The metabolic and genetic diversity of phenol-utilizing 119 bacterial strains isolated from the rivers polluted by ash dump leachate in Kohtla-Jarve, Estonia, has been studied Of eighteen different bacterial species identified, 82 % belong to the genus P s e u d o m o n a s. Comparison of genetic (phenol monooxygenase /PMO/ and catechol 2,3-dioxygenase /C230/ gene probes) and biochemical (PMO, C230, catechol 1,2-dioxygenase and protocatechuate 3,4-dioxygenase activities) data with species of isolated bacteria shows that in different polluted regions of the rivers different P s e u d o m o n a s f l u o r e s c e n s biotypes and P s. m e n d o c i n a are predominant and they harbor characteristic genetic traits. The incidence of plasmid-bearing bacteria is much higher in phenol-polluted waters (up to 81 % of the strains) than in nonpolluted river waters (38 %). We found three main types of induction of aromatic ring-fission pathways among the isolated phenol-growing bacteria which also grow on p-cresol. Some new bacterial isolates, such as P s. fluorescens strains MT4/4 and I16 revealed even higher biodegradation capabilities of volatile phenols in leachate than laboratory-selected phenol-growing bacteria.