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Ecotoxicology and Environmental Safety Feb 2006In this study, five carbamate insecticides were subjected to 96 h acute toxicity tests to examine their effects on three cyanobacteria, Anabaena flos-aquae, Microcystis... (Comparative Study)
Comparative Study
In this study, five carbamate insecticides were subjected to 96 h acute toxicity tests to examine their effects on three cyanobacteria, Anabaena flos-aquae, Microcystis flos-aquae, and Mirocystis aeruginosa, and five green algae, Selenastrum capricornutun, Scenedesmus quadricauda, Scenedesmus obliquus, Chlorella vulgaris, and Chlorella pyrenoidosa. The average acute toxicity of the carbamate insecticides to the cyanobacteria and the green algae was in descending order carbaryl>carbofuran, propoxur, metolcarb > carbosulfan. Wide variations in response to the tested carbamate insecticides occurred among the eight individual species of cyanobacteria and green algae. The sensitivity of various species of algae exposed to carbofuran, propoxur, metolcarb, and carbaryl varied over one order of magnitude, and that of algae exposed to carbosulfan varied over two orders of magnitude. With regard to the diffrential sensitivity of cyanobacteria and green algae, the cyanobacteria were less sensitive than green algae to carbosulfan and propoxur. The pollutants may initiate a shift of algal group structure; especially, a shift from dominance by green algae to dominance by cyanobacteria, and may sustain cyanobacterial blooms at particular times. Therefore, the descending order of the ecosystem risk was carbosulfan > propoxur > carbofuran > carbaryl, metolcarb. There was a strong variance between toxicity and ecosystem risk; i.e., "low toxicity" does not imply "low ecosystem risk."
Topics: Carbamates; Chlorophyta; Cyanobacteria; Insecticides; No-Observed-Adverse-Effect Level
PubMed: 16677910
DOI: 10.1016/j.ecoenv.2004.12.002 -
Journal of AOAC International 2005A simplified method for determining carbamate insecticides (including metolcarb, isoprocarb, fenobucarb, carbofuran, pirimicarb, and carbaryl) in Chinese medicinal herbs...
A simplified method for determining carbamate insecticides (including metolcarb, isoprocarb, fenobucarb, carbofuran, pirimicarb, and carbaryl) in Chinese medicinal herbs (White Peony Alba, Red Peony Root, and Baical Skullcap Root) is described. Standards were fortified into Chinese medicinal herbs at 3 levels (0.05-0.5 mg/kg). The carbamates were extracted with dichloromethane in a Soxhlet apparatus and analyzed by gas chromatography with a nitrogen-phosphorus detector. The results showed average recoveries between 80.77 and 104.56%. The method evidenced good robustness, accuracy, and precision for monitoring carbamates in Chinese medicinal herb samples, and it is a suitable alternative to replace the currently dedicated analytical systems. The minimum detectable amount ranged from 3.0 x 10(-10) to 5.0 x 10(-10)g, and the limit of quantification was 0.05 mg/kg. The method is rapid, simple, sensitive, and reproducible, and it can be conveniently used as a low-cost, rapid method for measuring the carbamate insecticide contamination of Chinese medicinal herbs.
Topics: Carbamates; Carbaryl; Carbofuran; Chromatography, Gas; Drugs, Chinese Herbal; Insecticides; Nitrogen; Pesticide Residues; Phosphorus; Plant Extracts; Pyrimidines; Reproducibility of Results; Soil Pollutants; Time Factors; Water Pollutants
PubMed: 16152951
DOI: No ID Found -
Se Pu = Chinese Journal of... Sep 1997Methomyl, metolcarb, propoxur, carbaryl, isoprocarb, diuron and bassa are all carbamate pesticides. In this paper, a reversed-phase HPLC method is described for analysis...
Methomyl, metolcarb, propoxur, carbaryl, isoprocarb, diuron and bassa are all carbamate pesticides. In this paper, a reversed-phase HPLC method is described for analysis of these carbamate pesticides in biological samples with Spherisorb C18 column (150 mm x 2.0 mm i.d., 5 microm), 60:40 (V/V) MeOH-H20 eluent and photodiode array detector. These pesticides were identified by their spectrum characteristics and retention times. Their quantity was determined by their peak area. The biological samples were extracted with C18 cartridge and eluted with ethyl acetate, and then analysed by HPLC. The sensitivity of detection for the seven carbamates was in the range of 1-2 mg/L of blood sample and 5-10 mg/L of urine sample. The recoveries of blood and urine samples were 70%-80% and 65%-82%, respectively. The method is simple, rapid and highly sensitive.
Topics: Carbamates; Chromatography, High Pressure Liquid; Pesticide Residues; Solid Phase Extraction
PubMed: 15739503
DOI: No ID Found -
Journal of Chromatography. A May 2003A dynamic ultrasound-assisted method for the extraction of N-methylcarbamates (oxamyl, dioxacarb, metolcarb, carbofuran, carbaryl and isoprocarb) from soils and foods is...
