Rock type | Average As concentration (mg/kg) | Range of concentration (mg/kg) |
---|---|---|
Igneous rock | ||
Basalt | 2.3 | 0.18–113 |
Andesite | 2.7 | 0.5–5.8 |
Granite | 1.3 | 0.2–15 |
Metamorphic rock | ||
Slate | 18 | 0.5–143 |
Sedimentary rock, sediments | ||
Shale/submarine shale | 3–15 | < 490 |
Marine sedimentsa | 14 | 0~580 |
Sandstone | 4.1 | 0.6–120 |
Limestone/dolomite | 2.6 | 0.1–20.1 |
Evaporite | 3.5 | 0.1–10 |
Ferrigenous sedimentary rocks | 1–2900 | |
River and lake sediments | 5 | < 1–13,000 |
Soli | 0.4–100 | |
Peaty soil | 13 | 2–36 |
Coal | 0.3–35,00 |