Degradation of lindane-(14)C in a mineral soil and in an organic soil.

Lindane, T-l,2,3,4,5,6-hexachlorocyclohexane (HCH), has been used, per s__eeor as the active ingredient of BHC (benzene hexachloride, in agriculture and public health for nearly three decades as a soil insecticide, foliar spray, seed dressing and for protection of stored grains. Many reports in the literature have alluded to the persistence of lindane in soil, its translocation into crops and contamination of food and animals (ULMANN 1972). Numerous reports indicate that lindane is readily degraded by some insects BROOKS 1972, 1974), plants (SAHA and LEE 1974; KOHLI et al 1976a, 1976b), micro-organisms in synethetic media (MATSUMURA and BENEZET 1973; ELSNER 1972; HAIDER and JAGNOW 1975; ENGST et al 1974; and FRANCIS et al 1975) and animals (CHADWICK et al 1975; FREAL and CHADWICK 1973; KURIHARA 1975; SAHA and BURRAGE 1976) into T1,2,3,4,5,6,-hexachlorocyclohexene (HCCH), 2,3,4,5,6-pentachloro2-cyclohexan-l-ol (PCCOL), y-2,3,4,5,6,-pentachlorocyclohex-l-ene (PCCH), hexachlorobenzene, pentachlorobenzene, and various isomers of di-, tri-, and tetrachlorobenzenes and chlorophenols, apparently through more than one pathway. Some other reports were reviewed by MATHUR and SAHA (1975). Very little information, however, is available on the degradation of lindane in soil. YULE et al (1967) reported that y-PCCH was the only identifiable product of a slow decomposition of lindane in soil. TSUKANO and KOBAYASHI (1972) found y-BTC (y-3,4,5,6-tetrachlorocyclohexene) in flooded rice field soil treated with lindane. Previous work in this laboratory has shown that lindane is slowly biodegraded to y-PCCH, y-BTC, 1,2,4-trichlorobenzene (TCB) 1,2,3,5and/or 1,2,4,5-tetrachlorobenzene (TtCB) and 1,2,3,4-TtCB in a flooded sandy loam soil (MATHUR and SAHA 1975).