Thermal and Non-thermal Effects

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Thermal and Non-thermal Effects of Non-ionizng
EMF Henry Lai Department of Bioengineering Unive
rsity of Washington Seattle, WA USA
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Thermal effects are relatively easy to
understand. -microwave cooking -heating causes
cellular and physiological changes Non-thermal
effects- biological responses not related to
heating or increase in temperature. -difficult to
prove Do non-thermal effects exist?
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• Arguments for non-thermal effects
• Effects at low intensity
• Heating effects different from EMF effects
• Modulations produce different effects at
• same exposure conditions
• (4)ELF EMF has biological effects

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Low Intensity Effects
de Pomerai (2000 0.001W/kg) Fesenko (1999
0.001 mW/cm2) Ivaschuk (1999 0.026W/kg) Kwee
(2001 0.0021W/kg) Magras and Xenos (1999
0.000118-0.001053mW/cm2) Mann (1998
0.02mW/cm2)  Marinelli (2004 0.036W/kg)
Navakatikian and Tomashevskaya (1994
0.0027-0.027W/kg) Nittby(2007 0.0006-0.06W/kg)
Persson (1997 0.0004-0.008W/kg) Phillips (1998
0.0024-0.024W/kg) Polonga-Moraru (2002
15mW/cm2) Pyrpasopoulou (2004 0.0005W/kg)
Salford (2003 0.02W/kg) Sarimov (2004
0.0054W/kg) Schwartz (1990 0.00015W/kg) Somosy
(1991 0.024W/kg) Stagg (1997 0.0059W/kg)
Wolke (1996 0.001W/kg)Yurekli (2006 0.0113W/kg)
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Microwave pulse hearing effect Auditory
system responses to microwave pulses at a
threshold of 0.6 mJ/g/pulse. -thermoelastic
effect -micro-thermal effects
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The Case of David de Pomerai De Pomerai et al.
(Nature 405417-418, 2000)- reported an increase
in a molecular stress response (heat shock gene
expression) in worms after exposure to a RFR at a
SAR of 0.001 W/kg.
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Dawe, Smith, Thomas, Greedy, Vasic, Gregory,
Loader, de Pomerai (2006) A small temperature
rise may contribute towards the apparent
induction by microwaves of heat shock gene
expression in the nematode Caenorhabditis
elegans. Bioelectromagnetics 27(2)88-97. We
conclude that our original interpretation of a
non-thermal effect of microwaves cannot be
sustained at least part of the explanation
appears to be thermal.
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Heating effects different from EMF
effects Wachtel (1975) Seaman Wachtel (78)-
activity of neurons insolated abdominal ganglion
of Aphysia- heating had opposite effect. de
Pomerai (2000, 2003)- needed thermal heating of
3oC to produce the same effect of a 0.5oC
increase by EMF EMF enhanced growth and
development of C. elegens, whereas heating
produced the opposite effects.
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But, microwave/RF heating is not the same as
heating. RFR energy absorption pattern in the
body is not uniform. (Chou, C.K., Guy, A.W.,
McDougall, J., Lai, H. Specific absorption rate
in rats exposed to 2450-MHz microwaves under
seven exposure conditions. Bioelectromagnetics
673-88, 1985. ) It is not possible to simulate
RF heating. Even if heat is removed when exposed
to RFR, i.e., no significant increase in
temperature is detected, thermoregulatory
responses are activated which can in turn lead to
alterations in other physiological responses.
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Modulations produce different effects at same
exposure conditions- e.g., frequency, exposure
system Frey (1975)-BBB- pulsed field more
effective than CW Oscar and Hawkins (1977)-BBB-
pulsed field more effective than CW Sanders
(1985)-brain metabolism- 500 pps more effective
than 250 pps modulation Arber and Lin
(1985)-neuron activity- AM increase CW
decrease Lai (1988)-hippocampal
acetylcholine-pulsed- CW no effect DAmbrosio
(2002)-genetic effect- modulated field- CW no
effect Huber (2002)-EEG- modulated field-CW no
effect Hoyto (2008)-lipid peroxidation, caspase
3 activity- modulated field- CW no effect
Luukkonen (2009)-free radicals-CW- modulated
field no effect
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Biological effects of ELF EMF are well
established. ELF EMF cannot produce significant
thermal effect.
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• Arguments for non-thermal effects
• Effects at low intensity
• Heating effects different from EMF effects
• Modulations produce different effects at
• same exposure conditions
• (4)ELF EMF effects

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Is thermal/non-thermal consideration a necessary
condition for EMF exposure standard setting?

