4.8.1 drinking water
No silver criterion appears to be necessary for human, laboratory animal, wildlife and livestock drinking water. The level used by Health and Welfare Canada in 1987 was 50 µg/L. Silver was dropped from the 1989 Guidelines for Canadian Drinking Water Quality since the 50 µg/L value was very conservative but was not scientifically defensible. A scientific risk assessment would likely determine a higher value as safe for drinking water, but such assessment has not been done.
4.8.2 recreation and aesthetics
No silver criterion appears to be necessary for this use of the water. The aquatic life criteria are more than adequate for any such uses.