Continuous ultrasound-assisted extraction coupled to on line filtration-solid-phase extraction-column liquid chromatography--post column derivatisation-fluorescence detection for the determination of N-methylcarbamates in soil and food.
A dynamic ultrasound-assisted method for the extraction of N-methylcarbamates (oxamyl, dioxacarb, metolcarb, carbofuran, carbaryl and isoprocarb) from soils and foods is proposed. The main factors affecting the extraction efficiency have been optimised by means of a central composite design. Pure water can be used as leaching agent. A flow injection manifold coupled to the extractor allows automation of the several steps involved in the analytical process. The method allows extraction of the carbamates from soil and food at 1 microg/g spiked level, with recoveries similar to those provided by the EPA 8318 method, without degradation of the target compounds during the extraction and with drastic shortening of the time required for this step (2 min vs. 4 h). Recoveries of the target analytes were 77-95% for spiked soil and 85-101% for spiked food. The detection and quantification limits were 12 and 40 ng/g, respectively, for all analytes, except carbaryl (detection and quantification limits 3 and 10 ng/ng, respectively). The relative standard deviations for repeatability and within-laboratory reproducibility were 3.1 and 7.5%, respectively.
Topics: Carbamates; Chromatography, Liquid; Filtration; Food Analysis; Reproducibility of Results; Sensitivity and Specificity; Soil; Spectrometry, Fluorescence; Ultrasonics
PubMed: 12862371
DOI: 10.1016/s0021-9673(03)00646-0 -
Wei Sheng Yan Jiu = Journal of Hygiene... Mar 2000The acute oral toxicity (LD50) of two pesticides combined from 3 categories of insecticides, i.e. organophosphates(OPs), pyrethroids and carbamates, was evaluated by...
The acute oral toxicity (LD50) of two pesticides combined from 3 categories of insecticides, i.e. organophosphates(OPs), pyrethroids and carbamates, was evaluated by Harris method on equal toxicity doses. The OPs compounds studied included: methylparathion, omethoate, methamidophos, phoxim, dichlorvos, profenofos, isocarbophos and malathion; the pyrethroids: alpha-cypermethrin, deltamethrin, fenvalerate and fenpropathrin; the carbamates: methomyl, isoprocarb and metolcarb. The mixtures of two OPs on the combination of dichlorvos plus omethoate and methamidophos plus profenofos showed additive effects, but methylparathion plus phoxim showed antagonistic effect. Most of the combination of OPs with pyrethroids showed synergistic effects, such as the mixtures of phoxim plus deltamethrin, phoxim plus alpha-cypermethrin, methlyparathion plus alpha-cypermethrin and ioscoarbphos plus fenpropthrin, with the exception of two mixtures showed additive effects: phoxim plus fenvalerate resulting in 1.5 times higher toxicity than expected, while dichlorvos plus deltamethrin resulting in less toxicity than expected. The effects of the mixtures of OPs and carbamates: phoxim plus methomyl and methamidophos plus metolcarb, were all additive, but the mixtures of he methylparathion plus methomyl showed antagonistic effect and malathion plus isoprocarb were synergistic. The biochemical mechanisms of changed toxicity of pesticides mixtures were discussed based on their toxicokinetics and toxicodynamics. It was concluded that the combined effects of insecticide mixtures were additive for OPs plus OPs or plus carbamates in most cased, but synergistic for OPs plus pyrethroids.
Topics: Animals; Drug Synergism; Female; Insecticides; Male; Methomyl; Methyl Parathion; Pyrethrins; Rats; Rats, Wistar
PubMed: 12725074
DOI: No ID Found -
FEMS Microbiology Letters Jul 2001A carbaryl hydrolase was purified to homogeneity from Arthrobacter sp. strain RC100 by protamine sulfate treatment, ammonium sulfate precipitation, and hydrophobic,...
A carbaryl hydrolase was purified to homogeneity from Arthrobacter sp. strain RC100 by protamine sulfate treatment, ammonium sulfate precipitation, and hydrophobic, anion-exchange, and gel filtration chromatographies. The native enzyme had a molecular mass of 100 kDa and was composed of two identical subunits with molecular masses of 51 kDa. The hydrolase activity was strongly inhibited by DIFP, PMSF, Hg(2+) and paraoxon but not by EDTA. The optimum pH and temperature for the enzyme activity were 9.0 and 50 degrees C, respectively. The enzyme hydrolyzed four N-methylcarbamate insecticides (carbaryl, xylylcarb, metolcarb and XMC), but was not able to hydrolyze fenobucarb, propoxur, and isoprocarb.
Topics: Arthrobacter; Carbaryl; Carboxylic Ester Hydrolases; Edetic Acid; Enzyme Inhibitors; Hydrogen-Ion Concentration; Insecticides; Kinetics; Mercury; Molecular Weight; Paraoxon; Protease Inhibitors; Protein Subunits; Substrate Specificity; Temperature
PubMed: 11445174
DOI: 10.1111/j.1574-6968.2001.tb10739.x