IARC MONOGRAPHS ON THE EVALUATION OF CARCINOGENIC ...

Thailand (median concentration, 0.664 μg/L). Levels were significantly higher in the
Thai samples.
1.3.5 Occupational exposure to aflatoxins
AFLATOXINS 187
Kussak et al. (1995) demonstrated the presence of aflatoxins in airborne dust from
feed factories.
During unloading of ships, aflatoxin B 1 has been found in bilge at levels as high as
300 ng/m 3 (Lafontaine et al., 1994).
Autrup et al. (1993) assessed the exposure to aflatoxin B 1 of workers in animal feed
processing plants in Denmark. The workers served as their own controls; blood samples
were taken after their return from vacation and after four weeks of work. Binding of
aflatoxin B 1 to serum albumin was measured. Seven of 45 samples were positive for
aflatoxin B 1 with an average daily intake of 64 ng/kg bw aflatoxin B 1. The exposed
workers had been unloading cargoes contaminated with aflatoxin B 1 or working at places
where the dust contained detectable amounts of aflatoxin B 1. This level of exposure
could partly explain the increased risk for liver cancer in workers in the animal feed processing
industry.
Ghosh et al. (1997) assayed airborne aflatoxin in rice- and maize-processing plants
in India using an indirect, competitive enzyme-linked immunosorbent assay. Levels of
airborne aflatoxin were always higher in the respirable dust samples (< 7 μm) than in
total dust samples. Concentrations of total airborne aflatoxin in the respirable dusts in the
rice mill were 26 pg/m 3 and 19 pg/m 3 in the workplace and the storage area, respectively.
Airborne aflatoxin was not detected in control sites of either of the grain-processing
plants or in total dust samples obtained from the maize plant. At three sites in the maizeprocessing
plant — the elevator (18 pg/m 3 ), the loading/unloading area (800 pg/m 3 ) and
the oil mill (816 pg/m 3 ) — airborne aflatoxin was present only in the respirable dust
samples.
In a study of factories in Thailand (Nuntharatanapong et al., 2001), samples of airborne
dust generated during handling of animal feed were analysed in order to assess
worker exposure to aflatoxins. The average aflatoxin level in the control air samples was
0.99 ng/m 3 . Higher levels of aflatoxins were found in the air samples taken by samplers
carried by five workers adding hydrated sodium calcium aluminosilicate to animal feed
(1.55 ng/m 3 ) and five workers adding glucomannan, a viscous polysaccharide, to animal
feed (6.25 ng/m 3 ). The exposed workers had altered lactate dehydrogenase isoenzyme
activity and tumour necrosis factor levels in plasma. These changes may be associated
with inhalation of mycotoxins and other contaminants in foodstuffs.