Table 3.
Dechlorination pathways of toxic congenersa identified by WHO [25] quantified by ADM in each sediment microcosms together with their quantification values (mole ‰)
| Dechlorination pathway | Average ± Standard deviation (mole‰)
|
||
|---|---|---|---|
| GR | FR | BH | |
| PCB 77 (34-34) --> PCB 35 (34-3) | 14.47±14.25 | 13.29±13.34 | 4.06±4.06 |
| PCB 77 (34-34) --> PCB 37 (34-4) | 18.22±17.51 | 10.22±10.27 | 5.45±4.43 |
| PCB 105 (234-34) --> PCB 66 (24-34) | 10.86±4.41 | 10.2±4.43 | 16.58±6.53 |
| PCB 114 (2345-4) --> PCB 63 (235-4) | 1.53±1.24 | 1.74±1.35 | 0.44±0.51 |
| PCB 114 (2345-4) --> PCB 74 (245-4) | 1.18±1.2 | 0.85±1.29 | 1.49±1.19 |
| PCB 118 (245-34) --> PCB 66 (24-34) | 30.57±16.47 | 16.64±11.75 | 31.26±15.94 |
| PCB 118 (245-34) --> PCB 67 (245-3) | 21.02±16.5 | 17.71±10.78 | 8.1±10.46 |
| PCB 118 (245-34) --> PCB 70 (25-34) | 24.68±15.5 | 22.42±10.58 | 12.96±11.58 |
| PCB 118 (245-34) --> PCB 74 (245-4) | 28.31±18.03 | 19.4±11.77 | 13.6±10.1 |
| PCB 123 (345-24) --> PCB 66 (24-34) b, g | 10.01±6.36 | 4.28±4.37 | 12.66±10.01 |
| PCB 123 (345-24) --> PCB 68 (24-35) | 3.71±3.04 | 4.16±3.37 | 3.72±4.26 |
| PCB 156 (2345-34) --> PCB 107 (235-34) b, f | 6.4±1.42 | 9.78±1.43 | 5.12±1.84 |
| PCB 156 (2345-34) --> PCB 118 (245-34) b, c | 4.81±2.43 | 3.6±1.44 | 6.93±1.86 |
| PCB 157 (234-345) --> PCB 105 (234-34) c | 0.2±0.38 | 0.07±0.22 | 0.24±0.43 |
| PCB 157 (234-345) --> PCB 108 (234-35) | 0.26±0.44 | 0.57±0.66 | 0.27±0.44 |
| PCB 157 (234-345) --> PCB 122 (345-23) | 0.32±0.48 | 0.49±0.62 | 0.2±0.35 |
| PCB 157 (234-345) --> PCB 123 (345-24) | 0.4±1.28 | 0.4±0.51 | 0.43±0.49 |
Pathways in bold are the major pathways in all microcosms.
a
Among the toxic congeners other than listed here, 81, 126 and 169 are not present in Aroclor 1254, and also 169 was not in the analysis method, therefore, they are not quantified by the model.
b, g, f
Major pathways seen in BH, GR, and FR microcosms, respectively.
c
Pathways resulting in no change in toxicity.