Ahangar Ahmad Gholamalizadeh, Smernik Ronald J, Kookana Rai S, Chittleborough David J
Soil and Land Systems, School of Earth and Environmental Sciences, The University of Adelaide, Waite Campus, Urrbrae, SA 5064, Australia.
Chemosphere. 2008 Jun;72(6):886-90. doi: 10.1016/j.chemosphere.2008.03.059. Epub 2008 May 13.
Even though it is well established that soil C content is the primary determinant of the sorption affinity of soils for non-ionic compounds, it is also clear that organic carbon-normalized sorption coefficients (K(OC)) vary considerably between soils. Two factors that may contribute to K(OC) variability are variations in organic matter chemistry between soils and interactions between organic matter and soil minerals. Here, we quantify these effects for two non-ionic sorbates-diuron and phenanthrene. The effect of organic matter-mineral interactions were evaluated by comparing K(OC) for demineralized (HF-treated) soils, with K(OC) for the corresponding whole soils. For diuron and phenanthrene, average ratios of K(OC) of the HF-treated soils to K(OC) of the whole soils were 2.5 and 2.3, respectively, indicating a substantial depression of K(OC) due to the presence of minerals in the whole soils. The effect of organic matter chemistry was determined by correlating K(OC) against distributions of C types determined using solid-state (13)C NMR spectroscopy. For diuron, K(OC) was positively correlated with aryl C and negatively correlated with O-alkyl C, for both whole and HF-treated soils, whereas for phenanthrene, these correlations were only present for the HF-treated soils. We suggest that the lack of a clear effect of organic matter chemistry on whole soil K(OC) for phenanthrene is due to an over-riding influence of organic matter-mineral interactions in this case. This hypothesis is supported by a correlation between the increase in K(OC) on HF-treatment and the soil clay content for phenanthrene, but not for diuron.
尽管土壤碳含量是土壤对非离子化合物吸附亲和力的主要决定因素这一点已得到充分证实，但很明显，有机碳归一化吸附系数（K(OC)）在不同土壤之间差异很大。导致K(OC)变异性的两个因素是土壤间有机质化学性质的差异以及有机质与土壤矿物质之间的相互作用。在此，我们对两种非离子吸附质——敌草隆和菲，量化了这些影响。通过比较脱矿质（氢氟酸处理）土壤的K(OC)与相应全土的K(OC)，评估了有机质 - 矿物质相互作用的影响。对于敌草隆和菲，氢氟酸处理土壤的K(OC)与全土的K(OC)的平均比值分别为2.5和2.3，这表明由于全土中矿物质的存在，K(OC)大幅降低。通过将K(OC)与使用固态（13）C核磁共振光谱法测定的碳类型分布相关联，确定了有机质化学性质的影响。对于敌草隆，无论是全土还是氢氟酸处理土壤，K(OC)与芳基碳呈正相关，与O - 烷基碳呈负相关，而对于菲，这些相关性仅存在于氢氟酸处理土壤中。我们认为，在这种情况下，对于菲而言，有机质化学性质对全土K(OC)缺乏明显影响是由于有机质 - 矿物质相互作用的主导影响。这一假设得到了菲在氢氟酸处理后K(OC)的增加与土壤粘土含量之间的相关性支持，但敌草隆不存在这种相关性。
