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METHOD 3050B ACID DIGESTION OF SEDIMENTS, SLUDGES, AND SOILS 1.0 SCOPE AND APPLICATION 1.1 This method has been written to provide two separate digestion procedures, one for the preparation of sediments, sludges, and soil samples for analysis by flame atomic absorption spectrometry (FLAA) or inductively coupled plasma atomic emission spectrometry (ICP-AES) and one for the preparation ofsediments, sludges, and soil samples for analysis of samples by Graphite Furnace AA (GFAA) or inductively coupled plasma mass spectrometry (ICP-MS). The extracts from these two procedures are not interchangeable and should only be used with the analytical determinations outlined in this section. Samples prepared by this method may be analyzed by ICPAES or GFAA for all the listed metals as long as thedetecion limits are adequate for the required end-use of the data. Alternative determinative techniques may be used if they are scientifically valid and the QC criteria of the method, including those dealing with interferences, can be achieved. Other elements and matrices may be analyzed by this method if performance is demonstrated for the analytes of interest, in the matrices of interest, at theconcentration levels of interest (See Section 8.0). The recommended determinative techniques for each element are listed below: FLAA/ICP-AES Aluminum Antimony Barium Beryllium Cadmium Calcium Chromium Cobalt Copper Iron Lead Vanadium Magnesium Manganese Molybdenum Nickel Potassium Silver Sodium Thallium Vanadium Zinc GFAA/ICP-MS Arsenic Beryllium Cadmium Chromium Cobalt Iron Lead Molybdenum SeleniumThallium

1.2 This method is not a total digestion technique for most samples. It is a very strong acid digestion that will dissolve almost all elements that could become “environmentally available.” By design, elements bound in silicate structures are not normally dissolved by this procedure as they are not usually mobile in the environment. If absolute total digestion is required use Method3052. 2.0 SUMMARY OF METHOD 2.1 For the digestion of samples, a representative 1-2 gram (wet weight) or 1 gram (dry weight) sample is digested with repeated additions of nitric acid (HNO3) and hydrogen peroxide (H2O2). 2.2 For GFAA or ICP-MS analysis, the resultant digestate is reduced in volume while heating and then diluted to a final volume of 100 mL. 2.3 For ICP-AES or FLAA analyses, hydrochloricacid (HCl) is added to the initial digestate and the sample is refluxed. In an optional step to increase the solubility of some metals (see Section 7.3.1: NOTE), this digestate is filtered and the filter paper and residues are rinsed, first CD-ROM 3050B - 1 Revision 2 December 1996

with hot HCl and then hot reagent water. Filter paper and residue are returned to the digestion flask, refluxedwith additional HCl and then filtered again. The digestate is then diluted to a final volume of 100 mL. 2.4 If required, a separate sample aliquot shall be dried for a total percent solids determination. 3.0 INTERFERENCES 3.1 Sludge samples can contain diverse matrix types, each of which may present its own analytical challenge. Spiked samples and any relevant standard reference material should beprocessed in accordance with the quality control requirements given in Sec. 8.0 to aid in determining whether Method 3050B is applicable to a given waste. 4.0 APPARATUS AND MATERIALS 4.1 Digestion Vessels - 250-mL.

4.2 Vapor recovery device (e.g., ribbed watch glasses, appropriate refluxing device, appropriate solvent handling system). 4.3 Drying ovens - able to maintain 30EC + 4EC.

4.4Temperature measurement device capable of measuring to at least 125EC with suitable precision and accuracy (e.g., thermometer, IR sensor, thermocouple, thermister, etc.) 4.5 4.6 4.7 Filter paper - Whatman No. 41 or equivalent. Centrifuge and centrifuge tubes. Analytical balance - capable of accurate weighings to 0.01 g.

4.8 Heating source - Adjustable and able to maintain a temperature of...