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Phosphate-solubilising bacteria are an important component of sustainable agriculture but their number and performance are reduced due to the presence of pesticides in soils. The potato requires a high amount of phosphorus making it a fertilizer-demanding crop. Therefore, the present study was conducted with the aim to develop pesticide-tolerant phosphate-solubilising bacterial inoculants for improving growth and phosphorus content in potato. Phosphate-solubilising bacteria were isolated from potato rhizosphere and screened for pesticide tolerance, phosphate solubilisation in the presence of pesticides and growth promotion of potato in pesticide-amended soils. Nineteen phosphate-solubilising bacteria isolated from potato rhizosphere showed phosphate solubilisation ranging from 115 to 747 µg ml−1 with significant difference among the isolates. Out of 19 isolates tested for tolerance against two commonly used pesticides in potato, two isolates showed tolerance up to 7.5 μl ml−1 (3 times the recommended dose) of chlorpyrifos and 0.75 g ml−1 (2 times the recommended dose) of carbofuran. These two pesticide-tolerant bacterial isolates also showed phosphate-solubilisation in the presence of chlorpyrifos and carbofuran, although the phosphate-solubilising ability decreased significantly with increased pesticide concentrations. The isolates were identified as Arthrobacter oxydans PR1PSB2 and Bacillus flexus PR2PSB1 based on phenotypic features, biochemical tests, and matrix-assisted laser desorption/ionisation-time of flight mass spectroscopy (MALDI-TOF–MS). The bacterial treatments Arthrobacter oxydans PR1PSB2 and Bacillus flexus PR2PSB1 alone or in combined application exhibited a significant increase in the growth parameters, phosphorus (P) content, and soil available P over the uninoculated control under greenhouse conditions in potato in the presence of pesticides. However, the plant growth promotion and P content decreased with an increase in pesticide concentrations. Pesticide-tolerant phosphate-solubilising Arthrobacter oxydans and Bacillus flexus from potato are reported for the first time.

Slow decline disease caused by Tylenchulus semipenetrans is a major threat to global citrus production. Identification of suitable bio-agents that can be applied through a drip irrigation system by growers becomes inevitable for successful citrus production. Hence, field experiments were conducted to evaluate the effect of different liquid bio-inoculants, such as Bacillus subtilis, Purpureocillium lilacinum, and Trichoderma viride delivered through drip irrigation system on acid lime trees naturally infected with T. semipenetrans. They were applied at 4 L/ha, and their effect was compared with that of the spot application of carbofuran 3G at 100 g per tree. All tested bio-inoculants substantially suppressed the population density of T. semipenetrans in soil and acid lime roots. Among the bio-inoculants, P. lilacinum with 54.9–74.4% and 53.4–74.3% reductions in population in soil and root, respectively, performed best, followed by B. subtilis and T. viride. The effect of P. lilacinum was comparable to that of the chemical standard check carbofuran in location I, but P. lilacinum surpassed carbofuran in location II. Survival in soil and colonization on acid lime roots by P. lilacinum was higher than by B. subtilis and T. viride. The egg mass parasitization by P. lilacinum was also 7.1–7.5 times higher than by T. viride. The suppression of T. semipenetrans by P. lilacinum led to an increase in the number of fruits (19.0–23.3%), fruit weight (20.2–22.3%), and fruit yield (35.4–40.3%) in acid lime trees. The cost–benefit ratio by P. lilacinum was also higher (1: 2.6–1: 3.0), whereas it was lower in carbofuran treatment (1: 2.3—1: 2.4). It is concluded that the delivery of liquid P. lilacinum at 4 L/ha through a drip irrigation system was highly effective and economical for the management of acid lime trees infected with T. semipenetrans under field conditions.

Field experiments were conducted to study the effect of different liquid bio-products such as neem seed kernel extract (NSKE), azadirachtin and humic acid delivered through drip irrigation system on acid lime trees naturally infested with citrus nematode, Tylenchulus semipenetrans. All the bio-products were applied at 4 L/ha twice at 30 days interval and their effect was compared with carbofuran 3G at 100 g/tree. All the tested bio-products significantly suppressed T. semipenetrans density in soil and acid lime roots. Among them, NSKE was superior that reduced T. semipenetrans population by 56.8–58.1% in soil and 46.4–56.2% in root. Azadirachtin was the next followed by humic acid. The effect of NSKE was comparable to the chemical standard check carbofuran in location I, but NSKE surpassed carbofuran in location II. Suppression of T. semipenetrans infestation and infection by NSKE lead to improvement in the number of fruits (21.3–22.3%) and fruit weight (17.4–20.8%) in acid lime trees. NSKE delivery through drip system resulted in 35.8–37.9% more fruit yield. The benefit-cost ratio was also higher in NSKE (1:3.7–1:4.8) where as it was lesser in carbofuran treatment (1:1.3–1:3.0).

