Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Diuron”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 199 records · Page 11Linked to original sources
PubMed2001

Determination of antifouling pesticides and their degradation products in marine sediments by means of ultrasonic extraction and HPLC-APCI-MS.

A method has been developed for the simultaneous determination of antifouling pesticides and some of their degradation products, e.g. dichlofluanid, diuron, demethyldiuron, 1-(3,4-dichlorophenyl)urea, sea-nine, Irgarol 1051 and one of its metabolites (2-methylthio-4-tert-butylamino-s-triazine) in marine sediments. The determination of these compounds in sediment samples was performed by means of methanolic ultrasonic extraction then clean-up on an Isolute ENV+ solid phase extraction (SPE) cartridge. The resulting extract was then analyzed by reversed-phase high-performance liquid chromatography coupled with atmospheric-pressure chemical-ionization mass spectrometry in negative and positive ion modes (HPLC-APCI-MS). Recovery ranged from 54-109% for the antifouling agents and their degradation products. The determination limits for the different compounds varied between 0.2 and 1.6 microg kg(-1) dry sediment. The analytical procedure was successfully applied to the determination of these pesticides and their degradation products in marine sediment samples from different marinas of the Catalan coast. The compounds detected were: diuron, dichlofluanid, demethyldiuron, sea-nine, and Irgarol 1051. The highest concentrations were those of diuron and Irgarol 1051--136 and 88 microg kg(-1), respectively.

Aniline Compounds↗
PubMed2006

Concentrations of antifouling biocides in sediment and mussel samples collected from Otsuchi bay, Japan.

Organotin compounds (OTs) and representative booster biocides were measured in sediment and mussels from Otsuchi Bay, Japan. The mean amounts of tributyltin (TBT) and triphenyltin (TPT) compounds in sediment were 13 microg kg(-1) dry and 3 microg kg(-1) dry, respectively. Representative booster biocides (Sea-Nine 211, Diuron, Dichlofluanid, Irgarol 1501, M1, which is a degradation compound of Irgarol 1051, and Copper pyrithione) were also detected in sediment from Otsuchi Bay. OT concentrations were higher than those of the measured booster biocides. Otsuchi Bay was divided into four parts by cluster analysis based on OT concentrations in sediment sampled from the bay. These areas included the vicinity of a shipyard, a small fishing port, the closed inner area of the bay, and the mouth of the bay. Higher concentrations of TBT and TPT and a higher ratio of TBT to total BTs were observed in the vicinity of the shipyard. A higher concentration of TPT in comparison with TBT was detected in a small fishing port. Furthermore, OT concentrations in the mouth of the bay were higher than those in the closed-off section. OT concentrations in mussels decreased with distance from the shipyard. Otsuchi Bay was then divided into three parts by cluster analysis based on the concentrations of representative booster biocides found in the bay's sediment. These areas included the vicinity of a shipyard, a small fishing port, and other sites. Concentrations of Diuron and Irgarol 1051 in the vicinity of a shipyard and a small fishing port were dramatically high in comparison with the other sites. Copper pyrithione and Dichlofluanid in addition to Diuron and Irgarol 1051 were also detected in the area of a small fishing port. The concentrations of antifouling biocides were highest in the water in front of the shipyard and showed a marked decrease with distance from the shipyard.

Animals↗
PubMed1997

Isoxaben soil biodegradation in pear tree orchard after repeated high dose application.

