A Diuron

Figure 5.2 Electrospray-MS-MS signal response of seven of the pesticides versus eluent flow rate, based on (a) peak area, and (b) peak height , atrazine . simazine A, diuron x, isoproturon , chlorfenvinphos , chlorpyrifos O, alachlor. Reprinted from J. Chromatogr., A, 937, Asperger, A., Efer, J., Koal, T. and Engewald, W., On the signal response of various pesticides in electrospray and atmospheric pressure chemical ionization depending on the flow rate of eluent applied in liquid chromatography-mass spectrometry , 65-72, Copyright (2001), with permission from Elsevier Science.

Figure 3. Effect of atrazine (A), diuron (B) and LY181977 (C) on oxygen evolution from wild type, atrazine resistant (DCMU4) and diuron resistant (Dr2) Chlamydomonas.

Although most nonionic organic chemicals are subject to low energy bonding mechanisms, sorption of phenyl- and other substituted-urea pesticides such as diuron to sod or sod components has been attributed to a variety of mechanisms, depending on the sorbent. The mechanisms include hydrophobic interactions, cation bridging, van der Waals forces, and charge-transfer complexes. 

A solvent free, fast and environmentally friendly near infrared-based methodology was developed for the determination and quality control of 11 pesticides in commercially available formulations. This methodology was based on the direct measurement of the diffuse reflectance spectra of solid samples inside glass vials and a multivariate calibration model to determine the active principle concentration in agrochemicals. The proposed PLS model was made using 11 known commercial and 22 doped samples (11 under and 11 over dosed) for calibration and 22 different formulations as the validation set. For Buprofezin, Chlorsulfuron, Cyromazine, Daminozide, Diuron and Iprodione determination, the information in the spectral range between 1618 and 2630 nm of the reflectance spectra was employed. On the other hand, for Bensulfuron, Fenoxycarb, Metalaxyl, Procymidone and Tricyclazole determination, the first order derivative spectra in the range between 1618 and 2630 nm was used. In both cases, a linear remove correction was applied. Mean accuracy errors between 0.5 and 3.1% were obtained for the validation set. 

These high levels were sporadic and transitory. However, some of them were high enough to have caused phytotoxicity, and more work needs to be done to establish whether herbicides are having adverse effects upon populations of aquatic plants in areas highlighted in this study. It should also be borne in mind that there may have been additive or synergistic effects caused by the combinations of herbicides found in these samples. For example, urea herbicides such as diuron and chlortoluron act upon photosynthesis by a common mechanism, so it seems likely that any effects upon aquatic plants will be additive. Similarly, simazine and atrazine share a common mechanism of action. 

Immunoassays for diuron (Figure 13) are another example of improved assay performance using heterologous assay conditions. One antibody was derived from a hapten that extended the dimethylamine side chain of diuron with methylene groups. 

Figure 13 Structures of haptens used for immunizing and coating antigens in a monoclonal antibody-based immunoassay for diuron. A sensitive assay was developed using coating hapten I that had the handle in a position different from the immunogen hapten. When the oxygen in the urea moiety of hapten I was replaced with a sulfur (hapten 11), increasing the heterology, even greater sensitivity was achieved...

Fig. 2 The germination of Equisetum arvense vegetative microspores in the presence of anticontractile agents (left) and energetic inhibitors 10"5M (right). 1- colchicine 2-cytochalasin B oua - ouabain, ant - antimycin A diu - diuron, val - valinomycin.

Comparison of the pesticide concentrations (ng/L) found in this study in sites HDCD and HD AD with those measured in a previous study performed in 2005 in the same sampling sites [ 16, 20] showed a general good agreement for all pesticides except for bentazone, MCPA, propanil, and atrazine, which presented now comparatively lower concentrations, and alachlor, malathion, diuron, and molinate, whose concentrations have increased considerably (Fig. 3). 

McCormick, L.L. and A.E. Hiltbold. 1966. Microbiological decomposition of atrazine and diuron in soil. Weeds 14 77-82. 

The separation of Diuron using the Pye 104 chromatographic is shown in Fig. 9.10 and, although greater sensitivity was obtained compared with the much older Perkin-Elmer instrument, both gave satisfactory results with adequate sensitivity. The response due to 0.04ng of Diuron is shown in (a), together with that from a soil extract (b) and a recovery on the same soil (c). 

