Translocation of polychlorobiphenyls in soil into plants: a study by a method of culture of soybean sprouts.

PCB translocation from soil into a plant through its roots was investigated by a method of culture of soybean sprouts on sand contaminated with Aroclor 1242 or 1254. A preliminary culture was carried out on clean sand in a cage with small holes in the bottom and then followed by a main culture on contaminated sand after the preliminary culture cage was placed upon a box filled with the contaminated sand. Consequently, roots of soybean sprouts were allowed to penetrate through the holes at the botton of the upper cage into the contaminated sand. Rates of transference of PCBs were found to be different among chlorobiphenyl isomers; low chlorobiphenyls were much more preferentially absorbed by sprouts that were the high chlorobiphenyls. This seemed to depend mostly on different water solubilities of the isomers and probably not on selective absorption of the isomers by sprouts. The usefulness of the method employed of the two-steps sprout culture on doubly layered soil, in investigations of translocation mechanisms of toxic chemicals in a soil-plant ecosystem, is also discussed.