Assessing Exposures to Compost Workers from Airborne BioHazards

Transcription

1 Assessing Exposures to Compost Workers from Airborne BioHazards Karen Bartlett 1, Jim Atwater 2 1 School of Population and Public Health 2 Department of Civil Engineering University of British Columbia, Vancouver, BC, Canada Karen.bartlett@ubc.ca

2 What is compost, anyway? Microbial processes break down complex biochemical structures and generate heat. Compost turns waste into nutrients for soil. Yard waste Food scraps Biosolids o C

3 What is compost, anyway? Self-generated heat kills pathogenic bacteria (good treatment for biosolids). Heat-loving microorganisms exponentially increase concentration. Spores released from microbes are allergenic and provoke inflammatory response. Aspergillus vesicle and conidia

4 What is compost, anyway? Self-generated heat kills pathogenic bacteria (good treatment for biosolids). Heat-loving microorganisms exponentially increase concentration. Spores released from microbes are allergenic and provoke inflammatory response. 3 µm Aspergillus vesicle and conidia

5 What is the hazard? Scale of municipal composting, volume of organic material handled, and process steps creates exposures to workers. Inhalation hazard is due to aerosolization of organic dust and microbial products. Urbanization of rural industry. Respiratory system & inhalation of particles

6 What is the hazard? Scale of municipal composting, volume of organic material handled, and process steps creates exposures to workers. Inhalation hazard is due to aerosolization of organic dust and microbial products. Urbanization of rural industry. Respiratory system & inhalation of particles

7 Goals of study: Evaluate exposures to airborne dust, microbes and microbial products. Determine tasks which may create higher exposures. Evaluate control measures to reduce exposures. Determine potential community exposures. Placing 7-hole sampler and pump for full shift exposure.

8 Site 1 Participating sites Located in high desert Feedstock = Biosolids Process = static aerated piles Site 2 Located in high desert Feedstock = Yard waste & biosolids Process = windrow piles Site 3 Located in coastal rainforest Feedstock = Yard waste Process = windrow piles

9 Exposure measurements: Dust PM ( 100 µm) Endotoxin (pro-inflammatory biochemical from bacterial cells) Aspergillus fumigatus (fungal opportunistic pathogen) Thermoactinomycetes (bacterial allergen associated with hypersensitive pneumonitis) Full day exposure: gravimetric and functional assay Task based grab samples for viable microorganisms

10 GM Dust Concentration (mg/m3) 8 Results: Dust concentration by area inside cab outside cab personal Site 1 Site 2 Site 3

11 GM Dust Concentration (mg/m3) 8 Results: Dust concentration by area inside cab outside cab personal Site 1 Site 2 Site 3

12 GM Endotoxin concentration (EU/m3) 1600 Results: Endotoxin by area inside cab outside cab personal Site 1 Site 2 Site 3

13 GM Endotoxin concentration (EU/m3) 1600 Results: Endotoxin by area inside cab outside cab personal Site 1 Site 2 Site 3 European Union EL = 90 EU/m 3

14 GM Endotoxin concentration (EU/m3) 1600 Results: Endotoxin by area inside cab outside cab personal Site 1 Site 2 Site 3 European Union EL = 90 EU/m 3

15 GM A. fumigatus CFU/m3 Results: Aspergillus fumigatus by site & task Site 1 Site 2 Site 3 1

16 GM A. fumigatus CFU/m3 Results: Aspergillus fumigatus by site & task Site 1 Site 2 Site 3 1

17 GM A. fumigatus CFU/m3 Results: Aspergillus fumigatus by site & task Site 1 Site 2 Site 3 1

18 GM Thermoactinomycetes (CFU/m3) Results: Thermoactinomycetes by site & task Site 1 Site 2 Site 3 1

19 GM Thermoactinomycetes (CFU/m3) Results: Thermoactinomycetes by site & task Site 1 Site 2 Site 3 1

20 Transfer station (preliminary data) Endotoxin Location Sample type Concentration (EU/m 3 ) Floor (pit) Worker 933 Safety Watch Station Area 262 Outside / Inside dozer Area 216 / 15 Outside / Inside crane Area 120 / 71

21 Transfer station (preliminary data) Endotoxin Location Sample type Concentration (EU/m 3 ) Floor (pit) Worker 933 Safety Watch Station Area 262 Outside / Inside dozer Area 216 / 15 Outside / Inside crane Area 120 / 71 European Union 8 hr exposure = 90 EU/m 3

22 Transfer station (preliminary data) Thermophilic organisms Location Thermoactinomycetes (bacteria) CFU/m 3 Aspergillus fumigatus (fungi) CFU/m 3 Upwind Downwind ND 65 Lobby Near safety watch ,073 Public tipping floor 1,456 20,509 Near crane ,880 Truck loading bay

23 Conclusions Cab offers reduction in exposure to dust and bioaerosols.

24 Conclusions Cab offers reduction in exposure to dust and bioaerosols. Cab must be air-conditioned and filters changed regularly.

25 Conclusions Cab offers reduction in exposure to dust and bioaerosols. Cab must be air-conditioned and filters changed regularly. Endotoxin concentration is related to feed stock.

26 Conclusions Cab offers reduction in exposure to dust and bioaerosols. Cab must be air-conditioned and filters changed regularly. Endotoxin concentration is related to feed stock. Task analysis can inform additional controls.

27 Acknowledgements WorkSafe BC funding Research coordinator Yat Chow Co-Op Students: Montana Burgess, Claire Jackson, Amanda Spreeuw, Daisy Zhang, Shallar Zhong, Brittany Devers, Carley MacIntyre Everyone at our sites. Thank you for participating!

28 Transfer Station Floor (pit) and crane

29 Site 3: Building windrow

30 Site 3: Turning pile with front end loader

31 Site 2: Turning pile: high energy equipment

32 Site 2: Turning pile with wildcat

33 Site 1: Biosolids mixed with bulking agents inside barn

34 Site 1: Mixing wood chips and biosolids