Table 1.
Environmental Quality Standards for heavy metals (also called WFD).
| Substance | CAS number | EQS-AAa Inside surface watersb nM e [μg L− 1] | EQS-AAa Other surface waters [μg L− 1] | EQS MPCc Inside surface watersb nM [μg L− 1] | EQS MPCc Other surface waters [μg L− 1] |
|---|---|---|---|---|---|
| Cadmium and its speciation (according to water hardness level d) | 7440-43-9 | ≤ 0.71 (class 1) | 1.78 | ≤ 4 (class 1) | ≤ 4 (class 1) |
| [0.08] | [0.2] | [0.45] | [0.45] | ||
| 0.71 (class 2) | 4 (class 2) | 4 (class 2) | |||
| [0.08] | [0.45] | [0.45] | |||
| 0.8 (class 3) | 5.34 (class 3) | 5.34 (class 3) | |||
| [0.09] | [0.6] | [0.6] | |||
| 1.33 (class 4) | 8.09 (class 4) | 8.09 (class 4) | |||
| [0.15] | [0.9] | [0.9] | |||
| 2.22 (class 5) | 13.3 (class 5) | 13.3 (class 5) | |||
| [0.25] | [1.5] | [1.5] | |||
| Lead and its speciation | 7439-92-1 | 34.7 | 34.7 | Groundless | Groundless |
| [7.2] | [7.2] | ||||
| Mercury and its speciation | 7439-97-6 | 0.25 | 0.25 | 0.35 | 0.35 |
| [0.05] | [0.05] | [0.05] | [0.05] | ||
| Nickel and its speciation | 7440-02-0 | 341 | 341 | Groundless | Groundless |
| [20] | [20] |
Environmental Quality Standard—annual average.
Inside surface waters include rivers, lakes and also water masses (artificial or seriously modified) related to them.
Environmental Quality Standard—maximal permissible concentration.
For cadmium and its compounds, EQS—AA values are functions of water hardness according to the five classes as follows: class 1: <40 mg CaCO3 L−1; class 2: 40–50 mg CaCO3 L−1; class 3: 50–100 mg CaCO3 L−1; class 4: 100–200 mg CaCO3 L−1; class 5: ≥ 200 mg CaCO3 L−1.
Molar concentrations have been chosen as reference unit for the sake of comparison facility and regarding to the standards of the WFD (Water Frame Directive), even if this latter uses mass concentrations.