Bioremediation of chromate-contaminated groundwater by reduction and precipitation in surface soils

• Published in: Journal of environmental quality Vol. 23; no. 6; pp. 1141 - 1150
• Main Authors: Losi, M E, Amrhein, C, Frankenberger, W T
• Format: Journal Article
• Language: English
• Published: Madison American Society of Agronomy 01.11.1994
• Subjects: Bioremediation; Groundwater pollution; Medicago sativa; Soil surfaces
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq1994.00472425002300060003x

The ability of soil to remove chromate from contaminated water was investigated by a glasshouse experiment in which samples of mixed thermic Typic Torripsamments soil were amended with 0, 12 and 50 Mg dried cattle manure per ha, planted with alfalfa (Medicago sativa) and irrigated under 4 different schemes for 20 weeks with water containing 1000 ug chromium(VI) per litre. Analysis of weekly samples of drainage water showed that chromium removal rates ranged from 51 per cent in unamended soil to up to 98 per cent in organic matter (OM)-amended soil. High-frequency (daily) irrigation increased the residence time of water in the bioreactive zone resulting in higher rates of chromium reduction/immobilization than weekly irrigation. Chromium removal increased with OM loading and the leachate chromium concentration was consistently below 50 ug per litre in the 50 Mg OM per ha treatments. The presence of alfalfa plants appeared to inhibit chromium reduction in OM-amended soils and alfalfa shoots took up less than 0.5 per cent of total added chromium. The proposed method could provide a cost-effective treatment for chromium-contaminated groundwater and longer-term field studies are recommended.