Study and Measurement in Out-Door Enviroment of the ELF Electromagnetic Fields Round the Municipalities of the Bay of Cadiz

A. Domínguez Chorat1*, G. Gutiérrez Amares2, L. Machuca Muñoz3

1Cátedra de Física Médica. Departamento Materno-Infantil y Radiología. Facultad de Medicina. Universidad de Cádiz. Edificio Servicios Generales, Dr. Marañón 3. Cádiz 11002. . E-mail: [email protected] 2Cátedra de Física Médica. Departamento Materno-Infantil y Radiología. Facultad de Medicina. Universidad de Cádiz. Edificio Servicios Generales, Dr. Marañón 3. Cádiz 11002. Spain. 3Cátedra de Física Médica. Departamento Materno-Infantil y Radiología. Facultad de Medicina. Universidad de Cádiz. Servicio de Radiofísica Hospitalaria. Hospital Universitario de . Edificio Servicios Generales, Dr. Marañón 3. Cádiz 11002. Spain.

Abstract. The occupational and residential exposure to electromagnetic fields with extremely low frequency (CEM-ELF) could be related with cancer risk, as certain previous epidemiology studies indicate. The goal of this job is to study and to measure the intensity of the existing CEM in the out-door environment through the streets of Cadiz Bay cities (Andalucia, Spain) and the later values found statistical analysis for Cadiz, , Rota, Sanlucar de Barrameda, San Fernando, El Puerto de Santa Maria, Puerto Real, Chiclana de la Frontera and . The found values comply with the actual Spanish Legislation.

1. Introduction and Objectives

There are epidemiology jobs that study health effects from CEM-ELF and show their relation with illnesses or the relation between the electrical cable code and cancer and other jobs that relate occupational activities with workers health risks [1][2][3][4][5]. During 1995-2000, Valladolid University in conjunction with CSIC, UNESA and REE collaborated with an investigation job about the biological effects of CEM-ELF [6]. This job found that the life of the chicken decreases under magnetic field exposition over 50 µT. Those are aggressive expositions: It exposes embryo cells to acute doses in relatively short exposition periods. We should consider that multiple expositions to specific low level CEM can mean a significant increase of the total exposition for the human body. As goal of this job, it is to control de existing CEM at the out-door in the streets of Cadiz Bay cities (Andalucia, Spain): Cadiz, Jerez de la Frontera, Rota, Sanlucar de Barrameda, San Fernando, El Puerto de Santa Maria, Puerto Real, Chiclana de la Frontera and Chipiona. Later the statistical analysis will be done.

2. Materials and Method

CEM-ELF were measured at cities streets during morning business hours. Electric current in Spain works at 50 Hz. The measurement equipment used has been the Gossen Metrawatt Camille Bauer Instrument MetraHit 26S, with MetraHit FMA1 probe and memory adapter MetraHit S-232-II with a frequency approach between 16 Hz and 2kHz. It has three electrical field measures approach scales between 0.0 and 300.0 V/m, 0.0 and 3000.0 V/m and 0.0 and 30000.0 V/m. with a 0.1 V/m resolution. And three other magnetic field measuring scales: 0.0 and 3.0 µT, 0.0 and 30.0 µT and 0.0 and 300.0 µT, with a 0.1 µT resolution. SI232 Accesory, directional RS232 interface adapter with a memory capacity until 128 kByte (aprox. 100.000 samples) or on-line job. Data Software METRAwin 1.0 for DOS and WINDOWS. Equipment calibrated by manufacturer.

Measuring was performed at sidewalks of each Cadiz Bay city, at regular intervals. We measure for 2 minutes. Measures were on “Near Field” conditions. Groups of 60 measures were registered for the magnetic field according to the consulted bibliography, Lindgren et al., 2001, which classify flow densities in three groups: Low density CEM, with less than 0.2 µT; Medium density CEM, between

1 0.2 µT and 1.0 µT; and High density CEM, with more than 1.0 µT [7]. We tried to compare the existing electrical field values with the permitted by the Spanish legislation, which have a limit of 5000 V/m for 50 Hz.

3. Results

During this job we obtained the following results.

The maximum magnetic flow density found was 7.92 µT, with an average value of 7.31 µT, in the proximity of a transformer in Jerez de la Frontera city. The arithmetic mean of magnetic flow densities distributed by the cities was 0.07 µT. For percentile 95, the analysis showed a 0.45 µT value. 84% of measures showed a value lower than 0.2 µT, coinciding with the low density border. Less than 0.5% showed high density values over 1.0 µT, all of them near electrical transformers.

