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National Cancer Institute... 1978A bioassay of technical-grade mexacarbate for possible carcinogenicity was conducted using Osborne-Mendel rats and B6C3F1 mice. Mexacarbate was administered in the feed,...
A bioassay of technical-grade mexacarbate for possible carcinogenicity was conducted using Osborne-Mendel rats and B6C3F1 mice. Mexacarbate was administered in the feed, at either of two concentrations, to groups of 50 male and 50 female animals of each species. The time-weighted average high and low dietary concentrations of mexacarbate were 418 and 209 ppm for male rats, 678 and 339 ppm for female rats, 654 and 327 ppm for male mice and 135 and 68 ppm for female mice. After a 78-week period of chemical administration, observation of rats continued for an additional 33 to 34 weeks and observation of mice continued for 14 to 15 additional weeks. For each species, 20 animals of each sex were placed on test as controls. All groups except the male control mice survived sufficiently long to be at risk from late-appearing tumors. Because of poor survival of the male control mice, a pooled control group was used for statistical analysis of tumor incidence in male mice. The possibility that female mice in this study did not receive maximum tolerated dosages of mexacarbate should be considered. Administration of mexacarbate had no significant effect on survival or body weights of female mice. No neoplasms occurred in statistically significant increased incidences when dosed rats were compared to controls. Among male mice surviving at least 56 weeks, significant associations with dietary concentrations were indicated by the Cochran-Armitage test for hepatocellular carcinomas, for subcutaneous fibrosarcomas and for fibromas of the skin. In none of these cases, however, were these results supported by significant Fisher exact tests. Under the conditions of this bioassay, sufficient evidence was not obtained for the carcinogenicity of mexacarbate for Osborne-Mendel rats or B6C3F1 mice.
PubMed: 12799715
DOI: No ID Found -
Bulletin of Environmental Contamination... Jul 1993
Topics: Animals; Carbamates; Insecticides; Lethal Dose 50; Lipid Peroxidation; Lymnaea; Molluscacides; Nervous System; Phorate; Phospholipids; Pyrethrins
PubMed: 8318776
DOI: 10.1007/BF00201002 -
Environmental Research Apr 1985The present study was undertaken to explore the acute toxicity of three carbamate pesticides, aldicarb, carbaryl, and mexacarbate, on a population of Paramecium...
Evaluation of carbamate toxicity: acute toxicity in a culture of Paramecium multimicronucleatum upon exposure to aldicarb, carbaryl, and mexacarbate as measured by Warburg respirometry and acute plate assay.
The present study was undertaken to explore the acute toxicity of three carbamate pesticides, aldicarb, carbaryl, and mexacarbate, on a population of Paramecium multimicronucleatum. The toxicity was evaluated by the Warburg respirometer and the static acute plate assay. Aldicarb, carbaryl, and mexacarbate were shown to significantly inhibit cumulative oxygen uptake at 24 hr in the paramecium culture at 160, 120, and 100 ppm, respectively. Aldicarb, carbaryl, and mexacarbate concentrations of 60, 20, and 10 ppm demonstrated no inhibition of cumulative oxygen uptake when compared to a paramecium control at 24 hr. Pesticide concentrations intermediate to the high and low concentrations demonstrated varying degrees of inhibition. Static plate assay data for aldicarb demonstrated LC50 values of 93, 104, 122, and 145 ppm at 24, 17, 13, and 9 hr, while carbaryl demonstrated LC50 values of 28, 34, 46, 65, and 105 ppm at 24, 17, 13, 9, and 7 hr, respectively. Mexacarbate LC50 values were 19, 25, 35, 57, and 83 ppm at 24, 17, 13, 9, and 7 hr. Oxygen uptake values compared favorably with the static assay data. Scanning electron micrographs demonstrated several morphologic changes in paramecium with increased pesticide concentration and exposure time including ciliary abnormalities and disruption of surface structure.
Topics: Aldicarb; Animals; Carbamates; Carbaryl; Dose-Response Relationship, Drug; Insecticides; Manometry; Microscopy, Electron, Scanning; Oxygen Consumption; Paramecium
PubMed: 3920045
DOI: 10.1016/0013-9351(85)90029-5 -
Environmental Science & Technology Jul 2020Sea urchin embryo assay was used to assess general toxicity at four wastewater treatment plant effluents of Biscay (Gorliz, Mungia, Gernika, and Galindo), and within the...
Sea urchin embryo assay was used to assess general toxicity at four wastewater treatment plant effluents of Biscay (Gorliz, Mungia, Gernika, and Galindo), and within the tested range, all the extracts showed embryo growth inhibition and skeleton malformation activities with EC values, in relative enrichment factor units, between 1.1-16.8 and 1.1-8.8, respectively. To identify the causative compounds, effect-directed analysis was successfully applied for the first time using a sea urchin embryo test to the secondary treatment of the Galindo effluent. To this end, two subsequent fractionation steps were performed using C18 (21 fractions) and aminopropyl columns (15 fractions). By this fractionation, the number of features detected by LC-HRMS in the raw sample was drastically reduced from 1500 to 9, and among them, two pesticides (mexacarbate, 17 ng/L, and fenpropidin, 23 ng/L), two antidepressants (amitriptyline, 304 ng/L, and paroxetine, 26 ng/L), and two anthelmintic agents (mebendazole, 65 ng/L, and albendazole, 48 ng/L) could be identified in the two toxic fractions. The artificial mixture of the identified six compounds could explain 79% of the observed effect, with albendazole and paroxetine as the predominant contributors (49% and 49%, respectively) affecting the sea urchin embryogenesis activity.
