Use of organo-zeolitic fertilizer to sustain plant growth and stabilize metallurgical and mine-waste sites. P. J. LEGGO. 1,* AND B. LEDÃ SERT. 2. 1 Department of ...
Mineralogical Magazine, October 2001, Vol. 65(5), pp. 563–570
Use of organo-zeolitic fertilizer to sustain plant growth and stabilize metallurgical and mine-waste sites P. J. LEGGO1,* 1 2
AND
B. LEDE´SERT2
Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK Se´dimentologie et Ge´odynamique, FRE 2255, Universite´ de Lille, France
ABSTR ACT
Land south of Lille, contaminated by heavy metals from local metal refining, has become the subject of intensive research. Topsoil from this area is used in the current work to investigate the growth behaviour of Spring wheat (Triticum aestivum L., cv. Paragon) when amended with organo-zeolitic fertilizer. Research has shown that soil substrates amended with ammoniated zeolitic tuff promote large populations of nitrifying bacteria which, as the result of ensuing enzyme reactions, produce available nitrogen together with H+ ions. It appears that the proton activity promotes cation mobilization allowing plant uptake to reach levels which, to a large extent, satisfy the nutritional requirements of the plant; only in the case of Zn is the level far exceeded. Very large differences in plant morphology occur when plants are grown in the amended substrates and the resulting development of large dense root systems, which have the ability to bind soil particles, are particularly important in their ability to reduce surface erosion and pollution from run-off.
K EY WORDS : heavy metals, organo-zeolitic fertilizer, plant morphology, surface erosion.
Introduction THE studied zone is located 40 km south of Lille, in northern France (Fig. 1), near Courcelles-lesLens, in close proximity to two large Pb-Zn smelters that have been in operation for about a century. These plants emitted large amounts of atmospheric dust until the 1970s after which they were either equipped with filters or underwent process design changes. As a consequence of dust fallout, the surrounding lands became heavily contaminated with Pb, Zn and Cd (Fig. 1). In addition, large amounts of slag are produced yearly (160,000 tons for one plant only) and stored in the open until the present day without any protection against erosional agents such as wind and rain. In one heap, 5 million tonnes of slag particles exist which reach a height of 50 m. The heap is characterized by steep slopes and small grain-size of
