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Assessing nickel bioavailability in smelter-contaminated soils
Jeffrey L Everhart1, David McNear, Edward Peltier
1Department of Plant and Soil Sciences, University of Delaware, Newark, DE 19717, USA. everhart_jeff@yahoo.com
The Science of the Total Environment
|February 28, 2006
Summary
Liming soils reduces nickel (Ni) bioavailability to plants and microbes, but increases Ni uptake in hyperaccumulating plants. A bacterial biosensor effectively predicts Ni bioavailability across different soil conditions.
Area of Science:
- Environmental Science
- Soil Science
- Environmental Chemistry
Background:
- Industrial pollution releases metal contaminants into soils, necessitating research on their bioavailability and health risks.
- Understanding metal contaminant availability to plants and microbes is crucial for human health and effective remediation strategies.
- Existing research on metal sorption in soils needs complementary studies on metal bioavailability.
Purpose of the Study:
- To investigate nickel (Ni) bioavailability in contaminated soils treated with limestone.
- To compare Ni accumulation in oat (Avena sativa) and Alyssum murale, and assess Ni bioavailability using a bacterial biosensor.
- To evaluate the effectiveness of liming and a bacterial biosensor in predicting Ni bioavailability.
Main Methods:
- Greenhouse studies using Welland Loam and Quarry Muck soils with varying pH, organic matter, and Ni concentrations.
- Cultivation of oat (Avena sativa) and Alyssum murale for Ni accumulation assessment.
- Application of a Ni-specific bacterial biosensor and chemical extraction techniques (MgCl2, Sr(NO3)2) for bioavailability determination.
Main Results:
- Increased soil pH due to liming correlated with decreased Ni bioavailability across all assessment methods.
- Alyssum murale showed increased Ni phytoextraction with higher soil pH, while Avena sativa did not.
- The Ni-specific bacterial biosensor accurately predicted Ni bioavailability, identifying higher availability at pH 5.1 and 6.
Conclusions:
- Liming effectively reduces Ni bioavailability in contaminated soils, but its effect on plant uptake varies by species.
- A Ni-specific bacterial biosensor is a reliable tool for assessing Ni bioavailability in diverse soil conditions.
- Integrated approaches combining plant growth, chemical extraction, and biosensor methods are recommended for comprehensive toxic metal bioavailability assessment.