Exposure of Indian agricultural workers to airborne microorganisms, dust and endotoxin during handling of various plant products.

Microbiological air sampling with the use of personal sampler was performed in 14 small agricultural facilities located in Aurangabad (Southern India), including 5 farms (at harvesting and threshing), 6 godowns (small food storing and processing settings) and 3 grain or cotton mills. In 12 facilities, including harvesting on farms, godowns and mills, concentrations of airborne microorganisms were relatively low, ranging from 1.5 x 10(3) - 8.2 x 10(4) cfu/m(3). The striking rise in the concentrations of airborne microbes, by 2-4 orders of magnitude, was noted on 2 farms during threshing of maize (4.2 x 10(6) cfu/m(3)) and pearl millet (1.1 x 10(7) cfu/m(3)). This was due to release of large quantities of bacteria. During threshing of maize, the most common microorganisms were thermophilic actinomycetes (40 % of the total count) and mesophilic actinomycetes of the genus Streptomyces (39 %), while during threshing of pearl millet the most abundant were corynebacteria (68 %) and Gram-negative bacteria (22 %). Mesophilic bacteria formed 16.7-100 % of the total airborne microflora and were prevalent in 11 out of 14 facilities. Thermophilic actinomycetes and fungi formed respectively 0-43.1 % and 0-83.3 % of the total count and were prevalent in 1 and 2 facilities. The concentrations of airborne dust and endotoxin recorded in the examined agricultural facilities, in most cases were very large and ranged from 2.5-257.5 mg/m(3), and from 0.0625-125.0 microg/m(3), respectively. In 10 out of 14 facilities, the concentrations of dust were of the order 10(1)-10(2) mg/m(3), ranging from 25.0-257.5 mg/m(3). Similarly, in 7 out of 14 facilities the concentrations of endotoxin were of the order 10(1)-10(2) microg/m(3), ranging from 31.25-125.0 microg/m(3). In conclusion, Indian agricultural workers could be exposed during handling of various plant materials to airborne biological hazards posing a risk of work-related respiratory disease. Of these, the most important are: bacterial endotoxin and allergenic species of bacteria and fungi. The greatest risk occurs at threshing of pearl millet and maize which requests an application of the appropriate prevention measures, such as wearing respirators by the workers and using modern threshing machines reducing the dustiness.