Environmental concerns groundwater pollution

Theng BKG, Kookana RS, Rahman A (2000) Environmental concerns of pesticides in soil and groundwater and management strategies in Oceania. In Huang PM, Iskandar IK (eds) Soils and groundwater pollution and remediation-Asia, Africa, and Oceania. Lewis Publishers, Boca Raton, FL, pp 42-79... 

The sorptive behavior of pesticides and organic pollutants can be studied from either equilibrium or kinetic viewpoints. While both are important, perhaps the time-dependent processes are least understood. As environmental concerns intensify about groundwater pollution, waste disposal, and soil detoxification, it will become increasingly important to better understand the kinetics and mechanisms of pesticide and organic pollutant interactions with soils. For comprehensive treatments on pesticides and... 

A further problem concerning the sampling location must be discussed. Many environmental queries include the question of the depth at which the sample must be taken. For example, it is of essential importance to know the depth or, better, the depth interval in the studies of soil, river, or groundwater pollution. The sampling depth must be adapted to the specific purpose of the investigation. Often this aim depends on the planned use of the soil area or water body. 

As indicated in Figure 1, all environmental media where pollutants could lodge have been of interest, including air, surface water and sediment, soil, and groundwater. The environmental pathways of greatest concern obviously vary from site to site. Figure 2 summarizes the media of principal interest at nine "typical" sites selected from an EPA survey of 160 sites. 

Thirty-four minor and trace elements are of potential environmental concern (n ). Sulfur is the element of major concern due to its abundance in flue gases from some coal-burning plants and its subsequent contribution to "acid rain." Sulfur as acidic ions of sulfate can also contribute to pollution of surface water and groundwater. Other elements of greatest concern are As, B, Cd, Pb, Hg, Mo, and Se. With the exception of B and Se, these elements are strongly associated with mineral matter in the coal and are concentrated in waste piles from coal preparation plants. If the waste disposal site is not constructed as a closed system, pollution of nearby groundwater is possible. Boron and Se may contribute to the pollution risk as they are associated with both mineral and organic components. On the other hand, certain coal-mine wastes have potential for recovery of valuable metals such as zinc and cadmium (18). 

Another major group of chemicals commonly encountered in conjimction with groundwater pollution are a group of LNAPLs referred to as the BTEX (benzene, toluene, ethyl benzene, and xylene) compounds. The BTEX compoimds are derived from petroleum, are major constituents in gasoline and other petroleum products, and represent a significant environmental concern with respect to pollution of the subsurface. 

The environmental protection agencies of most countries have identified agriculture as the largest nonpoint source of surface water pollution. This is a major problem in each country. Pesticides and nitrates from fertilizers are detected in the groundwater in many agricultural regions. Soil erosion is a concern in many countries. Pest resistance to pesticides continues to grow, and the problem of pesticide residues in food has yet to be resolved. All nations are more competitive in international markets than a few years ago. 

Abstract In the last decade, it became increasingly evident that the fuel oxygenate methyl tertiary butyl ether (MTBE) is nearly ubiquitous in the worldwide environment. The detection frequency of MTBE rivals other volatile organic compounds (VOCs) that have been produced and used for a much longer period of time. Its mere presence in water bodies used as drinking water reservoirs (rivers, lakes, or groundwater tables) has aroused concern about its potential sources, persistence, or possible adverse effects (aesthetic or toxic implications) for end-users and aquatic life. The purpose of this chapter is to provide an updated overview of the current environmental concentrations, the occurrence of the pollutant in the different aquatic compartments, the relevance of diffuse and point sources, and the different alternatives for remediation of MTBE contaminated sites. 

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