Fig. 9.10 Gas-chromatographic responses of extracts from soils (10g) containing Diuron after hydrolysis and bromination (a) 0.04ng standard (Rt=7min) (b) application of 2pl from 10ml of an extract of soil containing 0.04mg kg-1 and (c) recovery of Diuron added to soil at 0.8mg kg-1, 6pl being applied from a 50-fold dilution of (b). Pye 104 gas chromatography.

Farrington et al. [144] used the method of Sidwell and Ruzicka [126] as the basis for the development of a method for the positive monitoring down to 200pg kg-1 of Chlorobromuron, Chlorotoluron, Diuron, Linuron, Monolinuron, Chloroxuron, Monuron and Metobromuron in soils. 

The recoveries obtained for urons from samples of soil are shown in Table 9.16. Samples of soil were fortified by adding known volumes of solutions containing (a) Monuron, Metobromuron, Diuron and Chlorbromuron or (b) Monolinuron, Chlorotoluron, Tinuron and Chloroxuron. 

Fig. 9.11 Typical chromatograms obtained from 5pl injections of soil extracts (a) unfortified and (b) fortified with uron herbicides at 2mg kg-1.1, Monuron 2monoLinuron 3 Metobromuron 4 Chlorotoluron 5 Diuron 6 Linuron 7 Chlorbromuron and 8 Chloroxuron.

Smith and Fitzpatrick [252] have also described a thin layer method for the detection in water and soil of herbicide residues, including Atrazine, Barban, Diuron, Linuron, Monuron, Simazine, Trifluralin, Bromoxynil, Dalapon, Dicamba, MCPB, Mecoprop, Dicloram, 2,4-D, 2,4-DB, Dichloroprop, 2,4,5-T, and 2,3,6-trichlorobenzoic acid. 

Application of sludge on agricultural soils could result in these organics entering the food chain. As many of these compounds are toxic to humans or animals, their presence could be a constraint for the use of sludges as fertilisers. Some food companies have set soil limits above which crops grown on such contaminated soils are rejected [11] Aldrin/Dieldrin, 0.1 DDT, 0.75 and Diuron, 0.3mg/kg soil. 

Fig. 9a, b. Chromatograms obtained after pre-concentration of a 100 ml groundwater sample spiked at 1 p.g 1 1 through a a CP-cartridge b a cartridge filled with a polymer imprinted with terbuthylazine. Peaks 1 = deisopropylatrazine, 2 = deethylatrazine, 3 = simazine, 4 = atrazine, 5 = propazine, 6 = terbuthylazine, I.S. = internal standard (diuron). Reprinted with permission from Ferrer I, Lanza F, Tolokan A, Horvath V, Sellergren B, Horvai G, Barcelo D (2000) Anal Chem 72 3934. Copyright 2000 American Chemical Society... 

More than 25 different substituted urea herbicides are currently commercially available [30, 173]. The most important are phenylureas and Cycluron, which has the aromatic nucleus replaced by a saturated hydrocarbon moiety. Benzthiazuron and Methabenzthiazuron are more recent selective herbiddes of the class, with the aromatic moiety replaced by a heterocyclic ring system. With the exception of Fenuron, substituted ureas (i.e., Diuron, Fluometuron, Fig. 10, Table 3) exhibit low water solubilities, which decrease with increasing molecular volume of the compound. The majority of the phenylureas have relatively low vapor pressures and are, therefore, not very volatile. These compounds show electron-donor properties and thus they are able to form charge transfer complexes by interaction with suitable electron acceptor molecules. Hydrolysis, acylation, and alkylation reactions are also possible with these compounds. 

Synonyms AF 101 AI3-614378 Anduron Ansaron Bioron BRN 2215168 Caswell No. 410 CCRIS 1012 Cekiuron Crisuron Dailon DCMU DCMU 99 Dialer Dichlorfenidim 3-(3,4-Di-chlorophenol)-l,l-dimethylurea 3-(3,4-Dichlorophenyl)-l,l-dimethylurea A -(3,4-Dichloro-phenyl)-A,A-dimethylurea l,l-Dimethyl-3-(3,4-dichlorophenyl)urea Dion Direx 4L Diurex Diurol DMU DP hardener 95 Duran Durashield Dynex EINECS 206-354-4 EPA pesticide chemical code 035505 Farmco diuron Herbatox HW 920 Karmex Karmex diuron herbicide Karmex DW Krovar Lucenit Marmer NA 2767 NSC 8950 Seduron Sup r flo Telvar Telvar diuron weed killer UN 2767 Unidron Urox D USAF P-7 USAF XR-42 Vonduron. 

