procedure, using ultrapure grade reagents; firstly,
a hydrofluoricrnitric concentrated acid mixture
5 mlr5 ml. was added to the sample; after evaporation,
a nitricrhydrochloric concentrated acid
mixture 3 mlr9 ml. was added; after evaporation
again, the metals were dissolved by a 5% nitric
acid solution vrv.. The metal concentration
measured for the certified materials CRM 277
and Soil-7 Table 1., guarantee the analytical
results of this study. Additionally, X-ray diffraction
analysis, scanning electron microscopy and
optic microscopy were performed in grinding
sediment samples for assessing mineral composition
and grain size.