Oxidation of phenolic acids by soil iron and manganese oxides

Conference · · Soil Sci. Soc. Am. J.; (United States)

OSTI ID:5926727

Lehmann, R G; Cheng, H H; Harsh, J B

Phenolic acids are intermediary metabolites of many aromatic chemicals and may be involved in humus formation, allelopathy, and nutrient availability. Depending on their structures, six phenolic acids were shown to react at different rates with oxidized forms of Fe and Mn in a Palouse soil (fine-silty, mixed, mesic Pachic Ultic Haploxeroll). Increasing methoxy substitution on the aromatic ring of phenolic acids increased the reaction rate. Reaction rate was also increased for longer carboxyl-containing side chains. After 4 h reaction, little of the applied (10 mg kg/sup -1/ soil) p-hydroxybenzoic or p-coumaric acids had reacted, while 0 to 5, 70, 90, and 100% of the vanillic, ferulic, syringic, and sinapic acids, respectively, had reacted. After 72 h under conditions limiting microbial growth, none of the p-hydroxybenzoic, 30% of the p-coumaric, and 50% of the vanillic acids had reacted. The reaction was shown to be predominantly chemical, and not biological, since phenolic acid extractabilities were similar for Palouse soil and for Palouse soil pretreated with LiOBr to remove organic matter. When the Palouse soil was pretreated with a sodium dithionite-citrate solution to remove Fe and Mn oxides, none of the phenolic acids reacted after 1 h. The reaction of sinapic acid with Palouse soil was shown to produce Fe(II) and soluble Mn as reaction products. The reaction of phenolic acids with soil was thus shown to be an oxidation of the phenolic acids, coupled with a reduction of soil Fe and Mn oxides.

• Research Organization: Washington State Univ., Pullman
• OSTI ID: 5926727
• Report Number(s): CONF-871180-
• Conference Information: Journal Name: Soil Sci. Soc. Am. J.; (United States) Journal Volume: 51:2
• Country of Publication: United States
• Language: English

Related Subjects

510200 -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AROMATICS
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
HUMUS
HYDROXY COMPOUNDS
IRON COMPOUNDS
IRON OXIDES
MANGANESE COMPOUNDS
MANGANESE OXIDES
METABOLITES
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PHENOLS
SOIL CHEMISTRY
TOXICITY
TRANSITION ELEMENT COMPOUNDS