An analytical method for the accurate determination of carbamate pesticides, carbaryl, carbendazim, and carbofuran, in vegetables was established based on the isotope dilution liquid chromatography/tandem mass spectrometry (ID-LC/MS/MS) technique as a candidate reference method. For sample clean-up, a Carb/LC-NH2 solid-phase extraction (SPE) cartridge was employed to ensure an efficient recovery and color removal from the vegetable samples. Isotope analogues, 13C6-carbaryl, carbendazim-d4, and 13C6-carbofuran, were used as internal standards, respectively. This method was validated by measuring samples fortified with the three target analytes into vegetable samples and prepared homogeneous Korean cabbage powder samples in this laboratory. All results of the measured values agreed with the fortified values within their uncertainties. Repeatability and reproducibility of the method were both approximately 2%. As commercially available CRM contains only carbendazim, its content was analyzed by the developed method. The measured value of carbendazim in CRM was (0.0724 ± 0.0013) mg/kg agreeing with the certified value (0.074 ± 0.004) mg/kg. These validation data indicate the developed ID-LC/MS/MS method is reproducible, repeatable and reliable to be as a candidate reference method for accurate determination of carbamate pesticides in vegetables.

The root-knot nematode Meloidogyne incognita causes losses in tomato production, making new methods/products to control this parasite desirable. Garlic essential oil (GEO) is potentially useful for controlling M. incognita. Here, GEO was obtained by hydrodistillation, dissolved in water and used against M. incognita in vitro. At 63 μg mL−1, this oil was more active against M. incognita eggs and second-stage juveniles (J2) than the nematicide Carbofuran at 173 μg mL−1. The main components of the oil, according to gas chromatography-mass spectrometry analysis, are diallyl trisulphide (66.7%) and diallyl disulphide (21.3%), which presented lethal concentrations to 50% (LC50) J2 equal to 36.2 ± 1.7 and 134.4 ± 19.4 μg mL−1, respectively, while the LC50 for Carbofuran was 151.6 ± 2.1 μg mL−1. When the J2 submerged in a solution of the oil at 250 μg mL−1 were used to infest tomato plants, the number of galls and eggs of M. incognita in the roots were reduced to values statistically equal to those obtained when J2 were submerged in a solution of Carbofuran at 415 μg mL−1. The vapour of the oil was also as active in vitro against M. incognita eggs and J2 as the fumigant nematicide Dazomet. The infectivity and reproduction of M. incognita in tomato plants cultivated in substrate inoculated with eggs of the nematode and treated with 0.2 mL of oil per L of substrate were statistically equal to those observed when the oil was replaced by 0.25 g of Dazomet per L of substrate. These findings confirm the activity of GEO and its components against M. incognita, suggesting its potential as a new fumigant nematicide to control the nematode in tomato plants.

The field efficacy of liquid formulations of Pseudomonas fluorescens, Purpureocillium lilacinum and Trichoderma viride was investigated against natural populations of potato cyst nematodes (PCNs) Globodera rostochiensis and Globodera pallida. Two field experiments were conducted using these biocontrol agents applied as seed treatment (ST) at 1 L t−1 of seed and soil drenching (SD) at 5 L ha−1. Their effect was compared with carbofuran 3 G at 1 kg a.i. ha−1. Results showed that all the tested biocontrol agents were capable to reduce PCN egg density or multiplication rate, root penetration and egg numbers cyst−1 at various levels. The biocontrol efficacy also varied according to their delivery method. P. fluorescens-ST was found causing the highest reduction of egg density (83.1–86.5%), multiplication rate (83.1–86.5%), root penetration (67.1–68.1%) and egg numbers cyst−1 (35.4–36.0%). Similar efficacy was observed in P. lilacinum-SD that reduced egg density by 80.9–85.0%, multiplication rate by 80.7–84.3%, root penetration by 62.0–64.4% and egg numbers cyst−1 by 44.3–49.3%. The potato plants from P. fluorescens-ST and P. lilacinum-SD plots were 31.1–49.5% taller than untreated plants which also resulted in 27.2–32.0% higher tuber yield in P. fluorescens-ST and 25.9–30.2% in P. lilacinum-SD plots. The root colonisation of introduced P. fluorescens was 8.6–13.1 times higher in ST than SD. The trend was vice versa in P. lilacinum that colonised 3.1–3.6 times better in SD method than as ST. Their efficacy was comparable to carbofuran application. It is concluded that P. fluorescens-ST at 1 L t−1 of seed and P. lilacinum-SD at 5 L ha−1 are highly effective for management of PCN under naturally infested field conditions.

