Fate of pentachlorophenol-14C in rice plants under controlled conditions

After application of pentachlorophenol-14C at 23 kg/ha to flooded rice soil in a plant growth chamber, 36.5% was recovered in soil after one growing period and 30.1% after two periods. After one growing period, the residues were 28.61% unidentified unextractable substances, 0.51% unchanged free pentachlorophenol, 0.61% conjugated pentachlorophenol, 1.67% free tetra- and trichlorophenols, <0.01% conjugated trichlorophenols, 0.33% anisoles, and 4.74% highly polar, mostly nonhydrolyzable compounds (percent of applied radioactivity). In the second growing period, the portion of unextractable residues in soil increased; the composition of the extractable radioactivity was similar to that of the first vegetation period.