tailieunhanh - Heavy Metals Release in Soils - Chapter 6

Động học của vết kim loại EDTA-giải hấp từ đất bị ô nhiễm Một số tính năng của Chiết xuất hóa chất của kim loại vết đất Bất kể nguồn gốc của họ và lý do cho sự gia tăng nồng độ trong đất, kim loại vi lượng phải chịu trách nhiệm làm ô nhiễm chuỗi thức ăn bằng cách di chuyển về phía nước ngầm hoặc bằng cách tích lũy trong các nhà máy. Để dự đoán sự tồn tại và di động tiềm năng và khả dụng sinh học của các yếu tố này, duy nhất và / hoặc. | CHAPTER 6 Kinetic Study of Trace Metal EDTA-Desorption from Contaminated Soils A. Bermond and . Ghestem INTRODUCTION Some Features of the Chemical Extraction of Soil Trace Metals Regardless of their origins and the reasons for the increase in their concentration in soils trace metals are liable to contaminate food chains by migrating toward groundwater or by accumulating in plants. To predict the persistence and potential mobility and bioavailability of these elements single and or sequential extractions involving chemical reagents have been widely used. In the first case the extracted amounts of trace metals by a given chemical reagent are supposed to correlate with the amounts accumulated in plants. In the second case sequential extractions are mainly supposed to provide the localization of trace metals in soils the possible mobility and bioavailability are the result of the reactivity of trace metals in soils which depends on their localization in different soil components which is now usually called speciation. Note that by also using the term localization speciation of trace elements in soils is not fully defined as it is usually Ure 1991 by the different physicochemical forms of the same element. From a general point of view chemical extraction methods are more sensitive compared to physical methods of speciation and what we call sequential extraction consist of using successively different chemical reagents for extraction of trace elements from given soil compartments Belzile et al. 1989 Nirel and Morel 1990 terminating with their quantification in the extraction phase normally when equilibrium has been reached Whalley and Grant 1994 Bermond and Malenfant 1990 Belzile et al. 1989 Nirel and Morel 1990 . Several reagents are generally used and some classical chemical reagents which involve different chemical reactions complexation oxidation reduction etc. are given in Table . 131 2001 by CRC Press LLC 132 HEAVY METALS RELEASE IN SOILS Table Some .