Method for evaluating desorption rate of heavy metals and metalloids in polluted or standard-exceeding soil

Abstract

The invention provides a method for evaluating the desorption rate of heavy metals and metalloids in polluted or standard-exceeding soil. The desorption rate (v) of the heavy metals or the metalloidsin the soil is calculated according to a formula v = CEDA.Pc.k-1; the concentration (CEDA) of soil heavy metals or metalloids in a soil solid phase is obtained by adopting an EDTA chemical extractionmethod; a gradient diffusion film (DGT) experiment is used for obtaining soil mass (m), preparing soil slurry pretreatment water adding amount (Vw), heavy metal effective state concentration (CDGT) insoil and heavy metal or metalloid concentration (Csol) in a soil liquid phase; CDGT / Csol, CEDA / Csol and m / Vw are calculated, CDGT / Csol, CEDA / Csol and m / Vw are inputted into DIFS software to calculatea response time parameter (Tc) value of the heavy metal or the metalloid in the soil, and a primary dissociation constant (k-1) value of the heavy metal or the metalloid in the soil is derived by utilizing a formula; and the steps of Pc parameter acquisition and DGT determination are optimized so that popularization and application are facilitated.

Description

technical field [0001] The invention belongs to the technical field of activity or mobility evaluation of heavy metals and metalloids in soil, and in particular relates to a method for evaluating the desorption rate of heavy metals and metalloids in polluted or exceeded soil. Background technique [0002] According to the "National Soil Pollution Survey Bulletin" issued by the Ministry of Environmental Protection and the Ministry of Land and Resources in 2014, the overall situation of my country's soil environment is not optimistic, including cadmium, mercury, arsenic, copper, lead, chromium, zinc and nickel. The rate of exceeding the standard of metal points is 7.0%, 1.6%, 2.7%, 2.1%, 1.5%, 1.1%, 0.9%, 4.8%. Man-made activities such as industrial mining, agriculture and high background value of the soil environment are the causes of soil pollution or exceeding the standard the main reason. At present, the main measures for the treatment of contaminated soil are to fix or pas...

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Problems solved by technology

[0019] (3) theoretically k 1 +k -1 =1 / T c , while the method reduces to k 1 =1 / T c , resulting in discrepancies in the calculation results

However, how to further obtain the desorption rate of heavy metals in soil has not been reported in the literature.

[0022] From the above analysis, it can be seen that the existing technical means are still unable to obtain the desorption rate of heavy metals and metalloids in soil conveniently, quickly and accurately, and it is a difficult problem to obtain the desorption rate of heavy metals and metalloids in soil at least based on a single DGT measurement result.

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