An assessment of risks due to asbestos on farm tracks and rights of way in South Cambridgeshire

The presence of asbestos in the filling material in farm tracks and rights of way (ROW) in South Cambridgeshire leads to the possibility that residents and other users may be exposed to airborne asbestos fibres. Measurements have shown that concentrations of airborne asbestos fibres are low, but there is no known threshold of exposure below which there is absolutely no risk. Therefore, this study was undertaken to provide a quantitative estimate of the risk of lung cancer or mesothelioma being caused by exposure to airborne asbestos fibres from the ROW. The study was commissioned by the Cambridgeshire County Council and South Cambridgeshire District Council. From measurements of concentrations of airborne asbestos, we constructed estimates of the annual average concentrations for six ROW. These ROW had been selected in consultation with the Councils as being informative about the issues involved in dealing with the asbestos on ROW in South Cambridgeshire. Previous studies informed the choice and the chosen tracks included those previously identified as posing relatively higher risk. Airborne asbestos creates a risk to health if it is inhaled. Estimates of the amount of time that residents could or would spend on the ROW, combined with the likely concentrations of asbestos in air, gave estimates of the annual cumulative exposures. Worst case scenarios provided estimates of risk that are possible but unlikely. A realistic scenario indicated the more likely level of risk from long term residence and use of the ROW. The worst case estimates indicate the asbestos exposure on the ROW is unlikely to cause any deaths of the residents. However, for some of the ROW, the worst case predictions exceeded the upper boundary (of 10 in 100,000) of consensus values for the level of lifetime excess risk that could be deemed acceptable. Under the realistic exposure estimation for regular use of the ROW by residents of houses accessed from the ROW, all predicted lifetime excess risks were at or below that boundary level of acceptability and it is very unlikely that the health of any resident will be affected. The predicted risks have been compared to other more familiar risks. For example, the risks from smoking are much higher than those from the worst case scenario for exposure to airborne asbestos from the ROW. “”