一エレクトロニクス工場における産業衛生学的研究

In one of the buildings of a factory, each of which is provided with its own central air conditioning system, about 1, 000 employees working in it were exposed to trichloroethylene (Tri) gas, diffused from a washing apparatus. The air concentration of the gas was above 100 ppm, and the duration of the exposure was considered to cover several months.<BR>On the other hand, anemic sign on the skin and mucosa was found in many workers by the annual health examination, immediately before the finding of this air pollution by Tri. On account of this, the specific gravity of whole blood, hemoglobin (Hb) and hematocrit (Ht) were determined with all the workers of the factory.<BR>According to the relevant literature, negative views appeared predominant concerning the direct connection between the exposure to Tri and development of anemia. We performed study on this connection, using as controls the non-exposed workers of other buildings, with the following results : <BR>1) The concentration of Tri in environmental air, which was determined twice daily (at 11 : 30 a.m and 3 : 30 p.m.) and 70 times in total with the detector tube at 5 fixed points of the polluted building ranged 30-300 ppm. And it exceeded 100 ppm in more than half of the determinations.<BR>2) Urinary excretions of total trichloro-compunds (TTC) and trichloroacetic acid (TCA) from 25 workers of this building ranged 15.4-159.3 mg/4hrs. and 4.8-69 mg/4hrs, respectively. High Tri exposure can be estimated also from metabolites.<BR>3) Mean Hb was significantly lower in both males and females of the exposed group than in the non-exposed (P<0.01). Ht was significantly lower only in exposed males (P<0.01).<BR>4) As for the correlations of urinary TTC to Hb and Ht, both correlation coefficients were negative. But either was not significant statistically.<BR>5) Mean specific gravity of whole blood was, like Hb and Ht, significantly lower in both males and females of the exposed group (P<0.01). Some time after the improvement of environment, the mean specific gravity was elevated in the exposed group, finally becoming equal to that for the nonexposed group in both sexes.<BR>It became clear from these results that the blood values were lower in Tri-expose d than in non-exposed group. The findings indicated that the specific gravity of whole blood was restored to the normal with the liberation from the pollution. It is, however, difficult for the method of the present observation to attribute the above mentioned changes in blood values exclusively to Tri exposure, since these values are easily susceptible to the influences of various factors such as individual living state and nutritional condition.