Mercury distribution and mobility in contaminated soils from vicinity of waste incineration plant

Abstract

The potential bioavailability of Hg from soil might be estimated by a variety of chemical extraction procedures, differing in the extraction agent, its concentration, the sample weight, and the time of extraction. In this study, a comparative analysis of several extraction methods, commonly used for obtaining the mobile and potentially mobilizable phase of the mercury was carried out. Concentrated HNO 3 , 0.01 mol/L Na 2 S 2 O 3 , 0.05 mol/L EDTA and 0.11 mol/L CH 3 COOH were used as the single extraction agents. Moreover, the sequential extraction was performed. This procedure involved the following fractions: water soluble Hg, Hg extracted in acidic conditions, Hg bound to humic substances, elemental Hg and mercury bound to complexes, and residual Hg. The results showed that even strong acid HNO 3 is unable to release the mercury tightly bound to the soil matrix. This particular method with microwave digestion is commonly used for the estimation of anthropogenic pollution. Conversely, the lowest mercury yield was obtained using the acetic acid as the single extraction agent. In this case, the concentrations were below 0.15% of the total Hg content, which is a proportion generally defined as bioavailable to plants.

Applications of Organic and Inorganic Amendments Induce Changes in the Mobility of Mercury and Macro- and Micronutrients of Soils

“…In the treatments without artificial Hg application, the mobile Hg contents were under the detection limit of ICP-MS. Similarly to our previous observations [ 23 ], Ruggiero et al [ 24 ] also documented that most of the Hg in the long-term polluted soils was scarcely mobile and available. The Hg contents in digestates and fly ash are usually low as well [ 25 , 26 ] and did not affect the mobile portions of Hg in our experiment.…”