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At least 19 recordsLinked to original sources

PubMed2006

Dissipation and leaching of (14)C-monocrotophos in Soil Columns under subtropical climate.

Dissipation and leaching behavior of 14C-monocrotophos was studied for 365 days under field conditions using PVC cylinders. The first set (24 cylinders) was spiked with 1.0 microCi 14C-labeled monocrotophos along with 1.06 mg unlabeled monocrotophos to give a concentration of 2 mg kg -1 in the soil up to 15 cm depth. The second set (24 cylinders) received 14C-labeled monocrotophos along with other non-labeled insecticides viz., dimethoate @ 300 g a.i ha-1, deltamethrin @ 12.5 g a.i ha-1, endosulfan @ 750 g a.i ha-1, cypermethrin @ 60 g a.i ha-1, and triazophos @ 600 g a.i ha-1 at an interval of 15 days each as recommended for the cotton crop. 14C-monocrotophos dissipated faster, up to 45% in first 90 days in columns treated with only monocrotophos compared to 25% in columns that received monocrotophos along with other insecticides. However, both the columns showed similar residues 180 days onward. After 180 days of treatment, 46% radiolabeled residues were observed, which reduced up to 39.6% after 365 days. Leaching of 14C-monocrotophos to 15-30 cm soil layer was observed in both the experimental setups. In the 15-30 cm soil layer of both soil columns, up to 0.19 mg 14C-monocrotophos kg-1d. wt. soil was detected after 270 days.

Adsorption↗

PubMed1994

Metabolism of monocrotophos in animals.

Regarding the metabolic fate of monocrotophos, it appears that the mechanisms summarized below are largely independent of the animal species. Furthermore, significant sex dependency of any of these parameters has not been found. ABSORPTION: After oral administration to rats and goats, monocrotophos is rapidly and almost completely absorbed from the intestinal tract. There is convincing evidence that monocrotophos is readily absorbed after dermal administration to man, pigs, and rabbits. DISTRIBUTION: Monocrotophos and/or its metabolites are evenly distributed between the tissues and organs of the animals; usually, the highest concentrations are typically found in organs involved in the elimination process, i.e., liver and kidney. There are no indications for any organ-specific retention. In assessing the relevance of tissue residues, the fact that monocrotophos may contribute to the carbon pool and may thus, via de novo synthesis of endogenous compounds, lead to nonmonocrotophos-related 14C-residues needs to be considered. METABOLISM: The biotransformation of monocrotophos is well understood. Three different metabolic reactions are involved in the initial biotransformation: N-demethylation, O-demethylation, and cleavage of the vinyl phosphate bond. The compound is completely degradable, ultimately leading to CO2. All carbon atoms of the molecule have the potential to enter the carbon pool. EXCRETION: After absorption and biotransformation, monocrotophos and/or its metabolites are rapidly eliminated from the animals. Excretion is predominantly in the urine, typically 70-90% of the dose, and usually less than 10% is voided with the feces. Significant amounts, i.e., 6% of the crotonamide backbone, is expired as CO2 by rats. In lactating goats, approximately 2% of the dose is eliminated with the milk. Due to the water solubility of monocrotophos, some portion of the dose may escape biotransformation and consequently be excreted unchanged.

Animals↗

PubMed1994

Monocrotophos--worker safety.

Monitoring data on field-worker exposure studies show that prolonged or continued use of monocrotophos in plant protection may lead to significant dermal exposure with an impact on cholinesterase activity. Although oral uptake (suicide) is more hazardous than dermal exposure (spray work), both exposure routes may be potentially fatal. On the other hand, prompt therapy is successful even after a heavy oral dose. The epidemiological review did not reveal a prominent risk scenario. Justification of monocrotophos use depends on agricultural need and appropriate safety measures. Eighteen cases of monocrotophos poisoning have been identified in the literature and from the manufacturer's case file. Seven cases were occupational, and nine resulted from suicide attempts. One case was a nonprofessional accident, and one was recorded without details. Further monocrotophos poisoning cases may be concealed in the unspecified data on poisoning among tropical farming communities. However, the fact remains, that only a small number of reliably reported poisoning cases are attributable to monocrotophos products, and the reports confirm the efficacy of basic medical attention to poisoning. This is in contrast to the high hazard classification and to the high perceived hazard of the products in question. Safetywise, monocrotophos appears to be better than its reputation. A level of safety precautions normally recommended for pesticide work is sufficient, even under large-scale professional use conditions, to utilize monocrotophos safely.

