In 1997, the International Agency for Research on Cancer (IARC) classified crystalline free silica as a carcinogenic substance to human (Group 1). Exposure to crystalline free silica for a long period of term may damage human respiratory system seriously. Foundry is the basal industry in Taiwan, the dust containing crystalline free silica is produced in that working environment. Environmental monitoring of crystalline free silica is very difficult, this is because that the analysis of this substance is not only complicated but also costly. The main purpose of this project is to develop an inexpernsive alternative method of analysis with simpler process. First of all, we used the SKC aluminum cyclone and GS-3 cyclone to test the usability and the uniformity of the sampling method. Second, we used the method of Japanese JIS A1481 X-ray diffractometry to analyze samples. Third, we developed our own standard materials to build the calibration curve. Finally, we applied this method in the working environment. The results showed that the aluminum plates had a much better effect than zinc plates in identifying crystalline free silica. The all open-faced samples had good uniformity in the filter no matter how many middles were used, but not so good for the closed-faced sampling. The calibration curve had a good correlation coefficient (r=0.995). Due to different industrial operating patterns, the distribution of crystalline free silica concentration varied by the industrial environment. The dust consisted of 10- 30% of crystalline free silica in all samples obtained from the foundry environments. The crystalline free silica was accounted for less than 10% in the respirable dusts. These data suggest high concentrations of crystalline free silica at the foundry processing sites must be measured carefully. This simple and low cost method can be adapted to monitor improve the foundry working environment for improving workers’ health.
