HFEMF, we have examined the effects of 2.45-GHz EMF on micronucleus (MN) formation in Chinese hamster ovary (CHO)-K1 cells.

MN formation is induced by chromosomal breakage or inhibition of spindles during cell division and l...

The MN frequency in cells exposed to HFEMF at a SAR of lower than 50 W/kg did not differ from the sh...

Cite This Study
Koyama S, Isozumi Y, Suzuki Y, Taki M, Miyakoshi J. (2004). Effects of 2.45-GHz electromagnetic fields with a wide range of SARs on micronucleus formation in CHO-K1 cells. ScientificWorldJournal 4 Suppl 2:29-40, 2004.
Show BibTeX
@article{s_2004_effects_of_245ghz_electromagnetic_1110,
  author = {Koyama S and Isozumi Y and Suzuki Y and Taki M and Miyakoshi J.},
  title = {Effects of 2.45-GHz electromagnetic fields with a wide range of SARs on micronucleus formation in CHO-K1 cells.},
  year = {2004},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/15517100/},
}

Quick Questions About This Study

Researchers exposed hamster cells to WiFi-frequency radiation for two hours at different power levels. DNA damage occurred only at extremely high exposures (100-200 times typical phone levels), likely from heating effects rather than radiation itself, suggesting minimal risk from normal wireless device use.