The molecular composition of soil organic matter as determined by 13C NMR and elemental analyses and correlation with pesticide sorption
Ahmad, R., Nelson, P.N., and Kookana, R.S. (2006) The molecular composition of soil organic matter as determined by 13C NMR and elemental analyses and correlation with pesticide sorption. European Journal of Soil Science, 57 (6). pp. 883-893.
|PDF (Published Version) - Repository staff only - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader|
View at Publisher Website: http://dx.doi.org/10.1111/j.1365-2389.20...
Although the chemical composition of soil organic matter (SOM) is known to significantly influence sorption of pesticides and other pollutants, it has been difficult to determine the molecular nature of SOM in situ. Here, using 13C nuclear magnetic resonance (NMR) data and elemental composition in a molecular mixing model, we estimated the molecular components of SOM in 24 soils from various agro-ecological regions. Substantial variations were revealed in the molecular nature of SOM. As a proportion of soil carbon the proportion of the carbonyl component ranged from 0.006 to 0.05, charcoal from 0 to 0.15, protein from 0.09 to 0.29, aliphatic from 0.14 to 0.30, carbohydrate from 0.21 to 0.31, and lignin from 0.05 to 0.42. The relationships between Koc (sorption per unit mass of organic carbon) of carbaryl (1-naphthyl methylcarbamate) and phosalone (S-6-chloro-2,3-dihydro-2-oxobenzoxazol-3-ylmethyl O,O-diethyl phosphorodithioate) and the molecular nature of organic matter in the soils were significant. Of the molecular components estimated, lignin and charcoal contents correlated best with sorption of carbaryl and phosalone. Aliphatic, carbohydrate and protein contents were found to be negatively correlated with the Koc of both pesticides. The study highlights the importance of the molecular nature of SOM in determining sorption affinities of non-ionic pesticides and presents an indirect method for sorption estimation of pesticides.
|Item Type:||Article (Refereed Research - C1)|
|Keywords:||soil chemistry; nuclear magnetic resonance; soil organic matter; environmental quality; pesticide fate|
|SEO Codes:||96 ENVIRONMENT > 9609 Land and Water Management > 960999 Land and Water Management of Environments not elsewhere classified @ 100%|
|Deposited On:||26 Nov 2009 11:28|
|Last Modified:||18 Oct 2013 00:32|
Last 12 Months: 0
|Citation Counts with External Providers:|
Repository Staff Only: item control page