Background Aluminosis cases caused by black fused alumina were reported in a mining powder factory in Qingpu District of Shanghai, and late-onset cases in the factory are stll emerging in recent years.
Objectve This study is conducted to describe the epidemiologic characteristcs of aluminosis, especially late-onset aluminosis, caused by black fused alumina dust, and to bring the issue to the forefront.
Methods A total of 83 cases of aluminum pneumoconiosis diagnosed for the frst tme from 1989 to 2014 in a mining powder factory in Qingpu District of Shanghai were taken as study subjects, and the diagnosed stage of pneumoconiosis was the conclusion of the frst diagnosis. Historical records were collected to understand the basic settings of the factory and the concentratons of worker's dust exposure in workplace air. The concentraton of free SiO2 in black fused alumina dust was determined by pyrophosphate method. Work type-specifc cumulatve aluminosis incidences and latent period of late-onset aluminosis (cases diagnosed afer 2 years of dust removal) were analyzed.
Results The chemical compositon of black fused alumina used in this factory included Al2O3 (75%), Fe2O3 (>15%), TiO2 (3%), and SiO2 (7%); the content of free SiO2 in dust was 1.5%. The dust concentration fluctuated obviously in the same type of workstations, and had great differences among different types of workstations, with medians of 37.32-105.7 mg/m3. There were a total of 83 cases of aluminosis diagnosed in the past years, including 17 males and 66 females; the average (range) age of onset was 55.2 (32.5-79.9) years, and the average (range) duraton of dust exposure was 10.26 (3.0-19.0) years. Among them, 43 cases were diagnosed with frst-stage pneumoconiosis, and progression to advance pneumoconiosis occurred in 9 cases; 26 cases were second-stage pneumoconiosis, and progression to advance pneumoconiosis occurred in 9 cases; 14 cases were third-stage pneumoconiosis. By the end of investigation in 2014, 20 cases died (including 10 first-stage pneumoconiosis cases, 8 second-stage pneumoconiosis cases, and 2 third-stage pneumoconiosis cases) and 63 cases survived (including 24 frst-stage pneumoconiosis cases, 18 second-stage pneumoconiosis cases, and 21 third-stage pneumoconiosis cases). The diagnosed patents were with the job ttles of grinding, screening, fling, and grading, and the cumulatve incidence rates were 75.0% (21/28), 49.3% (35/71), 34.4 (11/32), and 30.2 (16/53), respectvely. Among the 83 cases, 77 cases (92.8%) were late-onset patents. Of the 43 cases frst diagnosed with frst-stage pneumoconiosis, 41 cases were late-onset pneumoconiosis, and their average (range) latent period was (22.49±7.51) (10.08-42.78) years. The 20-25 years latent period group (11/43, 25.6%) was the largest, while the > 30 years latent period group (5/43, 11.6%) was the smallest. The sequence of latent period among workers with different job ttles was as follows:grinders (17.80 years) < screening workers (20.97 years) < fling workers (25.99 years) < grading workers (27.30 years).
Conclusion Aluminosis caused by black fused alumina dust is characterized by high cumulatve incidence, late onset, agglomeraton of work types, and is predicted to repeatedly occur in the future. Therefore, it is necessary to strengthen occupatonal health surveillance of dust removal workers and to achieve early detecton, diagnosis, and treatment.
DownLoad: