The persistence and metabolism of isoproturon in soil

Muud, P.J.; Hance, R. J.; Wright, S. J. L.

doi:10.1111/j.1365-3180.1983.tb00545.x

Cited by 91 publications

(39 citation statements)

References 9 publications

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“…In soil from two sites along transect 2 (sites B and C), degradation showed first-order kinetics, with no rapid phase of degradation, and approximately 15% IPU remained after 65 days. In all sites, HPLC analysis revealed the temporary appearance of peaks with identical retention times to 3-(4-isopropyl-phenyl)-1-methylurea (MDIPU) and 3-(4-isopropyl-phenyl)-urea (data not shown), indicating that metabolism of IPU occurred by sequential N-demethylation, as outlined by Mudd et al (16).…”

Section: Resultssupporting

confidence: 52%

In-Field Spatial Variability in the Degradation of the Phenyl-Urea Herbicide Isoproturon Is the Result of Interactions between Degradative Sphingomonas spp. and Soil pH

Bending¹,

Lincoln²,

Sørensen

et al. 2003

Appl Environ Microbiol

146

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Substantial spatial variability in the degradation rate of the phenyl-urea herbicide isoproturon (IPU) [3-(4-isopropylphenyl)-1,1-dimethylurea] has been shown to occur within agricultural fields, with implications for the longevity of the compound in the soil, and its movement to ground-and surface water. The microbial mechanisms underlying such spatial variability in degradation rate were investigated at Deep Slade field in Warwickshire, United Kingdom. Most-probable-number analysis showed that rapid degradation of IPU was associated with proliferation of IPU-degrading organisms. Slow degradation of IPU was linked to either a delay in the proliferation of IPU-degrading organisms or apparent cometabolic degradation. Using enrichment techniques, an IPU-degrading bacterial culture (designated strain F35) was isolated from fast-degrading soil, and partial 16S rRNA sequencing placed it within the Sphingomonas group. Denaturing gradient gel electrophoresis (DGGE) of PCR-amplified bacterial community 16S rRNA revealed two bands that increased in intensity in soil during growth-linked metabolism of IPU, and sequencing of the excised bands showed high sequence homology to the Sphingomonas group. However, while F35 was not closely related to either DGGE band, one of the DGGE bands showed 100% partial 16S rRNA sequence homology to an IPU-degrading Sphingomonas sp. (strain SRS2) isolated from Deep Slade field in an earlier study. Experiments with strains SRS2 and F35 in soil and liquid culture showed that the isolates had a narrow pH optimum (7 to 7.5) for metabolism of IPU. The pH requirements of IPU-degrading strains of Sphingomonas spp. could largely account for the spatial variation of IPU degradation rates across the field.Concern about the environmental impact of pesticides most frequently arises from their ability to leach from soil and contaminate water resources. The phenyl-urea herbicides are of particular significance in this respect, since several members of the group, including isoproturon (IPU) [3-(4-isopropylphenyl)-1,1-dimethylurea] and diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] are degraded slowly in soil and are susceptible to leaching. As a result, IPU and diuron are frequently detected as contaminants of agricultural catchments in Europe (23).Studies of the fate of IPU in agricultural fields on contrasting soil types have revealed considerable spatial variability in degradation rates across fields (2,26,27). At two such sites in the United Kingdom, Deep Slade field in Warwickshire and Brimstone farm in Oxfordshire, IPU half-life in soil was found to vary between 6 and 30 days, with degradation rate linked to soil pH. Further studies by Bending et al. (3) demonstrated that soil pH controlled the ease of induction of growth-linked metabolism, with slow degradation rates at lower soil pH linked to apparent cometabolic degradation of the compound. At the Deep Slade site, various bacteria capable of degrading IPU have been isolated (8,19,21). However, the relative importance of each in the degradation...

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Section: Resultssupporting

confidence: 52%

In-Field Spatial Variability in the Degradation of the Phenyl-Urea Herbicide Isoproturon Is the Result of Interactions between Degradative Sphingomonas spp. and Soil pH

Bending¹,

Lincoln²,

Sørensen

et al. 2003

Appl Environ Microbiol

146

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“…6, step 1). MDIPU has previously been reported to be the main metabolite produced during the degradation of IPU in agricultural soils (4,6,13,16,19,22). An alternative metabolic pathway involving initial hydroxylation of the isopropyl side chain resulting in 2-hydroxy-IPU [3-(4-(2-hydroxyisopropyl)-phenyl)-1,1-dimethylurea] has also been described in agricultural soils (19,32).…”

Section: Discussionmentioning

confidence: 99%

“…As a result of its widespread and repeated use, IPU is frequently detected in groundwater and surface waters in Europe in levels exceeding the European Commission drinking water limit of 0.1 g l Ϫ1 (23,33,34). Degradation of IPU in agricultural soils occurs predominantly by microbiological processes (6,22). Several studies have demonstrated a slow natural attenuation rate in various soils and subsurface environments with respect to mineralization of the phenyl structure (4,15,17,18,26,35).…”

mentioning

confidence: 99%

Isolation from Agricultural Soil and Characterization of a Sphingomonas sp. Able To Mineralize the Phenylurea Herbicide Isoproturon

