Impact of Sewage Sludge Spreading on Soil and Crop quality – Results from a French thorough Survey

The spreading of urban sewage sludge is a constant cause of controversy, in particular as this practice is known to supply amounts of potentially toxic trace metals to the soil, particularly cadmium. In order to clarify some parts of this debate, this article presents a synthesis of the results of many studies carried out in France on the impact of sewage sludge spreading: old experiments as well as more recent trials. This paper deals mainly with cadmium but sometimes some interesting results relating to other trace metals are reported. Presented data are relative to: i) the soil quality such as total trace metal contents and results of partial extraction aimed at determining the most phytoavailable fractions; ii) the composition of cereal grain, chiefly wheat. Depending upon the period, the experiments were completely different as far as the tonnages of sludge applied and the quantities of cadmium involved. Three categories of trials stand out: 1) During the 1970s and 80s, sludges with a high trace metal content, especially cadmium, were spread at one experimental farm on sandy soils and in the Vexin area on silty topsoils. In all cases, a notable long-lasting impact was found on the total Cd content of the topsoil and the composition of cereal grains. The quantities of applied Cd were very high, from 3,600 g ha-1 to 641,000 g ha-1. 2) Sludges containing high amounts of industrial Ca were spread on acid soils in the Limoges region for more than 20 years. Increases of the cadmium content in the topsoil were only measured in fields where the cadmium input was the highest, of 300 to 600 g per ha. A clear increase in the Cd content of cereal grains has been noted as well. 3) During the 1990s and 2000s, numerous experiments with sewage sludge applications compatible with the French regulations were implemented. Local authorities launched many, relatively light, experiments in diverse areas and on diverse soil types. Research institutions carried out other, more exacting, trials. The quantities of Cd input varied from 0.6 to 270 g ha-1. In these cases, no impact was measurable on the composition of cereal grains

Teneurs totales en plomb en fonction de la profondeur dans les sols « naturels »

Ce petit texte rappelle un certain nombre de généralités relatives aux éléments en traces (dont le plomb) dans les « sols naturels », c’est-à-dire les sols agricoles ou forestiers non recouverts par des matériaux archéologiques et dont la morphologie, héritée de l’action des processus pédogénétiques, n’a pas été complètement effacée par des remaniements anthropiques.Sont présentés brièvement et illustrés : la définition des « concentrations pédogéochimiques naturelles » et des « teneurs agricoles habituelles » ; des données statistiques françaises portant sur plus de 10000 horizons de surface labourés et sur 260 solums analysés en région Nord-Pas de Calais; la faible mobilité du plomb dans les sols (à l’exception du cas des Podzosols) ; les flux de retombées atmosphériques et leur variabilité tant spatiale que temporelle; deux techniques pour déceler les contaminations anthropiques et évaluer leurs niveaux (relative topsoil enhancement et « comparaisons verticales »).This paper presents some general points relative to trace metals (especially lead) in « natural » soils. These are agricultural or forested soils which have not been buried by archaeological material and the morphology of which, inherited from the action of soil forming processes, has not been totally erased by anthropogenic reworking.Are briefly mentioned and illustrated: the definition of “natural pedogeochemical concentrations” and “usual agricultural contents”; statistical data for more than 10000 ploughed surface horizons nation-wide and 260 soil pits studied in the Nord-Pas de Calais region; the low mobility of lead in soils (with the noticeable exception of Podzosols); the fluxes of atmospheric fallout and their high variability in space and time; two techniques used in order to detect anthropogenic contaminations and assess their levels: relative topsoil enhancement (RTE) and “vertical comparison”.The RTE is the mere ratio of the total lead concentration in the surface layer (0-15 cm) divided by the concentration found at a depth of 30-45 cm. A value > 4 may indicate strong contamination by human activities. Unfortunately, this ratio is highly depending on the pedological nature of the semi-deep horizon and must be cautiously handled. It seems better to resort to the “vertical comparison” which is a simple and inexpensive approach.The latter consists in interpreting the distribution of total lead contents with depth, for 4-5 or 6 superposed horizons. A high lead content in the topsoil contrasting with low values at depth is rather an evidence of pollution. On the contrary, a high concentration in the topsoil keeping steady or going increasing with depth is rather the indication of a natural geochemical anomaly

High cadmium concentrations in Jurassic limestone as the cause for elevated cadmium levels in deriving soils: a case study in Lower Burgundy, France