Cholinesterase Inhibitors↗

PubMed2006

Films coated with molecular imprinted polymers for the selective stir bar sorption extraction of monocrotophos.

The flexibility and simplicity of stir bar sorption extraction (SBSE) have been combined with the selectivity of molecularly imprinted polymers (MIP). Stir bars were coated reproducible with a 180 microm film formed from a formic acid solution of nylon-6 polymer either nonimprinted or imprinted with monocrotophos. Time sorption profiles were measured for the extraction of monocrotophos from dichloromethane at the concentration of 10-200 micromol/L levels with both types of films in order to compare extraction characteristics. The results indicated that the MIP coated layer showed remarkable high affinity toward monocrotophos and equilibrium adsorption was attained rapidly (60 min) in contrast to free standing molecularly imprinted polymer in which equilibrium adsorption was normally attained after several hours. The stir bars coated with MIP films were capable of extracting four structural analogues of monocrotophos from dichloromethane solution, which suggests that both the amino group and PO part of these molecules is responsible for interaction with the imprinted polymer. Evidence was also presented by FT-IR analysis that the amide-hydrogen-bonding interaction between the MIP-coated films and monocrotophos was originated for monocrotophos recognition. To achieve selective extraction of monocrotophos from sample, stir bars coated with MIP films were washed with 10% (v/v) acetic acid/methanol and methanol. Clean extracts and yields of 95% were obtained, demonstrating the suitability of stir bar coated with MIP films for the analysis of environmental and biological samples. Compared with traditional MIP and SBSE, the MIP-coated film showed not only the high selectivity but also the rapid equilibrium adsorption.

Caprolactam↗

PubMed2005

Effect of chlorpyrifos and monocrotophos on locomotor behaviour and acetylcholinesterase activity of subterranean termites, Odontotermes obesus.

The acute toxicity of chlorpyrifos and monocrotophos to subterranean termites, Odontotermes obesus (Rambur), has been studied by a paper contact method. The LC50 values for chlorpyrifos and monocrotophos were 0.046 and 0.148 microg cm(-2), respectively. Chlorpyrifos was 3.22-fold more toxic than monocrotophos. The effect of the pesticides on locomotor behaviour (velocity) and head acetylcholinesterase (AChE: EC 3.1.1.7) activity was estimated in LC50-exposed termites at intervals of 4, 8, 12, 16, 20 and 24 h. Chlorpyrifos- and monocrotophos-treated termites showed, respectively, 97 and 88% reduction in locomotor behaviour (velocity) after 24 h. At all time intervals the chlorpyrifos-treated termites exhibited more AChE inhibition and showed greater distorted behaviour than those exposed to monocrotophos. In vitro studies indicated that the I50 value (50% inhibition) for chlorpyrifos against AChE was 8.75 times that of monocrotophos.

Animals↗

PubMed1995

Effects of the organophosphate insecticide, monocrotophos, on acetylcholinesterase activity in the nile tilapia fish (Oreochromis niloticus) brain.

The neurotoxic effects of monocrotophos on the brain of the nile tilapia fish (Oreochromis niloticus) were examined, using a static bioassay under laboratory conditions. By probit analysis the 96 h LC50 value of monocrotophos was 4.9 mg/l. After 96 h exposure to acute levels of monocrotophos, the brain acetylcholinesterase (AChE) activity decreased progressively as the concentration of monocrotophos increased. In addition, four weeks following transfer to toxicant-free water after exposure to 1 mg monocrotophos, nile tilapia fish brain regained 95% of control AChE activity. The results indicate that inhibition of AChE activity in fish exposed to monocrotophos may serve as an indicator of hazard due to application of this chemical in the natural environment.

Acetylcholinesterase↗

PubMed2005

Degradation of monocrotophos in soils.

