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Despite the steady growth in the organic sector in recent years, it remains a fledgling research area, particularly in Western Canada. Most of the information on the benefits and impacts of organic agriculture is based on research from Europe, and there has been comparatively little research focused on the contribution of organic production to sustainable agriculture in the Canadian context. While many recognize the intuitive appeal of organic agriculture as a low-input, holistic alternative to conventional production systems, serious questions remain about its long-term sustainability. . | ENVIRONMENTAL AND ECOLOGICAL CHEMISTRY - Vol. III - Pathways of Organic Chemical Contamination in Ecosystems - Padma T. Venkatraman PATHWAYS OF ORGANIC CHEMICAL CONTAMINATION IN ECOSYSTEMS Padma T. Venkatraman College of William and Mary USA Keywords Persistent Organic Pollutants Global transport Enantiomer ratios Stable isotopes. Contents 1. Introduction 2. Sources and Input of Organic Pollutants to the Environment 2.1. Diffusive versus Point Sources 2.2. Important Classes of Organic Pollutants 2.3. Degradable versus Persistent Pollutants 2.4. Pollutants of Emerging Concern 2.5. Compounds and Mixtures 3. Transport pathways within ecosystems 3.1. Effect of Chemical Properties 3.2. Environmental Factors Affecting Transport 4. Degradation pathways 4.1. Photodegradation 4.2. Hydrolysis 4.3. Biodegradation 5. Spatial scales of pollutant transport pathways 5.1. Local Transport 5.2. Regional Transport 5.3. National Scale 5.4. Continental Scale 5.5. Global Transport 5.5.1. Evidence in Support of Global Distillation 5.5.2. Cold Condensation and Accumulation 5.5.3 Significance of Global Transport 6. Use of geochemical tracers to track contaminant pathways through ecosystems 6.1. Isomer Ratios 6.1.1. Measurement of Isomer Ratios 6.1.2. Use of Isomer Ratios to Study Contaminant Pathways 6.2. Enantiomer Ratios 6.2.1. Measurement of Enantiomer Ratios 6.2.2. Use of Enantiomer Ratios to Study Contaminant Pathways 6.3. Stable Isotope Ratios 6.3.1. Measurement of Stable Isotope Ratios 6.3.2. Use of Elemental Stable Isotope Ratios to Study Contaminant Pathways 6.3.3. Use of Compound Specific Stable Isotope Ratios CSIRs to Study Contaminant Pathways 7. Future directions Encyclopedia of Life Support Systems EOLSS ENVIRONMENTAL AND ECOLOGICAL CHEMISTRY - Vol. III - Pathways of Organic Chemical Contamination in Ecosystems - Padma T. Venkatraman 8. Conclusions Acknowledgements Glossary Bibliography Biographical Sketch Summary This chapter examines the fate transport and degradation .