Exposure levels of ELF magnetic fields in the residential areas of Mangaung Metropolitan Municipality

Abstract

The aim of this study was to evaluate the exposure levels of ELF magnetic fields in the residential areas of Mangaung metropolitan municipality. Fifteen residential sites were randomly selected in Bloemfontein, nine in Botshabelo and six in Thaba Nchu areas of Mangaung. Measurements were collected at the distances of 3 m, 6 m and 9 m outside electrical substations, near every corner, using a Trifield meter model XE 100. Measurements were also collected from four different corners inside substations, near barrier screening and were referred to as a distance of 0 m (reference point). The results indicated a non-significant difference among 15 residential areas; BRE1 to BRE15 and six areas; TNRE1 to TRNE6. The exposure levels were significantly high in one residential area BORE1 (0.55 μT) as compared to other residential sites in Botshabelo (p < 0.001). The results obtained from the measurements also show a significant difference between the residential areas BORE4 and BORE8 (p < 0.01) as well as BORE4 and BORE9 (p < 0.006). The four distance interims also demonstrated a highly significant difference (p < 0.0001) when compared to one another. The t test showed a statistically significant difference for exposure levels recorded at 3 m, 6 m and 9 m in comparison to 0 m (p < 0.01). The exposure levels recorded at 3 m were also significantly different to those recorded at 6 m (p < 0.05) and 9 m (p < 0.01). The exposure levels measured at all distances are below the ICNIRP guidelines and the fields decrease rapidly with an increased distance from the source.

Magnetic Fields and Cancer: Epidemiology, Cellular Biology, and Theranostics

“…Another important issue is the exposure assessment. The exposure to MF can vary greatly over time and distance, has multiple sources, and is imperceptible and ubiquitous [42][43][44][45]. In exposed schools, children may experience a higher chance of receiving a mean exposure >0.4 µT during school hours [46,47]; whereas those living in big buildings or using electric heating appliances in larger families had a generally higher level of personal indoor exposure [48].…”

Exposure to Extremely Low-Frequency Magnetic Fields in Low- And Middle-Income Countries: An Overview

“…A house located 24 m away from a 400 kV power line yielded the highest measured value of 4 μT ( 33 ) . In studies on exposure of the general public in residential areas ( 23 , 24 , 34 , 38 ) , the mean exposure ranged from 0.15 μT obtained in a series of 74 outdoor measurements in an urban area in Romania ( 23 ) to 2.18 μT observed below a 500 kV power line in a village of a rural area in Brazil ( 38 ) . Three studies used the same measurement device ( 16 , 33 , 34 ) , while the rest of the studies used different devices ( Table 2 ).…”

Survey of public exposure to extremely low-frequency magnetic fields in the dwellings

“…Also, after switching on the refrigerator and television, an unexpected reduction in ELF magnetic field was observed in two of the residential (number 8 and 99), which should be increased. It is presumed that being located near big malls which have telecommunication tower and generators, can be the reason of higher exposure level observed in these houses (17). Magnetic field strength measured at different distances from television in point 13 and 21 were 0.95 and 0.75 µT, respectively.…”