The research was carried out on two different industrial wastes deposited on the premises of a chemical plant: used graphite electrode after electrolysis of brine applying the mercury-cathode method and coal catalyst past the usage period after the synthesis of vinyl chloride. The need for utilization of the waste necessitated development of a fast and reliable procedure for mercury determination. We have found procedures for mineralization of coal samples and determination of small concentrations of mercury by the cold vapour of atomic absorption spectrometry (CV AAS) in the available literature. Six procedures for passing mercury from the examined waste into solutions were tested, and mercury was assayed using the titration method of Wickbold and CV AAS. The results were evaluated statistically. It has been found that four ways to mineralize the examined industrial waste samples can be used.

Water and bottom sediment samples collected from a few fish-breeding ponds/reservoirs were subjected to tests. The aim of this paper was to determine the total content of aluminium and its fractions in the samples tested to estimate the potential risk to fish caused by the toxic forms of aluminium. The monomeric inorganic aluminium in waters was determined using the ion exchange and extraction-colorimetric method with oxychinoline according to Barnes's-Driscoll's procedure. The bottoms were fractionated using a three-step sequential extraction procedure and the microwave mineralisation. The total content of aluminium in waters and extracts was determined using the spectrophotometric method with eriochromocyanine R, and comparatively using the ICP OES technique. The results were subjected to statistical analysis. The level of concentration of labile Al in the waters about 26-34 μg/dm3 and content of exchangeable Al 5-34 mg/g range in bottom sediments are possibly hazardous to aquatic organisms.