The Vertical Movement of Cadmium, Nickel and Lead Through Undisturbed Cores Having a Surface Amended of Sewage Sludge

J. Nouri; B. J. Alloway; P.J. Peterson

The Vertical Movement of Cadmium, Nickel and Lead Through Undisturbed Cores Having a Surface Amended of Sewage Sludge

2001

J. Nouri | B. J. Alloway | P.J. Peterson

An experiment over a period of 14 months was carried out on duplicate undisturbed cores of 3 soils, with different textures using one sludge in order to obtain moreinformation on the vertical movement of heavy metals through sludge treated soil.Over the first 8 months the pH values were in this order : sandy silt loam > sandyclay> loamy sand of both control and sludge amended soils. The rainwater pH valuesduring the first 8 months were acidic, but during the following six months, theyincreased loan alkaline value. At the end weathering, it was found that only theamended surface and upper layers contained elevated concentrations of heavy metals.Thus the nature of soil was an extremely important factor in the downwardmovement of constituents. It appears that a guideline for sludge application to landthe pH of soils should be maintained at or above 6.5. Groundwater pollution waslikely to be the greatest in highly permeable sandy soils and these should not be usedfor the application of heavy metals. Soil water influenced the chemistry of surfacewaters and this affected the survival of fresh water fauna and flora.

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