Equilibrium metal concentration at zero net sorption (EMC{sub 0}): A new concept
- Univ. of British Columbia, Vancouver, British Columbia (Canada). Dept. of Soil Sciences
Heavy metals in soils and waters are of environmental concerns. Since total concentration of a metal in soil is not directly related to its bioavailability, soil tests rely on measurement of extractable or labile fractions of metals. However, reagents used in the measurements are significantly different from natural waters entering soils in terms of ionic strength, acidity, and heavy metal concentration, making the direct interpretation of test results difficult if correlation between chemical test data and plant response in the field is not available. It is suggested that EMC{sub 0} be used as an indicator of heavy metal status in soils. EMC{sub 0} can be determined as follows: solutions with various metal concentrations (C{sub 0}) in 0.005 M CaCl{sub 2} matrix are added to soil samples at a fixed soil/solution ratio. The suspensions are shaken 24 hrs to achieve equilibrium, and centrifuged. Metal concentrations in supernatants are analyzed and plotted against C{sub 0}. A regression line based on plotted data an da 1:1 line are drawn. The X-axis value corresponding t the intersection of the liens is EMC{sub 0}. At the intersection, metal concentration at equilibrium equals that in the initial solution; indicating net sorption of the metal is zero. A EMC{sub 0} value of 0.27 mg/kg Zn was determined in a soil sample from the Fraser Valley in British Columbia. The soil received heavy applications of poultry manure.This value is much greater than water soluble Zn (0.06 mg/kg) of the sample. The significance of EMC{sub 0} is when concentrations of a metal in natural waters are less than EMC{sub 0}, soil will release the metal to soil solution. EMC{sub 0} may be useful in comparing relative degrees of contamination in contaminated soils.
- OSTI ID:
- 398234
- Report Number(s):
- CONF-9511137-; ISBN 1-880611-03-1; TRN: IM9649%%442
- Resource Relation:
- Conference: 2. Society of Environmental Toxicology and Chemistry (SETAC) world conference, Vancouver (Canada), 5-9 Nov 1995; Other Information: PBD: 1995; Related Information: Is Part Of Second SETAC world congress (16. annual meeting): Abstract book. Global environmental protection: Science, politics, and common sense; PB: 378 p.
- Country of Publication:
- United States
- Language:
- English
Similar Records
Metal accumulation in corn and barley grown on a sludge-amended Typic Ochraqualf
Metal Adsorbance in Abattoir Wastewater Using Cross-Linked Chitosan Derivatives