In Situ Bioremediation through Mulching of Soil Polluted by a Copper–Nickel Smelter

Received for publication September 8, 2000. Bioremediation of a heavy metal–polluted soil was investigated in a 3-yr field experiment by adding mulch to a polluted forest floor. The mulch consisted of a mixture of compost and woodchips. The remediation treatment decreased the toxicity of the soil solution to bacteria as determined by the [3H]-thymidine incorporation technique, that is, by measuring the growth rate of soil bacteria extracted from unpolluted humus after exposing them to soil solution containing heavy metals from the experimental plots. Canonical correlation analysis was performed in order to identify the chemical and microbiological changes in the soil. The pH of the mulched organic layer increased by one unit. The concentration of complexed Cu increased and that of free Cu2+ decreased in the soil solution from the mulch treatment. According to basal respiration and litter decomposition, microbial activity increased during the 3 yr following the remediation treatment. The [3H]-thymidine incorporation technique was also used to study the growth rate and tolerance of bacteria to Cu. The bacterial growth rate increased and the Cu tolerance decreased on the treated plots. The structure of the microbial community, as determined by phospholipid fatty acid (PLFA) analysis, remained unchanged. The results indicate that remediation of the polluted soil had occurred, and that adding a mulch to the forest floor is a suitable method for remediating heavy metal–polluted soil

Environmental fate of triasulfuron in soils amended with municipal waste compost

This work was partially supported by the Leonardo da Vinci 2001. Degradation of imazosulfuron in soil. Pest Manage. Sci. program of the European Commission as part of the project 57:360–365. Pichon, V., C. Cau Dit Coumes, L. Chen, S. Guenu, and M.-C. Hen- ISDEPS 2002.The amendment of soil with compost may significantly influence the mobility and persistence of pesticides and thus affect their environmental fate. Factors like adsorption, kinetics, and rate of degradation of pesticides could be altered in amended soils. The aim of this study was to determine the effects of the addition of compost made from source-separated municipal waste and green waste, on the fate of triasulfuron [(2-(2-chloroethoxy)-N-[[4-methoxy-6-methyl- 1,3,5-triazin-2-yl)amino] carbonyl]benzenesulfonamide], a sulfonylurea herbicide used in postemergence treatment of cereals. Two native soils with low organic matter content were used. A series of analyses was performed to evaluate the adsorption and degradation of the herbicide in soil and in solution after the addition of compost and compost-extracted organic fractions, namely humic acids (HA), fulvic acids (FA), and hydrophobic dissolved organic matter (HoDOM). Results have shown that the adsorption of triasulfuron to soil increases in the presence of compost, and that the HA and HoDOM fractions are mainly responsible for this increase. Hydrophobic dissolved organic matter applied to the soils underwent sorption reactions with the soils, and in the sorbed state, served to increase the adsorption capacity of the soil for triasulfuron. The rate of hydrolysis of triasulfuron in solution was significantly higher at acidic pH and the presence of organic matter fractions extracted from compost also slightly increased the rate of hydrolysis. The rate of degradation in amended and nonamended soils is explained by a two-stage degradation kinetics. During the initial phase, although triasulfuron degradation was rapid with a half-life of approximately 30 d, the presence of compost and HoDOM was found to slightly reduce the rate of degradation with respect to that in nonamended soil.peer-reviewe

A review of the distribution of particulate trace elements in urban terrestrial environments and its application to considerations of risk

We review the evolution, state of the art and future lines of research on the sources, transport pathways, and sinks of particulate trace elements in urban terrestrial environments to include the atmosphere, soils, and street and indoor dusts. Such studies reveal reductions in the emissions of some elements of historical concern such as Pb, with interest consequently focusing on other toxic trace elements such as As, Cd, Hg, Zn, and Cu. While establishment of levels of these elements is important in assessing the potential impacts of human society on the urban environment, it is also necessary to apply this knowledge in conjunction with information on the toxicity of those trace elements and the degree of exposure of human receptors to an assessment of whether such contamination represents a real risk to the city’s inhabitants and therefore how this risk can be addressed

A long-term chemical and infrared spectroscopy study on a soil amended with municipal sewage sludge

