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Geochemical and Hydrological Reactivity of Heavy Metals in Soils - Chapter 2

Điều khiển khoáng sản trong keo-Giao thông vận tải trung gian của kim loại trong môi trường đất Trong những năm gần đây, không thích hợp xử lý chất thải khác nhau đã đặt ra mối đe dọa nghiêm trọng đến bề mặt và nguồn nước ngầm và phát triển thành quy mô toàn cầu một vấn đề ô nhiễm đất và nước [1]. | 2 Mineral Controls in Colloid-Mediated Transport of Metals in Soil Environments A.D. Karathanasis CONTENTS 2.1 Introduction 2.2 Case Study 1 2.2.1 Metal Solutions and Colloid Suspensions 2.2.2 Soil Monoliths 2.2.3 Leaching Experiments 2.2.4 Eluent Characterization 2.2.5 Colloid Elution 2.2.6 Metal Transport 2.3 Case Study 2 2.3.1 Metal Solutions and Colloid Suspensions 2.3.2 Soil Monoliths 2.3.3 Leaching Experiments 2.3.4 Colloid Elution 2.3.5 Elution of Desorbed Pb 2.4 Case Study 3 2.4.1 Metal Solutions and Biosolid Colloid Fractions 2.4.2 Leaching Experiments 2.4.3 Biosolid Colloid Elution 2.4.4 Metal Elution 2.5 Summary 2.6 Conclusions References 2003 by CRC Press LLC 2.1 INTRODUCTION In recent years improper disposal of various waste materials has posed serious threats to surface and groundwater supplies and developed into a global scale soil and water pollution problem 1 . Heavy metals account for much of the contamination found at hazardous waste sites in the United States and have been detected in the soil and groundwater at approximately 65 of the U.S. Environmental Protection Agency Superfund sites 2 . Dramatic increases in land application of agricultural and municipal biosolids have accentuated the problem. In spite of their beneficial contributions as nutrient sources and soil conditioners these amendments if not monitored pose a considerable environmental risk because of their high heavy-metal concentrations 3 . Traditionally hydrophobic environmental contaminants such as heavy metals were assumed to be relatively immobile in subsurface soil environments because they are strongly sorbed by the soil matrix. However under certain conditions colloid particles may exceed ordinary transport rates and pose a significant threat to surface and groundwater quality. This threat has been substantiated by recent research evidence showing that water-dispersed colloidal particles migrating through soil macropores and fractures can significantly enhance metal .