Laboratory of Soil Microbiology, Department of Agronomy, Cornell University, Ithaca, New York 14853.
Appl Environ Microbiol. 1982 May;43(5):1133-8. doi: 10.1128/aem.43.5.1133-1138.1982.
The rates of mineralization of phenol, benzoate, benzylamine, p-nitrophenol, and di(2-ethylhexyl) phthalate added to lake water at concentrations ranging from a few picograms to nanograms per milliliter were directly proportional to chemical concentration. The rates were still linear at levels of <1 pg of phenol or p-nitrophenol per ml, but it was less than the predicted value at 1.53 pg of 2,4-dichlorophenoxyacetate per ml. Mineralization of 2,4-dichlorophenoxyacetate was not detected in samples of lake water containing 200 ng of the chemical per ml. The slope of a plot of the rate of phenol mineralization in samples of three lakes as a function of its initial concentration was lower at levels of 1 to 100 mug/ml than at higher concentrations. In lake water and sewage supplemented with <60 ng of C-labeled benzoate or phenylacetate per ml, 95 to 99% of the radioactivity disappeared from solution, indicating that the microflora assimilated little or none of the carbon. The extent of mineralization of some compounds in samples of two lakes and sewage was least in the water with the lowest nutrient levels. No mineralization of 2,4-dichlorophenoxyacetate and the phthalate ester was observed in samples of an oligotrophic lake. These data suggest that mineralization of some chemicals at concentrations of <1 mug/ml is the result of activities of organisms different from those functioning at higher concentrations or of organisms that metabolize the chemicals at low concentrations but assimilate little or none of the substrate carbon.
酚、苯甲酸、苄胺、对硝基酚和邻苯二甲酸二（2-乙基己基）酯添加到湖水的浓度范围从几个皮克到纳克/毫升，其矿化率与化学浓度直接成正比。在 1 pg 以下的酚或对硝基酚每毫升的水平下，速率仍然是线性的，但在 1.53 pg 2,4-二氯苯氧乙酸每毫升的水平下，速率低于预测值。在每毫升含有 200 ng 该化学物质的湖水样品中未检测到 2,4-二氯苯氧乙酸的矿化。三个湖泊水样中苯酚矿化率随初始浓度变化的关系图的斜率在 1 至 100 μg/ml 的水平低于较高浓度的斜率。在湖水和补充了 <60 ng 放射性标记的苯甲酸或苯乙酸每毫升的污水中，95%至 99%的放射性物质从溶液中消失，表明微生物同化了很少或没有碳。在两个湖泊和污水的水样中，一些化合物的矿化程度在营养水平最低的水中最低。在贫营养湖中没有观察到 2,4-二氯苯氧乙酸和邻苯二甲酸酯的矿化。这些数据表明，在 <1 μg/ml 的浓度下，一些化学物质的矿化是浓度较高时起作用的生物或在低浓度下代谢化学物质但同化很少或没有基质碳的生物的活动的结果。