Sørensen

Ronen

Aamand

2001

Appl Environ Microbiol

134

141

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A soil bacterium (designated strain SRS2) able to metabolize the phenylurea herbicide isoproturon, 3-(4-isopropylphenyl)-1,1-dimethylurea (IPU), was isolated from a previously IPU-treated agricultural soil. Based on a partial analysis of the 16S rRNA gene and the cellular fatty acids, the strain was identified as a Sphingomonas sp. within the ␣-subdivision of the proteobacteria. Strain SRS2 was able to mineralize IPU when provided as a source of carbon, nitrogen, and energy. Supplementing the medium with a mixture of amino acids considerably enhanced IPU mineralization. Mineralization of IPU was accompanied by transient accumulation of the metabolites 3-(4-isopropylphenyl)-1-methylurea, 3-(4-isopropylphenyl)-urea, and 4-isopropyl-aniline identified by high-performance liquid chromatography analysis, thus indicating a metabolic pathway initiated by two successive N-demethylations, followed by cleavage of the urea side chain and finally by mineralization of the phenyl structure. Strain SRS2 also transformed the dimethylurea-substituted herbicides diuron and chlorotoluron, giving rise to as-yet-unidentified products. In addition, no degradation of the methoxy-methylurea-substituted herbicide linuron was observed. This report is the first characterization of a pure bacterial culture able to mineralize IPU.The phenylurea herbicide isoproturon, 3-(4-isopropylphenyl)-1,1-dimethylurea (IPU), which is used for pre-and postemergence control of annual grasses and broad-leaved weeds in wheat, rye, and barley crops, is among the most extensively used pesticides in conventional agriculture in Europe (34). Ecotoxicological data suggest that IPU and some of its metabolites are harmful to aquatic invertebrates (20), freshwater algae (25), and microbial activity (28). IPU is also suspected of being carcinogenic (2, 14). As a result of its widespread and repeated use, IPU is frequently detected in groundwater and surface waters in Europe in levels exceeding the European Commission drinking water limit of 0.1 g l Ϫ1 (23,33,34). Degradation of IPU in agricultural soils occurs predominantly by microbiological processes (6,22). Several studies have demonstrated a slow natural attenuation rate in various soils and subsurface environments with respect to mineralization of the phenyl structure (4,15,17,18,26,35). The detection of IPU as an environmental pollutant and its apparently low mineralization potential has stimulated research aimed at isolating and characterizing microbial cultures able to mineralize IPU. Enrichment culture techniques have been used with varied success in attempts to isolate IPU-degrading microorganisms. In previous studies, slurries of mineral media and soils from different agricultural fields failed to degrade IPU (4,19,35). Enrichment on the IPU metabolite 3-(4-isopropylphenyl)-1-methylurea (MDIPU) as the sole source of carbon and energy recently yielded a mixed bacterial culture able to perform growth-linked mineralization of MDIPU and 4-isopropylaniline (4IA) but with no degradation activity toward IPU (35)....

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“…The detection limit is 0.01 ppm. The period of study was suitable for dissipation of pesticide from crops to reach less than maximum residue limit permitted by Food Agriculture Organization (FAO) and World Health Organization(WHO) [16] .…”

Section: Resultsmentioning

confidence: 99%

Dissipation of Fenitrothion Residues in Some Fruits and Vegetables Using High-Performance Liquid Chromatography Method

Bahaffi¹,

Zainy²,

Hamza³

2005

sci

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ABSTRACT. High performance liquid chromatographic method was described for the determination of the dissipation of fenitrothion residues in some fruits and vegetables. Crops were sprayed with very dilute solution of fenitrothion, and collected daily one day after spraying for 7 to 13 days, and then extracted with acetonitrile and partitioning in normal hexane. Solid phase florisil cartridges were used for clean up. The analysis was carried out by reversed-phase high performance liquid chromatography (HPLC) with methanol-water (90:10) as a mobile phase. Detection limit is 0.01 mg/kg. The percentage of losses are 89.55, 85.71, 76.01, 93.39, 98.75, and 99.24 for rocket, parsley, lettuce, fig, grape and guava, respectively.

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The persistence and metabolism of isoproturon in soil

Cited by 91 publications

References 9 publications

In-Field Spatial Variability in the Degradation of the Phenyl-Urea Herbicide Isoproturon Is the Result of Interactions between Degradative Sphingomonas spp. and Soil pH

In-Field Spatial Variability in the Degradation of the Phenyl-Urea Herbicide Isoproturon Is the Result of Interactions between Degradative Sphingomonas spp. and Soil pH

Isolation from Agricultural Soil and Characterization of a Sphingomonas sp. Able To Mineralize the Phenylurea Herbicide Isoproturon

Dissipation of Fenitrothion Residues in Some Fruits and Vegetables Using High-Performance Liquid Chromatography Method

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