Seasonal variation in bioaerosol exposure during biowaste collection and measurements of leaked percolate

The seasonal variation in waste collectors' exposure to microorganisms, end otoxin and dust was measured with personal sampling equipment. The measurem ent was carried out in three different combinations of storage and collecti on system for biowaste: container/compactor truck (CIC), paper sack/compact or truck (P/C) and paper sack/platform truck (P/P). The maximum personal ex posure was found to occur during the summer at the following median levels: total microorganisms 9.2 x 10(5) cells m(-3), culturable fungi (moulds) 7. 8 x 10(4) cfu m(-3), Aspergillus fumigatus 2.9 x 10(-3) cfu m(3), mesophili c actinomycetes 9.0 x 10(2) cfu m(-3), bacteria 1.0 x 10(4) cfu m(-3), endo toxin 16 EU m(-3) (1.0 ng m(-3)) and dust 0.33 mg m(-3). A seasonal variati on was observed for microorganisms, moulds, A. fumigatus, mesophilic actino mycetes and endotoxin (P < 0.05). The highest exposure to moulds, A. fumiga tus and endotoxin occurred in the CIC system (P < 0.05) during the summer. Percolate from the biowaste was collected from the bottom of the compactor trucks. Concentrations of endotoxin ranged from 3.9 to 6.1 x 10(5) EU ml(-1 ) (25 to 52 mu g ml(-1)) and the microflora of the percolate was dominated by bacteria (1.2 to 2.3 x 10(9) cfu ml(-1)). A seasonal variation was obser ved for concentrations of total microorganisms, moulds and endotoxin with a maximum occurring during the summer (P < 0.05) and no differences were obs erved between percolate collected from the CIC and the PIC system, respecti vely. The high volume of percolate generated in biowaste may constitute a p otential health hazard to waste collectors on account of the high concentra tions of microorganisms and the risk of splashing during collection.