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

2018 · No effect · Low evidence

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No effectLow evidencePaper 2044

Study snapshot

Publicationmanual · 2018

Study typeexposure_assessment

Reported directionNo effect

Evidence ratingLow

Abstract

Exposure levels of ELF magnetic fields in the residential areas of Mangaung Metropolitan Municipality Rathebe P, Weyers C, Raphela F. Exposure levels of ELF magnetic fields in the residential areas of Mangaung Metropolitan Municipality. Environ Monit Assess. 2018 Aug 23;190(9):544. doi: 10.1007/s10661-018-6916-8. 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. ncbi.nlm.nih.gov

Machine Enhanced Logic

AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeexposure_assessment

Effect directionno_effect

PopulationResidential areas of Mangaung Metropolitan Municipality (Bloemfontein, Botshabelo, Thaba Nchu)

Sample size30

ExposureELF

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

Measurements of ELF magnetic fields were taken at 0 m (inside substations) and at 3 m, 6 m, and 9 m outside substations across 30 residential sites. One Botshabelo residential area (BORE1) had higher measured exposure (0.55 µT) than other Botshabelo sites (p<0.001), and several other between-site differences were reported. Field levels differed significantly by distance and decreased with increasing distance; all measured levels were reported to be below ICNIRP guidelines.

Outcomes measured

ELF magnetic field exposure levels (µT) at 0 m, 3 m, 6 m, 9 m from substations
Between-site differences in measured ELF magnetic fields
Comparison of measured levels to ICNIRP guidelines
Distance-related decay of magnetic field levels

View raw extracted JSON

{
  "study_type": "exposure_assessment",
  "exposure": {
    "band": "ELF",
    "source": "electrical substations (residential areas near substations)",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Residential areas of Mangaung Metropolitan Municipality (Bloemfontein, Botshabelo, Thaba Nchu)",
  "sample_size": 30,
  "outcomes": [
    "ELF magnetic field exposure levels (µT) at 0 m, 3 m, 6 m, 9 m from substations",
    "Between-site differences in measured ELF magnetic fields",
    "Comparison of measured levels to ICNIRP guidelines",
    "Distance-related decay of magnetic field levels"
  ],
  "main_findings": "Measurements of ELF magnetic fields were taken at 0 m (inside substations) and at 3 m, 6 m, and 9 m outside substations across 30 residential sites. One Botshabelo residential area (BORE1) had higher measured exposure (0.55 µT) than other Botshabelo sites (p<0.001), and several other between-site differences were reported. Field levels differed significantly by distance and decreased with increasing distance; all measured levels were reported to be below ICNIRP guidelines.",
  "effect_direction": "no_effect",
  "limitations": [],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "ELF",
    "extremely low frequency",
    "magnetic fields",
    "residential exposure",
    "electrical substations",
    "Trifield meter XE 100",
    "ICNIRP guidelines",
    "Mangaung",
    "Bloemfontein",
    "Botshabelo",
    "Thaba Nchu"
  ],
  "suggested_hubs": [
    {
      "slug": "who-icnirp",
      "weight": 0.6,
      "reason": "Abstract explicitly compares measured ELF magnetic field levels to ICNIRP guidelines."
    }
  ]
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1007/s10661-018-6916-8
PubMed: Not supplied

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