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Chromium speciation in a contaminated groundwater: redox processes and temporal variability
Asirvatham Ramesh Kumar1, Patel Riyazuddin
1Chemical Laboratory, South Eastern Coastal Region, Central Ground Water Board, E1, Rajaji Bhavan, Besant Nagar, Chennai, 600 090, India.
Environmental Monitoring and Assessment
|July 28, 2010
Summary
Groundwater chromium levels, including chromium(VI) and chromium(III), varied seasonally in a tannery area. Post-monsoon periods showed more oxidizing conditions and shifts in chromium species ratios.
Area of Science:
- Environmental Science
- Geochemistry
- Water Quality
Background:
- Tannery operations release chromium species into groundwater.
- Understanding chromium speciation and redox processes is crucial for environmental risk assessment.
Purpose of the Study:
- To investigate temporal variations of chromium species (Cr(III), Cr(VI), Cr(III)-organic) in tannery-contaminated groundwater.
- To analyze redox processes influencing chromium speciation over pre- and post-monsoon seasons.
Main Methods:
- Groundwater samples were collected from 15 dug wells over three years (May 2004 - January 2007).
- Analysis included chromium species concentrations and other matrix constituents.
Main Results:
- Groundwater was more oxidizing during post-monsoon periods.
- Chromium species concentrations generally decreased in post-monsoon, but Cr(VI)/Cr(Total) ratio increased.
- Redox reactions involving Fe(II) and Mn(IV) likely influenced chromium temporal variations.
Conclusions:
- Seasonal variations significantly impact chromium speciation and redox states in contaminated groundwater.
- Oxidation-reduction processes play a key role in chromium behavior, affecting its environmental fate.
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