Role of the light fraction of soil organic matter in trace elements binding

Abstract

The light fraction of soil organic matter (LF) has a rapid turnover and may be potentially metal-enriched, but the interaction between this pool of organic matter and trace elements has not been well studied. The present study aimed to investigate changes in LF content and its effect on heavy metals distribution and extractability in long-term contaminated soil by smelting activity. An incubation experiment was conducted on a surface horizon of Brunic Arenosol sampled from the previously-existing sanitary zone of Głogów smelter, for 450 days. The contaminated soil was divided into three combinations: with the addition of either triticate straw (at the dose of 4.5 Mg ha -1 ) or pig manure (at the dose of 40 Mg ha -1 ) or without any “foreign” organic materials (nil). The LF (ρ > 1.7 g cm -3 ) occurred to be metal-enriched and despite its low content (5.49%—nil, 7.18%—straw and 7.29%—manure combination) in the bulk soil, it was observed that initially Cd, Cu, Pb and Zn stock reached 16.2%, 11.9%, 18.0% and 32.3%, respectively. Incubation conditions where mineralization processes dominate led to a decrease in the LF share by about 12.6% in nil and 31.4–39.8% in the combinations with organic amendments. In consequence, the DOC (dissolved organic carbon) concentration doubled and metal distribution had changed. The increase in water-soluble (F1) fraction was observed for all metals, additionally for Cu, Pb, Zn in exchangeable fraction (F2) and in carbonate bound (F3) fraction for Cd and Zn. These results support the view that changes in the LF content may play a key role in controlling trace metals mobility, especially in long-term contaminated soil.

Development of a conceptual framework to evaluate organic fertilisers : assessment on soil quality and agronomic, environmental and economics aspects

“…In the same study, it was also shown that this size fractionation corresponded to the age of the aggregates with increasing C14 levels recorded for the smaller fractions (Quenea et al, 2008). Recent work from Wiatrowska and Komisarek (2019) has shown that binding on metals to the light fraction of fresh organic matter added to soil via manure or straw does not differ substantially from that of the original soil carbon pool, which would facilitate a single model concept to describe binding on metals to soil carbon in soil. On the other-hand, Li et al…”

Patterns of differentiation of the old arable horizon of fallow soils according to the content of mobile forms of manganese and copper

“…Linear models show a statistically significant strong (R 2 adj .=0.72) effect of OMP on the content of mobile forms of Mn (1), as well as a statistically significant but weak (R 2 adj .=0. 19) effect of pH on the content of mobile forms of Сu (2).…”

“…Shi et al [18] note a decrease in Cu sorption by soil during the formation of complexes with soluble organic matter. There is also an opinion that labile fractions of OM may play a key role in the control of Cu mobility, which may promote Cu migration in acidic soils [19].…”

Hierarchization of Physicochemical Factors during Simultaneous Removal of Lead and Copper from the Marrakech Municipal Discharge Soils

“…is suggested that it was more present in fine fractions (size <1 mm), as shown in Table 6 and proposed by many authors [46], and/or that it was more strongly retained in the coarse fraction (size >1 mm). Pb ions would not be readily available to the ligand as explained when discussing m/V effect: the chelator, EDTA or NTA, had to compete with the bonding strength of Pb to the soil and probably to the other constituents of the soil, in particular, organic matter [48]. As we have seen in Table 6, Pb was more present in the fine fraction than in the large fraction of the soil, and therefore it was more extracted from fraction F than from fraction C. is could explain the effect of the size of the soil particles on the extraction of Pb.…”