Table 1.
Dissolved trace metal(loid) concentrations at the different sites. The underlined metal concentrations exceeded the surface water quality standards. Elements shaded in grey were used to reconstitute the metal mixtures. All values are in µg/L.
| (µg/L) | Al | Cr | Mn | Fe | Ni | Cu | Zn | As | Cd | Pb |
|---|---|---|---|---|---|---|---|---|---|---|
| SN1 | 53.0 | 0.4 | 31.1 | 267 | 2.4 | 12.5 | 65.8 | 2.5 | 0.5 | 2.9 |
| D | 904 | 0.3 | 5298 | 10440 | 67.2 | 3.0 | 98621 | 131 | 3383 | 2.2 |
| SN2 | 84.3 | 0.3 | 264 | 709 | 5.0 | 4.3 | 3447 | 2.9 | 6.7 | 2.1 |
| K1 | 12.6 | 0.3 | 26.1 | 847 | 34.9 | 60.4 | 46.2 | 7.8 | 1.4 | 3.3 |
| K2 | 10.4 | 0.4 | 17.7 | 847 | 35.4 | 56.4 | 27.4 | 6.3 | 0.9 | 2.9 |
| Norm | 87 a | 5 b | / c | / c | 20 b | 7 b | 20 b | 3 b | 0.08–0.25 b (*) | 7.2 b |
* Surface water quality standard for Cd is dependent on hardness (0.08 < 40 mg CaCO3/L; 0.25 ≥ 200 mg CaCO3/L). a The surface water quality standard for Al was obtained from US Environmental Protection Agency (EPA) standards because there is no Belgian or European surface water quality standard for this element; b The surface water quality standards were obtained from the Flemish environmental legislation (VLAREM), which is based on the European legislation (EU 2008/105/EG); c Currently (2016), no surface water quality standards for Mn and Fe exist in the EU or the US.