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Non-Ionizing Radiation, Part 2: Radiofrequency Electromagnetic Fields Volume 102

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Non-Ionizing Radiation, Part 2: Radiofrequency Electromagnetic Fields Volume 102 NON-IONIZING RADIATION, PART 2: RADIOFREQUENCY ELECTROMAGNETIC FIELDS VOLUME 102 This publication represents the views and expert opinions of an IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, which met in Lyon, 24-31 May 2011 LYON, FRANCE - 2013 IARC MONOGRAPHS ON THE EVALUATION OF CARCINOGENIC RISKS TO HUMANS 4. OTHER RELEVANT DATA Data on specific absorption rate (SAR) and distribution of radiofrequency (RF) radiation inside tissues and organs and at the subcellular level are presented elsewhere in this Volume (Section 1.3, Dosimetry). 4.1 Genetic and related effects in these studies DNA damage was measured in peripheral blood lymphocytes and buccal cells 4.1.1 Humans by means of the alkaline or neutral single-cell gel electrophoresis assay (comet assay), which reveals During the past decades, extensive research alkali-labile lesions and single- and double- efforts have focused on determining the extent strand breaks in DNA, or by use of cytogenetic of DNA damage in eukaryotic and prokaryotic tests for chromosomal aberrations, micronucleus cells exposed to RF radiation. Several published formation and sister-chromatid exchange (SCE). reviews concluded that: (i) the existing data are The studies reviewed below are summarized in not sufficiently strong to suggest that RF radiation Table 4.1 and Table 4.2 (with details of the expo­ is directly genotoxic; (ii) exposure to RF radiation sure conditions). probably does not enhance the damage induced by known genotoxic agents; and (iii) some of the (a) Peripheral blood lymphocytes reported “adverse effects” may be attributed to (i) Occupational exposure hyperthermia induced by RF radiation (Brusick et al., 1998; Verschaeve & Maes, 1998; Moulder Garaj-Vrhovac et al. (1990a) were the first to et al., 1999, 2005; Heynick et al., 2003; Meltz, report an increased frequency of chromosomal 2003; Vijayalaxmi & Obe, 2004; Verschaeve, aberrations in the form of chromatid and chro­ 2005; Krewski et al., 2007; Lai, 2007; Vijayalaxmi mosome breaks, acentric fragments, dicentrics, & Prihoda, 2008; Phillips et al., 2009; Rüdiger, rings and polycentric chromosomes, as well as 2009a; Verschaeve, 2009; Verschaeve et al., 2010). micronuclei in 10 individuals employed in a International organizations and expert scientific radar service-station facility. The frequency of advisory groups in several countries, including cells with chromosomal aberrations and micro- Canada, France, the Netherlands, Sweden, the nuclei ranged from 1.6% to 31.5% and from 1.6% United Kingdom and the USA, have reached to 27.9%, respectively, in exposed subjects, while similar conclusions (ICNIRP, 2009). the corresponding values in controls were 1.8% This Section of theMonograph deals with and 1.5% [no range given]. studies on primary DNA damage in humans In a study in Australia, Garson et al. (1991) exposed occupationally or as mobile-phone users; collected lymphocytes from 38 radio linesmen, 285 286 IARC MONOGRAPHS – 102 MONOGRAPHSIARC 102 – Table 4.1 Genetic and related effects of radiofrequency radiation in peripheral blood lymphocytes of occupationally exposed individuals End-point No. of Occupation Frequency SAR or power Duration Results Reference subjects density Aneuploidy 18 Air-traffic controllers; 100 kHz to 300 GHz - 10–27 yr + Othman et al. (2001) engineers CA 10 Radar maintenance 0.2 MHz to 26 GHz 0.010–50 mW/cm2 8–25 yr + Garaj-Vrhovac et al. (1990a) workers CA 38 Radio linesmen 400 kHz to 20 GHz 614 V/m 5 yr – Garson et al. (1991) CA 6 Air-traffic radar- 1250–1350 MHz 0.01–20 mW/cm 2 16 yr + [after a 30-wk Garaj-Vrhovac et al. (1993) repairmen follow-up, total aberrations had decreased] CA 6 Transmission-antenna 450–900 MHz NR 1 yr – Maes et al. (1995) maintenance workers CA 20 Workers in 8 GHz 1 mW/cm2 6 yr + Lalić et al. (2001) telecommunication and (12 h/d) radio-relay stations CA 50 Air-traffic controllers, 100 kHz to 300 GHz NR 8–27 yr + Aly et al. (2002) engineers CA 49 Radio engineers 450–900 MHz NR 2.3 yr – Maes et al. (2006) (> 1 h/d) CA 10 Radar maintenance 1250–1350 MHz 0.010–20 mW/cm2 7–29 yr + Garaj-Vrhovac & Orescanin workers (2009) MN 10 Radar maintenance 0.2 MHz to 26 GHz 0.010–50 mW/cm2 8–25 yr + Garaj-Vrhovac et al. (1990a) workers MN NR Multiple occupations 1250–1350 MHz 0.01–20 mW/cm 2 15 yr + Fucić et al. (1992) MN 12 Radar maintenance 1250–1350 MHz 0.01–20 mW/cm 2 13 yr + Garaj-Vrhovac (1999) workers SB 40 Flight crew NR NR 5–18 yr – Cavallo et al. (2002) SB 49 Radio engineers 450–900 MHz NR 2.3 yr – Maes et al. (2006) (> 1 h/d) SB 10 Radar maintenance 1250–1350 MHz 0.010–20 mW/cm2 7–29 yr + Garaj-Vrhovac & Orescanin workers (2009) SCE 50 Air-traffic