Health effects of volcanic ash of Mt. Sakurajima; studies on calf lung and loggers

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In order to investigate the health effects of volcanic ash of Mt. Sakurajima, following studies were conducted.1. Dust induced pulmonary changes were searched in loggers who are exposed most frequently and heavily to volcanic ash. Although the levels of suspended particulate matter (SPM) of their working environment differed a great deal depending on the work areas, all the group of the loggers showed low prevalences of respiratory symptoms and average pulmonary functions were normal. No case with pneumoconiosis was found by the chest roentogenogram examination. These results among the highest exposed group suggest that volcanic ash is not likely to be a major cause of respiratory diseases for the general population.2. Reliability of the questinnaire survey for respiratory symptoms and the criteria for respiratory diseases in the srudy of the health effects of volcanic ash was examined in order to roleout the effects of seasonality of ash exposure. Using ATS-DLD to 380 women exposed to volcanic ash were surveyed repeatedly in both spring and summer. Results showed that prevalences of relatively severe symptoms or symptoms with higher frequencies, and diagnosis of respiratory diseases by combined multiple item criteria were relatively stable over the seasons. These findings indicate that by limiting analysis to questions related to frequent symptoms only , seasonal variation would be minimized and more stable results would be obtained.3. The availability of calf lung as a biological index of volcanic ash was examined by analyzing the elemental composition of lungs of cals bled in the area exposed to volcanic ash. Among the various elements, the content of silicon in the lung tissue was best correlated with the duration of exposure and showed the highest average value in the lungs of calf from highest exposed area. To confirm these findings, further study is currently under way.