genotoxic effects from RF fields in human blood cells
from Health Canada have failed to find evidence of genotoxicity
in human blood cells exposed for 24 hours to either pulsed or continuous
wave RF radiation from a 1.9 GHz field. The authors comment that
of the four studies assessing the effect of a 24-hour RF-field exposure
on human blood cells, only one has shown an increase in micronucleated
cells (a sign of chromosome damage). They suggest that the positive
study may have been due to increased temperatures in the cell cultures.
Reference: McNamee JP, Bellier PV, Gajda GB,
Lavallée BF, et al. (2003): No evidence for genotoxic effects
from 24 hr exposure of human leukocytes to 1.9 GHz radiofrequency
fields. Radiat Res 159:693-697.
The authors state that their study is the first large-scale investigation
in rats examining a potential genotoxic effect of chronic, low-level
exposure to 1.6 GHz RF radiation. Rats were exposed for 2 hours
per day, five days per week, for 2 years. The incidence of micronuclei
was no different in the red blood cells of exposed rats than in
Reference: Vijayalaxmi, Sasser L, Morris JE, Wilson BW, et al. (2003):
Genotoxic potential of 1.6 GHz wireless communication signal: in
vivo two-year bioassay. Radiat Res 159: 558-564.
For more on
these studies, see "Research
- Toxicological Experiments - cancer studies".
accessories do not increase energy absorption in the head
In the April
2000 issue of Which? Magazine, the UK Consumers' Association published
a report on hands-free accessories for mobile phones. They reported
that tests showed that the use of these accessories increases the
deposition of radiofrequency (RF) energy in the head by up to three
times compared to a mobile phone alone held close to the head.
Now a group
from the Motorola Florida Research Laboratories reports the opposite
- the hands-free accessories decrease the RF energy exposure in
the head. They state that the UK tests "were not performed
with internationally recommended methodologies for SAR measurements
aimed at determining compliance with RF-radiation exposure limits".
The authors point out two main deficiencies in the methodology used
in the UK study. The first was the use of a model without the equivalent
of the human torso. If at least some of the wire runs close to the
torso, the RF exposure is significantly lower in the head because
the human body attenuates the electromagnetic field along the wire.
The second was the positioning of the phone 13 mm from the ear,
which introduced an artificial reduction in SAR, compared to the
device operating next to the ear.
Reference: Bit-Babik, G, Chou CK, Faraone
A, Gessner A, et al. (2003): Estimation of the SAR in the human
head and body due to radiofrequency radiation exposure from handheld
mobile phones with hands-free accessories. Radiation Research 159:550-557.
report on RF health effects
Reports on the
health effects of RF radiation have appeared frequently from various
countries in the last few years. In addition to the reports from
the Royal Society of Canada and the Independent Expert Group on
Mobile Phones from the UK (see "Links"),
there have been others from the Netherlands (see "What's
New", April 2002) and from France and Norway ("What's
New", May 2003). Now the Swiss Federal bureau for environment,
forest and landscape has released a report on high frequency radiation
and health by Dr Röösli of the University of Bern and
Dr Rapp of the Institute for Social and Preventive Medicine at the
University of Basel. Their final conclusions are that "The
survey shows that no conclusive assessment of the risk to human
health may be made on the basis of present scientific data".
A summary in English can be found at www.umwelt-schweiz.ch/buwal/de/fachgebiete/fg_nis/news/2003-04-14-00385/index.html
CTIA announces new research programs
Telecommunications and Internet Association (CTAI) has announced
funding for Phase 2 of CRADA - the Cooperative and Development Agreement
with the Food and Drug Administration of the USA. The new research
will focus on epidemiology,
and in particular on the best epidemiological tools for measuring
exposure to RF energy from wireless phones. The two funded studies
are expected to conclude by the fall of 2005. More details can be
found at the CTIA web site www.wow-com.com
and at www.fda.gov.cellphones.
increase in brain tumour rates in New Zealand
A new study
has found no increase in the incidence
of malignant brain tumours in New Zealand since the introduction
of cell phones in 1987. This includes those sites of the head and
neck that hypothetically receive the highest levels of RF radiation
during phone use. However, acoustic
neuroma, a tumour type that has been implicated in studies by
Hardell's group (see "Research
- Clinical studies - Epidemiology"), was not included.
The authors caution that ecological
studies such as this are limited in many ways.
Reference: Cook A, Woodward A, Pearce N, Marshall
C (2003): Cellular telephone use and time trends for brain, head
and neck tumours. NZMJ 116:No. 117