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Kuttanad is a unique wetland agriculture system featuring polder-based rice cultivation below sea level. Facing increasing pollution threats from agrochemicals, this FAO-recognized Globally Important Agricultural Heritage System (GIAHS) needs constant monitoring and risk assessment. The present study investigated the seasonal dynamics of agricultural pesticide residues in fish cultured in the wetland system. A total of 217 fish samples were analyzed, spanning three different sampling stations of Kuttanad, viz., Vaikom, Ramankari, and Edathua, during pre-monsoon, monsoon, and post-monsoon seasons. The results revealed the presence of 14 pesticides across locations and seasons. The pesticides found in the highest concentrations were propetamphos (54.64 mg L−1), thiacloprid (46.78 mg L−1), and diphenylamine (24.70 mg L−1). The most frequently detected pesticides were propoxur, fenuron, and thiacloprid. Contaminants were detected more frequently during the post-monsoon season (49%) compared to the monsoon (38%) and pre-monsoon (13%) seasons, with imidacloprid being present in all three seasons. The target hazard quotients (THQ) for propetamphos, thiacloprid, and diphenylamine were determined to be 0.04, 0.004, and 0.0002, respectively. The hazard index (HI) calculated as the sum of THQ of quantified pesticides was 0.056, indicating a low to moderate risk. However, consistent monitoring of pesticides in the Kuttanad wetland agriculture system is important to ensure timely intervention to protect biodiversity and human health. [ABSTRACT FROM AUTHOR]

The widespread use of fenobucarb and propoxur insecticides for agricultural and non-agricultural purposes causes undesirable effects on human health and environment due to their residues in surface and ground water resources. In view of this, two new, simple, accurate, sensitive, economical and reproducible optical methods have been investigated for the determination of fenobucarb and propoxur insecticides in pure form, in their commercial formulations, and agricultural samples viz. water, grains and vegetables. The methods are based on the alkaline hydrolysis of the insecticides to methyl amine and the reaction of the latter to give colored products. In the spectrophotometric method, the methyl amine formed, in presence of carbon disulfide (CS2) and Ni(II) acetate gives a yellow colored complex, which was measured at 370 nm. Beer's law is valid in the concentration range of 0.41–8.29 and 0.42–8.37 µg mL−1 for fenobucarb and propoxur, respectively. The spectrofluorimetric method is based on the study of yellow-colored product, formed by the condensation of methyl amine with acetylacetone and formaldehyde (Hantzsch reaction), at pH 5.5. The reaction product exhibits fluorescence intensity at an emission wavelength of 470 nm after excitation at a wavelength of 390 nm for both fenobucarb and propoxur insecticides. The method has linearity range of 0.14–5.53 and 0.14–5.58 µg mL−1 for fenobucarb and propoxur, respectively. The different factors which affect the reactions were thoroughly studied and optimized. The proposed methods have been successfully applied to assay both insecticides in their commercial formulations and for recovery study from spiked environmental samples. The good results of recoveries of both insecticides demonstrate the accuracy and precision of both methods. [ABSTRACT FROM AUTHOR]

A solution with 0.38 mM of the pesticide propoxur (PX) at pH 3.0 has been comparatively treated by electrochemical oxidation with electrogenerated HO (EO-HO), electro-Fenton (EF), and photoelectro-Fenton (PEF). The trials were carried out with a 100-mL boron-doped diamond (BDD)/air-diffusion cell. The EO-HO process had the lowest oxidation ability due to the slow reaction of intermediates with OH produced from water discharge at the BDD anode. The EF treatment yielded quicker mineralization due to the additional OH formed between added Fe and electrogenerated HO. The PEF process was the most powerful since it led to total mineralization by the combined oxidative action of hydroxyl radicals and UVA irradiation. The PX decay agreed with a pseudo-first-order kinetics in EO-HO, whereas in EF and PEF, it obeyed a much faster pseudo-first-order kinetics followed by a much slower one, which are related to the oxidation of its Fe(II) and Fe(III) complexes, respectively. EO-HO showed similar oxidation ability within the pH range 3.0-9.0. The effect of current density and Fe and substrate contents on the performance of the EF process was examined. Two primary aromatic products were identified by LC-MS during PX degradation. [ABSTRACT FROM AUTHOR]

A total of 39 strains of Anopheles stephensi, an important urban malaria vector, were collected from various parts of India and maintained in the insectary for this study. Based on the egg-float ridge number, 19 strains were classified into ecological variants and 32 strains were exposed to chlorpyrifos and propoxur to investigate their resistance status. Filter paper containing freshly laid eggs was taken, the ridge numbers on the floats were counted under the microscope, and strains were classified into ecological variants. Of the 19 strains, 18 were of ‘type form’, with ridge numbers ranging from 15 to 21. The Papareddipalya (PRP) strain belonged to the ‘intermediate form’, with 14 to 17 ridge numbers. Larval bioassays were carried out according to the procedure of the WHO. For chlorpyrifos, the lowest LC50 value was 0.00107 mg/l (Padmanabhanagar strain) and the highest value was 0.0403 mg/l (GOA-A strain). Furthermore, the lowest LC90 value was 0.00368 mg/l (Delhi strain) and the highest was 0.1746 mg/l (GOA-A strain). For propoxur, the lowest LC50 value was 0.00029 mg/l (Goraguntepalya strain) and the highest value was 0.0037 mg/l (JP Nagar strain). Moreover, the lowest LC90 value was 0.00094 mg/l (Goraguntepalya strain) and the highest value was 0.0115 mg/l (JP Nagar strain). The tolerance values ranged from 1.26 to 37.68 for chlorpyrifos and from 1.34 to 12.77 for propoxur. All the type forms were from urban and semi-urban locations, and the intermediate strain was from a semi-urban location. The bioassay results indicated that the strains of An. stephensi were more susceptible to propoxur than to chlorpyrifos. [ABSTRACT FROM PUBLISHER]

Carbamate pesticides like propoxur have been shown to adversely affect memory and induce oxidative stress on both acute and chronic exposure. The present study was designed to explore the modulation of the effects of propoxur over cognitive function by progesterone (PROG) and 4′-chlorodiazepam (4CD). Cognitive function was assessed using step-down latency (SDL) on a passive avoidance apparatus, transfer latency (TL) on a plus maze and spatial navigation test on Morris water maze. Oxidative stress was assessed by examining brain malondialdehyde (MDA) and reduced glutathione (GSH) levels and catalase (CAT) activity. A significant reduction in SDL and prolongation of TL and spatial navigation test was found for the propoxur (10 mg/kg/d; p.o.) treated group at weeks 6 and 7 as compared with control. One-week treatment with 4CD (0.5 mg/kg/d; i.p.) antagonized the effect of propoxur on SDL, spatial navigation test as well as TL; whereas, PROG failed to modulate this effect at a dose of 15 mg/kg/d, i.p. Propoxur produced a statistically significant increase in the brain MDA levels and decrease in the brain GSH levels and CAT activity. Treatment with 4CD at the above dose attenuated the effect of propoxur on oxidative stress whereas PROG (15 mg/kg/d; i.p.) failed to influence the same. The results of the present study thus show that 4-CD has the potential to attenuate cognitive dysfunction and oxidative stress induced by toxicants like propoxur in the brain. [ABSTRACT FROM AUTHOR]

Pyrethroids are the insecticides of choice for the treatment of bednets for malaria control. Pyrethroid resistance in Anopheles spp. vectors may adversely impact malaria control measures, and therefore it is important to know the initial level of pyrethroid resistance before pyrethroid-treated bednets are introduced. Furthermore, a search for replacement insecticides is necessary to manage any eventual high-resistance levels to pyrethroid insecticides that may affect the effectiveness of treated bednets. This study reports on the susceptibility of Anopheles gambiae s.s. exposed for 1 h to the pyrethroid insecticide permethrin and the carbamate insecticide propoxur, at eight localities in the Greater Accra region of Ghana. The observed mortality rates ranged between 21–92% and 92–100% to permethrin and propoxur, respectively. The results also showed a reduction in the knockdown time (KD50 and KD95) in propoxur (mean KD50 = 20 min and mean KD95 = 31 min) when compared with permethrin (mean KD50 = 47 min and mean KD95 = 87 min). The results suggest that permethrin may not be effective in all areas. Where pyrethroid resistance is a problem, propoxur could be an alternative for indoor residual spraying and for insecticide-treated materials such as curtains and eave screens. [ABSTRACT FROM AUTHOR]

