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

The seasonal variation in waste collectors' exposure to microorganisms, endotoxin and dust was measured with personal sampling equipment. The measurement was carried out in three different combinations of storage and collection system for biowaste: container/compactor truck (CIC), paper sack/compactor truck (P/C) and paper sack/platform truck (P/P).

The maximum personal exposure 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), mesophilic actinomycetes 9.0 x 10(2) cfu m(-3), bacteria 1.0 x 10(4) cfu m(-3), endotoxin 16 EU m(-3) (1.0 ng m(-3)) and dust 0.33 mg m(-3).

A seasonal variation was observed for microorganisms, moulds, A. fumigatus, mesophilic actinomycetes and endotoxin (P <0.05). The highest exposure to moulds, A. fumigatus 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 observed for concentrations of total microorganisms, moulds and endotoxin with a maximum occurring during the summer (P <0.05) and no differences were observed between percolate collected from the CIC and the PIC system, respectively.

The high volume of percolate generated in biowaste may constitute a potential health hazard to waste collectors on account of the high concentrations of microorganisms and the risk of splashing during collection.