| Title |
A study on heavy metal resistance of enterobacteria isolated from streams receiving municipal and industrial wastewater |
| Authors |
신정식 ; 박성배 ; 정용 ; 권숙표 ( Jung Sik Shin ; Sung Bae Park ; Yong Chung ; Sook Pyo Kwon ) |
| Abstract |
This study was performed to investigate the distribution of enterobacteria resistant to heavy metal compounds (Pb(II), Zn(II), Co(II), Te(II), Cr(VI), Cd(II), Hg(II))in the stream water and sediment receiving municipal and industrial wastewater. The results were as follows: 1. Similar numbers of total count, coliforms and fecal califorms were present in stream waters receiving either industrial or municipal wastewater. However, the higher numbers of those bacteria were present in the stream sediment receiving industrial wastewater. The concentrations of Pb(II), Zn(II), Cr(VI), Cd(II) and Hg(II) were higher in the stream sediment receiving industrial than municipal wastewater. 2. The higher number of heavy metal-resistant bacteria were present in the stream water receiving industrial wastewater. The percentage of enteric strain isolates survived in＞10^(-3)M concentrations of Pb(II) and Zn(II) was over 97% Among the enteric strains isolated from the stream receiving municipal wastewater, 25.3% of the river water isolates and 32.9% of the sediment isolates were survived in＞10^3M concenration of Co(II). The percentage of enteric strain survived in＞10^(-3)M concentrations of Cr(VI) was 1.0% and 2.9% for the river water and sediment isolates from the stream receiving municipal wastewater, and 7.8% and 11.7%, for those from the stream receiving industrial wastewater. Among the enteric strain isolates from the rever water and sediment, none was survived in＞10^3M concentrations of Cd(II) and Hg(II). Only 2 strains (1.1%) of the sediment isolates from the stream receiving industrial wastewater was survived. Generally the enteric strain isolates showed the highest resistance to Zn(II) and then Pb(II), Co(II), Te(II), Cr(VI), Cd(II) and Hg(II) in decreasing order. 3. Bacteria isolated from the river water and sediment were streaked on Muller Hinton agar containing 10^(-3)M concenrations of 7 heavy metal compounds with various combinations. Among the enteric strains isolated from the stream receiving municipal wastewater, 47.9% of the sediment isolates were survived in the media containing more than 2 heavy metal compounds. While, the survival ratio was 81.0% and 85.0% from those in the stream receiving industrial wastewater. |