Table 4.
Estimated air concentrations of metals from passive samples taken in Dewey-Humboldt, and comparison to measured air samples and screening levels obtained from the Remedial Investigation Report for the Iron King Mine and Humboldt Smelter Superfund Site 20
| Metal | Estimated Air Concentration (ng/m3)
|
Measured Air Concentration (ng/m3) *
|
Screening Level+ | ||||
|---|---|---|---|---|---|---|---|
| Mean | SD | Median | Range | Mean | Maximum | ||
| As | 1.39 | 1.89 | 0.971 | 0.052–8.83 | 1.8 | 11.0 | 0.57 |
| Be | 0.028 | 0.032 | 0.021 | 0.002–0.158 | 0.71 | 1.4 | 1 |
| Mn | 35.1 | 36.9 | 28.8 | 0.083–157 | |||
| Ni | 3.71 | 3.66 | 2.12 | 0.074–11.7 | 3.4 | 20 | 5.1 |
| Cd | 0.385 | 0.350 | 0.153 | 0.012–1.06 | 0.46 | 5.5 | 1.4 |
| Pb | 5.34 | 5.53 | 3.29 | 0.254–21.3 | 3.0 | 8.7 | 150 |
| Al | 972 | 1107 | 465 | 10.1–3873 | 760 | 1500 | 5200 |
| Cr | 7.74 | 6.10 | 7.86 | 0.27–23.1 | 35 | 65 | 0.4 |
*
measurements taken in the Town of Humboldt;
+
for Pb this is the Annual Ambient Air Quality Standard, for all other metals it is the US EPA Residential Regional Screening Level 20