During the past nine years, each of the plots of a pear tree orchard were treated annually with the same herbicide treatment. The following herbicide treatments were compared, each being made by application of a mixture of two or three herbicides: 1a, no herbicide at all, weeds being hoed (control 1a); 2, diuron + paraquat 3 + 1 kg/ha; 3, simazine + paraquat 2 + 1 kg/ha; 4, isoxaben + diuron + paraquat 0.5 + 1.6 + 1 kg/ha; and 5, isoxaben + simazine + paraquat 0.5 + 1.25 + 1 kg/ha. In March 1996, one year after the final orchard herbicide treatment, isoxaben could not be detected in the soils of any field plots; isoxaben was incorporated at 0.74 mg/kg in the loamy soils sampled separately in each of the field plots, and the soils were incubated in the laboratory. Isoxaben soil half-lives were 92 days in the soils treated previously with herbicide treatments 1a, 2, or 3 and 42 days in the soils treated with herbicide treatments 4 and 5. The repeated isoxaben treatments applied in the past thus enhanced the isoxaben soil biodegradation; diuron, simazine, and paraquat had no influence on this rate enhancement. On the other hand, herbicide treatments 4 and 5 were applied in the orchard in April 1996 on the corresponding plots treated in this manner for the last nine years. Isoxaben + paraquat 0.5 + 1 kg/ha was applied simultaneously on other plots (control 1b) not treated in the past with isoxaben. During the growth season in the orchard, the isoxaben soil half-lives in the control plots 1b was 101 days, and 41 days in the plots where herbicide treatments 4 or 5 were applied.

Benzamides↗
PubMed2006

Methodology and evaluation of a highly sensitive algae toxicity test based on multiwell chlorophyll fluorescence imaging.

A new phytotoxicity bioassay based on chlorophyll fluorescence imaging of algae suspensions in multiwell plates is introduced. Phytotoxicity is quantified via inhibition of photosystem II quantum yield, Y(II), assessed with the saturation pulse method. The basics of this approach as well as the factors enhancing and limiting its performance are outlined. Compared to other established techniques the new system allows exceptionally rapid and accurate measurements of phytotoxicity using pulse-amplitude-modulation (PAM) fluorometry. While instrument related errors are negligibly small, optimal performance depends on appropriate choice of algae and illumination conditions. Illustrative examples for the response of Phaeodactylum tricornutum to diuron are presented. The standard deviation involved in the Y(II) determination of a single well amounts to the equivalent of 44 ng/L diuron. A decisive role is played by the light (measuring light, saturation pulses, actinic light) to which samples are exposed during the bioassay: (1) the inhibitor response is enhanced at high measuring light intensity. (2) Saturation pulses may be considered non-invasive only, if applied at low frequency and as long as physiologically healthy algae cultures are used. (3) Continuous actinic light may be problematic, as it induces complex physiological reactions that limit the performance of the approach; it is not required for assessment of diuron-type inhibitors at high measuring light intensity.

Biological Assay↗
PubMed2004

Application of solid-phase extraction and micellar electrokinetic capillary chromatography to the study of hydrolytic and photolytic degradation of phenoxy acid and phenylurea herbicides.

A degradation study of two phenoxy acid [(2,4-dichlorophenoxy) propanoic acid and (2,4,5-trichlorophenoxy) acetic acid] and two phenylurea (diuron and monolinuron) herbicides, spiked at 50 ppb in water, was performed. Some samples were subjected to neutral and basic hydrolysis; other samples were subjected to photolysis using either sunlight or a xenon arc lamp. After degradation, the water samples were preconcentrated using solid-phase extraction (SPE) with Carbopack B columns and analysed by a micellar electrokinetic capillary chromatography (MECC) system with UV detection at 210 nm. Phenoxyacetic acids were not degraded neither by hydrolysis nor by sunlight photolysis, but they were photodegraded when they were exposed to a xenon arc lamp, with half-lives around 300 min. Phenylurea herbicides were hydrolysed at the two-tested pH, with half-lives varying from 25 to 290 days. The main hydrolysis products were the corresponding chloroanilines. Diuron and monolinuron were also degraded when they were exposed to sunlight and xenon arc lamp. The main photodegradation pathway for diuron corresponded to dehalogenation, while for monolinuron dealkylation and hydroxylation were also postulated. The toxicity of the studied herbicides and their degradation products was evaluated by means of Microtox tests. The obtained results indicated that the toxicity of the degraded samples was higher than the toxicity of the herbicides.

Chromatography, Micellar Electrokinetic Capillary↗
PubMed2004

Sediments, nutrients and pesticide residues in event flow conditions in streams of the Mackay Whitsunday Region, Australia.

