The effect of soil extraction procedures and/or sample pretreatment (drying, freezing of the soil sample) on the extractability of cadmium and lead was tested in a model experiment, with an employment of optical emission and atomic ab- sorption spectrometry methods. In the first part, 6 extraction procedures were compared: 2 mol l-1 HNO3, 0.43 mol l-1 CH3COOH, 0.05 mol l-1 EDTA, Mehlich III extraction procedure (0.2 mol l-1 CH3COOH + 0.25 mol l-1 NH4NO3 + 0.013 mol.l-1 HNO3 + 0.015 mol.l-1 NH4F + 0.001 mol.l-1 EDTA), 0.01 mol.l-1 CaCl2, and deionised water. Addi-tionally, two methods of soil solution sampling were compared, and the centrifugation of satu-rated soil and the use of suction cups and dif-ferential pulse anodic stripping voltametry was applied to assess free and complexed metals portions. The results showed that different soil sample extraction methods and/or sample pre-treatments including soil solution sampling can lead to different absolute values of mobile cadmium and lead content in soils. However, the interpretation of the data can lead to similar conclusions as are apparent from the compari- son of the soil solution sampling methods where fairly good correlation was observed (for Cd r = 0.76, and for Pb r = 0.74). The ambiguous results were reported for voltammetric determinations of free and complex portions of Cd and Pb where a different behavior was observed for water extracts of soil and soil solution obtained using suction cups. Moreover, a changing extent of lead complexation was determined with prolonged storage of the samples. The results confirmed that soil and/or soil solution sampling under immediate soil conditions and limitations of pre-extraction operations are necessary.
Adriano, D.C. (2001) Trace elements in terrestrial environments: Biogeochemistry, bioavailability, and risks of metals. 2nd Edition, Springer-Verlag, New York.
Kabata-Pendias, A. and Pendias, H. (2001) Trace elements in soils and plants. 3rd Edition, CRC Press, Boca Raton.
Jones, D.L. (1998) Organic acids in the rhizosphere – A critical review. Plant and Soil, 205, 25-44.
Dessureault-Rompré, J., Nowack, B., Schulin, R. and Luster, J. (2006) Modified micro suction cup/rhizobox approach for the in-situ detection of organic acids in rhizosphere soil solution. Plant and Soil, 286, 99-107.
Meers, E., Du Laing, G., Unamuno, V., Ruttens, A. and Vangronsveld, J., Tack, F.M.G. and Verloo, M.G. (2007) Comparison of cadmium extractability from soils by commonly used single extraction protocols. Geoderma, 141, 247-259.
Menzies, N.W., Donn, M.J. and Kopittke, P.M. (2007) Evaluation of extractants for estimation of the phytoa-vailable trace metals in soils. Environmental Pollution, 145, 121-130.
Sastre, J., Hernández, E., Rodríguez, R., Alcobé, X., Vidal, M. and Rauret, G. (2004) Use of sorption and extrac-tion tests to predict the dynamics of the interaction of trace elements in agricultural soils contaminated by a mine tailing accident. Science of the Total. Environment, 329, 261-281.
Gray, C.W. and McLaren, R.G.. (2003) Effects of air drying or sample storage on soil-solution properties of biosolids-amended soil. Communications in Soil Science and Plant Analysis, 34, 2327-2338.
Pérez, D.V., de Campos, C. and Menequelli, N.A. (2004) Effects of soil sample storage treatment on the composition and Fe, Al, and Mn speciation of soil solutions obtained by centrifugation. Water, Air, & Soil Pollution, 151, 195-214.
Nolan, A.L., Lombi, E. and McLaughlin, M.J. (2003) Metal bioaccumulation and toxicity in soils – Why bother with speciation? Australian Journal of Chemistry, 56, 77-91.
Peijnenburg, W.J.G.M. and Jager, T. (2003) Monitoring approaches to assess bioaccessibility and bioavailability of metals: Matrix issues. Ecotoxicology and Environmental Safety, 56, 63-77.
Svete, P., Milacic, R. and Pihlar, B. (2000) Optimisation of an extraction procedure for determination of total water-soluble Zn, Pb and Cd and their species in soils from a mining area. Annali di Chimica, 90, 323-334.
Cances, B., Ponthieu, M., Castrec-Rouelle, M., Aubry, E. and Benedetti, M.F. (2003) Metal ions speciation in a soil and its solution: Experimental data and model results. Geoderma, 113, 341-355.
Nolan, A.L., McLaughlin, M.J. and Mason, S.D. (2003) Chemical speciation of Zn, Cd, Cu, and Pb in pore waters of agricultural and contaminated soils using Donnan analysis. Enviromental Scence & Technology, 37, 90-98.
Carballeira, J.L., Antelo, J.M. and Arce, F. (2000) Analysis of the Cu2+-soil fulvic acid complexation by anodic stripping voltametry using an elecrostatic model. Enviromental Scence & Technology, 34, 4969-4973.
Herrero, A.I., Bar-rado, E., Rey, F. and Machado, A.A.S.C. (2000) Influence of the ligand concentration and pH on the complexation of Cu(II) by a soil fulvic acid. Analusis, 28, 127-131.
van den Hoop, M.A.G.T., Porraso, R.D. and Benegas, J.C. (2002) Complexation of heavy metals by humic acids: analysis of voltammetric data by polyelectrolyte theory. Colloids and Sur-faces A, 203, 105-116.
