Dynamic monitoring and analysis of occupational hazards in working environment of foundry plant from 1987 to 2010 / 中华劳动卫生职业病杂志

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the characteristics and changing trend of occupational hazards in the working environment of a foundry plant from 1987 to 2010.</p><p><b>METHODS</b>The foundry plant of a large-scale automobile company in Hubei Province, China was chosen as the study site. The data on occupational hazards in the working environment of the foundry plant in the past years were collected, and additional measurements were performed. The means and geometric means of the concentrations of occupational hazards were calculated. The characteristics and changing trend of occupational hazards from 1987 to 2010 were presented.</p><p><b>RESULTS</b>There were dust, chemical, and physical occupational hazards in the working environment of the foundry plant, with silica dust, noise, and heat stress as the main ones. Dust, mainly silica dust, is found in all aspects of foundry. The mean concentration of silica dust was high (3.2∼8.2 mg/m(3)), exceeding the national occupational exposure limit (1 mg/m(3)). The mean concentrations of silica dust varied across different types of work, with higher levels in cast shakeout and finishing, overhead crane operation, and sand preparation. The mean concentration of respirable dust in the foundry plant was low (0.38 mg/m(3)), not exceeding the national occupational exposure limit (0.7 mg/m(3)). There were high concentrations of grinding wheel dust (10.6 mg/m(3)) and welding fume (5.7 mg/m(3)) in cast shakeout and finishing, exceeding the national occupational exposure limit (8 and 4 mg/m(3)). Coal dust was mainly found in melting as well as cast shakeout and finishing, with higher concentration in the former (4.7 mg/m(3). The main chemical occupational hazard in the environment of the foundry plant was formaldehyde (1.23 mg/m(3)), exceeding the national occupational exposure limit (0.5 mg/m(3)). The concentrations of ammonia, phenol, metal fume, sulfur dioxide, hydrogen sulfide, and phosphine in the foundry plant were low. The mean concentration of polycyclic aromatic hydrocarbons was 0.1405 µg/m(3), with a higher level in pouring. The main physical occupational hazards in the working environment of the foundry plant were noise and heat stress. Noise, mainly steady noise, was distributed in all workshops of the foundry plant, with a mean intensity of 85.1 db (A). Noise levels varied across different types of work, higher in cast shakeout and finishing (89.3 db (A)) and moulding (85.4 db (A)). Heat stress mainly existed in overhead crane operation (35.1°C), pouring (33.3°C), and melting (32.8°C).</p><p><b>CONCLUSION</b>Dust, chemical, and physical occupational hazards co-existed in the working environment of the foundry plant. High concentration of dust was widely distributed in many workshops and across many types of work, but the dust concentration showed a downward trend. Chemical occupational hazards included ammonia, phenol, hydrogen sulfide, and metal fume, most at low concentrations. High-intensity noise was widely distributed in all working positions of foundry process and mainly from equipment operation, collision between parts, and gas injection. High-intensity heat stress mainly existed in overhead crane operation, pouring, and melting.</p>