Biological. Degradation of radiolabeled diuron (20 ppm) was not observed after 2 wk of culturing with Fusarium and two unidentified microorganisms. After 80 d, only 3.5% of the applied amount evolved as C02 (Lopez and Kirkwood, 1974). In 8 wk, <20% of diuron in soil (60 ppm) was detoxified (Corbin and Upchurch, 1967). 3,4-Dichloroaniline was reported as a minor degradation product of diuron in water (Drinking Water Health Advisory, 1989) and soils (Duke et al, 1991). 

Under aerobic conditions, mixed cultures isolated from pond water and sediment degraded diuron (10 pg/mL) to 3-(3-chlorophenyl)-l,l-dimethylurea (CPDU), 3,4-dichloroaniline, 3 (3,4-dichlorophenyl)-l-methylurea, carbon dioxide, and a monodemethylated product. The extent of biodegradation varied with time, glycerol concentration, and microbial population. The degradation half-life was <70 d at 30 °C (Ellis and Camper, 1982). 

Thom and Agg (1975) reported that diuron is amenable to biological treatment with acclimation. Soil Several degradation pathways were reported. The major products and reaction pathways include formation of l-methyl-3-(3,4-dichlorophenyl)urea and 3-(3,4-dichlorophenyl)urea via Wdealkylation, a 6-hydroxy derivative via ring hydroxylation, and formation of 3,4-dichloroaniline, 3,4-dichloronitroaniline, and 3,4-dichloronitrobenzene via hydrolysis and oxidation (Geissbiihler et al, 1975). 

Incubation of diuron in soils releases carbon dioxide (Madhun and Freed, 1987). The rate of carbon dioxide formation nearly tripled when the soil temperature was increased from 25 to 35 °C. Reported half-lives in an Adkins loamy sand are 705, 414, and 225 d at 25, 30, and 35 °C, respectively. However, in a Semiahoo mucky peat, the half-lives were considerable higher 3,991, 2,164, and 1,165 d at 25, 30, and 35 °C, respectively (Madhun and Freed, 1987). Under aerobic conditions, biologically active, organic-rich, diuron-treated pond sediment (40 pg/mL) converted diuron exclusively to CPDU (Attaway et al., 1982, 1982a Stepp et al., 1985). At 25 and 30 °C, 90% degradation was observed after 55 and 17 d, respectively (Attaway, 1982a). 

Hill et al. (1955) studied the degradation of diuron using a Cecil loamy sand (1 ppm) and Brookstone silty clay loam (5 ppm) in the laboratory maintained at 27 °C and 60% relative humidity. In both soils, diuron was applied on four separate occasions in 22 wk. In both instances, the investigators observed 40% of the applied amount degraded in both soils. The half-lives in field soils ranged from 133 to 212 d with an average half-life of 328 d. 

In a field application study, diuron did not leach below 5 cm in depth despite repeated applications or water addition (Majka and Lavy, 1977). 

Groundwater. According to the U.S. EPA (1986), diuron has a high potential to leach to groundwater. 

Chemical/Physical. Diuron decomposes at 180 to 190 °C releasing dimethylamine and 3,4-dichlorophenyl isocyanate. Dimethylamine and 3,4-dichloroaniline are produced when hydrolyzed or when acids or bases are added at elevated temperatures (Sittig, 1985). The hydrolysis half-life of diuron in a 0.5 N NaOH solution at 20 °C is 150 d (El-Dib and Aly, 1976). When diuron was pyrolyzed in a helium atmosphere between 400 and 1,000 °C, the following products were identified dimethylamine, chlorobenzene, 1,2-dichlorobenzene, benzonitrile, a trichlorobenzene, aniline, 4-chloroaniline, 3,4-dichlorophenyl isocyanate, bis(l,3-(3,4-dichlorophenyl)urea), 3,4-dichloroaniline, and monuron [3-(4-chlorophenyl)-l,l-dimethylurea] (Gomez et al., 1982). Products reported from the combustion of diuron at 900 °C include carbon monoxide, carbon dioxide, chlorine, nitrogen oxides, and HCl (Kennedy et al., 1972a). 

