Soil Quality Standards for Trace Elements: Derivation, Implementation, and Interpretation

Contents......Page 8
List of Figures......Page 12
List of Tables......Page 14
Acknowledgments......Page 16
About the Editors......Page 18
Workshop Participants......Page 20
1.1 Introduction to the Workshop......Page 22
1.2 Deriving, Implementing, and Interpreting SQS for TEs......Page 24
References......Page 26
2.2.1 Background Concentrations......Page 28
2.2.2 How Soils Affect the Availability and Toxicity of Added TEs......Page 33
2.3 Conceptual Model of the Soil-Organism System......Page 34
2.4 Implications for Setting Soil Quality Standards......Page 36
2.5 Models of TE Uptake and Toxicity to Soil Organisms......Page 37
2.6.1 The Free Ion Activity Model and Biotic Ligand Model......Page 38
2.6.3 The Free Ion Approach......Page 43
2.7 Empirical Toxicity Models......Page 44
2.8 Direct Measurement of TE Pools......Page 47
2.9 Consideration of Modifying Soil Factors in Soil Quality Standards......Page 51
2.9.1 Differences between Laboratory and Field Conditions in Ecotoxicity Studies......Page 54
2.10 Effects of Spiking Soils with Soluble TE Salts on Soil Solution Chemistry and Toxicity Measurements......Page 55
2.11 Minimizing Spiking-Induced Artifacts in the Laboratory......Page 57
2.12 Correction Factors for Existing Toxicity Data......Page 58
2.13 Recommended "Best Practice" TE Dosing in Laboratory Ecotoxicity Experiments......Page 59
2.14 Biotic Factors Affecting Organism Response to TE Dose......Page 60
2.14.1 Quantity and Quality of the Ecotoxicological Data......Page 61
2.14.3 Taxonomic Diversity Needed......Page 64
2.14.4 Selection of Species......Page 65
2.14.5 Appropriateness of Toxicity Endpoints......Page 71
2.14.6 Type of Ecotoxicity Data......Page 72
2.14.7 Use of Acute and Chronic Data......Page 73
2.14.8 Dealing with Multiple Toxicity Data for Species......Page 74
2.14.9 Choice of Distribution for SSD......Page 75
2.14.10 Level of Protection to Be Provided......Page 76
2.14.12 Mixture Considerations......Page 77
2.14.13 Secondary Poisoning......Page 82
2.15.1 Modeling......Page 84
2.15.2 Measurement......Page 86
References......Page 87
3.1 Introduction......Page 102
3.2.2 Comparison among Jurisdictions......Page 103
3.2.3 Proportion of Total Exposure Allocated to Background......Page 104
3.3 Inhalation......Page 106
3.3.2 Particle Deposition......Page 107
3.3.3 Toxicity......Page 109
3.4 Soil Ingestion......Page 110
3.4.1 Recommended Soil Ingestion Values for Children Based on Tracer Studies......Page 112
3.4.2 Recommended Soil Ingestion Values for Adults Based on Tracer Studies......Page 114
3.5 Food Chain Exposure......Page 115
3.5.2 Dietary Preferences......Page 116
3.5.3 Soil-Plant Transfer......Page 117
3.6 Statistical Characterization of Exposure......Page 119
3.6.1 Probabilistic versus Deterministic Assessments......Page 120
3.6.2 Uncertainty Factors......Page 121
3.7 Essential TEs......Page 122
3.7.1 Homeostasis and the Setting of SQSs......Page 123
3.7.2 Dose-Response Relationships for Essential Elements......Page 124
3.7.3 Interaction of Essential and Nonessential TEs......Page 125
3.8 Bioavailability and Bioaccessibility......Page 126
3.8.1 Use of In Vitro Gastrointestinal Methods to Estimate TE Bioavailability......Page 129
3.9.1 Benchmark Dose versus NOAEL/LOAEL......Page 131
3.9.2 Bridging Ambient Exposure to Literature Doses......Page 132
3.9.3 Sensitive Subpopulations......Page 134
3.10 Summary and Conclusions......Page 135
References......Page 137
4.1 Introduction......Page 144
4.2 The Use of Soil Quality Standards......Page 145
4.3 Frameworks for the Implementation and Use of SQSs for TEs......Page 147
4.4 Accounting for Ambient Background Concentrationsin the Implementation of TE SQSs......Page 148
4.5 Accounting for (Bio)availability in the Derivation of TE SQSs......Page 151
4.6 Accounting for Mixtures of TEs in Regulatory Frameworks......Page 154
4.8 Data Sources......Page 155
4.9 Communication......Page 156
References......Page 157
5.1 Introduction......Page 162
5.2 Soil Quality Standards for TEs and Best Practice......Page 163
References......Page 165
Abbreviations......Page 166