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Degradation of Triazine-2-(14)C Metsulfuron-Methyl in Soil from an Oil Palm Plantation.

Ismail BS, Eng OK, Tayeb MA - PLoS ONE (2015)

Bottom Line: The principal degradation product after 60 days was CO2.The higher cumulative amount of (14)CO2 in (14)C-triazine in the non-sterilized soil compared to that in the sterile system suggests that biological degradation by soil micro-organisms significantly contributes to the dissipation of the compound.The major routes of degradation were O-demethylation, sulfonylurea bridge cleavage and the triazine "ring-opened."

View Article: PubMed Central - PubMed

Affiliation: School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor, Malaysia.

ABSTRACT
Triazine-2-(14)C metsulfuron-methyl is a selective, systemic sulfonylurea herbicide. Degradation studies in soils are essential for the evaluation of the persistence of pesticides and their breakdown products. The purpose of the present study was to investigate the degradation of triazine-2-(14)C metsulfuron-methyl in soil under laboratory conditions. A High Performance Liquid Chromatograph (HPLC) equipped with an UV detector and an on-line radio-chemical detector, plus a Supelco Discovery column (250 x 4.6 mm, 5 μm), and PRP-1 column (305 x 7.0 mm, 10 μm) was used for the HPLC analysis. The radioactivity was determined by a Liquid Scintillation Counter (LSC) in scintillation fluid. The soil used was both sterilized and non-sterilized in order to observe the involvement of soil microbes. The estimated DT50 and DT90 values of metsulfuron-methyl in a non-sterile system were observed to be 13 and 44 days, whereas in sterilized soil, the DT50 and DT90 were 31 and 70 days, respectively. The principal degradation product after 60 days was CO2. The higher cumulative amount of (14)CO2 in (14)C-triazine in the non-sterilized soil compared to that in the sterile system suggests that biological degradation by soil micro-organisms significantly contributes to the dissipation of the compound. The major routes of degradation were O-demethylation, sulfonylurea bridge cleavage and the triazine "ring-opened."

No MeSH data available.


Related in: MedlinePlus

Experimental set-up for the study of metsulfuron-methyl degradation in soil.
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pone.0138170.g001: Experimental set-up for the study of metsulfuron-methyl degradation in soil.

Mentions: Samples of the Bernam Series soil was collected from the field experimental site at Sungai Buloh Estate. The soils samples were passed through a 2 mm sieve and used immediately. Each soil sample (100 g) was placed in a sample bottle, connected to the trap bottle. The trap bottle was connected to an ethylene glycol (25 mL) bottle to trap any organic volatiles. Lastly the ethylene glycol bottle was connected to a 0.1 M KOH (25 mL) bottle to trap 14CO2 evolved as a result of microbial activity (Fig 1). The flask was corked with a rubber stopper. The soil was maintained at the water holding capacity of 50% throughout the experiment. This was achieved by periodically weighing the flask and by the addition of water as required. The experiment was conducted in a “controlled environment” chamber with the temperature maintained at 30°C (±1°C) and the humidity at 80% (±2%), in total darkness. The experiment was replicated three times.


Degradation of Triazine-2-(14)C Metsulfuron-Methyl in Soil from an Oil Palm Plantation.

Ismail BS, Eng OK, Tayeb MA - PLoS ONE (2015)

Experimental set-up for the study of metsulfuron-methyl degradation in soil.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4593563&req=5

pone.0138170.g001: Experimental set-up for the study of metsulfuron-methyl degradation in soil.
Mentions: Samples of the Bernam Series soil was collected from the field experimental site at Sungai Buloh Estate. The soils samples were passed through a 2 mm sieve and used immediately. Each soil sample (100 g) was placed in a sample bottle, connected to the trap bottle. The trap bottle was connected to an ethylene glycol (25 mL) bottle to trap any organic volatiles. Lastly the ethylene glycol bottle was connected to a 0.1 M KOH (25 mL) bottle to trap 14CO2 evolved as a result of microbial activity (Fig 1). The flask was corked with a rubber stopper. The soil was maintained at the water holding capacity of 50% throughout the experiment. This was achieved by periodically weighing the flask and by the addition of water as required. The experiment was conducted in a “controlled environment” chamber with the temperature maintained at 30°C (±1°C) and the humidity at 80% (±2%), in total darkness. The experiment was replicated three times.

Bottom Line: The principal degradation product after 60 days was CO2.The higher cumulative amount of (14)CO2 in (14)C-triazine in the non-sterilized soil compared to that in the sterile system suggests that biological degradation by soil micro-organisms significantly contributes to the dissipation of the compound.The major routes of degradation were O-demethylation, sulfonylurea bridge cleavage and the triazine "ring-opened."

View Article: PubMed Central - PubMed

Affiliation: School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor, Malaysia.

ABSTRACT
Triazine-2-(14)C metsulfuron-methyl is a selective, systemic sulfonylurea herbicide. Degradation studies in soils are essential for the evaluation of the persistence of pesticides and their breakdown products. The purpose of the present study was to investigate the degradation of triazine-2-(14)C metsulfuron-methyl in soil under laboratory conditions. A High Performance Liquid Chromatograph (HPLC) equipped with an UV detector and an on-line radio-chemical detector, plus a Supelco Discovery column (250 x 4.6 mm, 5 μm), and PRP-1 column (305 x 7.0 mm, 10 μm) was used for the HPLC analysis. The radioactivity was determined by a Liquid Scintillation Counter (LSC) in scintillation fluid. The soil used was both sterilized and non-sterilized in order to observe the involvement of soil microbes. The estimated DT50 and DT90 values of metsulfuron-methyl in a non-sterile system were observed to be 13 and 44 days, whereas in sterilized soil, the DT50 and DT90 were 31 and 70 days, respectively. The principal degradation product after 60 days was CO2. The higher cumulative amount of (14)CO2 in (14)C-triazine in the non-sterilized soil compared to that in the sterile system suggests that biological degradation by soil micro-organisms significantly contributes to the dissipation of the compound. The major routes of degradation were O-demethylation, sulfonylurea bridge cleavage and the triazine "ring-opened."

No MeSH data available.


Related in: MedlinePlus