Mr E. A. Walker enquired whether there was any information on the relative amounts consumed of con- taminated food produced locally and of similar food, and its level of contamination, imported into the study area.
Inreply, DR B. E. Davies said that he knew of no studies which have attempted to answer this question other than one presently in hand at Shipham.That study was being undertaken by the Department of the Environment but results had not yet been published.
Dr K. A. Joysey asked whether studies had been conducted on possible relationships between the pre-valence of dental caries and the catchment areas of different dental practitioners.
In reply, Dr R. J. Anderson said that such studies had not been carried out. However, an estimate of the extent by which DMF values are influenced by local practioners can be estimated by comparing the pro-portion of teeth which have been filled to the total DMF value for that location or group of children. In all the dental findings this ratio was very similar ,indicating that the differences observed were probably not due to differences in the local patterns of dental practice.
Dr Betsy T. Kagey asked what the fluoride levels were, and whether the study areas had been subjected to fluoridated water.
In reply, DrB E. Davies said that although the local granites contain appreciable fluoride which is reflected in the composition of some surface waters, the water piped to Bere Alston contains ≤0.1 mg F-/litre as measured at the treatment