A long-term field experiment was carried out to evaluate the effect of a seven-year soil amendment with municipal sewage sludge on chemical fertility, soil enzyme activities and the changes in the composition of humic substances. The amended soil showed an increase in total and NaOH soluble organic C, available P and K. The heavy metals contained in the sludge did not affect soil phosphatases (alkaline phosphomonoesterase and phosphodiesterase), arylsulphatase or L-asparaginase activity, even if the concentration of total and available Cu, Ni and Zn increased in the arable layer of soil. The fulvic acids FT-IR spectra showed that amended soil contains a higher concentration of carboxylic and aliphatic groups and polysaccharides compared to unamended soil. The polysaccharide increase in the seven-year amended soil is attributable to the humification process since only a small amount of polysaccharides were present in the sludge. The humic acids FT-IR spectra showed that amended soil contained a higher concentration of aliphatic and N-containing groups and a lower concentration of polysaccharides than unamended soil. The humification parameters (i.e. humification ratio, humification index and degree of humification) highlighted the differences in the humification status between sludge humic-like substances and humus from soil, but were unable to show the differences between unamended and amended soils.Étude chimique et spectroscopique à long terme sur un sol amendé par épandage des eaux de l'égout municipal. On a effectué une étude de terrain sur sept ans pour évaluer l'effet, sur la fertilité chimique, sur les activités enzymatiques du sol et sur les variations dans la composition de substances humiques, d'un sol amendé pendant sept ans avec des eaux d'égout. On a relevé, dans le sol ainsi soumis à épandage, une augmentation de C organique total et humifié et de P et K disponibles. La présence de métaux lourds dans les eaux d'égout n'affectent pas l'activité de phosphatase du sol (phospho-monoestérase et phospho-diestérase), aryl-sulfatase ou L-asparaginase, même si l'on a pu relever une augmentation de la teneur en Cu, Ni et Zn totaux et disponibles dans la couche arable du sol. Le spectre FT-IR de l'acide fulvique a montré que les sols amendés contiennent une concentration plus élevée de groupes carboxyliques et aliphatiques et de polysaccharides que le sol non amendé. On peut attribuer au processus d'humification l'augmentation en polysaccharides du sol amendé pendant sept ans, car les eaux d'égout ne contenaient qu'une quantité réduite de polysaccharides. Le spectre FT-IR de l'acide humique a montré que, comparé au sol non amendé, le sol amendé présente une teneur plus élevée en groupes aliphatiques et en groupes azotés et une concentration plus basse de polysaccharides. Les données provenant du paramètre d'humification (c'est-à-dire rapport d'humification, grade d'humification et indice d'humification) ont mis en évidence les différences de condition d'humification entre les substances humicoles contenues dans les eaux d'égout et l'humus contenu dans le sol, mais non les différences entre sol amendé et sol non amendé

A spectroscopic study of soil fulvic acid composition after six-year applications of urban waste compost

A FT-IR, $^1$H- and $^{13}$C-NMR study was carried out to determine the changes in the composition of fulvic acids (FA) in a soil that was repeatedly amended with urban waste compost (UWC). Fuloic acids were extracted from a clay-loam soil (unamended soil - UNS), a compost and two soil-compost mixtures. One soil sample was taken from a freshly prepared laboratory mixture (LAS) while the other was collected from a 6-year field experiment 8 months after the last amendment (6YAS). Spectroscopic analyses of fuloic acids extracted from compost and unamended soil showed that the former had a higher content of aliphatic and carboxylic groups and a lower content of carbohydrates and aromatic C. Immediately after compost addition, soil fuloic acids had a higher content of aliphatic C-H and carboxylic groups and a lower content of aromatic rings and polysaccharides. The results showed that there was a progressive modification of soil organic matter during the six-year field experiment. Although the concentration of aliphatic chains, aromatic rings and polysaccharides tended to return to the value of the unamended control, a greater variety in functional groups was observed by the spectroscopic analysis.Étude spectroscopique de la composition des acides fulviques du sol après six ans d'application de compost à base de déchets solides urbains. La présente expérimentation avait pour but de déterminer les modifications que subit la composition des acides fulviques du sol suite à des amendements répétés de composts à base de déchets solides urbains (UWC). Les acides fulviques étaient extraits d'un sol argilo-limoneux (sol non amendé - UNS), d'un UWC et de deux mélanges sol-compost - un échantillon de sol provenant d'un mélange fraîchement préparé en laboratoire (LAS) et un second échantillon prélevé sur place 8 mois après le dernier d'une série de traitements avec compost effectués durant six années (6YAS). Les analyses spectroscopiques effectuées ont démontré que, par rapport au sol non amendé, le compost possède une teneur plus élevée en groupes aliphatiques et carboxyliques et une teneur moindre en hydrates de carbone et C aromatiques. Immédiatement après l'addition de compost, les acides fulviques du sol se modifient, présentant une teneur plus élevée en C-H aliphatiques et groupes carboxyliques et une concentration moindre en noyaux aromatiques et hydrates de carbone. Pendant l'intervalle de 8 mois écoulé entre le dernier amendement et le prélèvement des échantillons de sol, les données des analyses spectroscopiques pour 6YAS, LAS et UNS montrent que la substance organique du sol a subi une évolution, la concentration en chaînes aliphatiques, noyaux aromatiques et polysaccharides tendant à se rapprocher des valeurs du contrôle non amendé