|Lerch, Robert - Bob|
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/20/2007
Publication Date: 11/20/2007
Citation: Wu, S.H., Goyne, K.W., Lerch, R.N., Lin, C.H., Anderson, S.H. 2007. Adsorption of the isoxaflutole degradates to aluminum and iron hydrous oxides [abstract]. ASA-CSSA-SSSA Annual Meeting Abstracts. ASA-CSSA-SSSA Annual Meeting. November 4-8, 2007, New Orleans, LA. 288-1. Interpretive Summary:
Technical Abstract: Isoxaflutole is relatively new herbicide which rapidly hydrolyzes to a diketonitrile (DKN) degradate after field application. Subsequently, DKN is degraded to form a benzoic acid (BA) derivative and other inactive degradates. However, our understanding of soil solid phases influencing or governing the fate of DKN and BA in soils is still poor. Due to the anionic nature of DKN and BA in natural waters, we hypothesize that variable-charged minerals may be important adsorbents for isoxaflutole degradates. Our previous research indicated: (1) that DKN is adsorbed to hydrous aluminum and iron oxides (HAO and HFO, respectively); (2) DKN is adsorbed to HFO to a greater extent; and (3) slight hysteresis exists between DKN adsorption and desorption isotherms when the degradate is reacted with HAO. The objective of our current study is to: (1) examine the influence of soil mineral chemical composition (HAO and HFO) on BA adsorption and retention; (2) investigate the influence of pH on DKN and BA adsorption to HFO and HAO; and (3) elucidate the mechanism(s) of DKN and BA binding to metal hydrous oxide surfaces using FTIR spectroscopic investigations. Results from ongoing work will be presented, and comparisons/contrasts between DKN and BA interactions with HAO and HFO will be discussed.