Effects of ground water pollution

For millennia, man has disposed of his waste products in a variety of ways. The disposal method might reflect convenience, expedience, expense, or best available technology, but in many instances, leachate from these wastes have come back to haunt later generations. This is largely because we have not thought out the consequences of our actions. Ground-water pollution may lead to problems of inconvenience, such as taste, odor, color, hardness, or foaming; but the pollution problems are far more serious when pathogenic organisms, flammable or explosive substances, or toxic chemicals or their by-products are present, particularly when long-term health effects are unknown.

Individual polluted ground-water sites generally are not large, but once polluted, ground water may remain in an unusable or even hazardous condition for decades or even centuries. The typically low velocity of ground water prevents a great deal of mixing and dilution; consequently, a contaminant plume may maintain a high concentration as it slowly moves from points of recharge to zones of discharge.

An oil-field brine holding pond was constructed adjacent to a producing well in central Ohio in 1968. Two years later when the well was plugged, the holding pond was filled, graded, and seeded. The chloride concentration in the ground water in the vicinity of the former pond still exceeded 36,000 mg/1 some 10 years after the operation began and 8 years after reclamation.

Scores of brine holding ponds were constructed in central Ohio during an oil boom in 1964; many are still in use. In 1978 a number of test holes were constructed within 200 feet of one such pond. Within this area shallow ground water contained as much as 50,000 mg/1 of chloride. Moreover, brine-contaminated ground water provides part of the flow of many streams and this has caused degradation of surface-water quality.

Documentation of the migration of leachate plumes originating at garbage dumps and landfills is becoming increasingly abundant. Data show that under certain hydrologic conditions leachate plumes can move considerable distances and degrade ground water throughout wide areas. Furthermore, the problem is worldwide. Exler3z described a situation in southern Bavaria, Germany, where a landfill has been in operation since 1954 The wastes are dumped into a dry gravel pit. As Figure 116 illustrates, data collected from 1967 to 1970 showed the narrow lense-shaped plume had migrated nearly 2 miles.