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Public approval of an environmental analysis and impact assessment project is usually coupled with different conditions that the project is required to meet. Environmental impact assessment (EIA) constitutes an important basis for decisions regarding possible imposition of conditions. The main focus of the present chapter is to clarify the roles that EIAs can have in such decision-making processes.

The present chapter discusses and reviews the various types of environmental impacts (natural and man-made); the need for EIA data and its proper handling; the different environmental administrative procedures used in EIA projects; the EIA characteristics (in terms of their goals, impact indicators, impact estimation, applicability); the different EIA methods; and a general conceptual framework that could be applied to any environmental project.

Improved environmental performance in industry and society is a concept now a quarter-century old. Efforts in this regard have yielded much in the way of environmental improvement. It is easy to demonstrate that most of the activities of today's industrial society are unsustainable. Unfortunately, much of the talk about sustainability lacks a basic understanding of what truly sustainable activity would be. To set sustainability as a target or a goal for our industrial society, it is important to quantify that target or goal.

Currently, the transportation industry is under increasing pressure to use alternate or secondary materials because of its high-volume consumption of bulk materials (such as natural fine and coarse aggregates) in road construction. Materials including industrial by-products, concrete aggregates, old asphalt pavement, scrap tires, fly ash, steel slag, and plastics are often used as alternate materials for natural aggregates. As these products are not normal construction materials, there are concerns about their environmental suitability, recyclability and sustainability in concrete and road pavement applications, as well as their environmental impact on surface and ground waters.

The present chapter (a) evaluates the general concepts of sustainability, (b) reviews and evaluates the various types of solid wastes that are currently used as road construction and repair (C&R) materials, (c) discusses both the chemical and physical properties of such wastes and their engineering uses, and finally (d) presents the general project approaches of a major research program to investigate the environmental impact of highway C&R materials on surface and ground waters.

Scrap tires are a high-profile waste material. There are serious concerns over the ever-mounting scrap tire problem. A need exists for increasing available reuse measures to their full potential and developing new and feasible scrap tire reuse alternatives. The growing interest in utilizing waste materials in engineering applications has opened the possibility of constructing hydraulic structures with scrap tires. Applications of scrap tires in hydraulic engineering benefits the environment by reducing the waste, yet one may ask whether scrap tires leach compounds that may adversely affect the environment. Before uses of scrap tires in hydraulic engineering practices, it is important to consider and evaluate any possible environmental implications, for example, potential surface water pollution, and groundwater and soil contamination. This chapter focuses on state-of-the-knowledge about the reuses of scrap tires in hydraulic engineering projects and discusses existing and new utilization methods for potential source reduction, which may be effective in solving the waste tire problem. In this chapter, the problems associated with scrap tires are identified, the physical and chemical properties of tire material are summarized, existing scrap tire applications in hydraulic engineering are reviewed, new applications are developed and analyzed, technical and economic feasibilities are investigated, and environmental impact is assessed. Several case studies are presented.

The generation and disposal of biosolids produced at municipal wastewater treatment plants is a major environmental issue. Approximately 900 kg of biosolids on a dry basis are produced from the treatment of 1 million gallons of wastewater. These solids are typically dewatered on site and disposed of at landfills, incinerators or on agricultural fields. Disposal of sewage sludge on agricultural fields recycles the nutrients captured from municipal wastewater into agricultural soils. However, biosolids applied as soil amendments can contain significant quantities of hazardous organic chemicals derived from the municipal wastewater or organic metabolites produced during waste treatment. These organics have the potential to adversely impact the soil receiving the biosolids, surface and groundwater in the vicinity of application, crops grown on sludge-amended soils, and animals and humans that may consume the crops grown on the soils. This chapter presents a thorough discussion of the fate of hazardous organic chemicals associated with biosolids recycled as soil amendments.

The purpose of this chapter is to provide a comprehensive review of water movement in roadways so that this knowledge may be used in environmental impact studies of traditional and recycled pavement materials. Long term leaching of contaminants is dictated in part by the hydrology of the roadway environment. To determine the hydraulic regimes in the field, ingress and egress routes and the hydraulic conductivity of the materials need to be known. This paper demonstrates that the major water ingress routes are along cracks, joints, and shoulders. It is shown that both saturated and unsaturated conditions in the field occur, suggesting that the contaminant leaching studies that consider saturated conditions only may overlook the effects of unsaturated conditions and the effects of wetting and drying. Furthermore, moisture content and unsaturated conditions have significant spatial and temporal variations in pavement systems. The hydraulic conductivity of pavement materials presented in the literature vary significantly due to various pavement designs, however, the hydraulic conductivity of pavement is less significant in influencing pavement system hydraulic regime than are cracks, joints, shoulders, and drainage systems.

An evaluation methodology was developed for assessing potential ecological risks posed by constituents released from waste and industrial byproducts used in highway construction. This methodology is discussed in the context of United States Environmental Protection Agency's (U.S. EPA) environmental risk assessment framework. Concerted efforts have been made to incorporate important components of the U.S. EPA's risk assessment framework with the Oregon State University (OSU) methodology's own innovative testing and measurement components for assessing potential ecological risks. The evaluation methodology includes leaching tests that are designed to describe (quantification of characteristics of leachate, such as the constituents released, the chemical matrix, the rate of release) and the potential for ecological risk, i.e., of industrial wastes used in highway construction). Environmental removal, reduction, and retardation tests combined with an integrated chemical and biological assessment prescribed in the OSU methodology contribute substantially in characterizing the exposure and ecological effects of leachate constituents.

When residues such as municipal solid waste incineration slag are used as construction materials they are commonly enclosed in a technical construction, which acts as a barrier. This will limit the exposure to water and the atmosphere and thereby delay the resulting leaching process. From a risk assessment perspective there is a great need to qualitative analyze the technical construction, its function, relevant emission scenarios and boundary conditions. The objective is to give a description of the processes and events that are crucial for assessing the leaching of contaminants from roads where residues are used as construction material. One method to describe a complex system is by using . The function of the system is broken down into a number of important components, properties and processes through a top-down approach. The method has successfully been used within rock engineering and nuclear waste disposal research, and is here employed on the use of residual materials in road constructions. Based on the analysis of the system it is concluded that a road ought to be treated as an integrated system instead of treating the system components and processes separately. The role of the road shoulders as water and gas vents remains as the most important mechanism governing emissions from roads where residues are used as an alternative unbound material.

In order to study the environmental analysis and impact assessment (EAIA) of contaminants leached from road construction and repair (C&R) materials, the present chapter introduces an advanced technique called "Forensic Analysis and Genetic Source Modeling". This consists of an environmental "molecular marker" approach that is integrated with various statistical/mathematical modeling tools. It generally aims to characterize the organic molecular composition of leachates from road construction materials as well as to confirm their source. Accordingly, the main goals in this chapter are to: (1) review different organic contaminants (such as petroleum hydrocarbons, pesticides, phthalates, phenols, PCBs, organotin compounds, and surfactants) leached from solid wastes used as road construction materials and/or their leachates; (2) evaluate the different analytical techniques used for the determination of these organic compounds; (3) discuss the current instrumental developments and advances for the identification and characterization of these contaminants; and (4) present data for a major research program that investigated the environmental impact of highway construction materials on surface and ground waters.