Seeds of papaya fruit (Carica papaya) are usually unused for the industry, but they have been previously reported to be anthelmintic. However, the effects and mechanisms involved in papaya seeds against root-knot nematodes (RKN) are poorly studied in soil incorporation. Here, we investigated soil biofumigation with papaya seeds against the RKN Meloidogyne incognita and the effect of their volatile organic compounds (VOCs) separately from non-VOCs. Soil biofumigation reduced the number of galls and eggs of RKN about 100% in tomato roots, by using seeds macerates at 4.0 g 100 mL−1, which is a feasible amount for field applications. The VOCs emitted by the seeds killed 80% of M. incognita second-stage juveniles after a few hours of exposure. Furthermore, the whole volatilome of the papaya seed was identified by gas chromatography. Some of the compounds have already been studied against RKN. Therefore, we examined the efficacy of all nonstudied compounds against M. incognita. The most promising compounds were vinyl acetate, phenylacetaldehyde and benzylacetonitrile with lethal concentrations (LC50) of 61.5, 101.3 and 14.4 μg mL−1, respectively. When vinyl acetate and phenylacetaldehyde were applied to the soil at the recommended commercial nematicide dose (396 μg mL−1), the effect on M. incognita was better than the commercial nematicide (Carbofuran), reducing 70% of the number of galls and eggs. However, benzylacetonitrile reduced galls and eggs only by 25%. These results provide evidence for biofumigation with papaya seeds as a sustainable approach to control RKN and the potential use of their VOCs as nematicidal compounds.

In the present study, two agro-industrial wastes, sugarcane bagasse, and peanut shell were employed as support of magnetite nanoparticles for the synthesis of magnetic bio-composites: magnetic sugarcane bagasse (MBO) and magnetic peanut shell (MPSo). The presence of magnetite was verified by Raman spectroscopy. Magnetic nanoparticles shape and size distribution were studied by TEM, while composites morphologies were observed by SEM. Structural characteristics of the pesticides and their possible chemical adsorption on composites were analyzed by FTIR. The removal was carried out by a batch adsorption process, and UV-VIS technique was used for pesticide concentration estimation. Elovich model described better all systems pointing out to a chemical adsorption process occurring. Experimental data isotherms of carbofuran and iprodione can be best explained by more than one mathematical model, but Sip was the ordinary equation in all systems. Maximum adsorption capacities of 175 and 89.3 mg/g for carbofuran, and 119 and 2.76 mg/g for iprodione, were obtained for MBo and MPSo, respectively.

The development and validation of a capillary electrophoresis–tandem mass spectrometry method for the determination of nine pesticides residues in corn samples is presented. The residues of thiabendazole, aminocarb, imazalil, atrazine, metazachlor, metoxuron, carbofuran, metosulam, and imazapyr have been extracted from corn samples using QuEChERS based extraction procedure. The optimal separation of investigated pesticides was achieved in less than 6 min with 0.1 mol L−1 formic acid (pH 2.4) as the background electrolyte using a poly(vinyl alcohol)-coated capillary. The coefficient of determination (r2), in the range of 5 to 200 μg L−1, were greater than 0.995. Recoveries ranged from 70% to 110%. Relative standard deviations were lower than 7.8%. The limits of detection (LODs) ranged from 0.03 to 0.28 μg kg−1, while the limits of quantitation (LOQs) ranged from 0.10 to 0.93 μg kg−1, which are several times lower than the established maximum residue limits. These results suggest that the method attends the international legislation for all the analyzed pesticides in corn and that it has the potential to be successfully applied to other food matrices.

Trace and toxic pesticide residues may still remain on crops after harvest. Thus, maximum residual levels (MRLs) of pesticides on crops have been regulated. To determine whether the remaining pesticide residue level is below MRL, time-consuming sample pretreatment is needed prior to analysis of crop samples by suitable analytical tools. By elimination of sample pretreatment steps, a high-throughput method can be developed to determine the presence of pesticide residues directly on intact crops. Carbon fiber ionization mass spectrometry (CFI-MS) is effective in determining analytes with different polarities in solid, liquid, and vapor phases in open air. Moreover, the vapor derived from solid or liquid samples possessing high vapor pressure can be readily detected by CFI-MS. The setup of CFI-MS is straightforward. A carbon fiber (diameter of ~ 10 μm and length of ~ 1 cm) is placed close (~ 1 mm) to the inlet of the mass spectrometer applied with a high voltage (− 4.5 kV). No direct electrical contact applied on the carbon fiber is required. When placing the sample with certain vapor pressure underneath the carbon fiber, analyte ions derived from the sample can be readily detected by the mass spectrometer. Given that most pesticides possess a certain vapor pressure (~ 1.33 × 10−5–~ 1.33 × 10−4 Pa), we herein develop a qualitative and quantitative analysis method to determine pesticide residues on intact fruits such as tomato based on CFI-MS without requiring any sample pretreatment. Atrazine, ametryn, carbofuran, chlorpyrifos, isoprocarb, and methomyl were selected as model samples. Low limits of detection (at nM range) were achieved for the model pesticides using the current approach. Moreover, we demonstrated that the precision and accuracy of quantitative analysis of ~ 5% and ~ 2%, respectively, could be achieved using this approach.