The degradation of a widely used organophosphorus insecticide, monocrotophos (dimethyl (E)-1-methyl-2-methylcarbamoyl vinyl phosphate) in two Indian agricultural soils at two concentration levels, 10 and 100 microg g(-1) soil under aerobic conditions at 60% water-holding capacity at 28+/-4 degrees C was studied in a laboratory. The degradation of monocrotophos at both concentrations in black vertisol and red alfinsol soils was rapid accounting for 96-98% of the applied quantity and followed the first-order kinetics with rate constants (k) of 0.0753 and 0.0606 day(-1) and half-lives (t1/2) of 9.2 and 11.4 days, respectively. Degradation of monocrotophos in soils proceeded by hydrolysis with formation of N-methylacetoacetamide. Even three additions of monocrotophos at 10 microg g(-1) soil did not result in its enhanced degradation. However, there was cumulative accumulation of N-methylacetoacetamide in soils pretreated with monocrotophos to the tune of 7-15 microg g(-1) soil. Both biotic and abiotic factors were involved in degradation of monocrotophos in soils.

Agriculture↗

PubMed1998

Decomposition of monocrotophos in aqueous solution by UV irradiation in the presence of titanium dioxide.

The decomposition of monocrotophos in aqueous solution by UV/TiO2 reduction process was studied under various pH values, TiO2 dosages, light intensities, dissolved oxygen levels and other operating conditions. The presence of dissolved oxygen inhibits the recombination of electrons and holes, and enhance the decomposition of monocrotophos by UV/TiO2 process, but excessive dissolved oxygen posed no further effect on the decomposition of monocrotophos. The decomposition rates of monocrotophos were significantly higher for acidic solutions than those for alkaline solutions. Increasing the light intensity would drastically increase the decomposition rate of monocrotophos, but was ultimately influenced by the amount of TiO2 present in solutions. The quasi-global kinetics based on a simplified consecutive reaction scheme was developed to describe the temporal behavior of monocrotophos decomposition in aqueous solution by UV/TiO2 process.

Animals↗

PubMed2001

Genotoxic effect of monocrotophos to sentinel species using comet assay.

Monocrotophos is the single largest selling agrochemical in India. Sensitive biomarkers to study the genotoxic effects caused by monocrotophos in aquatic organisms, especially fish, are lacking. The fish used in this study are Tilapia mossambica, which are edible, commercially valuable and distributed all over India. The objective of this study was to study DNA strand breaks induced by monocrotophos in T. mossambica in vivo using single-cell micro gel electrophoresis/comet assay. Tilapia were treated orally with 0.313, 0.625, 1.25, 1.875, 2.5, 3.125, 3.75 and 4.375 ppm of monocrotophos and the assay was performed on nucleated erythrocytes after 24, 48, 72 and 96 h. A significant increase in mean comet tail-length (5.21-7.46 microM), indicating DNA damage, was observed at all the doses with monocrotophos when compared to controls (3.36 microM). The mean tail-length showed a dose-related increase and time-dependent decrease. The maximum increase in mean comet tail-length was observed at 24 h. Relative to these effects, reductions in mean comet tail-length were seen at 48 and 72 h. By 96 h, values had returned to control levels at all doses, indicating repair of the damaged DNA and/or loss of heavily damaged cells. The study reveals that the comet assay is a sensitive and rapid method to detect genotoxicity of monocrotophos and other environmental pollutants in sentinel species.

Animals↗

PubMed2000

Reaction behaviors of decomposition of monocrotophos in aqueous solution by UV and UV/O processes.

The decomposition of monocrotophos (cis-3-dimethoxyphosphinyloxy-N-methyl-crotonamide) in aqueous solution by UV and UV/O(3) processes was studied. The experiments were carried out under various solution pH values to investigate the decomposition efficiencies of the reactant and organic intermediates in order to determine the completeness of decomposition. The photolytic decomposition rate of monocrotophos was increased with increasing solution pH because the solution pH affects the distribution and light absorbance of monocrotophos species. The combination of O(3) with UV light apparently promoted the decomposition and mineralization of monocrotophos in aqueous solution. For the UV/O(3) process, the breakage of the >C=C< bond of monocrotophos by ozone molecules was found to occur first, followed by mineralization by hydroxyl radicals to generate CO(3)(2-), PO4(3-), and NO(3)(-) anions in sequence. The quasi-global kinetics based on a simplified consecutive-parallel reaction scheme was developed to describe the temporal behavior of monocrotophos decomposition in aqueous solution by the UV/O(3) process.

