Page 153 - Partition & Adsorption of Organic Contaminants in Environmental Systems

144 CONTAMINANT SORPTION TO SOILS AND NATURAL SOLIDS

Marlette soil

Helena Mississippi
Spectral Intensity
River sediment

Spectacle Island
sediment

Fort Point Channel
sediment

400 200 0 -200
Chemical Shift (ppm)
13
Figure 7.15 Solid-state C-NMR spectra of selected soil and sediment samples. [Data
from Kile et al. (1999).]

comparisons (Figure 7.15). Analyses of the spectra of a number of “clean” soils
and freshwater sediments (including those not reported here) indicate that the
soils generally have higher combined fractions of polar O-alkyl and carboxyl-
amide-ester components than the sediments. The aromatic carbon fractions
observed (110 to 160ppm) fall largely into the range of 26 ± 8% for both soils
and sediments; there is no clear pattern that the sediments exhibit higher aro-
matic fractions. For Marlette soil and Helena Mississippi River sediment, the
aromatic carbon fractions are about 20% and 33%, respectively, which include
all aromatic carbons with polar and nonpolar groups and other unsaturated
carbons. The respective carbon fractions for polar O-alkyl (45 to 110ppm) and
carboxyl-amide-ester (160 to 200ppm) groups other than phenols (140 to
160ppm) are 56% and 35%, respectively. The difference in alkyl carbon
content between the samples is relatively minor (25% versus 33%). The higher
K oc values of PAHs on Helena Mississippi River sediment than on Marlette