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Is thermal/non-thermal consideration a necessary
condition for EMF exposure standard setting?
My answer is no. Standards
should base on at what level of exposure
biological/health effects are observed.
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The de Lorge Experiments de Lorge and Ezell
(1980) trained rats on an auditory observing-
response task. Rats were then irradiated with
1280-MHz or 5620-MHz RFR during performance.
Disruption of behavior was observed at SAR of
3.75 W/kg for 1280-MHz and 4.9 W/kg for 5620-MHz.
Disruption occurred within 30-60 minutes of
exposure. It is concluded that the rats
observing behavior is disrupted at a lower power
density at 1.28 than at 5.62 GHz because of
deeper penetration of energy at the lower
frequency, and because of frequency-dependent
differences in anatomic distribution of the
absorbed microwave energy.
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de Lorge (1984) trained monkeys on the auditory
observing- response task. Monkeys were exposed
to RFR of 225, 1300, and 5800 MHz. Disruption of
performance was observed at 8.1 mW/cm2 (SAR 3.2
W/kg) for 225-MHz, 57 mW/cm2 (SAR 7.4 W/kg) for
1300 MHz, and 140 mW/cm2 (SAR 4.3 W/kg) for 5800
MHz, when body temperature increased by
1oC. Conclusion Disruption of behaviour occurred
when an animal was exposed at a SAR 4 W/kg
(whole body average). Disruption occurred after
30-60 minutes of exposure and when body
temperature increased by 1oC.
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Thomas et al. (1975) tested 5-10 min after 30
min exposure to pulsed 2450-, 2860-, 9600-MHz
RFR. DRL response disrupted at 2450-MHz gt 2 W/kg,
2860 MHz gt2.7 W/kg, 9600-MHz gt1.5 W/kg. Schrot
et al. (1980) bar press for food after 30 min
exposure to pulsed 2800-MHz RFR disrupted at SARs
of 0.7 and 1.7 W/kg.
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Does RFR produce behavioral effects below 4 W/kg
after short-term exposure? YES In many
instances, effects on behavior were observed at a
SAR less than 4 W/kg. (DeWitt et al. 1987 0.14
W/kg Gage 1979 3 W/kg King et al. 1971 2.4
W/kg Lai et al. 1989 0.6 W/kg Mitchell et al.
1977 2.3 W/kg Navakatikian and Tomashevskaya
1994 0.027 W/kg Schrot et al. 1980 0.7 W/kg
Thomas et al. 1975 1.5 to 2.7 W/kg Wang and
Lai 2000 1.2 W/kg).
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Low Intensity Effects
de Pomerai (2000 0.001W/kg) Fesenko (1999
0.001 mW/cm2) Ivaschuk (1999 0.026W/kg) Kwee
(2001 0.0021W/kg) Magras and Xenos (1999
0.000118-0.001053mW/cm2) Mann (1998
0.02mW/cm2)  Marinelli (2004 0.036W/kg)
Navakatikian and Tomashevskaya (1994
0.0027-0.027W/kg) Nittby(2007 0.0006-0.06W/kg)
Persson (1997 0.0004-0.008W/kg) Phillips (1998
0.0024-0.024W/kg) Polonga-Moraru (2002
15mW/cm2) Pyrpasopoulou (2004 0.0005W/kg)
Salford (2003 0.02W/kg) Sarimov (2004
0.0054W/kg) Schwartz (1990 0.00015W/kg) Somosy
(1991 0.024W/kg) Stagg (1997 0.0059W/kg)
Wolke (1996 0.001W/kg)Yurekli (2006 0.0113W/kg)
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Other considerations
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Effects of long-term exposure
DAndrea et al. (1986a) 2450 MHz, 7 hrs/day, 7
days/wk, 14 weeks, 0.7 W/kg- disrupted operant
behavior. DAndrea et al. (1986b) 2450 MHz, 7
hrs/day, 7 days/wk, 90 days, 0.14 W/kg- small
disruption in operant behavior. The threshold
for behavioral and physiological effects of
chronic RFR exposure in the rat occurs between
0.5 mW/cm2 (0.14 W/kg) and 2.5 mW/cm2 (0.7 W/kg).
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Interactions with Other Environmental
Factors Example Kues and Monahan 1992 and
Kues et al. 1990 1992 reported synergistic
effects of drugs on corneal endothelium damages
and retinal degeneration in the monkey induced by
repeated exposure to RFR. They found that
application of the drugs timolol and pilocarpine
to the eye before RFR exposure could lower the
threshold of the RFR effect by 10 folds (from 10
to 1 mW/cm2). There are many reports of EMF
interaction with drugs/chemicals, stressors,
ionizing radiation, etc.