Negative correlations between KOC for the HF-treated soils and
O-alkyl C and alkyl C are significant, but account for only 11%
and 17% of KOC variability, respectively. These negative correlations
may reflect a lower affinity of these carbon types for diuron, but
they may also be due to blocking of higher affinity sites by organic
matter constituents rich in these functional groups. Indeed,
Ahangar et al. (2009) found that removal of a lipid fraction rich
in alkyl C increased KOC for diuron and phenathrene, while
Mitchell and Simpson (2013) reported that removal of O-alkyl rich
organic matter also increased KOC.