Table 1.
Input parameters with distributions and statistics for exposure assessment
| Model parameter | Unit | Probability distribution function and parameter statistics | Reference | ||
|---|---|---|---|---|---|
| Distribution | Mean/maximum | Minimum/S. deviation | |||
| Volume of water ingested when farming | ml/day | Uniform | 10 | 15 | Shuval et al. (1997) |
| Volume of water captured by green salad vegetables | ml/g | normal | 0.108 | 0.019 | Hamilton et al. (2006) |
| Pathogen reduction by washing salad | log10 units | Pert | 1 | 0.2 | Predmore and Li (2011) |
| Irrigation frequency | Days per year | Normal | 243.1 | 4.6 | Surveys (2011) |
| Consumption frequency | Days per year | Normal | 131.6 | 2.6 | Surveys (2011) |
| Concentration of E. coli O157:H7 in water | MNP/l | Log-normal | – | – | Lab. analyses (2012) |
| Concentration of E. coli O157:H7 in green salad | MNP/100 g | Log-normal | – | – | Lab. analyses (2012) |
| Concentration of G. lamblia in water | Cyst/l | Log-normal | – | – | Lab. analyses (2012) |
| Concentration of G. lamblia in green salad | Cyst/20 g | Log-normal | – | – | Lab. analyses (2012) |
| Parameter G. lamblia (r) | – | Uniform | 0.0198 | 0.02 | Haas et al. (1999) |
| Parameter E. coli O157:H7 (α, β) | – | Uniform | α = 0.373 | β = 39.71 | Teunis et al. (2008) |
| Mass of green salad consumption | g/person/day | Normal | 26.03 | 30.2 | U.S. EPA (2009) |
| Exposed population | Inhabitants | Normal | – | – | Surveys (2011) |