Ultrasound-assisted emulsification-microextraction coupled to HPLC was applied to the determination of propoxur in environmental and beverage samples. Carbon tetrachloride (the extraction solvent) is added to the aqueous sample, and the liquids are sonificated at 60 °C, upon which an emulsion is formed. This is followed by centrifugation the lower phase being analyzed by HPLC. The extraction solvent, its volume, extraction time, temperature and salt concentration were optimized. Linear range (0.01–10 µg mL-1), correlation coefficient (0.9965), detection limit (1 ng mL-1 at a SNR of 3), and precision (4.5% RSD, n = 5) were determined. The technique was applied to the determination of propoxur in environmental and beverage samples and no target analyte was found in these samples. Therefore, samples were spiked and recoveries of 93–106% and RSDs of 1.5–6.2% were obtained. [ABSTRACT FROM AUTHOR]

Because of the widespread use of pesticides for domestic and industrial applications the evaluation of their genotoxic effects is of major concern to public health. Although various experimental data have provided evidence that pesticides can possess genotoxic properties in animals and in in vitro test systems after acute and chronic exposure, the information on the genotoxic effects of some of pesticides is limited and inconsistent. In the present study, the genotoxic potential of commonly used pesticides (i.e., dimethoate and methyl parathion from the organophosphate class, propoxur and pirimicarb from carbamates, and cypermethrin and permethrin from pyrethroids) have been evaluated. The genotoxic effects of these substances were examined using the single cell gel electrophoresis (comet) assay in freshly isolated human peripheral lymphocytes. The cells were incubated with 10, 50, 100 and 200 µg/ml concentrations of the test substances for 0.5 h at 37°C and DNA damage was compared with that obtained in lymphocytes from the same donor not treated with substances. Hydrogen peroxide, 100 µM, was used as a positive control. Within the concentration ranges studied, no significant cytotoxic effects were observed. Dimethoate and methyl parathion at 100 and 200 µg/ml; propoxur at 50, 100 and 200 µg/ml, and pirimicarb, cypermethrin and permethrin at 200 µg/ml significantly increased DNA damage in human lymphocytes. [ABSTRACT FROM AUTHOR]

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The insecticides demeton, dimetoat, dichlorovos, endosulfan, trichlorofon, carbaryl, lindane, methoxychlor, propoxur and malathion were examined for their ability to induce chromosomal aberrations in the bone marrow cells of the Syrian hamster ( Mesocricetus auratus) treated in vivo. Mutagenicity of commercial preparations was examined at four doses: LD; 1/2, 1/5 and 1/10 LD. The positive control was an IP injection of cyclophosphamide to hamsters at a dose of 40 mg/kg body wt. Demeton, dichlorovos and endosulfan gave positive results. Malathion, dimethoate and the mixture of methoxychlor and propoxur were weakly clastogenic; at some doses these compounds induced statistically significant increases in the number of aberrations. Trichlorfon and the mixture of carbaryl and lindane were negative in this test. [ABSTRACT FROM AUTHOR]

Copyright of Rechtsmedizin is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A bacterium capable of degrading propoxur (2-isopropoxyphenyl- N-methylcarbamate) was isolated from soil by enrichment cultures and was identified as a Pseudomonas species. The organism grew on propoxur at 2 g/l as sole source of carbon and nitrogen, and accumulated 2-isopropoxyphenol as metabolite in the culture medium. The cell free extract of Pseudomonas sp. grown on propoxur contained the activity of propoxur hydrolase. The results suggest that the organism degraded propoxur by hydrolysis to yield 2-isopropoxyphenol and methylamine, which was further utilized as carbon source. [ABSTRACT FROM AUTHOR]