The Mackay Whitsunday region covers 9000 km(2) in northeastern Australia. A study of diffuse pollutants during high flow events was conducted in coastal streams in this region. Sampling was conducted in the Pioneer River catchment during a high flow event in February 2002 and in Gooseponds Creek, Sandy Creek and Carmila Creek in March 2003. Concentrations of five herbicides; atrazine (1.3 microg l(-1)), diuron (8.5 microg l(-1)), 2,4-D (0.4 microg l(-1)), hexazinone (0.3 microg l(-1)) and ametryn (0.3 microg l(-1)) and high concentrations of nutrients (total nitrogen 1.14 mg l(-1), total phosphorus 0.20 mg l(-1)) and suspended sediments (620 mg l(-1)) were measured at Dumbleton Weir on the lower reaches of the Pioneer River. Drinking water guidelines for atrazine and 2,4-D were exceeded at Dumbleton Weir, low reliability trigger values for ecosystem protection for diuron were exceeded at three sites and primary industry guidelines for irrigation levels of diuron were also exceeded at Dumbleton Weir. Similar concentrations were found in the three smaller streams measured in 2003. Herbicides and fertilisers used in sugarcane cultivation were identified as the most likely major source of the herbicide residues and nutrients found.

Agriculture↗
PubMed2004

Herbicide contamination and the potential impact to seagrass meadows in Hervey Bay, Queensland, Australia.

Low concentrations of herbicides (up to 70 ng l(-1)), chiefly diuron (up to 50 ng l(-1)) were detected in surface waters associated with inter-tidal seagrass meadows of Zostera muelleri in Hervey Bay, south-east Queensland, Australia. Diuron and atrazine (up to 1.1 ng g(-1) dry weight of sediment) were detected in the sediments of these seagrass meadows. Concentration of the herbicides diuron, simazine and atrazine increased in surface waters associated with seagrass meadows during moderate river flow events indicating herbicides were washed from the catchment to the marine environment. Maximum herbicide concentration (sum of eight herbicides) in the Mary River during a moderate river flow event was 4260 ng l(-1). No photosynthetic stress was detected in seagrass in this study during low river flow. However, with moderate river flow events, nearshore seagrasses are at risk of being exposed to concentrations of herbicides that are known to inhibit photosynthesis.

Disasters↗
PubMed2003

Application of new high-performance liquid chromatography and solid-phase extraction materials to the analysis of pesticides in human urine.

A method for the simultaneous determination of diuron and linuron pesticides in human urine was developed, using both solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) phases made in our own laboratory. These materials were prepared by sorption of polysiloxanes onto a silica surface, followed by immobilization. The HPLC columns were prepared from poly(methyloctylsiloxane), PMOS, immobilized onto silica with microwave radiation while the SPE cartridges where made with poly(methyloctadecylsiloxane), immobilized thermally. Method validation was performed for diuron and linuron for three fortification levels. The recoveries obtained were 85-103%, the inter- and intra-assay precisions were less than 1.6 and 1.8%, respectively. The limits of quantitation and detection for diuron were 2.4 and 8.0 microg/l and for linuron were 5.0 and 12 microg/l, respectively.

Chromatography, High Pressure Liquid↗
PubMed1998

Dissipation of some citrus selective residual herbicides in an irrigation well.

The aim of this work was to study the behaviour of some of the main citrus selective residual herbicides in the water of an irrigation well. The chemicals used were: atrazine, simazine, terbuthylazine, terbutryn, terbumeton, bromacil and diuron. The simetric triazines and bromacil were analyzed by gas chromatography and diuron by HPLC. The mentioned pesticides were introduced in the well in order to simulate a point-source contamination. Levels of contamination of the well due to herbicide application were about 1 mg/l, however, dissipation of the herbicides was almost complete 8 days after application, except for bromacil and diuron which persisted longer than the s-triazines.

Chromatography, Gas↗
PubMed2003

Combined toxicity effects of MTBE and pesticides measured with Vibrio fischeri and Daphnia magna bioassays.

