ETUDE DE LA FORME PHYSICO-CHIMIQUE ET DE LA BIODISPONIBILITE DU CUIVRE DANS DES SYSTEMES CULTURAUX EXPERIMENTAUX; APPLICATION A L'UTILISATION AGRICOLE DE BOUES DE STATION D'EPURATION B. BERTHET, C. METAYER, J. C. AMIARD, et C. AMIARD-TRIQUET Centre de Dosage des Eldments Traces, U.E.R. des Sciences Pharmaceutiques, 1 rue Gaston Veil, 44035 Nantes Cedex, France (Received September 26, 1983; revised December 21, 1983) Abstract Introduction In order to appraise the influence of the physico-chemical forms of Cu on its biological availability, we have brought this metal in experimental systems under different forms according to whether it was associated with the soil, with mineral fertilizers or with sewage sludges. These sludges were rich in organic matter and carbonates and some of them contained Fe and A1 oxides and hydroxides. Experimental Procedures Different vegetables were cultivated in plant pots filled with a marked garden soil which was submitted to different treatments: - reference series without any dressing, - series with a mineral fertilizer (125-111-150 units per hectar), - series with incorporation of sewage sludges (25 t of dry sludges per hectar and complementary mineral manure). These experimental cultures were submitted to natural atmospheric conditions and the leached waters were collected. Global analysis of copper were made on waters, culture substrates and various organs of the vegetables. Moreover, sludges and soils were submitted to a selective extraction procedure to determine the physico- chemical forms of Cu. Results and Discussion The total contents of Cu in the sewage sludges were important compared to those of the soils. But the determination of the physico-chemical forms of Cu indicated a small availability of this metal in both sludges and soils. In accordance with these results, the exports via leached waters were very low, whatever the treatment may be, in case of normal outflow. On the contrary, with a disturbed flow, leading to a temporary lack of oxygen, the concentration of Cu in leached waters increased markedly. In the same way, exports via vegetables were very low, without any significant difference between sludge and mineral fertilizer treatments. Onion roots are the greatest accumulators of Cu. This vegetable being excepted, the concentrations are the same order of magnitude. Accumulation in reproductive parts, grains and pods of french beans for example, is important and sometimes higher than in the leaves. The exports being identically low whatever the treatment may be and the inputs being higher with the sewage sludges, an increase of total Cu content in the soil has been observed after this type of treatment. Water, Air, and Soil Pollution 23 (1984) 293-307. 0049-6979/84/0233-0293502.25. © 1984 by D. Reidel Publishing Company.