Cadmium (Cd) is a highly toxic element and its presence in the environment needs to be closely monitored. Recent systematic surveys in French soils have revealed the existence of areas in eastern and central France, which show systematically high cadmium concentrations. It has been suggested that at least part of these anomalous levels are of natural origin. For the Lower Burgundy area in particular, a direct heritage from the Jurassic limestone bedrock is highly suspected. This potential relationship has been studied in several localities around Avallon and this study reports new evidence for a direct link between anomalously elevated cadmium contents of Bajocian and Oxfordian limestone and high cadmium concentrations in deriving soils. Soils in this area show cadmium concentrations generally above the average national population values, with contents frequently higher than the ‘upper whisker' value of 0.8μgg−1 determined by statistical evaluation. In parallel, limestone rocks studied in the same area exhibit cadmium concentrations frequently exceeding the mean value of 0.030-0.065μgg−1 previously given for similar rocks by one order of magnitude, with a maximum of 2.6μgg−1. Mean ratios between the cadmium concentrations of limestone bedrock and deriving soils (Cdsoil/Cdrock), calculated for different areas, range from 4.6 to 5.7. Calculations based on the analyses of both soils from a restricted area and fragments of bedrock sampled in the immediate vicinity of high-concentration soils are around 5.5-5.7. Cdsoil/Cdrock is useful in determining the potential of soils in Lower Burgundy to reflect and exacerbate the high concentrations of cadmium present in parent bedrock

Contribution à l'étude des propriétés de rétention en eau des sols argileux : importance de la prise en compte de l'organisation de la phase argileuse.

Ary Bruand : Present address : Institut des Sciences de la Terre d'OrléansInternational audienceLes propriétés de rétention en eau des argiles des sols sont discutées à partir d'échantillons non pertubés de sols argileux. Les résultats montrent que, si la quantité et la nature minéralogique de l'argile expliquent en partie les valeurs mesurées, il est nécessaire de tenir compte aussi de l'organisation des particules d'argile telle qu'elle se présente au sein d'échantillons "naturels". Le volume massique de fragments non perturbés, pris à leur capacité au champ, se présente comme le paramètre le plus adapté à cette caractérisation

Zinc Redistribution in a Soil Developed from Limestone During Pedogenesis

International audienceThe long-term redistribution of Zn in a naturally Zn-enriched soil during pedogenesis was quantified based on mass balance calculations. According to their fate, parent limestones comprised three Zn pools: bound to calcite and pyritesphalerite grains, bound to phyllosilicates and bound to goethite in the inherited phosphate nodules. Four pedological processes, i.e., carbonate dissolution, two stages of redox processes and eluviation, redistributed Zn during pedogenesis. The carbonate dissolution of limestones released Zn bound to calcite into soil solution. Due to residual enrichment, Zn concentrations in the soil are higher than those in parent limestones. Birnessite, ferrihydrite and goethite dispersed in soil horizon trapped high quantities of Zn during their formation. Afterwards, primary redox conditions induced the release of Zn and Fe into soil solution, and the subsequent individualization of Fe and Mn into Zn-rich concretions. Both processes and subsequent aging of the concretions formed induced significant exportation of Zn through the bottom water table. Secondary redox conditions promoted the weathering of Fe and Mn oxides in cements and concretions. This process caused other losses of Zn through lateral exportation in an upper water table. Concomitantly, eluviation occurred at the top of the solum. The lateral exportation of eluviated minerals through the upper water table limited illuviation. Eluviation was also responsible for Zn loss, but this Zn bound to phyllosilicates was not bioavailabl

Association of KIR2DS1 and KIR2DS3 with fatal outcome in Ebola virus infection

Zaïre ebolavirus (ZEBOV) infection rapidly outruns the host's immunity and leads to death within a week. Fatal cases have been associated with an aberrant innate, proinflammatory immune response followed by a suppressed adaptive response leading to the rapid depletion of peripheral NK cells and lymphocytes. A critical role for NK cells has been suggested but not elucidated. In this genetic study, we investigated the association of KIR genotype with disease outcome by comparing genotypes of a Gabonese control population, IgG+ contacts, survivors, and fatalities of ZEBOV infection. We showed that the activating KIR2DS1 and KIR2DS3 genes associate with fatal outcome in Ebola virus infection. In addition, this study brings supplemental evidence in favor of the specificity of the IgG+ contact population. The outcome of fulminating Ebola virus infection could depend in part on the host's inherited KIR gene repertoire. This supports a key role for KIRs in disease susceptibility to infections