Methyl-tert-butyl ether (MTBE), a fuel oxygenate that is added to gasoline, commonly contaminates aquatic systems, many of which are already contaminated with pesticides. The toxic effects (EC(50) value) of several pure pesticides (Diuron, Linuron, Dichlofluanid, Sea nine, Irgarol and tributyltin (TBT)) were measured and compared with the EC(50) value of the pesticide mixed with MTBE, using the Vibrio fischeri and Daphnia magna acute toxicity assays. The interaction between chemicals was evaluated in terms of the effects of mixing on the EC(50) value (i.e. the concentration (mg/L) of a compound or mixture that is required to produce a 50% change in a toxic response parameter) and the time required to generate the toxic response. Presence of MTBE enhanced the EC(50) value of several pesticides (Diuron, Dichlofluanid, TBT and Linuron) and/or the toxic response manifested more rapidly than with pure pesticides. Toxicity enhancements were quite substantial in many cases. For example, the presence of MTBE increased the toxicity of Diuron by more than 50% when tested with the V. fischeri assay (5, 15 and 30 min exposure). Also, the toxic response manifested itself within 5 min whereas without the MTBE the same response arose in 30 min. Presence of MTBE increased the toxicity of Dichlofluanid by 30% when measured with the D. magna assay. Toxicities of only two pesticides (Sea nine and Irgarol) were not raised by the presence of MTBE.

Animals↗
PubMed2002

Toxicity evaluation of new antifouling compounds using suspension-cultured fish cells.

A simple, rapid toxicity test was developed using the suspension-cultured fish cell line CHSE-sp derived from chinook salmon Oncorhynchus tshawytscha embryos in order to assess the toxicity of new marine antifouling compounds. The compounds tested were copper pyrithione, Diuron, Irgarol 1051, KH101, Sea-Nine 211, and zinc pyrithione, all of which have been nominated in Japan as possible replacements for organotin compounds. The in vitro acute toxicity (24-h EC50) of the six compounds to these fish cells was evaluated using the dye Alamar Blue to determine cell viability, and then correlated with the results of in vivo chronic toxicities (28-day LC50) to juvenile rainbow trout Oncorhynchus mykiss. The suspension-cultured fish cells were found to be suitable for the screening of such chemicals before performing an in vivo test. The toxicities of the test compounds obtained from both tests, shown in decreasing order, were as follows: copper pyrithione > zinc pyrithione > KH101 > or = Sea-Nine 211 > Diuron > Irgarol 1051. The herbicides Diuron and Irgarol 1051 showed the least toxicity, while the pyrithiones had the greatest toxicity.

Animals↗
PubMed2006

Influence of harvesting method and washing on the presence of pesticide residues in olives and olive oil.

The influence of the preliminary steps in olive oil production (harvesting and washing) on pesticide residues in olives and olive oil has been investigated. Analyses were performed by GC-MS/MS and revealed that endosulfan sulfate and two herbicides (diuron and terbuthylazine) were the most frequently found residues in olives and olive oil. The harvesting method has a decisive influence on herbicide concentrations found in olives. Thus, 16 and 48% of the olive samples harvested on the ground after falling from the tree presented concentrations higher than the maximum residue limit (MRL) for diuron and terbuthylazine, respectively. In olives harvested directly from the tree, diuron was not found at concentrations higher than MRL and terbuthylazine was found in only 10% of the samples. The washing step performed routinely in olive mills was effective in removing the superficial contamination by herbicides present in olives harvested on the ground. Nevertheless, even after washing, the olive oil obtained from ground olives showed herbicide residue concentrations higher than those obtained from tree olives.

Agriculture↗
PubMed2002

New type of dual-channel PAM chlorophyll fluorometer for highly sensitive water toxicity biotests.