Nedeltcheva, T., Atanassova, M., Dimitrov J. and Stanislavova, L. (2005) Determination of mobile form contents of Zn, Cd, Pb and Cu in soil extracts by combined stripping voltametry. Analytica Chimica Acta, 528, 143-146.
Sauvé, S., Norvell, W.A., McBride, M.B. and Hendershot, W.H. (2000) Speciation and compexation of cadmium in extracted soil solutions. Science of the Total Environment, 34, 261- 296.
Almas, A., McBride, M.B. and Singh, B.R. (2000) Solubility and lability of cadmium and zinc in two soils treated with organic matter. Soil Science, 165, 250-259.
McBride, M.B., Martinez, C.E., Topp, E. and Evans, L. (2000) Trace metal solubility and speciation in a calca-reous soil 18 years after no-till sludge application. Soil Science, 165, 646-656.
Bor?vka, L., Huan, W.C., Kozák, J. and Kri?toufková, S. (1996) Heavy contamination of soil with cadmium, lead and zinc in the alluvium of the Litavka River. Rostlinná Vyroba, 42, 543-550.
Quevauviller, P., Ure, A., Muntau, H. and Griepink, B. (1993) Improvement of analytical measurements within the BCR–program – Single and sequential extraction procedures applied to soil and sediment analysis. International Journal of Environmental Analytical Chemistry 51, 129-134.
Mehlich, A. (1984) Mehlich 3 Soil Test Extractant: A modification of Mehlich 2 Extractant. Communications in Soil Science and Plant Analysis, 15, 1409-1416.
Novozamsky, J., Lexmond T.M. and Houba V.J.G. (1993) A single extraction procedure of soil for evaluation of uptake of some heavy metals in plants. International Journal of Environmental Analytical Chemistry, 51, 47- 58.
Kiekens L. and Cottenie A. (1985) In: Leschber, R., Ed., Chemical methods for assessing bio-available metals in sludges and soils. Elsevier Applied Science, London, 42.
Nolan, A.L., Zhang, H. and McLaughlin, M.J. (2005) Prediction of zinc, cadmium, lead, and copper avai- lability to wheat in contaminated soils using chemical speciation, diffusive gradients in thin films, extraction, and isotopic dilution techniques. Journal of Environment- al Quality, 34, 496-507.
Jaklová-Dytrtová, J., ?estáková, I., Jakl, M., Száková, J., Miholová, D. and Tlusto?, P. (2008) The use of differential pulse anodic stripping voltametry and diffusive gradient in thin films for heavy metals speciation in soil solution. Central European Journal of Chemistry, 6, 71- 79.
?ichorová, K., Tlusto?, P., Száková, J., Ko?ínek, K. and Balík, J. (2004) Horizontal and vertical variability of heavy metals in soil at a polluted area. Plant, Soil, and Environment, 50, 525-534.
Le?tan, D., Gr?man, H., Zupan, M. and Ba?ac, N. (2003) Relationship of soil properties to fractionation of Pb and Zn in soil and their uptake into Plantago lanceolata. Soil and Sediment Contamination, 12, 507-522
Davidson, C.M., Ferreira, P.C.S. and Ure, A.M. (1999) Some sources of variability in application of the three- stage sequential extraction procedure recommended by BCR to industrially-contaminated soil. Fresenius Journal of Analytical Chemistry, 363, 446-451.
Száková, J., Tlusto?, P., Balík, J., Pavlíková, D. and Balíková, M. (2001) Application of sequential extraction procedure to evaluation of influence of sewage sludge amendment on Cd and Zn mobility in soil. Chemické Listy, 95, 645-648.
Miller, W.P., Martens, D.C., Zelazny, L.W. and Kornegay, E.T. (1986) Forms of solid phase copper in copper-en- riched swine manure. Journal of Environmental Quality, 15, 69-72.
Wang, Z., Shan, X. and Zhang, S. (2001) Comparison of speciation and bioavailability of rare earth elements between wet rhizosphere soil and air-dried bulk soil. Analytica Chimica Acta, 441, 147-156.
Száková, J., Tlusto?, P., Balík, J., Pavlíková, D. and Balíková, M. (2000) Efficiency of extractants to release As, Cd and Zn from main soil compartments. Analusis, 28, 808-812.
Tack., F.M.G.., van Ranst, E., Lievens, C. and Vanden- berghe, R.E. (2006) Soil solution Cd, Cu and Zn con- centrations as affected by short-time drying or wetting: The role of hydrous oxides of Fe and Mn. Geoderma, 137, 83-89.
Tawinteung, N., Parkpian, P., DeLaune, R.D. and Juq- sujinda, A. (2005) Evaluation of extraction procedures for removing lead from contaminated soil. Journal of Environmental Science and Health Part A, 40, 385-407.
Sakurai, Y., Murayama, S., Makino, T., Maejima, Y. and Sugahara, K. (2007) Chemical form of soluble cadmium and copper in arable soils and its implication to their mobility. Japan Agricultural Research Quarterly, 41, 139 -145.
Sauvé, S., McBride, M.B. and Hendershot, W.H. (1997) Speciation of lead in contaminated soils. Environmental Pollution, 98, 149-155.
Ge, Y., Murray, P. and Hendershot, W.H. (2000) Trace metal speciation and bioavailability in urban soils. Environmental Pollution, 107, 137-144.
Jaklová-Dytrtová, J., ?estáková, I., Jakl, M. and Navrátil, T. (2009) Electrochemical detection of cadmium and lead complexes with low molecular weight organic acids. Electroanalysis, 21, 573-579.