Table 5.
Estimated low-dose lifetime extra bladder and lung cancer risks versus dose and equivalent drinking water inorganic arsenic concentration (per 10,000)a extrapolated from data in Chen et al. (2010a, b) using constrained and unconstrained model averaging.
| Extra Risk | Average daily inorganic arsenic dose (µg/kg-day) |
|||||||
|---|---|---|---|---|---|---|---|---|
| 0.064 | 0.071b | 0.12 | 0.19 | 0.26 | 0.33 | 0.75 | 1.45 | |
|
Equivalent daily drinking water inorganic arsenic concentration (µg/L) | ||||||||
| 1 | 1.5 | 5 | 10 | 15 | 20 | 50 | 100 | |
| Bladder Cancer | ||||||||
| Constrained Models | ||||||||
| Mean | −0.1 | 0.0 | 0.5 | 1.2 | 2.0 | 2.7 | 7.3 | 15.5 |
| 97.5th percentile | −0.2 | 0.0 | 1.7 | 4.1 | 6.6 | 9.0 | 23.6 | 47.9 |
| Unconstrained Models | ||||||||
| Mean | −0.5 | 0.0 | 2.7 | 4.8 | 7.0 | 9.0 | 17.7 | 29.5 |
| 97.5th percentile | −1.3 | 0.0 | 6.3 | 10.3 | 14.2 | 17.7 | 32.1 | 51.4 |
| Lung Cancer | ||||||||
| Constrained Models | ||||||||
| Mean | −0.1 | 0.0 | 0.4 | 0.9 | 1.5 | 2.0 | 5.2 | 10.4 |
| 97.5th percentile | −0.2 | 0.0 | 1.5 | 3.6 | 5.6 | 7.7 | 19.8 | 39.0 |
| Unconstrained Models | ||||||||
| Mean | −1.1 | 0.0 | 5.3 | 7.6 | 10.0 | 11.9 | 19.4 | 28.4 |
| 97.5th percentile | −7.0 | 0.0 | 32.0 | 43.0 | 54.0 | 63.0 | 91.0 | 119 |
a
These extra risk estimates are estimated based on model-estimated background rates for the constrained and unconstrained models of 4.2X10−3 and 2.4X10−3 respectively for bladder cancer and 2.3X10−2 and 2.0X10−2 respectively for lung cancer (Table 4).
b
To illustrate model uncertainty when extrapolating from the Chen et al. (2010a, b) study data to much lower arsenic doses, the background level of exposure population, specifically 0.071 µg/kg-day (see Section 3.2.1).