A combination of instrumental neutron activation analysis (INAA) and instrumental photon activation analysis (IPAA) methods
has been developed for multielement determinations in a variety of sludges and fertilizers. The precision and accuracy of
both the methods have been evaluated by analyzing replicate samples, NBS standard reference materials, and an interlaboratory
intercomparison sewage sludge sample. The concentration rages of up to 50 elements in raw and chemical sludges, sludge-based
fertilizers, and other organic and inorganic fertilizers are reported here. The advantages and limitations of the INAA and
IPAA methods are also discussed here.