Amresco acryl-40, see Acrylamide AMS, see a-Methylstyrene n-Amyl acetate, see Amyl acetate Amyl acetic ester, see Amyl acetate Amyl acetic ether, see Amyl acetate Amylene, see 1-Pentene a-n-Amylene, see 1-Pentene p-n-Amylene, see cis-2-Pentene cis-p-Amylene, see cis-2-Pentene frans-p-Amylene, see trans-2-Venlene sec-Amyl ethanoate, see Amyl acetate Amyl ethyl ketone, see 5-Methyl-3-heptanone Amyl hydride, see Pentane Amyl methyl ketone, see 2-Heptanone n-Amyl methyl ketone, see 2-Heptanone AN, see Acrylonitrile Anaesthetic ether, see Ethyl ether Anamenth, see Trichloroethylene Anduron, see Diuron Anesthenyl, see Methylal Anesthesia ether, see Ethyl ether Anesthetic ether, see Ethyl ether Anhydrous ammonia, see Ammonia Aniline oil, see Aniline Anilinobenzene, see 4-Aminobiphenyl Anilinomethane, see Methylaniline 2-Anidine, see o-Anisidine 4-Anisidine, see p-Anisidine 2-Anisylamine, see o-Anisidine... 

BRN 1912585, see Hexachlorobenzene BRN 1912384, see 2,4-Dinitrotoluene BRN 1913355, seep,p -DDE BRN 1914064, see Di-fl-butyl phthalate BRN 1914072, see p,p -DDD BRN 1915474, see Chlordane BRN 1915994, see Di-fl-octyl phthalate BRN 2049930, see Naled BRN 2051258, see Pindone BRN 2052046, see 2,6-Dinitrotoluene BRN 2054389, see 4,6-Dinitro-o-cresol BRN 2055620, see 2,4,5-T BRN 2057367, see Methoxychlor BRN 2059093, see Parathion BRN 2062204, see Benzyl butyl phthalate BRN 2215168, see Diuron BRN 2542580, see EPN BRN 2807677, see 2-Acetylaminofluorene BRN 3195880, see a-BHC BRN 3196099, see Camphor BRN 3910347, see cis-Chlordane, frans-Chlordane Brocide, see 1,2-Dichloroethane Brodan, see Chlorpyrifos Bromchlophos, see Naled Bromex, see Naled Bromic ether, see Ethyl bromide Bromobenzol, see bromobenzene 4-Bromobiphenyl ether, see 4-Bromophenyl phenyl ether 4-Bromodiphenyl ether, see 4-Bromophenyl phenyl ether p-Bromodiphenyl ether, see 4-Bromophenyl phenyl ether Bromoethane, see Ethyl bromide Bromofluoroform, see Bromotrifluoromethane Bromofume, see Ethylene dibromide Brom-o-gaz, see Methyl bromide Bromomethane, see Methyl bromide Bromomethyl chloride, see Bromochloromethane... 

CP 1309, see Pentachlorophenol CPD-244, see 2-Nittopropane CPD-926, see Dibenzofuran 4-CPPE, see 4-Chlorophenyl phenyl ether p-CPPE, see 4-Chlorophenyl phenyl ether Crag sevin, see Carbaryl Crawhaspol, see Trichloroethylene 2-Cresol, see 2-Methylphenol 4-Cresol, see 4-Methylphenol oCresol, see 2-Methylphenol p-Cresol, see 4-Methylphenol Crestoxo, see Toxaphene Crestoxo 90, see Toxaphene oCresylic acid, see 2-Methylphenol p-Cresylic acid, see 4-Methylphenol oCresyl phosphate, see Tri-ocresyl phosphate Crisalin, see Trifluralin Crisalina, see Trifluralin Crisfuran, see Carbofuran Crisulfan, see a-Endosulfan, p-Endosulfan Crisuron, see Diuron Crolean, see Acrolein Crop rider, see 2,4-D Crotenaldehyde, see Crotonaldehyde Crotilin, see 2,4-D Crotonal, see Crotonaldehyde Crotonic aldehyde, see Crotonaldehyde CRS, see Phenol Crunch, see Carbaryl Cryptogil OL, see Pentachlorophenol CS, see oChlorobenzylidenemalononitrile, Methyl mercaptan... 

Dipropylmethane, see Heptane Dipropylnitrosamine, see A-Nitrosodi-n-propylamine Di-n-propylnitrosamine, see A-Nitrosodi-n-propylamine iV,lV-Dipropyl-4-trifluoromethyl-2,6-dinitroaniline, see Trifluralin Dirax, see ANTU Direx 4L, see Diuron... 

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