It is important to evaluate leaching behavior in agricultural soils to prevent the pollution of groundwater by pesticides. We identified the distribution coefficients (Kd) of ten pesticides with different physicochemical properties and compared their leaching characteristics using wick lysimeters from three distinct soil types on Jeju Island. The Kdvalues varied by pesticide and soil, but were within the range of 1.2 to 4231 L kg−1. Based on the European standard (Kd −1), six pesticides (alachlor, ethoprophos, carbofuran, napropamide, tebuconazole, and etridiazole) were mobile in at least one tested soil, and their soil organic carbon affinity was ≤ 5.811. This value differed greatly from the other pesticides (16.533 and higher). The solubility of the six mobile pesticides was ≥ 32 mg L−1, which substantially differed from the other pesticides (≤ 0.71 mg L−1). Thus, we conclude that our mobility assessment, which is based on Kdvalues, can be used to predict the leaching of pesticides in the volcanic ash soils of Jeju Island. The use of pesticides should be strictly controlled to reduce the possibility of groundwater contamination.

A controlled-release formulation (CRF) of the nematicide carbofuran (CAB) was prepared using ionically cross-linked chitosan (CHS). Four cross-linker agents were assessed, among which sulfate (SUL) obtained the highest encapsulation efficiency. Several parameters for the encapsulation of the pesticide were optimized, including pH, SUL/CHS molar ratio, stirring time, and stirring speed. The EE and the pesticide loading (PL) were 67% and 24%, respectively, in the optimized process. Scanning electron microscopy (SEM) images for empty microparticles (EMP) showed a rough and porous surface, with particle size of 1023 nm, whereas the CRF surface was found to be smoother, with a particle size of 1127 nm. The release kinetics of CAB from CRF and commercial carbofuran (CC) were evaluated in water under laboratory conditions, and the release data were fitted to the generalized Korsmeyer-Peppas model. The results indicated that the release of CAB was accomplished by a diffusion-controlled process. The CAB release from CRF was slower than that from CC, and required 6 days for 70% release, whereas CC required 5 days for 100% delivery of the pesticide. A diffusion coefficient (n) of 0.603 was determined, meaning that delivery was not governed by Fick’s laws of diffusion, but by an anomalous transport mechanism.

Made available in DSpace on 2020-12-12T02:06:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-05-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) This study aimed to evaluate histological changes in targeted tilapia organs exposed to sublethal concentrations of carbofuran. Fishes with an average weight of 67.5 ± 2.0 g were exposed to sublethal concentrations (0.0044, 0.0088, 0.0440, and 0.0880 mg L−1) of carbofuran for 7 days. In the end of the experiment, the gill, the liver, and the kidney samples were collected for histological evaluation. In gills exposed to 0.0044 mg L−1 of carbofuran, an increase in interlayer epithelium and disruption of the secondary lamella was observed, while in other concentrations (0.0088, 0.0440, and 0.0880 mg L−1), only blood congestion in the secondary lamellae occurred. In the liver samples of exposed tilapias, all carbofuran concentrations caused hepatocyte hypertrophy with the nuclei displaced to the cell periphery, stasis within the sinusoid capillaries, and necrosis points. All sublethal concentrations tested caused detachment of the glomerular capsule, necrosis in the proximal and distal tubules, and absence of intercellular space in the kidney of exposed tilapia. The presence of carbofuran in aquatic environments at concentrations from 0.0044 mg L−1 and exposure periods longer than 7 days alters the gill, the liver, and the kidney histology and consequently compromising the fish’s health. Brazil University (UNIVBRASIL), Street Carolina Fonseca, 584 Laboratory of Ecotoxicology and Occupational Health Center of Aquaculture of Unesp (CAUNESP), Street Prof. Paulo Donato Castellane Laboratory of Ecotoxicology and Pesticide Efficacy of the Barretos Educational Foundation, Prof. Roberto Frade Monte Avenue, 389 Department of Cell and Molecular Biology Colorado State University Laboratory Minimization and Wastewater Treatment Institute of Technology and Research Tiradentes University, Murilo Dantas Avenue Laboratory of Ecotoxicology and Occupational Health Center of Aquaculture of Unesp (CAUNESP), Street Prof. Paulo Donato Castellane CAPES: 01

Carbofuran is an anticholinesterase carbamate commonly used as an insecticide, nematicide and acaricide in agricultural practice throughout the world. However, data on its sorption in temperate soils from Europe is limited. Laboratory studies were conducted to determine the adsorption of carbofuran on three distinct Austrian soils using batch experiments and radiometric techniques. Carbofuran adsorption capacity of the soils was found to be low in the three soils tested and showed to be related to the soils clay and organic carbon contents. The pesticide presented linear adsorption isotherms in all of the three soils. Due to the low sorption of carbofuran in the soils tested and to its high water solubility, there is a risk of migration to water bodies through run off and consequent negative effects on aquatic organisms and soil biota.

