Cho Young-Cheol, Sokol Roger C, Frohnhoefer Robert C, Rhee G-Yull
Wadsworth Center, New York State Department of Health, Albany, New York 12201, USA.
Environ Sci Technol. 2003 Dec 15;37(24):5651-6. doi: 10.1021/es034600k.
Reductive dechlorination of individual PCB congeners in Aroclor 1248 was investigated using sediment microorganisms from the St. Lawrence River (NY). No dechlorination was observed at Aroclor concentrations below 40 ppm [137 nmol (g of sediment)(-1)]. Above this threshold, congeners could be divided into three categories: group A, congeners that dechlorinated above 40 ppm; group B, congeners that dechlorinated only at high concentrations above 60 ppm [206 nmol (g of sediment)(-1)]; and group C, lower chlorinated congeners that increased in concentration. The dechlorination rate of congeners in groups A and B was a linear function of their initial sediment concentration. For group A congeners, the concentration intercepts of this linear function were the same as their concentrations in the Aroclor at the threshold concentration, and these therefore represented the threshold values. However, the intercepts of group B congeners were significantly higher than their levels at the threshold Aroclor concentration and were equivalent to their concentrations in Aroclor 1248 at about 75 ppm [258 nmol (g of sediment)(-1)]. The final concentrations of group A and group B congeners at the end of dechlorination were the same, regardless of their initial concentrations. These final concentrations were significantly lower than their threshold values. The accumulation rate of group C congeners was a linear function of their initial concentrations, and the total accumulation was greater at higher Aroclor concentrations in sediments.
利用来自纽约州圣劳伦斯河的沉积物微生物，对Aroclor 1248中各多氯联苯同系物的还原脱氯作用进行了研究。当Aroclor浓度低于40 ppm [137 nmol/(克沉积物)]时，未观察到脱氯现象。高于此阈值时，同系物可分为三类：A组，在40 ppm以上发生脱氯的同系物；B组，仅在高于60 ppm [206 nmol/(克沉积物)]的高浓度下发生脱氯的同系物；C组，低氯代同系物，其浓度增加。A组和B组同系物的脱氯速率是其初始沉积物浓度的线性函数。对于A组同系物，该线性函数的浓度截距与其在阈值浓度下Aroclor中的浓度相同，因此这些代表阈值。然而，B组同系物的截距显著高于其在阈值Aroclor浓度下的水平，相当于其在约75 ppm [258 nmol/(克沉积物)]的Aroclor 1248中的浓度。脱氯结束时，A组和B组同系物的最终浓度相同，与其初始浓度无关。这些最终浓度显著低于其阈值。C组同系物的积累速率是其初始浓度的线性函数，沉积物中Aroclor浓度较高时，总积累量更大。
