Hydrochemistry and radioactivity in the rivers of Biscay (Spain)

For a research project on the evaluations of radioactive constituents in ecological segments of Biscay (Spain), nuclides in water of the main rivers and hydrochemical parameters (pH, conductivity, temperature, percentage of saturation in oxygen and chemical components) were measured. Radioactive data obtained after statistical treatment at 95% confidence level, were as follows; i) Total alpha and beta idexes with a gas flow detector on dry residues not greater than 2 and 10 mg/cm''2, respectively and ii) gamma emitters with a low level spectrometer (Ge-HP detector + 8000 channels analyser) on the dry residue of more than 8 litres and a counting period of 4 days. This paper include 28 samples from the following rivers: Nervion (10), Ibaizabal (5), Cadagua (8), Barbadun, Butron, Oca, Lea and Artibay. On the basis of average values, studied rivers are characterized as follows: Nervion (important amount of Cs. 137 and the greatest beta index), Ibaizabal (high K.40 contents), Cadagua (the biggest alpha index ) and low radionuclides concentrations in the other rivers. Finally, the application of multivariate statistical techniques, mainly cluster analysis, is tried to find out relations between chemical and radioactive constituents. (Author)