[Phage count in the waters of the Canal Imperial de Aragón and the Ebro River in Saragossa].

Saragossa city supply channel and the river Ebro (up and downstream urban sewage) were studied for the presence of coliphages and B. fragilis phages and their relationship with the bacterian faecal indicators. In the supply channel the coliphages geometric mean was of 130 ufp/100 ml, and showed no correlation with faecal and total coliforms, but it showed indirect correlation with ambient temperature. In the river Ebro the coliphages geometric mean ranged from 290 to 8,000 ufp/100 ml; the relationship with total and faecal coliforms and faecal streptococci was high, but they were temperature independent. With the methodology utilized B. fragilis phages only were recovered in samples with faecal coliforms levels > 1 x 10(4) ufc/100 ml.