In relation to Electrical field values, the maximum average value found was 958.1 V/m, under an electrical line at Jerez de la Frontera. The arithmetic mean is under 3 V/m. The statistical analysis provides us a percentile 95 of 21 V/m.

4. Discussion.

Electrical leaks produced in some electrical lines are the most common sources of electromagnetic fields, specially for the high voltage lines. It happens by the transformer neutral cable or by metallic objects (like hot water heaters connected to central heating pumps by tubes, which is solved with isolating pieces). Cadiz Bay does not have district heating systems as other regions or countries because warm weather avoid them. For this reason the CEM are normally created by electrical source and not for electricity distribution different than cables. Also Cadiz Bay does not have at this moment electrical powered subway public transportation, which shows important changes for CEM until 30 µT. [7].

Values similar to the ones found in 1996 at housing in-door at Goteborg by Hammerius have been found in this study [8]. In 1993, Maravada [9] published a job with similar results to this ones. The exposition average for this job is 0.07 µT, lower than the one from Portier in 1998 [10], or the one found by Llanera in 1997 [11], also lower than the one from Duglosz in 1989 [12] and the one from Lindgren in 2001 [7] about CEM at city environment. The CEM Values for cities at Cadiz Bay be away under the Spanish legislation established limits, which are 5000 V/m for electric field and 100 µT for magnetic flow density at 50 Hz.

5. Conclusions

Generally, it tends to consider the city environment as low level electromagnetic field areas. But those levels change depending of each city structure and according the consulted bibliography. Around the 85% of the streets studied receive densities of 0.1 µT and electric fields of 0.5 V/m or less which are lower than the 0.2 µT considered as a minimum level associated with cancer risk, level adopted from other precedent epidemiologic studies. The highest magnetic flows densities were always found near electrical transformers and sometimes near places with high power electrical systems such air conditioning units or anti-theft systems. The electrical fields always increase their power if we are under electrical lines, being higher when the voltage of the line is higher. Sometimes upward oscillations are found near to electrical or security systems at commercial premises or banks proximities.

6. Appreciations

This study is part of the “Cadiz Province Electromagnetic Contamination”, at present project financed by the Excelentísima Diputación de Cadiz. We want to show them our recognition.

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7. References

1. Feychting, M.; Ahlbom, A. Magnetic fields and cancer in children residing near Swedish high- voltage power lines. Am. J. Epidemiology 138: 467-481. (1993). 2. Stenlund, C.; Floderus, B. Occupational exposure to magnetic fields in relation to male breast cancer and testicular caner: a Swedish case-control study. Cancer-Causes-Control 8(2): 184- 191. (1997). 3. Hardell, L.; Holmberg, B.; Malker, H.; Paulsson, L.E. Exposure to extremely low frequency electromagnetic fields and the risk of malignant diseases–an evaluation of epidemiological and experimental findings. European J. Cancer prevention 4 (suppl 1): 3-107. (1995). 4. Wertheimer, N.; Leeper, E. Electrical wiring configurations and chilhood cancer. Am. J. Epidemiology 109: 273-384. (1979). 5. Floderus, B.; Persson, T.; Stendlund, C. Lågfrekventa magnetfält i arbetsmiljön-Referensvärden och exponering i olika yrkesgrupper. Arbetsmiljöfonden, Rapport 91-15267. (1994). 6. Universidad de Valladolid, CSIF, UNESA, REE: Cinco años de Investigación sobre los efectos biológicos de los campos electromagnéticos de frecuencia industrial en los seres vivos. 1995- 2000. 7. Lindgren, M.; Gustavsson, M.; Hamnerius, Y.; Galt, S. ELF magnetic fields in a City Environment. Bioelectromagnetics 22: 87-90. (2001) 8. Hamnerius, Y.; Nilsson, R.; Galt, S. Case control study of gliomas and domestic exposure to magnetic fields, radon and ionizing radiation. Abstract Book, 3erd International Congress of EBEA, Nancy, France. (1996). 9. Maravada, P.S. Characterization of power frequency magnetic fields in different environments. IEEE Trans Power Delivery, 8(2): 598-606. (1993). 10. Portier, C.J.; Wolfe, M.S. Assessment of health effects from exposure to power-line frequency electric and magnetic fields. NIEHS Working Group Report, North Carolina, Research Triangle Park. (1998). 11. Lanera, D.; Zapotosky, J.E.; Colby, J.A. Study of magnetic fields from power-frequency current on water lines. Bioelectromagnetics 18: 307-316. (1997) 12. Dlugosz, L.J.; Byers, T.; Vena, J.; Zielezny, M. Ambient 60-Hz magnetic flux density in an urban neighbourhood. Bioelectromagnetics 10: 187-196. (1989).

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