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
siteswere 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 0m(p < 0.01). The exposure levels recorded at 3m
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.
