Assessment of airborne dust associated with chemical plant: A case study

The process of alumina production involves refining of bauxite ore into tri-hydrated alumina (Al2O3, 3H2O) by chemical method followed by process of calcinations. This method possesses various kinds of dust hazards in its work environment amongst the people involved. Poor health of industrial employees in India is due to its occupational environment (Park & Park, 1970), which is a major concern now-a-days. Attempts have been made to recognize the potential sources of airborne dust and to assess the dust load upon exposed workers at different work sites of alumina plants by comparing the observations with the standard values called 'Threshold Limit Values' (T.L.V.) assigned by the international body ACGIH (American Conference of Governmental and Industrial Hygienists), USA, and also permissible exposure limit values prescribed in the second schedule Section F of Factories Act (Amendment), 1987. Alumina plant operation includes various physical operations like crushing, grinding, conveying, loading, transporting, etc., which generate finer particles. It can cause serious health hazards on inhalation, depending upon its size, shape, constituents and duration of exposure. Out of all these parameters, concentration of respirable fraction of airborne dust (0.5 to 5.0 micron size) and its free silica content have been reported to cause lung fibrosis as well as occupational disorders. In the present study, attempts have been made to make a survey of respirable fraction of the airborne dust (that remains suspended in air for quite an appreciable time) associated with various operations according to job profiles. It also outlines the probable control measures in order to provide a healthy working environment. Present work aims at identifying and evaluating the degree of workplace dust with special reference to respirable fraction and for recommending suitable suggestive control measures for an effective management of occupational environment.