Table 2 Procedure used for 5-step Tessier sediment extractions.

1. Exchangeables

8 mL 1.0 M MgCl₂ adjusted to pH = 5–7

1 hr at room temperature

2. Carbonates

8 mL 1.0 M sodium acetate adjusted to pH = 5 with acetic acid

5 hrs at room temperature

3. Fe and Mn oxides

10 mL 0.04 M Hydroxylamine HCl in 25% (v/v) acetic acid

6 hrs at 96°C

4. Organics/Sulfides

3 mL 30% H₂O₂ adjusted to pH 2 with HNO₃

2 hrs at 85°C

3 mL 30% H₂O₂ adjusted to pH 2 with HNO₃

2 hrs at 85°C

Cool. At room temperature add 5 mL of 3.2 N ammonium acetate in 20% (v/v) HNO₃, dilute to 20 mL and agitate an additional 30 minutes

5. Residual

Microwave digestion [99]