TY - JOUR

T1 - Heavy metal binding by hydrophobic and hydrophilic dissolved organic carbon fractions in a Spodosol A and B horizon

AU - Guggenberger, Georg

AU - Glaser, Bruno

AU - Zech, Wolfgang

PY - 1994/1

Y1 - 1994/1

N2 - For a one year period intact Spodosol soil columns were percolated weekly with H2Odeion, 1.58 mmol H2SO4 L-1, and 0.79 mmol H2SO4 L-1+0.64 mmol HNO3 L-1, respectively. Decomposition rates, soil organic carbon (OC) solubilization, dissolved organic carbon (DOC) fractions, and Cr-, Cu-, and Cd-binding by dissolved hydrophobic and hydrophilic acids were studied. Acid treatment reduced significantly OC respiration as well as OC solubilization in the humic layers. The reduced OC solubility at acid addition was more pronounced for the less polar hydrophobic compounds, resulting in a decrease of the hydrophobic acids (from ca. 65 to 40-45% of DOC), and in an increase of the hydrophilic acids (from ca. 25 to 40-45% of DOC). For B horizon leachates, DOC increased at acid treatment. Generally, hydrophobic acids were retained preferentially in the B horizon. Also in the B horizon output there was an increase of the hydrophilic acids as acidity increased (from ca. 40 to 50% of DOC). Differences between the two acid treatments were negligible. The degree of metal-organic complexes decreased in the order Cr >Cu >Cd, from A to B horizon leachates, and with increasing acidity. Hydrophilic acids were found to be the dominating ligands in complexing Cr and Cu. Actual Cr- and Cu-binding by hydrophilic acids exceeded that by hydrophobic acids 2-8 times. As the hydrophilic acids represented the most mobile DOC components in the soil columns, in particular with increasing acidity, significant amounts of Cr and Cu in the B horizon leachates were organically complexed, although a great proportion of the hydrophobic acids was retained in the B horizon.

AB - For a one year period intact Spodosol soil columns were percolated weekly with H2Odeion, 1.58 mmol H2SO4 L-1, and 0.79 mmol H2SO4 L-1+0.64 mmol HNO3 L-1, respectively. Decomposition rates, soil organic carbon (OC) solubilization, dissolved organic carbon (DOC) fractions, and Cr-, Cu-, and Cd-binding by dissolved hydrophobic and hydrophilic acids were studied. Acid treatment reduced significantly OC respiration as well as OC solubilization in the humic layers. The reduced OC solubility at acid addition was more pronounced for the less polar hydrophobic compounds, resulting in a decrease of the hydrophobic acids (from ca. 65 to 40-45% of DOC), and in an increase of the hydrophilic acids (from ca. 25 to 40-45% of DOC). For B horizon leachates, DOC increased at acid treatment. Generally, hydrophobic acids were retained preferentially in the B horizon. Also in the B horizon output there was an increase of the hydrophilic acids as acidity increased (from ca. 40 to 50% of DOC). Differences between the two acid treatments were negligible. The degree of metal-organic complexes decreased in the order Cr >Cu >Cd, from A to B horizon leachates, and with increasing acidity. Hydrophilic acids were found to be the dominating ligands in complexing Cr and Cu. Actual Cr- and Cu-binding by hydrophilic acids exceeded that by hydrophobic acids 2-8 times. As the hydrophilic acids represented the most mobile DOC components in the soil columns, in particular with increasing acidity, significant amounts of Cr and Cu in the B horizon leachates were organically complexed, although a great proportion of the hydrophobic acids was retained in the B horizon.

UR - http://www.scopus.com/inward/record.url?scp=0028182134&partnerID=8YFLogxK

U2 - 10.1007/BF01257119

DO - 10.1007/BF01257119

M3 - Article

AN - SCOPUS:0028182134

VL - 72

SP - 111

EP - 127

JO - Water, Air, & Soil Pollution

JF - Water, Air, & Soil Pollution

SN - 0049-6979

IS - 1-4

ER -