A new type of dual-channel PAM chlorophyll fluorometer has been developed, which is specialised in the detection of extremely small differences in photosynthetic activity in algae or thylakoids suspensions. In conjunction with standardised algae cultures or isolated thylakoids, the new device provides an ultrasensitive biotest system for detection of toxic substances in water samples. In this report, major features of the new device are outlined and examples of its performance are presented using suspensions of Phaeodactylum tricornutum (diatoms) and of freeze-dried thylakoids of Lactuca sativa (salad). Investigated and reference samples are exposed to the same actinic intensity of pulse-modulated measuring light. The quantum yields are assessed by the saturation pulse method. Clock-triggered repetitive measurements of quantum yield typically display a standard deviation of 0.1%, corresponding to the inhibition induced by 0.02 mug diuron l(-1). Hence, for diuron or compounds with similar toxicity, the detection limit is well below the 0.1 mug l(-1) defined as the limit for the presence of a single toxic substance in water by the European Commission drinking water regulation. The amounts of water and biotest material required for analysis are very small, as a single assay involves two 1 ml samples, each containing ca. 0.5 mug chlorophyll. Both with Phaeodactylum and thylakoids the relationship between inhibition and diuron concentration is strictly linear up to 10% inhibition, with very similar slopes. Apparent inhibition depends on the actinic effect of the measuring light, showing optima at 6 and 4 mumol quanta m(-2) s(-1) with Phaeodactylum and thylakoids, respectively.

Journal Article↗
PubMed2005

Herbicide leaching on a recharge area of the Guarany aquifer in Brazil.

The region of Ribeirão Preto City, located in Southeast of Brazil, São Paulo State, is an important sugarcane, soybean, and corn producing area with a high level of pesticides utilization. This region is also an important recharge area for groundwater supply of the Guarany aquifer. Since the past ten years atrazine, simazine, ametryn, tebuthiuron, diuron, 2,4-D, picloram, and hexazinone are the main herbicides used in this area. In order to study a possible leaching of some of these herbicides into the aquifer, surface, and groundwater samples were collected in a watershed during the years of 1996 to 2003, from different locations. To detect and quantify the herbicides a GC-MS (gas chromatograph/mass spectrometry) method was used. The response of the herbicides analyzed was linear over the concentration range of 0.02 to 2.0 microg/L. Analysis of groundwater revealed that the herbicides tebuthiuron, diuron, atrazine, simazine, and ametryn were not present in the samples. In the surface water collected in 1997, ametryn was present in two out of nine locations with concentrations ranging from 0.17 and 0.23 microg/L, which is above the allowable 0.1 microg/L according to the European safety level. The leaching potential of tebuthiuron, diuron, atrazine, simazine, 2,4-D, picloram, and hexazinone has been evaluated using CMLS-94, "Chemical Movement in Layered Soil," as simulation model. No leaching into the depth of the water table at 40 m was found.

Agriculture↗
PubMed1985

Photosynthesis involvement in the mechanism of action of diphenyl ether herbicides.

Photosynthesis is not required for the toxicity of diphenyl ether herbicides, nor are chloroplast thylakoids the primary site of diphenyl ether herbicide activity. Isolated spinach (Spinacia oleracea L.) chloroplast fragments produced malonyl dialdehyde, indicating lipid peroxidation, when paraquat (1,1'-dimethyl-4,4'-bipyridinium ion) or diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] were added to the medium, but no malonyl dialdehyde was produced when chloroplast fragments were treated with the methyl ester of acifluorfen (methyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid), oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene], or MC15608 (methyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-chlorobenzoate). In most cases the toxicity of acifluorfen-methyl, oxyfluorfen, or MC15608 to the unicellular green alga Chlamydomonas eugametos (Moewus) did not decrease after simultaneous treatment with diuron. However, diuron significantly reduced cell death after paraquat treatment at all but the highest paraquat concentration tested (0.1 millimolar). These data indicate electron transport of photosynthesis is not serving the same function for diphenyl ether herbicides as for paraquat. Additional evidence for differential action of paraquat was obtained from the superoxide scavenger copper penicillamine (copper complex of 2-amino-3-mercapto-3-methylbutanoic acid). Copper penicillamine eliminated paraquat toxicity in cucumber (Cucumis sativus L.) cotyledons but did not reduce diphenyl ether herbicide toxicity.

