Impact of an urban effluent on the bacterial community structure in the Arga River (Spain), with special reference to culturable Gram-negative rods

Citation
M. Goni-urriza et al., Impact of an urban effluent on the bacterial community structure in the Arga River (Spain), with special reference to culturable Gram-negative rods, CAN J MICRO, 45(10), 1999, pp. 826-832
Citations number
37
Categorie Soggetti
Biotecnology & Applied Microbiology",Microbiology
Journal title
CANADIAN JOURNAL OF MICROBIOLOGY
ISSN journal
00084166 → ACNP
Volume
45
Issue
10
Year of publication
1999
Pages
826 - 832
Database
ISI
SICI code
0008-4166(199910)45:10<826:IOAUEO>2.0.ZU;2-R
Abstract
The Arga River is an interesting system in which to study the impact of urb an effluent pollution because it receives a single effluent in the form of wastewater discharge from the city of Pamplona. To analyze the extent of th is discharge, total bacteria, culturable heterotrophic bacteria, and Gram-n egative heterotrophic bacteria were enumerated and 409 isolates of the latt er were identified. One sampling station was located upstream from the infl ow, while five were located up to 30 km downstream. Bacterial counts increa sed drastically downstream from the wastewater inflow. Total bacterial numb ers decreased along the 30 km downstream, the last station attaining simila r values to those recorded upstream from the discharge. However culturable heterotrophic and Gram-negative heterotrophic bacteria levels generally rem ained significantly higher within the 30 km zone investigated. Among the 40 9 isolates identified, Aeromonas spp, were the most frequent both upstream and downstream from the discharge. In contrast, although strains belonging to different genera of Enterobacteriaceae were found in all stations, their occurrence was significantly higher just downstream from the polluted disc harge. Acinetobacter spp., which were never found upstream, were detected i n all stations below the discharge. Our results clearly show that the bacte rial community structure changes definitively downstream from the discharge and that Aeromonas were common throughout the sampling zone. Thus they can not be considered good indicators of pollution in this setting compared to some genera of Enterobacteriaceae or some species of Acinetobacter: the dis tribution of which correlated better with the distance from the wastewater discharge.