Schwermetallgehalte von Wirtschaftsdüngern in Deutschland und der EU

Animal manure is a significant source of heavy metal input into agricultural soils. The total amount of manure rather than the concentration of heavy metals per unit of manure is the significant value. Unit concentration cannot be used for calculation and assessment of the total heavy metal load as animal manure replaces mineral fertilizers and a considerable proportion of the metals in animal manure is part of an internal farm metal cycle. Thus determined, it becomes apparent that net heavy metal loads from manure are lower - except for Cu and Zn - than those caused by the application of mineral fertilizers and especially of sewage sludge or municipal waste compost. The most promising way to reduce heavy metal loads in animal manure appears to be to reduce the metal concentrations in animal feed (further details are expected from the KTBL-Workshop Feeding strategies for the reduction of trace elements/heavy metals in animal manure in April, 2002).