Recent research has demonstrated the potential of using filamentous fungi to form pellets with microalgae (biopellets), in order to facilitate harvesting of microalgae from water following algae-based treatment of wastewater. In parallel, there is a need to develop techniques for removing organic pollutants such as pesticides and pharmaceuticals from wastewater. In experiments using the microalga Chlorella vulgaris, the filamentous fungus Aspergillus niger and biopellets composed of these microorganisms, this study investigated whether fungal-assisted algal harvesting can also remove pesticides from contaminated water. A mixture of 38 pesticides was tested and the concentrations of 17 of these were found to be reduced significantly in the biopellet treatment, compared with the control. After harvesting, the concentration of total pesticides in the algal treatment did not differ significantly from that in the control. However, in the fungal treatment and biopellet treatment, the concentration was significantly lower (59.6 ± 2.0 µg/L and 56.1 ± 2.8 µg/L, respectively) than in the control (66.6 ± 1.0 µg/L). Thus fungal-assisted algal harvesting through biopellet formation can also provide scope for removing organic pollutants from wastewater, with removal mainly being performed by the fungus. Electronic supplementary material The online version of this article (10.1007/s10532-018-9852-y) contains supplementary material, which is available to authorized users.

As compared to their temperate counterparts, few toxicity tests have been conducted so far into the evaluation of the sensitivity of indigenous tropical species to pesticides. Especially mixture toxicity assessments appear to be scarce. To contribute to increase our knowledge in this arena, we evaluated the acute toxicity of diuron and carbofuran and their mixtures to the neotropical oligochaetes Allonais inaequalis and Dero furcatus, and the ostracod Strandesia trispinosa. Tests were performed with both the pure active ingredients, as well as their formulated products. The toxicity of the latter to the three test organisms was generally greater than that of the pure active ingredients, although absolute differences were rather small. The sensitivity of the indigenous species was slightly greater than temperate test species from the same taxonomic groups. The concentration addition conceptual model best described the results of the mixture toxicity data. Derived deviations of this model appeared to be dependent on the test organism and as to whether the pesticides were applied as active ingredients or their commercial products. Reported field concentrations of the two pesticides indicate risks to freshwater biota, especially if they are both present. The test species used in the present study are concluded to be suitable candidates as surrogate test organisms in local pesticide risk evaluations.

An experimental study evaluating the effect of bioaugmentation and antibiotic (oxytetracycline) application on pesticide degradation and microbial community structure of a biomixture used in a biopurification system (BPR) was conducted. The bioaugmentation employed a carbofuran-degrading bacterial consortium. The non-bioaugmented biomixture showed excellent performance for removal of atrazine (t1/2: 9.9 days), carbendazim (t1/2: 3.0 days), carbofuran (t1/2: 2.8 days), and metalaxyl (t1/2: 2.7 days). Neither the addition of oxytetracycline nor bioaugmentation affected the efficiency of pesticide removal or microbial community (bacterial and fungal) structure, as determined by DGGE analysis. Instead, biomixture aging was mainly responsible for microbial population shifts. Even though the bioaugmentation did not enhance the biomixtures′ performance, this matrix showed a high capability to sustain initial stresses related to antibiotic addition; therefore, simultaneous elimination of this particular mixture of pesticides together with oxytetracycline residues is not discouraged.

In this paper, quantum dot (QD)-based molecularly imprinted polymer (MIP) was fabricated and successfully utilized as a fluorescent probe for highly selective and sensitive detection of carbofuran in water samples. The MIPs were synthesized followed by a multi-step swelling and polymerization method, and then labeled with CdSe/ZnS QDs via gradual solvent evaporation. Then the prepared QDs-MIP microspheres were introduced to flow cytometry by virtue of their good dispersibility in water, and fast adsorption and desorption. Under optimized conditions, the fluorescence intensity of QDs-MIP decreased linearly with the increasing of carbofuran in the concentration range of 1 - 20 μg L-1 (R2 > 0.99) and it can detect down to 0.2 μg L-1 of carbofuran. This method was simple, selective and applied successfully to the optosensing of trace carbofuran in water samples with good recoveries ranging from 94.1 ± 3.7 to 98.4 ± 4.5%.

Plant protection products including pesticides are extensively used in worldwide agriculture. In order to protect consumer health, maximum residue limits (MRL) have been established in many countries and by the Codex Alimentarius Commission. In Thailand, the MRL regulation exists but is not fully enforced. Thus, the purpose of this study was to determine pesticide residues in cabbages and tomatoes sold in Thailand and to evaluate if washing vegetables by running water method can remove pesticide residues. 82 cabbage and 100 tomato samples were collected from markets in Bangkok and the metropolitan Bangkok area. They were extracted and quantitatively analyzed for 42 pesticides by GC-MS/MS. Pesticide residues were detected in all of the cabbage samples, representing a rate of pesticide detection of 100%. These samples contained pesticides at levels that exceeded the recommended MRL, denoting a 100% rate of MRL exceedance. Pesticide residues were also detected in all of tomato samples but incidence of MRL exceedance in tomato samples was 82%. Washing cabbages under running water significantly reduced carbofuran residues by 93% and dimethoate residues by 65% (p 0.05) in tomato samples. Therefore, this study has documented evidence of remarkable pesticide residues detected in the cabbage and tomato sold in Thailand. These strongly suggest that Thai government authorities should implement the proper routine monitoring program of pesticide residues in vegetables and fruits. Washing vegetables before consumption is advisable as this considerably reduces the risk of exposure to pesticide residues.

