§ 131.46 Aquatic life criterion for cadmium in Oregon.
(a) Scope. This section promulgates an acute aquatic life criterion for cadmium in freshwaters in Oregon.
(b) Criterion for cadmium in Oregon. The aquatic life criterion in Table 1 applies to all freshwaters in Oregon where fish and aquatic life are a designated use.
Table 1—Cadmium Aquatic Life Criterion for Oregon Freshwaters
| Metal | CAS No. | Criterion Maximum Concentration (CMC) 3 (µg/L) |
|---|---|---|
| Cadmium 1 2 | 7440439 | [e (0.9789 × ln(hardness) − 3.866)] × CF Where CF = 1.136672 − [(ln hardness) × (0.041838)]. |
1 The criterion for cadmium is expressed as the dissolved metal concentration.
2 CF is the conversion factor used to convert between the total recoverable and dissolved forms of cadmium. The term (ln hardness) in the CMC and the CF equation is the natural logarithm of the ambient hardness in mg/L (CaCO3). The default hardness concentrations from the applicable ecoregion in Table 2 of paragraph (c) of this section shall be used to calculate cadmium criteria in the absence of sufficiently representative ambient hardness data.