Translocation of the polychlorinated biphenyl Aroclor 1254 from soil into carrots under field conditions

The extent and selectivity of transfer of the components of the polychlorinated biphenyl (PCB) Aroclor 1254 from a sandy loam soil into carrots under field conditions were studied. Five of the gas chromatographic peaks of this PCB, designated 1, 4, 5, 8, and 10 with increasing retention time, were quantitated. After 23 months the concentration of peak 10 in soil remained unchanged, but peak 1 decreased by 34 +/- 3%. Lesser chlorinated peak 1 was translocated from soil into carrots five to eight times more than highly chlorinated peak 10. The residues (in ppm) of peaks 1 and 10 in carrot root were 30 to 50% and 3 to 4%, respectively, of that of the soil: The degree of translocation for PCBs was of the same order of magnitude as for the persistent organochlorine insecticides. Carrot foliage contained 1 to 6% as much of the PCB residues (in ppm) as the soil. Since peak 1 was present in about 2.5 times greater amount than peak 10 in foliage, whereas it was present in about five to nine times greater amount in roots, direct foliar contamination by soil dust is suggested.