Original Article

 

Author: E. Petrova
Clinic of Occupational Diseases, University MHAT “St. Ivan Rilski”, Sofia

 

Author for contacts: E. Petrova, Clinic of Occupational Diseases, University Hospital “St. Ivan Rilski“, 15 Acad. Ivan Geshov Blvd, Sofia 1431. e-mail: mdepetrova@yahoo.com

 

Keywords: iron foundry, pneumoconioses, COPD, boundary pneumoconioses, dose/effect

 

Abstract
Objectives: To describe the exposures of pneumotropic risk factors, radiological, functional pulmonary changes, to identify dose/effect correlations and pulmonary diseases of workers in the iron founding industry exposed to mineral quartz and bentonite containing dust, metal dust and irritant chemical factors in the air of the working environment and to propose adequate methods for medical screening.
Materials and methods: The objects of medical screening in a nested case control cross sectional study were 1111 people (845 men and 245 women) from four iron foundries in Bulgaria (“Leyarmash”, Sofia, “Chugunoleene”, Ihtiman, “Osam EAD”, Lovech and “Energoremont”, Kresna) with a mean production exposure of 15.5 years and a mean age of 46.6 years. All participants were asked questions on their occupation, occupational pneumotropic production risk factors, and harmful habits. A complete physical examination was conducted, emphasizing on the pulmonary system; as well as pulmonary radiographs (classified according to ILO’80), spirometry, nonparametric, correlation and variation statistical analysis using SPSS software.
Results and discussion: The highest proportions of dust exposed workers and prolonged dust exposure were, as in order, in “Leyarmash”, “Chugunoleene”, “Osam EAD” and “Energoremont”, while the toxic factors dominated in “Chugunoleene”, followed by “Leyarmash”, “Osam EAD” and “Energoremont”. The mean production exposure in “Osam” was 11.5 years, in “Energoremont” - 12.2 years, in “Chugunoleene” - 13.3 years and in “Leyarmash” - 15.5 years. The subjective symptoms and the pathological physical pulmonary findings were respectively: in “Leyarmash” - 38.3% and 17.2%, in “Chugunoleene” - 31.1% and 11.4%, “Osam” - 32.0% and 25.6%, and in “Energoremont” - 27.7% and 17.0%. The boundary p, q, r opacities dominated in “Energoremont” (36.1%), followed by “Chugunoleene” (25.7%), “Osam” (23.4%) and “Leyarmash” (22.2%), while the highest proportions of manifested p, q and r opacities were present in “Energoremont” workers (13.9%), followed by “Leyarmash” (12.7%), “Osam” (11.9%) and “Chugunoleene” (7.3%). The mean duration of production dust exposure necessary for the development of 1/1 + p, q, r opacities (expression of manifested pneumoconiosis) ranged from 9.2 years to 12.2 years, and for the development of boundary (0/1, 1/0) p small opacities (expression of the L control), it was approximately 10.8 to 13.9 years. Significant correlations were established between the duration of dust exposure and p, q and r opacities. The mixed ventilatory disorders (MVD) dominated in workers of “Leyarmash”, Sofia, followed by small airways obstruction (SAO) in Sofia, Kresna, Ihtiman and Lovech, and mixed ventilatory disorders (MVD) + SAO in Ihtiman, Lovech and Kresna.
Conclusions: 1. The iron foundry is characterized by various harmful factors of production, with a leading part of the inorganic dust. 2. The subjective clinical symptoms are moderately manifested. 3. The functional disorders are manifested primarily as obstructive disorders in the upper and lower respiratory tract and/or mixed ventilatory disorders. 4. There is a dose/effect correlation of the onset of initial p, q and r opacities and the mean duration of dust exposure (9.2 years). 5. A slight negative correlation is found between age and FEF50%. 6. The occupational pulmonary dust diseases present clinically as initial/boundary disorders (control „L“ and „Z“), followed by COPD, compensatory emphysema, pneumoconiosis, and mixed pneumoconiosis in welders and are caused by inorganic dust. The compensatory emphysema has a high proportion, while lung cancer cases are several (total of 3). 7. The expected pulmonary pathology in the workers from the iron foundries requires the conduction of surveys, examinations from occupational physician - pulmonologist, pulmonary spirometry and radiographs on 1-3 year period.