Investigation of groundwater flow with the aid of indium—EDTA-complex using neutron activation for the determination of the tracer

Indium-EDTA-tracer detected in water samples by neutron activation analysis was used in a multitracer karst experiment carried out in the catchment area of Ljubljanica springs (Yugoslavia) in 1975. For this purpose it was tried, to develop the detection procedure in such a manner, that the samples could be processed with reduced labour demand and reduced interferences by water ingredients. This was attained by liberating the indium from the EDTA-complex and subsequent coprecipitation on bismuth-hydroxide which yields no interfering γ-emitters under irradiation with reactor neutrons. Flow parameters in the Ljubljanica karst system were measured and are presented.