Interactions between metals and soil organic matter in various particle size fractions of soil contaminated with waste water

Abstract

. Interactions between metals and soil organic matter in various particle size fractions of soil contaminated with waste water. Geoderma, Elsevier, 2009Elsevier, , vol. 1, pp. 217-223. 10.1016Elsevier, /j.geoderma.2008 Open Archive TOULOUSE Archive Ouverte (OATAO) OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. Only scarce field studies concern the consequences of natural soil organic matter (SOM) and metal interactions on SOM dynamics in soils. We investigated the interactions of four metals (Pb, Zn, Cu and Cd) with the SOM associated to five different size fractions (between 2000 µm and b2 µm) of a sandy top soil contaminated by waste water. Metal, organic carbon and nitrogen concentrations were measured and chemical extractions (with Na 4 P 2 O 7 and EDTA) were also performed to assess the variations of SOM-metal interactions irrespective of the size fraction. In addition, as in that selected contaminated site, maize (C 4 plant), replaced C 3 crops 15 years ago, natural isotopic 13 C labelling gave new insights into SOM turnover. First, the results suggest that metals influence the SOM dynamics in that sandy soil: a C 3 "old carbon" enrichment was observed in the small or clay size fractions, while the "new" C 4 carbon associated with sandy soil particles presents a rapid turnover. Metal accumulation in the clay fraction is attributed to particulate organic matter (poorly associated) and SOM decay which overtime accumulated metals and eventually these metal-SOM associations prevent the biological decomposition of such carbon pools. Moreover, the δ 13 C signals, C/N ratios and results from chemical extractions clearly showed differences in the origin, nature and reactivity of the SOM as a function of the size fraction with consequences on the metal behaviour. Differences were observed between metals studied: Zn seems to be mainly bound to SOM associated with clay particles, while Pb seems to prefer to interact directly with the mineral surfaces versus the SOM.

The influence of weathering and soil organic matter on Zn isotopes in soils

“…Therefore, the enrichment in light Zn isotopes with an increasing proportion of stable OC likely results from the stabilization of plant-derived Zn-organic compounds, which are usually relatively enriched in light Zn isotopes (Jouvin et al, 2012;Moynier et al, 2009;Weiss et al, 2005;Viers et al, 2007Viers et al, , 2015Couder et al, 2015;Tang et al, 2016;Caldelas and Weiss, 2017), through association with the soil mineral matrix. This interpretation is in line with previous studies that report plant-derived Zn being mainly found in organo-metallic complexes associated with the clay fraction which are relatively resistant to biodegradation (Quenea et al, 2009). …”

Distribution characteristics of cadmium and lead in particle size fractions of farmland soils in a lead–zinc mine area in Southwest China

“…Colloid has the highest distribution factor of the Cd and Pb. Studies on the relationship among urbanized areas, waste water and mining area soil present the same results, suggesting that Cd and Pb accumulate primarily in fine particles (Luo et al 2011;Harter and Naidu 1995;Quenea et al 2009). Macro-aggregates have the highest mass loading for Cd and Pb, followed by colloid and micro-aggregates, in a study of typical black and bog arable soils (Gong et al 2012).…”

The heavy metal partition in size-fractions of the fine particles in agricultural soils contaminated by waste water and smelter dust

“…Acosta et al [11] figured out that the high amounts (60-80%) of calcite and dolomite was the main reason of metals accumulation in fine fractions in the soils of urban parks in Murcia City, Spain. Quenea et al [12] found that Zn seemed to be mainly bounded to soil organic matter associated with clay particles, while Pb seemed to prefer to interact directly with the mineral surfaces versus the organic matter in a soil contaminated by waste water. Tang et al [13] analyzed organic carbon and heavy metals contents for the separated nanocolloidal particles (five fractions from 250 m to <0.1 m) from some mining sites in China and observed a good correlation between Cu, Cd and organic carbon.…”