An acryloyl β-cyclodextrin (A-β-CD) monolithic column for solid-phase microextraction (SPME) and determination of carbofuran and carbaryl by high-performance liquid chromatography (HPLC) have been prepared through a “one-step” polymerization method. The synthesis conditions, including the volume of cross-linker, the ratio and volume of mixed porogenic solvent consisted of methanol and N,N-dimethylformamide were optimized. The prepared monolithic column was characterized by thermogravimeteric analysis (TGA), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and Brunner-Emmet-Teller (BET) measurement. The eluent type, volume and flow rate, sample volume, flow rate, acidity, and ionic strength were optimized in detail. Under the optimized conditions, a simple, rapid, and sensitive SPME-HPLC method was developed for determination of carbofuran and carbaryl in rice samples. The method yielded a linear calibration curve in the concentration ranges of 1.5–200 μg/kg for carbofuran and 0.3–200 μg/kg for carbaryl with correlation coefficients (R 2) of above 0.9955. Limits of detection (S/N = 3) were 0.5 μg/kg for carbofuran and 0.1 μg/kg for carbaryl, respectively. The recoveries of this method ranged from 88.1 to 105.8%. The relative standard deviations were less than 8.1%.

Among the main problems faced by soybean producers is the nematode Meloidogyne incognita. Because nematicides that are more efficient and less toxic to humans and the environment than those available are desirable to control this pathogen, this work aimed at studying the essential oil of Cinnamomum cassia, which has been described as active in vitro against the nematode Bursaphelenchus xylophilus. At the concentration of 62 µg mL−1, it performed better than the nematicide carbofuran at 173 µg mL−1 in an in vitro assay with M. incognita eggs and second-stage juveniles. The main components of this oil were identified by gas chromatography–mass spectrometry analysis and submitted to in vitro assays with the nematode, which showed (E)-cinnamaldehyde (83.3% of the oil) as responsible for the nematicidal activity. Emulsions of the oil (500 µg mL−1) and this aldehyde (416 µg mL−1) reduced the numbers of M. incognita galls and eggs in soybean plants to values statistically equal to those obtained with carbofuran (415 µg mL−1). Vapors of the essential oil and (E)-cinnamaldehyde were also as active as the fumigant nematicide Basamid against M. incognita according to an in vitro assay. Cultivation of soybean plants in substrate inoculated with M. incognita eggs and treated with Basamid at 0.25 g (L of substrate)−1 or (E)-cinnamaldehyde at 1.0 mL (L of substrate)−1 caused a reduction in the nematode population to values statistically equal to each other. These results make (E)-cinnamaldehyde very promising for the development of new products to control M. incognita in soybean fields.

Biopurification systems (BPS) are employed for the treatment of pesticide-containing wastewaters. In this work, a biomixture (active core of BPS) complemented by the addition of the fungus Trametes versicolor was evaluated for the elimination of a mixture of pesticides under different treatment conditions. The biomixture achieved high removal of all the pesticides assayed after 16 d: atrazine (68.4%, t1/2: 9.6 d), carbendazim (96.7%, t1/2: 3.6 d), carbofuran (98.7%, t1/2: 3.1 d) and metalaxyl (96.7%, t1/2: 3.8 d). Variations in the treatment conditions including addition of the antibiotic oxytetracycline and co-bioaugmentation with a bacterial consortium did not significantly affect the removal performance of the biomixture. Bacterial and fungal community profiles determined by DGGE analyses revealed changes that responded to biomixture aging, and not to antibiotic or pesticide addition. The proposed biomixture exhibits very efficient elimination during simultaneous pesticide application; moreover, the matrix is highly stable during stressful conditions such as the co-application of antibiotics of agricultural use. UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro en Investigación en Contaminación Ambiental (CICA)

