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

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 Na4P2O7 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 (C4 plant), replaced C3 crops 15 years ago, natural isotopic 13C labelling gave new insights into SOM turnover. First, the results suggest that metals influence the SOM dynamics in that sandy soil: a C3 "old carbon" enrichment was observed in the small or clay size fractions, while the "new" C4 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 δ13C 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

Study of the trace metal ion influence on the turnover of soil organic matter in cultivated contaminated soils

The role of metals in the behaviour of soil organic matter (SOM) is not well documented. Therefore, we investigated the influence of metals (Pb, Zn, Cu and Cd) on the dynamic of SOM in contaminated soils where maize (C4 plant) replaced C3 cultures. Three pseudogley brown leached soil profiles under maize with a decreasing gradient in metals concentrations were sampled. On size fractions, stable carbon isotopic ratio (d13C), metals, organic carbon and nitrogen concentrations were measured in function of depth. The determined sequence for the amount of C4 organic matter in the bulk fractions: M3 (0.9) > M2 (0.4) > M1 (0.3) is in agreement with a significant influence of metals on the SOM turnover. New C4 SOM, mainly present in the labile coarser fractions and less contaminated by metals than the stabilised C3 SOM of the clay fraction, is more easily degraded by microorganism

doi:10.1016/j.envpol.2007.06.054

Kinetically defined metal fractions mimic mobility aspects of heavy metals. Abstract Kinetic EDTA and citrate extractions were used to mimic metal mobilization in a soil contaminated by metallurgical fallout. Modeling of metal removal rates vs. time distinguished two metal pools: readily labile (Q M1 ) and less labile (Q M2 ). In citrate extractions, total extractability (Q M1 þ Q M2 ) of Zn and Cd was proportionally higher than for Pb and Cu. Proportions of Pb and Cu extracted with EDTA were three times higher than when using citrate. We observed similar Q M1 /Q M2 ratios for Zn and Cu regardless of the extractant, suggesting comparable binding energies to soil constituents. However, for Pb and Cd, more heterogeneous binding energies were hypothesized to explain different kinetic extraction behaviors. Proportions of citrate-labile metals were found consistent with their short-term, in-situ mobility assessed in the studied soil, i.e., metal amount released in the soil solution or extracted by cultivated plants. Kinetic EDTA extractions were hypothesized to be more predictive for long-term metal migration with depth

Etude de quelques réactifs chimiques pour l'extraction du mercure des sols

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Analyses of soil cadmium and copper contents on a Domérien soil series of Burgundy in France

The aim of this study is to determine the availability of cadmium (Cd) in the soil of Yonne district, Burgundy, France. Soil samples were collected from surface-ploughed layer in fields across the southern part of the Yonne district, Burgundy, France. Some results analysing soil Cd and Cu contents on Domérien region of Burgundy has been presented. This is to know the relationship between extracting time and extracted Cd and Cu contents from the two sites’ soils (Dubloc, Bierry) in the Domérien soil series. A total of 68-107% Cd and 20-28% Cu were extracted from the soil in 1440 min. The two soils were acidic, and around 70% of Cd contents were extracted in 20 min of extraction, while around 65% of Cu contents were extracted in 30 min of extraction. The Cd extraction was blocked at the mid-extraction time, while the Cu extraction kept on increasing up to the end of the extraction time. Cadmium extraction increased with increase in pH value in the present experiment. Copper content shows same tendency with Cd.Keywords: Atomic absorption spectrophotometer, cadmium availability, copper extraction, Domérien soil series, extracting time, soil analysesAfrican Journal of Biotechnology, Vol 13(12), 1343-135

Contribution à l'étude de la disponibilité des éléments traces métalliques (Pb,Cu, Cd) des sols à l'aide du réactif EDTA

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Etude des colloïdes naturels présents dans les eaux gravitaires de sols contaminés (relation entre nature des colloïdes et réactivité vis-à-vis des métaux (Zn, Cd, Pb, Cu))

PARIS-AgroParisTech Centre Paris (751052302) / SudocFONTAINEBLEAU-MINES ParisTech (771862302) / SudocSudocFranceF

Étude cinétique de l'extraction des métaux traces des sols (application à l'évaluation de l'efficacité de techniques de réhabilitation in situ)

PARIS7-Bibliothèque centrale (751132105) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Kinetics as a tool to assess the immobilization of soil trace metals by binding phase amendments for in situ remediation purposes.

International audienceMany soil remediation techniques consist in decreasing the mobility of trace metals by means of adding trace metal binding phases. For this study, whose aim is to assess the efficiency of soil remediation method by binding phase amendment, a kinetic fractionation method that provides the labile and slowly labile trace metal amounts in soil has been introduced. Manganese oxides (vernadite) and insolubilized humic acids (IHA) have been used as binding phases for the remediation of four heavily polluted soils. Vernadite amendments are effective for lead and cadmium remediation, whereas IHA amendments are only effective for copper remediation. In most cases, the labile metal fractions decrease dramatically in amended soils (up to 50%); on the other hand, the amounts of total extracted metal near the point of thermodynamic equilibrium often show no significant difference between the amended soil and the control soil. These results highlight the utility of kinetic fractionation in assessing the efficiency of soil remediation techniques and, more generally, in evaluating trace metal mobility in soils and its potential advantages compared to extraction schemes performed under equilibrium conditions. In the future, this kinetic method could be considerably simplified so as to consume much less time allowing its routine use

Etude des colloïdes naturels présents dans les eaux gravitaires de sols contaminés (relation entre nature des colloïdes et réactivité vis-à-vis des métaux (Zn, Cd, Pb, Cu))

PARIS-AgroParisTech Centre Paris (751052302) / SudocFONTAINEBLEAU-MINES ParisTech (771862302) / SudocSudocFranceF