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Use of CAH-degrading bacteria as test-organisms for evaluating the impact of fine zerovalent iron particles on the anaerobic subsurface environment
- Source :
- Chemosphere. 134:338-345
- Publication Year :
- 2015
- Publisher :
- Elsevier BV, 2015.
-
Abstract
- The release of fine zerovalent iron (ZVI) particles in the environment after being introduced for in-situ treatment of compounds like chlorinated aliphatic hydrocarbons (CAHs) may raise questions toward environmental safety, especially for nanoscale materials. Classical single-species ecotoxicity tests do focus on aerobic conditions and are only relevant for the scenario when ZVI-particles reach surface water. Herein, we present an alternative approach where a CAH-degrading mixed bacterial culture was used as test-organisms relevant for the anaerobic subsurface. The impact of different ZVI particles on the bacterial culture was evaluated mainly by quantifying ATP, a reporter molecule giving a general indication of the microbial activity. These lab-scale batch tests were performed in liquid medium, without protecting and buffering aquifer material, as such representing worst-case scenario. The activity of the bacterial culture was negatively influenced by nanoscale zerovalent iron at doses as low as 0.05 g Lā1. On the other hand, concentrations up to 2 g Lā1 of several different types of microscale zerovalent iron (mZVI) particles stimulated the activity. However, very high doses of 15ā30 g Lā1 of mZVI showed an inhibiting effect on the bacterial community. Negative effects of ZVIs were confirmed by H2 accumulation in the batch reactors and the absence of lactate consumption. Observed inhibition also corresponded to a pH increase above 7.5, explicable by ZVI corrosion that was found to be dose-dependent. The obtained results suggest that low doses of mZVIs will not show severe inhibition effects on the microbial community once used for in-situ treatment of CAHs.
- Subjects :
- Environmental Engineering
Halogenation
Iron
Health, Toxicology and Mutagenesis
Environment
PH increase
Corrosion
Environmental Chemistry
Anaerobiosis
Groundwater
Environmental Restoration and Remediation
Zerovalent iron
Bacteria
biology
Chemistry
Public Health, Environmental and Occupational Health
General Medicine
General Chemistry
biology.organism_classification
Pollution
Hydrocarbons
Biodegradation, Environmental
Microbial population biology
Environmental chemistry
Ecotoxicity
Anaerobic exercise
Surface water
Water Pollutants, Chemical
Subjects
Details
- ISSN :
- 00456535
- Volume :
- 134
- Database :
- OpenAIRE
- Journal :
- Chemosphere
- Accession number :
- edsair.doi.dedup.....caed10afc634bd5545e95335f8fdd051