Pye V I, Patrick R
Science. 1983 Aug 19;221(4612):713-8. doi: 10.1126/science.6879171.
Ground water contamination is of increasing concern in the United States because about 50 percent of our drinking water comes from well water. The causes of contamination stem from both point sources and nonpoint sources. Since ground water moves slowly, the contaminant may affect only a small portion of an aquifer for a considerable period of time. Deleterious effects on human health have resulted from pathogenic organisms in ground water and from its toxic chemical composition. It is difficult to estimate the extent of contamination on a national basis as the frequency of instances of contamination is very variable. Remedial actions to clean up aquifers are difficult, expensive, and sometimes not feasible. Many of the laws and regulations that control ground water contamination are designed with other main objectives.
在美国，地下水污染日益受到关注，因为我们大约50%的饮用水来自井水。污染的原因既有点源污染，也有非点源污染。由于地下水流动缓慢，污染物可能在相当长的一段时间内仅影响含水层的一小部分。地下水中的致病生物及其有毒化学成分已对人类健康造成有害影响。由于污染事件的发生频率差异很大，因此很难在全国范围内估计污染的程度。清理含水层的补救措施困难、昂贵，有时甚至不可行。许多控制地下水污染的法律法规是出于其他主要目标而制定的。