controllers 100 kHz to 300 GHz NR 8–27 yr – Aly et al. (2002) SCE 49 Radio engineers 450–900 MHz NR 2.3 yr – Maes et al. (2006) (> 1 h/d) + increase; –, no effect; CA, chromosomal aberration; d, day; h, hour; MN, micronucleus formation; NR, not reported; SAR, specific absorption rate; SB, DNA single- and double-strand breaks; SCE, sister-chromatid exchange; wk, week; yr, year Radiofrequency electromagnetic fields Table 4.2 Genetic and related effects of radiofrequency radiation in peripheral blood lymphocytes and buccal cells of mobile-phone users End-point No. of Frequency SAR Duration Results Reference subjects Peripheral blood lymphocytes CA 24 890–960 MHz NR 2 yr + Gadhia et al. (2003) CA 25 NR 0.1–1.9 W/kg 3–5 yr + Gandhi & Singh (2005) MN 24 800–2000 MHz 0.6–1.6 W/kg 1–5 yr + Gandhi & Anita (2005) SB 24 800–2000 MHz 0.6–1.6 W/kg 1–5 yr + Gandhi & Anita (2005) SCE 24 890–960 MHz NR 2 yr + Gadhia et al. (2003) Buccal cells MN 25 NR 0.1–1.9 W/kg 3–5 yr + Gandhi & Singh (2005) MN 85 NR 0.3–1.0 W/kg 2.3 yr (1 h/d) + Yadav & Sharma (2008) MN 112 NR NR 5–10 yr (3 h/wk) – Hintzsche & Stopper (2010) +, increase; –, no effect; CA, chromosomal aberration; d, day; h, hour; MN, micronucleus formation; NR, not reported; SAR, specific absorption rate; SB, DNA single- and double-strand breaks; SCE, sister-chromatid exchange; wk, week; yr, year who erected and maintained broadcasting, tele­ Garaj-Vrhovac et al. (1993) observed a decline in communication and satellite RF-transmission the total number of chromosomal aberrations. towers, and found no increase in the frequency A preliminary study conducted by Maes of chromosomal aberrations compared with the et al. (1995) involved six workers in charge of frequency in 38 controls working as clerical staff. maintaining transmission antennae linked to a In this study, exposure to RF radiation was at or mobile-phone network, and six matched controls. below occupational limits for Australia. No increase in the frequency of chromosomal Fucić et al. (1992) measured the surface area aberrations was observed in the maintenance of micronuclei in lymphocytes of workers in workers. The authors mentioned the limited size multiple occupations exposed to pulsed micro­ of the study and the fact that exposure to RF waves, X-rays (< 25 mSv during the previous radiation was intermittent. They then extended 2 years) and vinyl-chloride monomer (VCM; the study to 49 professionally employed radio average concentration, 50 ppm). The sample engineers working in the field, and 11 adminis­ size in each category was not mentioned in the trative staff. Some of these had participated in paper. There were increased numbers of smaller the earlier study. No differences between exposed micronuclei in individuals exposed to X-rays and and controls were observed with the alkaline VCM, indicating a clastogenic effect. Increased comet assay, the assay for chromosomal aberra­ numbers of smaller as well as larger micronuclei tion, or the test for SCE (Maes et al., 2006). were found in individuals exposed to microwaves, Garaj-Vrhovac (1999) examined 12 subjects suggesting a dual role of this type of radiation, as employed in repair services for radar equip­ clastogen and aneugen. ment and antennae, and reported frequencies In a regular 30-week follow-up investiga­ of 8–23 micronuclei per 500 cells in exposed tion of six individuals who were acutely exposed workers compared with 2–7 per 500 cells in to pulsed-wave RF radiation of high power control subjects; this difference was statistically density at an air-traffic radar-repair station, significant. 287 IARC MONOGRAPHS – 102 Lalić et al. (2001) investigated 20 workers Cavallo et al. (2002) studied 40 airline pilots in telecommunication and radio-relay stations and flight technicians exposed to cosmic rays, who were exposed to non-ionizing electromag­ electromagnetic fields from radar equipment, netic fields, and 25 subjects employed as X-ray pollutants from jet-propulsion fluid etc. and 40 technicians, nurses and engineers in radiology, non-exposed individuals working on the ground. exposed to ionizing radiation. The analysis indi­ In the comet assay, visual examination of the cated an increased frequency of chromosomal results revealed a small increase in the frequency aberration in both groups. The incidence of of DNA strand breaks in exposed individuals dicentric chromosomes was higher in the group compared with ground staff, but this increase exposed to non-ionizing radiation than in the was not statistically significant. group exposed to ionizing radiation. Garaj-Vrhovac & Orescanin (2009) used the Othman et al. (2001) studied professional comet assay to measure DNA strand breaks and air-traffic controllers and engineers exposed to the test for sensitivity to bleomycin described by RF radiation emitted by different pieces of equip­ Michalska et al.
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