Absorption↗

PubMed2002

Monocrotophos induced dysfunction on estrous cycle and follicular development in mice.

Monocrotophos a organophosphate pesticide was administered orally at doses of 1.6, 3.3, 6.6, 10 and 13 mg/kg body weight/day to normal virgin Swiss albino mice for 30 days. The vaginal smear and body weight of the mice were recorded daily and mice were sacrificed on 31st day. The ovaries from each animal was serially sectioned and stained for follicular studies. Estrous cycle was affected by showing a significant decrease in the number of estrous cycle and duration of proestrus, estrus and metestrus with concomitant significant increase in the duration of diestrus in all the treated groups, except with 1.6 mg/kg body weight/day monocrotophos treated group. There were significant decrease in the small, medium, large and total number of healthy follicles and increase in the medium, large and total number of atretic follicles with 6.6, 10 and 13 mg/kg body weight/day monocrotophos treatment. However, there were no significant change in the number of healthy and atretic follicles with 1.6 and 3.3 mg/kg/bodyweight/day monocrotophos treatment. There was no change organs weight except for a significant decrease in weight of the ovary with 3.3, 6.6, 10 and 13 mg/kg body weight/day and uterus and body weight with 10 and 13 mg/kg body weight/day monocrotophos treatment. Interruption in estrous cycle, decrease in healthy follicles and increase in atretic follicles may be due to harmonal imbalance or toxic effects of monocrotophos, which adversely effects reproductive function, as it has also analgesic and sedative action.

Animals↗

PubMed1991

A comparative study of blood changes and brain acetylcholinesterase inhibition by monocrotophos and its analogues in rats.

The effects of monocrotophos and its newly synthesized analogues, RPR-II and RPR-V, on hematology and blood chemistry 24 hr post-treatment were studied in rats given doses of 0.96, 1.23, and 3.0 mg/kg po, respectively. It was found that monocrotophos caused a significant increase in the mean WBC count. RPR-V, a significant decrease in hematocrit and RBC count, whereas RPR-II did not alter any hematological parameter. The activities of membrane-bound enzymes in serum were not significantly changed by all three compounds except for a statistically significant increase of 38% in SGOT activity by RPR-II. Only monocrotophos caused a significant inhibition of the brain acetylcholinesterase activity. In vitro studies with partially purified preparations of rat brain cholinesterase revealed that monocrotophos was the most potent anticholinesterase agent, followed by RPR-II and RPR-V. All three compounds caused inhibition of rat brain cholinesterase by decreasing the Vmax and increasing the Km values, indicating a mixed type of inhibition. The two analogues appeared to be less neurotoxic than monocrotophos.

Acetylcholinesterase↗

PubMed2004

Esterase-mediated tolerance to a formulation of the organophosphate insecticide monocrotophos in the entomopathogenic fungus, Beauveria bassiana (Balsamo) Vuill: a promising biopesticide.

The use of biopesticides compatible with chemical pesticides is recommended in pest management as an effective and ecologically sound strategy. The entomopathogenic fungus Beauveria bassiana (Balsamo) Vuill, which is used as a biopesticide, was found to exhibit and lose tolerance to two organophosphorus insecticides widely used in Indian fields. The pattern of response is similar to the esterase-mediated organophosphate tolerance in aphids achieved through esterase gene duplication. Therefore the role of esterase in the tolerance exhibited by isolates of B. bassiana to the organophosphate, monocrotophos, was studied. Both the total soluble protein content and esterase activity were found to increase significantly in B. bassiana cultures that were able to grow in the presence of monocrotophos. With the hitherto established linkage between esterase overproduction and organophosphate tolerance in insects and the observed similarity in response of the insects and B. bassiana to the chemical, it is concluded that tolerance to monocrotophos in B. bassiana may be due to a mechanism similar to that operating in insects. Habituation of the fungus to monocrotophos to initiate expression of esterase gene may help in achieving compatibility between the two.

Adaptation, Physiological↗

PubMed1994

Formulation of monocrotophos.

