Table 3.
Summary comparison of exposure assumptions.
| End Use | LRT Guidance | Daily Exposure Volume (L) | Exposure Frequency (days/ year) | Fraction of Population Exposed | Key Assumptions |
|---|---|---|---|---|---|
| Toilet flush water | 2017/2021 | 0.00003 | 365 | 1 | Adopted from Australian guidelines1; approximately 1 second of hand to mouth exposure2; 3 flushes per day |
| Clothes washing | 2017 | 0.00001 | 365 | 1 | Adopted from Australian guidelines1; assumed frequency; only used in indoor use calculation |
| Clothes washing | 2021 | 0.00001 | 100 | 1 | Adopted from Australian guidelines1; assumed frequency |
| Unrestricted irrigation and dust suppression | 2017/2021 | 0.001 | 50 | 1 | Adopted from Australian guidelines for municipal irrigation1; excludes food crops; frequency selected for dry climates |
| Cross-connection of treated water with potable water | 2017/2021 | 2 | 1 | 0.1 | Target group for accidental ingestion may be young children (6.5% of population under age 5)3; only used in indoor use calculation |
| Potable consumption | 2017 | 2 | 365 | 1 | Potable consumption1 |
| Fire Suppression | 2021 | 0.002 | 20 | 1 | Data from Water Services Association of Australia “Health Risk Assessment of Fire Fighting from Recycled Water Mains”4 |
| Car Washing | 2021 | 0.001 | 12 | 1 | Assumed frequency; assumed similar exposure as garden irrigation1 |
| Decorative Fountains A | 2021 | N(−1.05,0.81)a,b × 10−3 | 50 | 1 | Assumed similar exposure as car washing5; two distributions fitted to same data |
| Decorative Fountains B | 2021 | U(0.06, 3.79)a × 10−3 | 50 | 1 | Assumed similar exposure as car washing5; two distributions fitted to same data |
References:
a
Values are mL.
b
Values are log10.