| Popis: |
Routine dust and radiological statistics have been examined for 274 British collieries for the period 1970-1975. These data were used to identify collieries where progression of simple pneumoconiosis appeared unusually high or low in relation to the dust levels. Eight of these collieries were selected for further study. For each selected colliery, an assessment was made of pre-1970 dust conditions, the pattern of dust distribution in the coalface area and the time spent by faceworkers at other collieries. Composition, size and toxicity characteristics of the dusts were also measured, as were oxides of nitrogen levels. The apparently anomalous results at five collieries are at least partly explicable in terms of environmental and manpower movement considerations. Similar information, however, does not explain the marked increase in progression of simple pneumoconiosis observed in 1972 at the other collieries. It is possible that in these cases the apparent discrepancies may be associated with temporal variations in the radiological technique. |
