This report (HPA-RPD-005) describes the investigation and identification of sources of residential magnetic field exposures in the UKCCS.
The Residential Sources Study was set up to investigate the sources of power frequency magnetic fields that contributed to average residential exposure estimates of 0.2 microtesla and above in the UK Childhood Cancer Study (UKCCS). The work was carried out as part of an extension of the UKCCS EMF Hypothesis - that exposure to extremely low frequency electromagnetic fields (EMFs), specifically power frequency magnetic fields, may play a role in the aetiology of childhood cancer.
There were two stages to the project; in Stage 1 the main objective was to identify power frequency magnetic field sources in the neighbourhood of the homes that might explain the UKCCS residential exposures. When there was no obvious explanation for the high exposure, the home and its corresponding matched case control were nominated for Stage 2 of the study, involving an internal inspection.
At the start of Stage 1, the original UKCCS data were reviewed and verified, and 196 homes were identified for the study. In the period between March and June 2003 all the sites were visited to identify and evaluate potentially significant magnetic field sources in the vicinity of the properties. Records showing overhead and underground distribution mains circuits, and service connections, were provided by the electricity industry.
The Stage 2 assessment was restricted to the homes occupied by the original UKCCS study homeowners giving written consent for participation in the Residential Sources Study. This report describes the source categories which account for elevated residential exposure in the UKCCS. The findings offer an initial technical basis for possible options for mitigating EMF exposure in the UK.