Topics: Animals; Biological Assay; Embryo, Nonmammalian; Embryonic Development; Sea Urchins; Wastewater; Water Pollutants, Chemical
PubMed: 32525664
DOI: 10.1021/acs.est.0c01504 -
Bulletin of Environmental Contamination... May 1975Field samples of freshwater algae were examined to determine the effect of the insecticide Zectran on photosynthesis rate. Concentrations of Zectran between 10 and 10(3)...
Field samples of freshwater algae were examined to determine the effect of the insecticide Zectran on photosynthesis rate. Concentrations of Zectran between 10 and 10(3) parts per billion (ppb) affected neither O2 production nor NaH14CO3 uptake in any of the seven genera tested. However, Zectran at a concentration of 10(4) ppb after 1 hour effected a reduction in photosynthesis of Chroococcus, Oedogonium and in a mixed sample composed of Zygnema,Mougeotia and Spirogyra. Mougeotia, Spirogyra and Schizogonium were not affected by exposure to 10(4) ppb Zectran after 1 hour, but O2 production was significantly reduced after 24 hours of exposure to this same concentration.
Topics: Bicarbonates; Carbamates; Carbon Dioxide; Chlorophyll; Eukaryota; Insecticides; Oxygen; Photosynthesis; Time Factors
PubMed: 1148411
DOI: 10.1007/BF01685180 -
Archives of Environmental Contamination... 1977
Topics: Animals; Carbamates; Fishes; Insecticides; Water; Water Pollutants; Water Pollutants, Chemical
PubMed: 318533
DOI: 10.1007/BF02097779 -
Journal of Agricultural and Food... 1974
Topics: Bacteria; Biodegradation, Environmental; Carbamates; Culture Media; Fungi; Insecticides; Soil Microbiology; Water Microbiology
PubMed: 4840505
DOI: 10.1021/jf60193a035 -
Journal of Chromatography Sep 1979A rapid and sensitive analytical technique to quantify carbamate insecticides at nanogram levels is reported using resin column and sorption, and desorption followed by...
A rapid and sensitive analytical technique to quantify carbamate insecticides at nanogram levels is reported using resin column and sorption, and desorption followed by N-P gas-liquid chromatography (GLC) analysis. The carbamates were extracted from natural water by percolation through a column of Amberlite XAD-2, followed by elution with ethyl acetate. The carbamate residues were directly analyzed by GLC with a Tracor Model 702 N-P detector. The recoveries for several carbamates including aminocarb, mexacarbate, carbaryl, propoxur, carbofuran, pirimicarb and methiocarb were from 86 to 108% at 1.0 and 0.01 ppm levels. Only 41 to 58% was recovered for methomyl. The extraction efficiency of Amberlite XAD-2 was pH-dependent as indicated in the extraction of aminocarb. More than 90% of the added aminocarb was recovered from phosphate buffer by the described method at pH 5.0 to 7.5 at 5.0 and 0.5 ppm levels.
Topics: Carbamates; Chromatography, Gas; Chromatography, Ion Exchange; Insecticides; Water; Water Pollutants; Water Pollutants, Chemical
PubMed: 536444
DOI: 10.1016/s0021-9673(00)92596-2 -
Toxicology Letters Dec 1983k2, Kd and ki, for 2 organophosphorus (Phorate and Formothion) and 2 carbamate pesticides (Mexacarbate and Carbaryl) using acetylcholinesterase present in homogenates of...
k2, Kd and ki, for 2 organophosphorus (Phorate and Formothion) and 2 carbamate pesticides (Mexacarbate and Carbaryl) using acetylcholinesterase present in homogenates of the nervous tissue of the snail Lymnaea acuminata, were determined. Calculation of zero time velocities demonstrated that even in their P-S form the organophosphate compounds inhibited snail acetylcholinesterase. The kinetic constants of the 2 carbamates have been explained on the basis of their structure. The toxicity of the 4 pesticides has been explained on the basis of their kinetic constants.
Topics: Acetylcholinesterase; Animals; Carbamates; Cholinesterase Inhibitors; In Vitro Techniques; Insecticides; Kinetics; Nervous System; Organophosphorus Compounds; Phosphorylation; Snails
PubMed: 6658844
DOI: 10.1016/0378-4274(83)90136-4 -
Journal of Chromatography Nov 1980A simplified and sensitive method for the analysis of eight carbamate insecticide residues in foliage, forest soil and fish tissue by direct gas-liquid chromatography...
A simplified and sensitive method for the analysis of eight carbamate insecticide residues in foliage, forest soil and fish tissue by direct gas-liquid chromatography (GLC) is described. After fortification, the carbamate residues were extracted from the natural substrates by homogenization in ethyl acetate. The interfering co-extratives present in the crude extracts were removed by filtration through Whatman GF/A glass microfibre after coagulation. The carbamate residues were re-extracted into dichloromethane and directly analyzed intact by GLC with a Tracor Model 702 nitrogen-phosphorus detector. The rate of recovery for aminocarb, carbofuran, carbaryl, methomyl, mexacarbate, pirimicarb and propoxur was better than 80% at 5.0-ppm and 0.50-ppm levels. Slightly less than 60% was recovered for methiocarb.
Topics: Animals; Carbamates; Chromatography, Gas; Fishes; Insecticides; Meat; Plants; Soil; Soil Pollutants
PubMed: 7451606
DOI: 10.1016/s0021-9673(00)84929-8