Mobilisation of Cu from soils by dissolved natural and processed humic substances

Comparison of Natural Humic Substances and Synthetic Ethylenediaminetetraacetic Acid and Nitrilotriacetic Acid as Washing Agents of a Heavy Metal–Polluted Soil

“…Despite these limitations, the data in Table 2 indicate that HS is a less efficient extractant than EDTA and NTA, in accordance with the results in Table 1 The constants cannot explain the discrepancy between the substantial amounts of Cu (∼54%) extracted by HS compared with the very limited extractability of Pb (<4% of total content) in as much as the Cu‐HS and Pb‐HS constants are similar. Despite this, the present investigation has, in accordance with previous studies (Conte et al, 2005; Bianchi et al, 2008; Steponkaite et al, 2008; Borggaard et al, 2009), demonstrated that HS is an environmentally friendly and fairly effective washing agent for soils polluted with Cd, Cu, and other pollutants.…”

“…Th e constants cannot explain the discrepancy between the substantial amounts of Cu (~54%) extracted by HS compared with the very limited extractability of Pb (<4% of total content) in as much as the Cu-HS and Pb-HS constants are similar. Despite this, the present investigation has, in accordance with previous studies (Conte et al, 2005;Bianchi et al, 2008;Steponkaite et al, 2008;Borggaard et al, 2009), demonstrated that HS is an environmentally Table 3. Percentages of total cadmium, copper, and lead obtained by single-step extraction at a solution/soil ratio of 100 by 50 mmol L −1 dissolved organic carbon of ethylenediaminetetraacetic acid, nitrilotriacetic acid, and humic substances and by the control (0.05 mol L −1 KNO 3 ) followed by sequential extraction partitioning the remaining heavy metals in four fractions: exchangeable, carbonate-bound, oxide-bound and residual.…”

“…Therefore, HS cannot be recommended for cleaning Pb‐polluted soil, at least not if it is a calcareous soil that has been polluted over a long time because removal of the pollutant from such soils is especially difficult (Heil et al, 1999; Kim et al, 2003; Meers et al, 2007). On the other hand, because substantial amounts of Cd and Cu can be removed by HS (Tables 1, 3, 4) (Bianchi et al, 2008; Steponkaite et al, 2008; Borggaard et al, 2009), HS may replace EDTA and NTA as a cleaning agent for Cd‐ and Cu‐polluted soils. Replacement of the synthetic EDTA and NTA by the natural HS is environmentally very attractive.…”

“…Although soluble HS seem to possess substantial capacity to extract heavy metals from soils, few studies have been published on the use of soluble HS for washing heavy metal–polluted soils (Steponkaite et al, 2008; Borggaard et al, 2009). Therefore, the aim of this paper is to present the results obtained by comparing the efficiency of soluble HS with that of the commonly used EDTA and NTA as washing agents (i.e., as extractants of cadmium [Cd], copper [Cu], and lead [Pb]) from a strongly polluted calcareous, long‐term equilibrated (nonspiked) urban soil.…”

Accumulation of selected trace elements in soil and roadside trees – case study

“…availability for plants, determined by means of different extraction solutions, e.g. 0.1 mol dm -3 NaNO 3 , 0.01 mol dm -3 CaCl 2 ), buffer ammonium acetate CH 3 COONH 4 (pH 7 and 4.8), diluted acids (2.5% CH 3 COOH, 1 mol dm -3 HCl), and complexing extractants (0.05 mol dm -3 EDTA and 0.005 mol dm -3 DTPA) (Sabienë and Brazauskienë 2004, Soriano-Disla et al 2010, Ivezić et al 2013, Lima et al 2016. Assessments of the state of soil pollution with toxic metals are frequently based on their total or pseudototal content.…”