Surfactant - aided bioremediation of chlorpyrifos in the soil
2010
Bobiles, S.C., Bicol Univ., Legazpi City 4500, Albay (Philippines). Coll. of Science | Librojo-Basilio, N.T., Philippines Univ. Los Baños, College, Laguna (Philippines). Inst. of Chemistry | Varca, L.M., Philippines Univ. Los Baños, College, Laguna (Philippines). National Crop Protection Center
The effect of a surfactant, coconut fatty alcohol sulfate (CFAS), on biodegradation rate of chlorpyrifos, an organophosphate insecticide, was conducted to evaluate the possible use of CFAS to facilitate bioremediation. Four soil treatments (with or without CFAS and chlorpyrifos) with three replicates each were compared in terms of total bacterial colonies. Total bacterial colonies served as an indication rate of the rate of biodegradation. The soil has pH 6.0, 3.55% organic matter content, 88.28% (w/w) water holding capacity and clay loam texture. Mean total bacterial colonies expressed as 10sup3 / 10 g soil for T1 (control), T2 (with CFAS) and T3 (with chlorpyrifos) ranged from 20 to 519 which did not differ significantly from each other. Total bacterial colonies for T4 (with chlorpyrifos and CFAS) ranged from 3 to 2870. From 14 to 21 days, the mean total, bacterial colonies for T4 increased by 1,893%. The increasing trend continued until 43 days. From 21 to 43 days, total bacterial colonies increased by 220%. Mean concentration levels for chlorpyrifos were significant at 0 and 43 days. Values (ug/g) for T3 were: 1,439 at 0 day and 837 at 43 days, for T4 were 836 at 0 day and 434 at 43 days. T4 (with chlorpyrifos and CFAS) had a higher percentage decrease (48.09%) which complemented with high mean total bacterial colonies for this treatment compared with T3 (with chlorpyrifos) with a percent decrease of 41.83%. The results showed that CFAS enhanced the rate of biodegradation of chlorpyrifos in the soil by increasing the bioavailability of chlorpyrifos for the growth and metabolism of bacteria.
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