Spatially Explicit Analysis of Metal Transfer to Biota: Influence of Soil Contamination and Landscape

Concepts and developments for a new field in ecotoxicology, referred to as “landscape ecotoxicology,” were proposed in the 1990s; however, to date, few studies have been developed in this emergent field. In fact, there is a strong interest in developing this area, both for renewing the concepts and tools used in ecotoxicology as well as for responding to practical issues, such as risk assessment. The aim of this study was to investigate the spatial heterogeneity of metal bioaccumulation in animals in order to identify the role of spatially explicit factors, such as landscape as well as total and extractable metal concentrations in soils. Over a smelter-impacted area, we studied the accumulation of trace metals (TMs: Cd, Pb and Zn) in invertebrates (the grove snail Cepaea sp and the glass snail Oxychilus draparnaudi) and vertebrates (the bank vole Myodes glareolus and the greater white-toothed shrew Crocidura russula). Total and CaCl2-extractable concentrations of TMs were measured in soils from woody patches where the animals were captured. TM concentrations in animals exhibited a high spatial heterogeneity. They increased with soil pollution and were better explained by total rather than CaCl2-extractable TM concentrations, except in Cepaea sp. TM levels in animals and their variations along the pollution gradient were modulated by the landscape, and this influence was species and metal specific. Median soil metal concentrations (predicted by universal kriging) were calculated in buffers of increasing size and were related to bioaccumulation. The spatial scale at which TM concentrations in animals and soils showed the strongest correlations varied between metals, species and landscapes. The potential underlying mechanisms of landscape influence (community functioning, behaviour, etc.) are discussed. Present results highlight the need for the further development of landscape ecotoxicology and multi-scale approaches, which would enhance our understanding of pollutant transfer and effects in ecosystems

Vers une sucrerie zéro effluent, le cas de la raffinerie de sucre

International audienceWherever in the world, limitation of the environmental impact is a constant orientation of the sugar industry. Membrane technologies have already demonstrated their efficiency in separating organic and mineral components from effluent streams in order to recover and eventually recycle them. Based on combination of nanofiltration and electrodialysis, Eurodia has developed a process to treat the decolorization eluates in sugar industry.La réduction des effluents est une évolution générale et constante dans les industries sucrières. Dans cette démarche vers le zéro rejet, les technologies membranaires ont d'ores et déjà fait la preuve de leur efficacité. Parmi celles-ci, la nanofiltration et l'électrodialyse sont particulièrement adaptées à la séparation des matières organiques et minérales en vue de leur élimination ou de leur recyclage. Pour les raffineries de sucre, Eurodia a mis au point un procédé de traitement des éluâts de décoloration de sucres basé sur la combinaison de ces deux technologies. Abstract Wherever in the world, limitation of the environmental impact is a constant orientation of the sugar industry. Membrane technologies have already demonstrated their efficiency in separating organic and mineral components from effluent streams in order to recover and eventually recycle them. Based on combination of nanofiltration and electrodialysis, Eurodia has developed a process to treat the decolorization eluates in sugar industry

Volatilisation d'ammoniac après épandage de lisier en conditions tropicales. Cas des prairies d'altitude et de la canne à sucre à l'île de la Réunion

Cette étude vise à acquérir des connaissances sur la volatilisation d'ammoniac après épandage de lisier à la Réunion, pour laquelle il n'existe pas de référence. Nous avons retenu deux situations caractéristiques, contrastées et amenées à perdurer: épandage de lisier bovin sur prairies dans les Hauts et épandage de lisier porcin sur les surfaces cannières. Nous avons caractérisé l'effet du mulch de canne à sucre par comparaison à un sol nu. La volatilisation d'ammoniac a été suivie avec la méthode du bilan de masse et le déterminisme de l'infiltration de l'azote ammoniacal du lisier et celui du pH et de son évolution ont été étudiés sur des micro-placettes. Le comportement des prairies d'altitude est proche de celui des prairies de climat tempéré avec des pertes de l'ordre de 40% de l'azote ammoniacal apporté; le rôle du couvert sur l'infiltration du lisier est déterminant pour la volatilisation d'ammoniac. Les résultats sur canne à sucre montrent que l'épandage en présence du mulch conduit à la perte de la quasi-totalité de l'azote ammoniacal du lisier, ce qui réduit fortement l'intérêt agronomique et environnemental de cette pratique; sur sol nu, les pertes, de moitié inférieures, sont comparables à celles mesurées en régions tempérées sur sol cultivés; l'effet du mulch est expliqué par sa capacité de rétention du lisier et d'augmentation de la surface d'échange avec l'atmosphère. Ces connaissances sur la volatilisation d'ammoniac pourraient, à terme, être incorporées dans des modules "Volatilisation" permettant de prendre en compte ces pertes environnementales dans des modèles de gestion globale des matières organiques. (Résumé d'auteur

Ecological intensification of agricultural production systems through waste recycling: the ISARD project

absen

Ecological intensification of agricultural production systems through waste recycling

Session 4: Management of natural resources and waste for UPHInternational audienceOrganic waste (OW) generated by human activity is continuously increasing worldwide. Agriculture generates large amounts of OW derived mostly from livestock farming and agroindustries. Furthermore, OW flows are increasing as a result of urban development- wastewater, sludge and municipal waste may be treated to different degrees. These wastes are often applied on cultivated lands on the outskirts of cities. OW are sources of organic matter that may increase soil fertility and reduce the need for chemical fertilizers, thus enhancing sustainable agricultural production. They may also carry contaminants, and inappropriate application may lead to an accumulation of mineral, organic or metallic contamination, thus degrading soil quality and possibly increasing the risk of pollutant transfer to the harvested crops. The multiplication of product types and the diversity of situations in which they are produced and used are factors that should be considered to enhance OW management in agriculture. The ISARD project aims to develop a global approach for integrating knowledge concerning OW recycling in agriculture. Innovation in this project is related to the territorial approach with organic matter stemming from either agriculture or households, and mainly in suburban areas. The project is being implemented at four locations, with the following specific recycling issues: o Metropolitan Dakar (Senegal): possible ways of using mixed composts o Mahajanga region (Madagascar): making and using municipal waste compost o Versailles area (France): recycling stable manure and wastewater treatment sludge on cultivated plots o Réunion Island (France, Indian Ocean): organizing and assessing the recycling of various wastes at a territory level The expected result to be delivered when the project is completed is a generic methodology that will make it possible for agronomists working with rural stakeholders to create highly efficient cropping and farming systems based on the use of a wide range of organic wastes