concentrated with TIOA in toluene. the actinides in the soil samples. Many individual procedures have been developed for Np, Pu, Am, and Cm in soil matrices and have been reported in the literature. Procedures have been also reported for separation of these elements in groups of two or more. The evolution of these procedures has been based on the insurance that the actinides have been completely solubilized and equilibrated with tracer, when added, The method of assay also has influenced the concentration technique. Virtually all methods involve drying the soil, charring the organic and humus, and grinding and sieving the sample. However, in the HASL procedure, Harley (1972), the organic is ground up with the sample and destroyed by HNO;-HC1 acid when the Pu is leached. Bernhardt (1976) evaluated sample collection and analyses techniques for environmental Pu. The greatest controversy has been connected with the leach method versus complete dissolution. For large (1 kg) samples, the acid leach has proven to be the only practical procedure. Leaching methods have been successful with Pu activities, particularly when they are not refractory and loosly bound to the matrix. Geiger (1959) discussed the relative ease of Al(NOQ 4) 4~-HNO3 leaching of Pu from soils exposed to reactor effluents. Bond and Clark (1958) discuss efficiency of leaching Rainier and Tamalpais nuclear debris with groundwater, from the Nevada Test Site, as a function of leaching temperature. Thomas (1957) reports on leaching with HNO; and HF in the analysis of Bravo Shot soils. Olafson et ai. (1957) wet ashed New Mexico soils with HNO3~ HC10,-HF and isolated the Pu on a LaF3 carrier. Everett and Drake (1960) have leached fused Nevada soil samples, covering a wide range of activity, with HNOg and reported good yields on the leach solution, but measurements on the residue were not indicated. More recently, Bishop et ai. (1971) tested 50-g acid leaching and Sill's fusion methods for 72%Pu in soil using tracer techniques with comparable results. with TLOA-xylene. They used an HNQ3-HF leach and concentrated Corley et al. (1971) successfully leached 239Pu from Hanford surface soil (10-g) using an HC1, HNO, cycle and anion exchange and TTA extraction and evaporated the organic phase directly onto a Pt disc. Sill (1975) performed experiments on soils heated to different temperatures and then leached with various combinations of acids. His plutonium activity balances showed the fate of sample and tracer Pu for each and the fact that HF had a large effect on obtaining the true Pu concentration in the soil. The most referred to leaching techniques are those of Talvitie (1971) for 1-g quantities and of Chu (1971) for bulk samples. The HASL acid leach has been adapted to i-kg and 3-kg soils by Major et al. (1972) and is sometimes complicated by colloid formation. Poet and Martell (1972) used an acid leach but did not use HF for Am and Pu. Fowler and Essington (1974) report on a method for plutonium in soil, the HASL-LASL leach method. This formed the basis for the procedure described in AEC Regulatory Guide 4.5, Anonymous (1974a), which was stated to be "acceptable to the Regulatory staff for sampling and analysis of plutonium in soil with the sensitivity and accuracy needed to adequately monitor plutonium in soil in the environs of fuel processing and fuel fabrication facilities." The procedures involved HNO3-HF leaching, a leach with HCl, and complexing with H3B03. A precipitation of Fe(OH); is made with NaOH, carrying down undissolved residues which are then treated with HNO, and H3B0, before any undissolved residue is discarded and the Pu purified by usual anion exchange techniques. Hayes et al. (1975) simply leached estuarine soils with HC1 and 550 Bently et al, (1971) used acid leach on 50-g soila followed by HDEHP extraction and a LaF, precipitation and reported 90% yields. Noshkin and Bowen (1973) leached ocean sediments with HNO3. Koide et al, (1975) applied the acid leach techniques of Talvitie and Wong to both atmospheric dusts and marine sediments. Complete dissolution techniques are satisfactory for limited sample sizes. Crouch and Cook (1956) reported on fusion of irradiated rocks, soil, and organic matter, and report losses due to fusion insolubles in samples over 250 mg and spattering difficulties, Merritt {1958} fused Chalk River soils with alkalai hydroxides and carbonates but reported interferences from large amounts of alkalai. 5111 (1961), and Sill and Williams (1971) have extensively studied the fusion of refractory silicas and later Sill and co-workers (1974) extended the method. For soils and air dusts, after a preliminary HF treatment, sequential potassium fluoride and potassium pyrosulfate fusions are performed. Bretthauer and Hahn (1975) proposed the fusion method as a reference method for Pu in soil. Butler et al. (1971) use a similar technique on 5-g samples but extracts with TIOA and then a LaF3 precipitation. Complete acid dissolutions of soil samples are suitable for samples up to 100 g, at which point the procedure becomes lengthy and uneconomical. Wet ashing, involving complete acid dissolution, has been found to be the method of choice by Major et al. (1965a, 1971) and has been applied to soil samples up to 100 g. HNO3-HC10, was used to destroy the organic matter followed by HNO;-HF treatment. Residues were separated, dissolved, and recombined and concentrated by coprecipitation with Fe({OH)3. The isolation of the other actinides in soil does not differ materially from that of Pu except in the concentration steps. Major et al. (1971) used, for the Nevada soils, a eeries of HF, HNO3-HC1 steps and H3B03 to decompose the silicon fluorides, and subsequently isolate by anion exchange and HDEHP extraction. Nevissit et al. (1975) reported on complete acid dissolution techniques similar to the above for both Pu and Am in Bikini soils, They fused any residues with a NaOH/Naj,CO3 mixture and extracted with TIOA. Edgington et al. (1975) applied the methods of Talvitie and Wong to the determination of Pu and Am in Lake Michigan sediments and extracted the Am with Aliquat 336S. Kleinberg (1967), in the LASL collected radiochemical procedures, reporta on individual and sequential procedures in Nevada soil debris. For Am and Cm samples up to a few grams, Smith (1967) found LaF, precipitation after dissolution was satisfactory for 0.1 to 0.3 g soil, but for larger samples, HDEHP extractions were necessary. Barnes (1967) used anion exchange and elution with dilute thiocyanate for Cm. Smith (1967) used Zr and Sr hold back for Np and a LaF precipitation. Wolfsberg and Daniels (1967) concentrated the actinides from 250-g dissolved samples, first with TBP and then with HDEHP. S111 et ail. (1974) applied his fusion method followed by extraction with Aliquat 336 separating out first Am, Cm, and then Np and Pu.