| dc.description.abstract | Chemical hazards are the main hazardous characteristics of plastic surface treatment industry. Direct contact with dangerous and harmful substances will cause occupational disease. This study made occupational exposure assessment on the workers of coating and printing sections of a plastic surface treatment plant W. The objective was to realize the actual exposure and health risk for the workers in plastic surface treatment industry. The assessment included preliminary hazard analysis, statistical analysis and additive effect assessment, health risk assessment, and suggestions for chemical classification management.
Having six similar exposure groups in this study of chemicals hazard, these were blending operations in Coating Section 3 (SEG01), blending operations in Coating Section 5 (SEG03), wiping operations in Coating Section 3 (SEG02), wiping operations in Coating Section 5 (SEG04), screen printing operation (SEG05) and the inspection and spray printing operation (SEG08).
This study adopted outlier detection method to test the compliance with the historical data for the measurements on working environment in 2014. It revealed that the measurements in 2014 were in a frequency distribution with the historical data. Additive effect was utilized to assess chemicals hazard and found the values from the blending operations in Coating Section 3 (SEG01) and Coating Section 5 (SEG03) were 0.16 and 0.54, respectively. In the wiping operations, the value of additive effect assessment in Coating Section 3 (SEG02) was 0.28 and that of Coating Section 5 (SEG04) was 0.15. Similarly, the values of additive effect assessment in the screen printing operation (SEG05) and the inspection and spray printing operation (SEG08) were 0.23 and 0.02, respectively. The value of SEG03 was the highest of all. However, all these values were less than 1 and were complied with the allowable limit in the working environment.
In the health risk assessment, the chronic inhale hazard index (HI) of SEG01 was 8.74*10-5 and that of SEG03 was 1.75*10-4. The HI value of SEG03 was higher than SEG01. The hazardous substances in both operations, from high to low, were xylene, n-hexane, toluene, and acetone. In the wiping operations, the values of HI in SEG 02 and SEG04 were 2.12*10-4 and 1.11*10-4 respectively. The HI value of SEG02 was higher than SEG04. The most hazardous chemical was n-hexane. The results from health risk assessment were similar with the additive effect assessment. The HI value in chronic inhale risk of screen printing operation SEG05 was 3.57*10-5 and the hazardous substances were xylene, toluene, n-hexane, and 2-butoxyethanol. The HI value of the inspection and spray printing operation of SEG08 was 6.00*10-6 and the hazardous substance was butanone. The HI value of SEG02 was the greatest of all. However, all these operations were having HI values less than 1 and were complied with the limit of working environment. The cancer HI value of isophorone was 1.08*10-8, which was less than the acceptable cancer risk of 1.00*10-6.
The ranks of abnormal rates from health examination from high to low were 6.6% in SEG01, 6.3% in SEG03, 6.0% in SEG02, 5.8% in SEG08, 3.8% in SEG04, and 3.4% in SEG05. The abnormal rate of SEG01 was the highest, which was different from the health exposure risk assessment. For the T-tests of significant difference between similar exposing group and the indirect operators, the leukocyte of the wiping operation workers of SEG02 and red blood cell of the blending operation workers of SEG01 and SEG03 were with significant differences.
Concluding from the above analyses, the exposure conditions of both coating and printing sections of plastic surface treatment in W company meet statutory standards. The blending operation in Coating Section 5 (SEG 03) was with the highest hazard value in the chemicals additive effect. The wiping operation in Coating Section 3 (SEG 02) was having the highest chronic inhale HI value and leukocyte abnormal rate. Moreover, the blending operation in Coating Section 3 (SEG 01) and Coating Section 5 (SEG 03) showed the greatest abnormal rate of red blood cell. These findings indicated the necessity of implementing engineering and management improvement and persistent monitoring on the aforementioned areas.
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