Background Due to the fact that chemical nematicides frequently cause environmental pollution and toxic hazards to human, plants, and domestic animals, certain biocontrol agents of environmentally and toxicologically safe properties and secure to human and animals were tested against root-knot nematode Meloidogyne incognita on cowpea. Objective The protective effect of two isolates of Bacillus subtilis, B. pumilus, or Pseudomonas fluorescens on M. incognita reproductive parameters infecting cowpea was examined, and consequently, plant growth and yield parameters were investigated. The nematicide, Furadan (10% G) was, also, included in this study for comparison. Results Bacillus subtilis (Bs2) recorded the highest average total percentage reduction (82%) of M. incognita reproductive parameters followed by B. pumilus Bp2 (81.8%). Also, Carbofuran 10% recorded the highest average total percentage reduction (76.5%) in terms of numbers of second-stage juveniles (J2) in plant roots and soil as well as nematode galls and eggmasses compared to the untreated check. The highest total average percentage plant growth increase (99%) was obtained by B. pumilus (Bp1), but B. subtilis (Bs2) and medium recorded 26.3 and 12.8% only, respectively. P. fluorescens (Pf1) scored the highest yield increase (97%) followed by Pf2 (63.8%). Number of bacterial nodules showed the highest percentage increase (78%) by P. fluorescens (Pf2). B. pumilus (Bp1) caused the highest increase of phenolic compound contents followed by P. fluorescens (Pf1). The nematicide Carbofuran 10% G was the first in increasing soluble protein contents followed by P. fluorescens (Pf1). Bacillus pumilus (Bp1) caused the highest total contents of photosynthetic pigments followed by P. fluorescens (Pf1) and (Pf2). Conclusions The tested biocontrol agents could achieve various degrees of M. incognita control on cowpea under screen house conditions with consequent increase in cowpea growth and yield parameters. These bacterial isolates need to be studied under different field conditions for confirmation.

In order to contribute to the increase of the body of knowledge on the sensitivity of tropical indigenous species to pesticides, acute and chronic toxicity tests were conducted with the neotropical cladoceran Ceriodaphnia silvestrii. Tests were carried out with the active ingredients diuron and carbofuran and one of their commercial formulations, the Diuron Nortox® 500 SC and the Furadan® 350 SC, respectively. For carbofuran, the active ingredient was more toxic than the commercial product, whereas for diuron, the commercial product appeared more toxic. In addition, hormetic effects on fertility were recorded for intermediate diuron concentrations. Acute and chronic toxicity data indicated that C. silvestrii was among the most sensitive invertebrate species for both test compounds. Based on concentrations measured in Brazilian water bodies, these compounds represent ecological risks for causing direct and indirect toxic effects on C. silvestrii and other aquatic organisms. Our results support previous claims on the advantages of using native species to better tune ecological risk assessment of chemicals in tropical ecosystems.

This work studied the effect of biogenic manganese oxides (Bio-MnOx) on carbofuran degradation.The results showed that 21.05 % and 90.63 % carbofuran, respectively, were degraded in 4 days by Bio-MnOx with and without NaN3 at initial pH 4.80, whereas carbofuran was hardly degraded by chemical manganese oxides in the same condition. Bio-MnOx promoted carbofuran hydrolysis by changing the pH of the environment and encouraged carbofuran phenol cleavage by its oxidization. Both the oxidation of carbofuran phenol by Bio-MnOx and the reoxidation of the released Mn(II) by Mn(II)-oxidizing microorganisms ensured the continuous reactivity of Bio-MnOx and prevented the secondary pollution of Mn(II). Carbofuran phenol was the major transformation product in the degradation and was further oxidized into small organic molecules as monitored by a GC/MS analyzer. This report offers an efficient, feasible, and no-secondary-pollution approach to controlling carbofuran pollution.

Wildlife poisoning is an important conservation threat for endangered species in India. There are no publications in the scientific literature that identify the specific poisons or chemicals involved in wildlife poisoning cases from the state of Kerala. In this report, all cases of wildlife mortality recorded between 2011 and 2013 at the office of the Assistant Forest Veterinary Officer, Periyar Tiger Reserve in Kerala were reviewed and cases where poisoning was considered as a differential diagnosis were identified. Specific poisons or chemicals were identified in three cases, while in a fourth, poisoning was determined to have occurred based on physical traces of the poison in gut contents. The poisons identified include carbofuran (a carbamate pesticide) in a bonnet macaque (Macaca radiata), warfarin (a rodenticide) in a mortality event involving four wild boars (Sus scrofa), endosulfan (an organochlorine pesticide) toxicity in a gaur (Bos gaurus) and imidacloprid (a neonicotinoid pesticide) toxicity in a wild adult Asian elephant (Elephas maximus). This communication thus reports for the first time on the specific chemical compounds identified in wildlife poisoning cases from Kerala state and argues for greater regulation of the sale and use of such toxic compounds in India.

Persistence and metabolism of carbofuran in the soil and sugarcane plant were studied under tropical sugarcane ecosystem. Residues of carbofuran and its metabolites in the soil, sugarcane leaf, and juice were determined by employing matrix-specific sample preparation methods and gas chromatography equipped with mass spectrometry. The recoveries of carbofuran, 3-keto carbofuran, and 3-hydroxy carbofuran were in the range of 88.75 ± 2.58-100.25 ± 2.38, 90.38 ± 2.61-98.24 ± 4.78, and 89.25 ± 3.11-98.10 ± 3.19%, respectively, at three levels of fortification across the three matrices involved in the study. At recommended dose (carbofuran 3% CG at 2 kg a.i./ha), the initial deposit of carbofuran in the soil was 14.390 ± 1.727 μg/g. The total residues comprising both carbofuran and 3-hydroxy carbofuran were detected up to 105 days after treatment with the half-life of 10.83 days. The parent compound and its metabolite were detected and quantified in the sugarcane plant (leaves and juice) from 14 days after application of carbofuran in the soil. The total residues (carbofuran and 3-hydroxy carbofuran) were detected in the leaves and cane juice up to 75 and 30 days after treatment, respectively.