Monocrotophos is an old product that is still very much appreciated as a low-cost and efficient insecticide. Due to its water solubility, formulation recipes are rather simple and no sophisticated equipment is required in a formulation plant. Formulations can easily be manufactured locally where they are going to be used. Formulants and the formulation process do not add much to the total product cost. Monocrotophos is chemically not very stable. A consequence of this property is the marginal shelf life of formulations when stored under tropical conditions. On the other hand, the limited stability of monocrotophos is a most favorable feature in the environment that outweighs the marginal shelf life. By strictly using the "first in-first out" system in stock management, no major problems relating to storage stability will be encountered. An unfavorable characteristic of monocrotophos is its high mammalian toxicity. The objective of future projects will be to develop less toxic formulations.

Drug Stability↗

PubMed1988

Biochemical changes in the liver of fish, Tilapia mossambica (Peters), during continuous exposure to monocrotophos.

The purpose of the present investigation was to determine the effect of continuous exposure to the organophosphate monocrotophos at 2.5 ppm for over a period of 2 through 45 days on protein, RNA, and DNA contents and on 5'-nucleotidase activity in the liver of Tilapia mossambica. Protein content was decreased by 45% after 5 days, returned to control levels at 10-30 days, and again decreased by 45 days. DNA content was decreased by 2 days, returned to control values by 5 days, and remained constant throughout the exposure. In contrast, RNA content was significantly lower starting from 2 through 45 days of exposure. 5'-Nucleotidase activity showed a transient increase at 5 and 30 days of monocrotophos exposure. These results indicate that monocrotophos altered the protein, DNA, and RNA contents and the 5'-nucleotidase activity levels as early as 2 and 5 days. However, these changes were reversed by 10 days and after a short period of recovery, the alterations reappeared. This supports our earlier histological observations of hepatic pathology during monocrotophos exposure.

Animals↗

PubMed2002

Detection of DNA damage in mouse peripheral blood leukocytes by the comet assay after oral administration of monocrotophos.

The objective of this study was to determine if single/double strand DNA breaks could be induced by monocrotophos (organophosphorus pesticide) in mice in vivo using the comet assay. Mice were dosed orally with 0.046, 0.093, 0.186, 0.373 and 0.746 mg/kg body weight of monocrotophos, and the assay was performed on whole blood after 24, 48 and 72 h. A significant increase in mean comet tail length indicating DNA damage was observed at 24 and 48 h post-treatment with monocrotophos when compared to controls. A decrease in the mean tail length was observed at 72 h post-treatment indicating repair of the damaged DNA. The mean tail length showed a dose-related increase and time dependent decrease. The study reveals that comet assay is a sensitive and rapid method to detect genotoxicity of monocrotophos.

Administration, Oral↗

PubMed2006

Isolation and characterization of a denitrifying monocrotophos-degrading Paracoccus sp. M-1.

A bacterium strain, which is capable of degrading monocrotophos, was isolated from sludge collected from the bottom of a wastewater treatment system of a chemical factory, and named M-1. On the basis of the results of the cellular morphology, physiological and chemotaxonomic characteristics and phylogenetic similarity of 16S rDNA gene sequences, the strain was identified as a Paracoccus sp. The ability of the strain to mineralize monocrotophos was investigated under different culture conditions. Other organophosphorus insecticides and amide herbicides were also degraded by M-1. The key enzyme (s) involved in the initial biodegradation of monocrotophos in M-1 was shown to be a constitutively expressed cytosolic protein. The addition of M-1 (10(6) CFU g(-1)) to fluvo-aquic soil and a high-sand soil containing monocrotophos (50 mg kg(-1)) resulted in a higher degradation rate than that obtained from noninoculated soil. This microbial culture has great potential utility for the bioremediation of wastewater or soil contaminated with organophosphorus pesticides and amide herbicides.

Biodegradation, Environmental↗

PubMed1999

Impact of monocrotophos on protein and carbohydrate metabolism in different tissues of albino rats.

The impact of monocrotophos on protein and carbohydrate metabolism in different tissues of albino rats was investigated. The monocrotophos (0.25 mg/ml) was orally intubated into an experimental group of rats. In another group, the same amount of water was orally intubated (control group) for 29 days. The protein content was increased in liver, serum and spleen of albino rats after treatment with monocrotophos. The protein content decreased in muscle and kidney, and overall the free sugar level decreased in all tissues. The glycogen content increased in muscle, serum and kidney after treatment with monocrotophos, and the glycogen content and reducing sugar level decreased in liver and spleen. The significance of these results is discussed.

Animals↗