| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4408817 | Chemosphere | 2014 | 5 Pages |
•A biosensor is developed using thiosulfate oxidizing bacteria (TOB) for groundwater.•Primary detection of TOB activity is with increase in electrical conductivity (EC).•Increasing thiosulfate concentration (100–600 mg L−1) induced a lag period in EC rise.•SOB was inhibited by 16.7–100% in the presence of Cr6+ (50–1000 μg L−1).•Real groundwater (Cr6+ contaminated) with SOB has given EC50 of Cr6+ 78.96 μg L−1.
The effect of Cr6+-contaminated groundwater was assessed using thiosulfate-oxidizing bacteria (TOB). Electrical conductivity (EC), pH, and sulfate production were determined based on thiosulfate oxidation. Final pH values in the different test treatments of Cr6+-contaminated groundwater (50–1000 μg Cr6+ L−1) ranged from 2.02 ± 0.09 to 7.76 ± 0.07 and EC ranged from 5.95 ± 0.03 to 3.63 ± 0.03 mS cm−1. Inhibition of TOB due to Cr6+ was between 16.7% and 100%, with higher levels of inhibition occurring at higher Cr6+ concentrations. The median effective concentration (EC50) was 78.96 μg Cr6+ L−1. These data demonstrate that TOB can detect less than 100 μg L−1 of Cr6+ in the groundwater and can be used as an effective bioassay for toxicity assessment.