Note sur deux paléosols lessivés de l'Avallonnais

Baize D. Note sur deux paléosols lessivés de l'Avallonnais. In: Bulletin de l'Association française pour l'étude du quaternaire, vol. 5, n°1, 1968. pp. 45-53

Naissance et évolution des sols - La pédogenèse expliquée simplement

International audienceLe sol est trop souvent assimilé à l’humus, aux vers de terre et à de nombreuses petites bêtes. Or il ne se réduit pas à cela. Parlons d’ailleurs plutôt de sols au pluriel, tant leurs apparences et leurs propriétés sont multiples, fruits de leurs divers héritages.Cet ouvrage vous permettra de découvrir ce que l’on appelle la pédogenèse : la naissance et le développement des sols. Leur formation, le rôle des constituants minéraux, les facteurs et les principaux processus de pédogenèse à l’œuvre sous nos climats tempérés sont expliqués ici simplement. La difficile estimation de l’âge des sols et la vitesse de leur évolution sont discutées, ainsi que de nombreuses autres questions fondamentales. Les types de sols les plus fréquents en France dans les bassins sédimentaires — les luvisols, les planosols et les brunisols — sont traités de façon détaillée, comme d’ailleurs les anthroposols, des sols urbains très artificialisés, voire totalement « fabriqués » par l’homme. Beaucoup de réalités peu connues sont mises en valeur, telle l’importance majeure des constituants minéraux et de leurs organisations, et plusieurs idées fausses sont réfutées, comme le caractère ubiquiste du lessivage des argiles. Synthèse facile à lire et richement illustrée, ce livre est destiné à des étudiants, des enseignants, des chercheurs d’autres disciplines et des amateurs naturalistes

La cartographie des "petites régions naturelles" et des "paysages pédologiques". Application dans le département de l'Yonne

Baize Denis. La cartographie des "petites régions naturelles" et des "paysages pédologiques". Application dans le département de l'Yonne . In: Annales de Géographie, t. 105, n°589, 1996. pp. 319-329

Cadmium in soils and cereal grains after sewage-sludge application on French soils. A review

Recycling sewage sludges as fertilisers on soils for crop production has several potential benefits such as providing large amounts of phosphorous and organic matter. However, the spreading of urban sewage sludge is a constant cause of controversy because it is known to introduce potentially toxic trace metals into the soil, particularly cadmium. In order to clarify this debate, this review article presents a synthesis of the results of several studies carried out in France on the impact of sewage-sludge spreading. This article reports mainly Cd results but also some results on other trace metals such as Cr, Cu, Hg, Ni, Pb and Zn. Two kinds of data are presented: (1) soil data including total metal contents and data from partial extraction to evaluate the phytoavailable fractions, and (2) plant data including metal content of wheat, a major agricultural crop. The field experiments involved very different amounts of applied sewage sludges and Cd. Indeed, three categories of experiments stand out, the first and second involving high amounts of applied Cd, and the third involving low amounts of applied Cd: (1) during the 1970s and '80s, sludges with a high trace metal content, especially Cd, were spread at the INRA trials at Couhins experimental farm on sandy soils and in the Vexin area on silty topsoils. The quantities of applied Cd were very high, ranging from 3600 g to 641 000 g per ha. Here, the results show a notable impact on total Cd contents of topsoil and cereal grains. (2) Sludges containing high levels of industrial cadmium were spread on acid soils in the Limousin region for more than twenty years up to 1998. Topsoil Cd contents were measured in fields where the cadmium input was highest, of 300 to 600 g Cd per ha. Here, a clear increase in the Cd content of cereal grains was found. (3) During the 1990s and 2000s, numerous experiments with sewage-sludge applications compatible with the new French regulations of 1998 were implemented. The amounts of applied Cd were therefore much lower, from 0.6 to 270 g/ha. Here, no impact was detected on the composition of cereal grains. This review article concludes that the application of huge quantities of sewage sludges in the 1970s and '80s had a clear and long-lasting effect on both soil and grain Cd compositions. Nonetheless, spreading sewage sludge in accordance with the new French regulations had no significant impact on soil and cereal-grain Cd concentrations