M. Deutsch
1965
<p>Shallow<span> aquifers, commonly the most important sources of ground water, are also those most susceptible to </span>contamination<span>. The mode of entry of contaminants to </span>shallow<span> aquifers is (1) directly, via wells or secondary openings </span>in<span> consolidated rocks, (2) percolation through the zone of aeration, (3) induced infiltration through the zone of saturation, and (4) interaquifer leakage or flow through open holes. </span>Natural<span> removal or degradation of contaminants is by filtration, dispersion, sorption, ion exchange, oxidation, and various biochemical processes. These phenomena are controlled by the physical environment, structure; mineralogy, and hydraulic characteristics of the earth materials contacted by the liquid wastes. When liquid wastes enter an </span>aquifer<span> directly, there is little or no </span>natural<span> treatment by filtration, sorption, or oxidation. Purification is only by those processes that operate within the </span>aquifer<span> under anaerobic conditions. Contaminants from </span>natural<span> sources that enter aquifers under saturated‐flow conditions are degraded primarily by dilution. The </span>natural<span> processes effective </span>in<span> reducing </span>contamination<span> from surface‐water sources depend on the hydraulic regimen </span>involved<span>, which vary with individual cases. Liquid wastes percolating through the zone of aeration are those most likely to be purified by </span>natural<span> environment processes. </span>Natural<span> processes, however, do not effectively remove or degrade all contaminants, especially some of the many highly stable compounds that have gained widespread use </span>in<span> recent years, such as synthetic detergents. Comprehensive interdisciplinary research into the ability of various earth materials to remove many types of contaminants under varying hydrologic conditions is needed.</span></p>
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10.1111/j.1745-6584.1965.tb01219.x
en
Wiley Blackwell
Natural controls involved in shallow aquifer contamination
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