title: Land spreading of sewage sludge in forest plantations: effects on the growth of the duckweed Lemna minor and trace metal bioaccumulation in the snail Cantareus aspersus.
abstract: Wastewater plants generated annually millions of tons of sewage sludge (SS). Large amounts of this organic residue are spread on agricultural lands as a fertilizer, although it is viewed as a major potential source of contamination, presenting a danger to the terrestrial and aquatic environments. This study was undertaken to evaluate the impact of this practice on the duckweed Lemna minor and the snail Cantareus aspersus. Sludge was applied to soil either at six different loading rates equal to 0, 0.4, 3, 10, 30, and 60 tons dry matter (DM) ha(-1) for L. minor test or at three rates equal to 0, 30, and 60 tons DM ha(-1) for C. aspersus test. At the highest rate of SS application (60 tons DM ha(-1)), the eluates showed that an increase in pH (6.1) resulted in a decrease in Al levels. Thus, the high stimulation of L. minor growth observed after this high rate of SS application can be explained by (i) a reduction in Al toxicity after precipitation and (ii) macro- and micronutrient enrichment. At a rate of SS application of only 30 tons DM ha(-1), growth appeared to be slightly significant (p < 0.05), in spite of the significant increase in essential mineral elements. However, it is very difficult to discriminate between Al toxicity and pH effects. For the test with C. aspersus, the snail biomass was not affected by sludge application over the exposure period. Mortality was extremely low, with a rate of less than 4 % at the last sampling date. Yet, Cu, Pb, and Cd accumulated significantly in the soft body of snails exposed to SS application, suggesting that the amount of metals excreted is lower than that absorbed. In contrast, Zn levels remain constant, inferring that absorption and elimination of Zn are balanced at the beginning of the experiment.
authors: Department of Agronomy, National School of Agriculture of Meknès, km. 10, Route Haj Kaddour, B.P. S/40, 50001, Meknes, Morocco.|Jean-François Champollion University Center for Teaching and Research, Place Verdun, 81000, Albi, France.|University of Bourgogne Franche-Comté UMR CNRS 6249, 16 Route de Gray, 25000, Besançon, France.
authors: Bourioug
authors: B
authors: Mohamed
authors: University of Bourgogne Franche-Comté UMR CNRS 6249, 16 Route de Gray, 25000, Besançon, France.
authors: Gimbert
authors: G
authors: Frédéric
authors: University of Bourgogne Franche-Comté UMR CNRS 6249, 16 Route de Gray, 25000, Besançon, France.
authors: Alaoui-Sehmer
authors: AS
authors: Laurence
authors: University of Bourgogne Franche-Comté UMR CNRS 6249, 16 Route de Gray, 25000, Besançon, France.
authors: Badot
authors: B
authors: Pierre-Marie
authors: University of Bourgogne Franche-Comté UMR CNRS 6249, 16 Route de Gray, 25000, Besançon, France.
authors: Alaoui-Sossé
authors: AS
authors: Badr
authors: University of Bourgogne Franche-Comté UMR CNRS 6249, 16 Route de Gray, 25000, Besançon, France. lotfi.aleya@univ-fcomte.fr.
authors: Aleya
authors: A
authors: Lotfi
mesh_terms: D000383:Agriculture; D000818:Animals; D029064:Araceae / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D005308:Fertilizers; D065928:Forests; D019216:Metals, Heavy / Q000032:analysis* / Q000378:metabolism / Q000633:toxicity; D012722:Sewage / Q000737:chemistry*; D012908:Snails / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis* / Q000378:metabolism / Q000633:toxicity; D014131:Trace Elements / Q000032:analysis / Q000378:metabolism / Q000633:toxicity; D014865:Waste Disposal, Fluid / Q000379:methods
chemical_list: D005308:Fertilizers; D019216:Metals, Heavy; D012722:Sewage; D012987:Soil; D012989:Soil Pollutants; D014131:Trace Elements
keywords: Bioaccumulation; Cantareus aspersus; Lemna minor; Phototoxicity; Sewage sludge