Transport and Fate of Polycyclic Aromatic Hydrocarbons in Soil-Plant System

Preface

PART I SOIL
Chapter 1 The forms and availability of PAHs in soil3
1.1 The forms of PAHs in soil3
1.1.1 Fractionation methods of PAH residues in soil4
1.1.2 Desorbing fraction of PAHs in soil5
1.1.3 Non-desorbing fraction of PAHs in soil7
1.1.4 Bound residues of PAHs in soil10
1.2 The availability of PAHs in soil12
1.2.1 Available fractions of PAHs in soils as a function of aging time13
1.2.2 Microbial degradation of available fractions of PAHs in soils15
1.2.3 Transformation of available fraction of PAHs to bound residue in soils17
1.2.4 Butanol-extraction technique for predicting the availability of PAHs in soil18
1.2.5 Phytoavailability of bound-PAH residues in soils18
Chapter 2 Gradient distribution of PAHs in rhizosphere soil24
2.1 Gradient distribution of PAHs in rhizosphere soil: a greenhouse experiment25
2.1.1 Gradient distribution of phenanthrene and pyrene in rhizosphere26
2.1.2 Gradient distribution of root exudates in rhizosphere27
2.1.3 The correlations of PAH concentration gradient with the conc entration gradient of root exudates in rhizosphere30
2.2 In situ gradient distribution of PAHs in rhizosphere soil: a field study33
2.2.1 In situ gradient distribution of PAHs in rhizosphere soil34
2.2.2 Rhizosphere effects on PAH distribution in soil37
2.3 Rhizospheric gradient distribution of bound-PAH residues in soils40
2.3.1 Gradient distribution of bound-PAH residues in rhizosphere41
2.3.2 Mechanism of rhizospheric gradient distribution of bound-PAH residues in soils46
Chapter 3 Partition of PAHs among soil， water and plant root48
3.1 Sorption of PAHs by soils with heavy metal co-contaminants49
3.1.1 Sorption isotherms of phenanthrene by soils50
3.1.2 Sorption of phenanthrene by heavy metal-contaminated soils52
3.1.3 Mechanisms of the heavy metal enhanced-sorption of phenanthrene by soils53
3.2 Dissolved organic matter （DOM） influences the partition of PAHs between soil and water57
3.2.1 Effect of inherent DOM on phenanthrene sorption by soils59
3.2.2 Effect of exotic DOM on phenanthrene sorption by soils63
3.3 Partition of polycyclic aromatic hydrocarbons between plant root and water67
3.3.1 Partition of phenanthrene between roots and water68
3.3.2 Estimation of partition coefficient of phenanthrene between root and water using a position model70
3.3.3 Partition of phenanthrene between root cell walls and water71
Chapter 4 Impact of root exudates on the sorption， desorption and availability of PAHs in soil73
4.1 Impact of PAHs on root exudate release in rhizosphere73
4.1.1 Impact of PAH contamination levels on root exudation in rhizosphere74
4.1.2 Distribution of root exudates in different layers of rhizosphere soil77
4.2 Impact of root exudates on PAH sorption by soils77
4.2.1 Root exudate ponent-influenced sorption of PAH by soil78
4.2.2 Mechanism discussions80
4.3 Impact of root exudates on PAH desorption from soils83
4.3.1 Desorption of PAHs from soils as a function of root exudate concentration84
4.3.2 PAH desorption by root exudates in different soils86
4.3.3 Effects of soil aging on PAH desorption by root exudates from soil87
4.3.4 Desorption of different PAHs by root exudates in soil88
4.3.5 Impact of root exudate ponents on PAH desorption in soil89
4.3.6 Dissolved organic matter in soils with the addition of root exudates90
4.4 Impact of root exudates on PAH availabilities in soils92
4.4.1 Impact of root exudates on n-butanol-extractable pyrene in soil93
4.4.2 Impact of root exudate ponents on the n-butanol-extractable pyrene in soil95
4.4.3 Mechanisms by which root exudate and its ponents influence PAH availa-bility in soil98
Chapter 5 Low-molecular-weight organic acids （LMWOAs） influence the transport and fate of PAHs in soil101
5.1 LMWOAs-influence the PAH sorption by different soil particle size fractions102
5.1.1 Fractionation protocol of different soil particle size fractions103
5.1.2 PAH sorption by different soil particle size fractions106
5.1.3 Effects of LMWOAs on PAH sorption by different soil particle size fractions108
5.1.4 Mechanisms of LMWOA-influenced PAH sorption by different soil particle size fractions109
5.2 LMWOAs enhance the PAH desorption from soil114
5.2.1 LMWOA-enhanced desorption of PAH from PAH-spiked soil115
5.2.2 LMWOA-enhanced desorption of PAHs from soils collected from a PAH- contaminated site118
5.2.3 Mechanisms of LMWOA-enhanced desorption of PAHs from soils124
5.3 Impact of LMWOAs on the availability of PAHs in soil127
5.3.1 Impact of LMWOAs on the butanol-extractable PAHs in soils128
5.3.2 Mechanism discussions132
5.4 Elution of soil PAHs using LMWOAs133
5.4.1 Elution of PAHs in soil columns by LMWOAs135
5.4.2 Distributions of PAHs in soil columns136
5.4.3 Butanol-extractable and nonextractable PAHs in soil