Persistence of endrin in Indian rice soils under flooded conditions

Persistence and biodegradation of carbofuran in flooded soils

“…Although sorption behavior of carbofuran in these soils is not known, studies with parathion (0,0-diethyl O-p-nitrophenyl phosphorothioate) and lindane ( -1,2,3,4,5,6-hexachlorocyclohexane) tend to show almost irreversible nature of sorption of these insecticides in Kari and Pokkali soils (Wahid, 1976). Also, according to earlier reports (Siddaramappa and Sethunathan, 1975; Gowda and Sethunathan, 1976), initial recoveries of y-and /3-hexachlorocyclohexane and endrin (l,2,3,4,10,10-hexachloro-6,7-epoxy-l,4,4a,5,6,7,8,8aoctahydro-l,4-endo,endo-5,8-dimethanonaphthalene) were relatively low in Kari and Pokkali soils.…”

“…Likewise, y-and ß-hexachlorocyclohexane (Siddaramappa and Sethunathan, 1975) and endrin (Gowda and Sethunathan, 1976) showed extremely long persistence in Kari soil despite favorable conditions of flooding in contrast to the reported instability of these chlorinated hydrocarbon insecticides in predominantly anaerobic flooded conditions (Sethunathan, 1973). More rapid degradation of carbofuran in Pokkali soil than in Kari soil, despite several common characteristics, could be largely ascribed to the remarkable differences in the pH attained by these soils following flooding.…”

Soil Metabolism of a New Herbicide, [14C]Pyribenzoxim, under Flooded Conditions

“…The ranges of pH in nonsterile and sterile conditions were near neutral values; 6.6-8.6 and 6.7-8.1, respectively (Figure 2B). A negative redox potential and neutral pH are known to attain the flooded conditions within a few days after flooding (29)(30)(31). The results of microbial plate counts, including untreated and solvent-treated soil samples ( 23), indicated that the soil microorganisms remained viable throughout the study in nonsterile conditions (Figure 3).…”

“…The half-life of pyribenzoxim was calculated to be 1.3 and 9.4 days for nonsterile and sterile soils, respectively, when pyribenzoxim was treated at a concentration of 0.04 mg/kg on a sandy loam soil flooded with distilled water at 20 ( 2 °C. Although significant abiotic dissipation of pyribenzoxim was observed under sterile condition, the microbial process accelerated the degradation of the herbicide by about 7-fold (22,29,31,39,40). The major metabolites formed were 2,6-bis(4,6dimethoxypyrimidin-2-yloxy)benzoic acid (M1) and 2-hydroxy-6-(4,6-dimethoxypyrimidin-2-yloxy)benzoic acid (M2).…”

Baseline Risk Assessment for the F-Area Burning/Rubble Pits and Rubble Pit

“…Laboratory experiments indicate that a large number of soil niicroorgankms are able to biodegrade endrin under aerobic conditions (Patil et al 1970). Endrin was biodegraded most rapidly in organic-rich soils and most slowly in sandy soils (Gowda and Sethunathan 1976).…”