Availability of heavy metals from sewage sludge and its possible impact on regulatory activity in Italy

This paper reports the preliminary results obtained by a sequential extraction method based on Rudd's procedure that can be used to determine various chemical forms of heavy metals present in sludge. The impact of heavy metals present in sewage sludge for agricultural use is determined by their mobility and bioavailability. These parameters heavily depend on the chemical forms of the metals present. This study proposes a procedure that may be adopted in further studies for a more appropriate normative than the present European Economic Community Directive no. 278/86. By providing data on both metal mobility and total heavy metal concentration, the researcher may draw adequate guidelines that reflect the true environmental risk involved in the use of sludge for agriculture.