Sequential Extractions: Wet chemical procedures utilizing progressively stronger reagents/“solvents” to preferentially remove mineral species, or compounds, to separate them from a complex matrix. Individual procedures are dictated by sample chemistries.

Example 1: Copiapites: a hydrated iron sulfate mineral with a formula: Fe 2+ Fe 3+ 4 (SO 4 ) 6 (OH) 2 · 20(H 2 O) Q G A Ac Zc G G A A Ac G X-ray Diffraction (XRD) Weathering crusts forming on the Henryville bed (HEN-2). (photo: Nelson Shafer, IGS) 10 cm

1-9 g, dry sulfate crust, homogenized in 250 ml glass beaker stirred for 24 hours, at 70 o C, filtered with 0.8µm cellulose nitrate filter, supernatant reserved, residue subtracted from initial mass 100 ml 1.0N HCl de-ionized H 2 O supernatant transferred to a 100 ml volumetric flask and filled to volume 10 ml supernatant transferred back to 250 ml beaker and NaOH pellets added to remove Fe-hydroxides. Sample filtered, Fe-hydroxides discarded. BaCl 2 added to supernatant to precipitate BaSO 4 90 ml supernatant reserved for AAS metals analysis 10 ml 0.5M BaCl % HNO 3

Example 2: house paintroad Bloomington Soil Pb

2 g, dry soil, homogenized Exchangeable Fraction Absorbed Fraction Organically-Bound Fraction Residual Fraction Carbonate-Bound Fraction in 50 ml centrifuge tube 25 ml 0.5M KNO 3 25 ml distilled H 2 O 25 ml 0.5M NaOH 25 ml 0.05M Na-EDTA 25 ml 4.0M HNO 3 stirred for 16 hours, centrifuged, filtered with Whatman#42 filter, supernatant reserved for analysis stirred for 6 hours, centrifuged, filtered, supernatant reserved for analysis stirred for hours, centrifuged, filtered, supernatant reserved for analysis stirred for 2 hours, centrifuged, filtered, supernatant reserved for analysis heated (70-80 o C) for hours in an oven, centrifuged, filtered, supernatant reserved for analysis Sposito, G., Lund, L.J., and Chang, A.C., 1982, Trace Metal chemistry in arid-zone field soils amended with sewage sludge: I. Fractionation of Ni, Cu, Zn, Cd, and Pb in solid phases: SSSA Journal, 46:

Alva, A.K., Huang, B., Paramasivam, S., 2000, Soil pH affects copper fractionation and Phytotoxicity: Soil Science Society of America Proceedings, 29:

Bruchert, V., 1998, Early diagenesis of sulfur in estuarine sediments: the role of sedimentary humic and fulvic acids: Geochimica et Cosmochemica Acta, 62:

Chao, T.T., and Theobald, Jr., P.K., 1976, The significance of Secondary Iron and Manganese Oxides in Geochemical Exploration: Economic Geology, 71:

Li, X., Coles, B.J., Ramsey, M.H., Thornton, I., 1995, Sequential extraction of soils for multielement analysis by ICP-AES: Chemical Geology, 124: (N. Atlantic seafloor manganese nodules )