Soil organic carbon amended soils

Tokunaga T.K., Wan J., Firestone M.K., Hazen T.C., Olson K.R., Herman D.J., Sutton S.R., Lanzirotti A. In situ reduction of chromium (VI) in heavily contaminated soils through organic carbon amendment. J Environ Qual 2003 32 1641-1649. 

Initial total PAH concentration 1.4g/kg Total petroleum hydrocarbons 5.7-7.0g/kg Sandy loam Organic carbon content 1.8% Soil moisture 80% of WHC Solid phase organic amendment Seech et al. (1994)... 

McDowell, W. H., W. S. Currie, J. D. Aber, and Y. Yano. 1998. Effects of chronic nitrogen amendment on production of dissolved organic carbon and nitrogen in forest soils. Water, Air and Soil Pollution 105 175-182. 

A number of indexes based on the distribution of organic C in humic and nonhumic fractions are used for the evaluation of the humification level in organic amendments and amended soils (Senesi, 1989). Among others these include the degree of humification (DH), which is calculated as DH% = 100 x (HAC + FAC)/ TEC the humification rate (HR), which is calculated as HR% = 100 x (HAC + FAC)/ TOC and the humification index (HI), which is calculated as HI = NHC/ (HAC + FAC) (Sequi et al., 1986 Ciavatta et al., 1988). TOC represents the total organic carbon in the sample TEC represents the total extractable C by an alkaline solution (NaOH and/or Na4P207) HAC and FAC represent the C content in HA and FA fractions, respectively and NHC represents the nonhumified C content calculated by difference, that is, NHC = TEC - (HAC + FAC). 

Table 3. Concentrations of LAS, NP, NPIEO, NP2EO, PCBs, and percent organic carbon in the sludge amended soil.

Fig.4. Concentrations of PCBs and percent organic carbon in sludge amended soil after the last sludge application.

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