Journal Article↗
PubMed1984

Adaptive reorganization of protein and lipid components in chloroplast membranes as associated with herbicide binding.

Cultivation of Spirodela oligorrhiza ( Kurtz ) Hegelm on a sublethal dose of atrazine results in a higher linolenic to linoleic acid ratio in the thylakoid membrane lipids, less starch, more osmiophilic globules, and a reduced stroma lamellar system. Also, the grana become randomly oriented and contain more numerous and elongated lamellae. These alterations in the lipid composition and ultrastructure of the chloroplast resemble those previously observed in triazine-resistant weed biotypes and in chloroplasts developed under low light. Thylakoid membranes from atrazine-adapted plants revealed an additional high-affinity binding constant for [14C]-diuron but the number of diuron binding sites actually decreased by 20 times compared to controls. The 32,000-dalton membrane protein of the chloroplast is synthesized actively, but its breakdown appears decreased compared to control plants. The adaptive reorganization of thylakoid components may be a compensatory mechanism for maintenance of a functional interaction of the proteins and lipids of the photosystem II complex.

Adaptation, Physiological↗
PubMed2006

The interactive effects of binary mixtures of three antifouling biocides and three heavy metals against the marine algae Chaetoceros gracilis.

Three of the most commonly used antifouling booster biocides that are usually combined with copper or copper compounds are Irgarol 1051, Diuron, and Zn pyrithione. This study represents an assessment of the interactive effects of the antifouling biocides combined with each other, and with three heavy metals (Cu, Cd, and Zn) in binary mixtures, on the marine algae Chaetoceros gracilis. Seventy-two hour growth inhibition tests were carried out, and the IC50 values of the chemicals were determined along with growth inhibition (%) for several concentrations. The joint effect of the binary mixtures of all the chemicals was assessed by using two models, concentration addition model and the model of probabilities. The following increasing order of toxicity was obtained: Cd < Zn < Cu < Diuron < Zn pyrithione < Irgarol 1051. The interactive effects of the organic chemicals combined with each other on the growth of Ch. gracilis were firmly synergistic. Irgarol 1051 combined with Cd performed synergistic effects, and Zn pyrithione with copper and cadmium action was strictly antagonistic, and the results of the two models were in agreement in almost all mixtures.

Cadmium↗
PubMed1987

Extrachromosomal genetics in the yeast Kluyveromyces lactis. Isolation and characterization of antimycin-resistant mutants.

Antimycin-resistant (AR) mutants of the yeast Kluyveromyces lactis, obtained either spontaneously or after manganese treatment, were isolated and genetically characterized. Most of the mutants obtained after manganese mutagenesis and two spontaneous mutants, tolerated high antimycin concentrations (more than 10 micrograms/ml) and were extrachromosomal. One mutant which grew only in low antimycin (1 microgram/ml) showed a Mendelian type of inheritance. The extrachromosomal mutants could be assigned to at least two genetic loci (ARI and ARII). Mutants representative of these two groups showed increased resistance to the antibiotic when the respiration of whole cells or mitochondria was studied. Extrachromosomal mutants of Saccharomyces cerevisiae resistant to antimycin were also induced with manganese, isolated and characterized. Comparative studies of the antimycin-resistant mutants of K. lactis and S. cerevisiae permitted the following observations: a) K. lactis is more resistant to antimycin, funiculosin, mucidin and diuron than S. cerevisiae, as are the AR mutants; b) K. lactis shows correlated sensitivity to funiculosin differing in this aspect from S. cerevisiae; c) the antimycin-resistant mutants of K. lactis belonging to group II (ARII) were also resistant to diuron, tolerating concentrations of more than 200 micrograms/ml; d) all extrachromosomal antimycin-resistant-mutants of S. cerevisiae and some of the AR mutants of K. lactis were more sensitive to mucidin than the wild type.

Alkenes↗