James S C
Am J Public Health. 1977 May;67(5):429-32. doi: 10.2105/ajph.67.5.429.
The leachate from five municipal landfills (containing no industrial waste or sewage sludge) was studied in 1975 by the U. S. Environmental Protection Agency (EPA). Copper was not present in concentrations above EPA standards. Zinc concentrations decreased with age of the site and were below standards. The amounts of cadmium and chromium appear to vary greatly from site to site. Lead, selenium, iron, and mercury were present at each site in concentrations above standards, regardless of site age. Although raw leachate contains concentrations of heavy metals in excess of the drinking water standards, it is not clear how likely it would be for these recorded levels to be found in drinking water supplies or for contamination to reach the human body. Before leachate reaches an aquifer, it is subject to the attenuating effect of the unsaturated zone. If municipal solid waste is placed directly into ground water, or if leachate is allowed to drain directly into surface water, severe damage to water quality can result. Further study of the environmental effects of leachate are being undertaken by the Environmental Protection Agency.
1975年，美国环境保护局（EPA）对五个城市垃圾填埋场（不含工业废物或污水污泥）的渗滤液进行了研究。铜的浓度未超过EPA标准。锌浓度随场地使用年限的增加而降低，且低于标准。镉和铬的含量在不同场地之间似乎差异很大。铅、硒、铁和汞在每个场地的浓度都高于标准，与场地使用年限无关。尽管原生渗滤液中重金属的浓度超过了饮用水标准，但尚不清楚这些记录水平在饮用水供应中出现的可能性有多大，或者污染到达人体的可能性有多大。在渗滤液到达含水层之前，它会受到非饱和带的衰减作用。如果将城市固体废物直接排入地下水，或者让渗滤液直接排入地表水，可能会对水质造成严重损害。环境保护局正在对渗滤液的环境影响进行进一步研究。