Acetlycholinesterase (AChE, EC3.1.1.7) is an important serine esterase that catalyzes the hydrolysis of acetylcholine in the cholinergic system. Using the brine shrimp Artemia salina, we estimated the effects of four biocides (carbofuran, chlorpyrifos, dimethoate, and endosulfan) on nauplii mortality and AChE activity. Lethal concentration 50 (LC50) was calculated for 24, 48, and 72 h in order to select a relevant value for the suite of AChE assays. The LC50s of the four biocides to A. salina ranged from 2 to 8 mg/L for 24 h, 0.9 to 2.5 mg/L for 48 h, and 0.1 to 0.9 mg/L for 72 h, respectively. Selected doses within the LC50 value of each biocide significantly inhibited AChE activity for 24 h. In addition, these concentrations reduced dose-dependently hatching rate of A. salina cysts. This result suggested that both cysts and nauplii have sensitivities to environmental biocides-triggered toxicity. Also, AChE approach with A. salina nauplii revealed that biocides may have a toxic cholinergic effect on Artemia by inhibiting AChE activity.

Zeolite NaY modified with cetyltrimethylammonium bromide (CTAB) was considered for extraction/preconcentration of carbamate pesticides using an on-line SPE-HPLC system. The simultaneous determination of carbamate pesticides, including aldicarb, carbofuran, carbaryl, isoprocarb, methiocarb and promecarb, was performed by HPLC–UV using a LichroCART RP-18 column with gradient elution of methanol and 0.1 % acetic acid. The sorbent presented admicelles of CTAB on its surfaces and exhibited a sorption capacity of 180–18,600 mg kg−1 sorbent, which could be re-modified for at least five extraction cycles. The quantitative retention of target pesticides on the admicellar sorbent involved hydrophobic and π-cation interaction, while pesticides were eluted from the admicellar SPE column using only 750 μL of methanol. LODs and LOQs of the proposed method were 0.005–140 and 0.02–600 μg L−1, respectively. The analytes were effectively concentrated with the enrichment factors between 5 and 551. The developed on-line admicellar SPE-HPLC system was successfully applied to the determination of carbamate pesticides in ten environmental water samples from different sources. Recoveries of spiked samples at a concentration of 0.1–5 mg L−1 ranged from 77 to 111 %.

Pesticide biopurification systems contain a biologically active matrix (biomixture) responsible for the accelerated elimination of pesticides in wastewaters derived from pest control in crop fields. Biomixtures have been typically prepared using the volumetric composition 50:25:25 (lignocellulosic substrate/humic component/soil); nonetheless, formal composition optimization has not been performed so far. Carbofuran is an insecticide/nematicide of high toxicity widely employed in developing countries. Therefore, the composition of a highly efficient biomixture (composed of coconut fiber, compost, and soil, FCS) for the removal of carbofuran was optimized by means of a central composite design and response surface methodology. The volumetric content of soil and the ratio coconut fiber/compost were used as the design variables. The performance of the biomixture was assayed by considering the elimination of carbofuran, the mineralization of 14C-carbofuran, and the residual toxicity of the matrix, as response variables. Based on the models, the optimal volumetric composition of the FCS biomixture consists of 45:13:42 (coconut fiber/compost/soil), which resulted in minimal residual toxicity and ∼99 % carbofuran elimination after 3 days. This optimized biomixture considerably differs from the standard 50:25:25 composition, which remarks the importance of assessing the performance of newly developed biomixtures during the design of biopurification systems. Ministerio de Ciencia, Tecnología y Telecomunicaciones/[FI-093-13/802-B4-503]/MICITT/ Costa Rica Food and Agriculture Organization/[TC COS5/029]/FAO/Costa Rica Universidad de Costa Rica/[802-B2-046]/UCR/Costa Rica Universidad de Costa Rica/[802-B4-503]/UCR/Costa Rica UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro en Investigación en Contaminación Ambiental (CICA)

Esterase enzymes play an important role in biology because they are responsible for the hydrolysis of choline esters. In their absence, the original state of the post synaptic membranes cannot be reestablished. Therefore, the aim of the work is to study the inhibiting action exerted by the group of compounds on these enzymes. Among these class of inhibiting compounds, pesticides are important because of the potential danger as a result of their large scale use in agriculture. Pesticides are generally determined using liquid or gas chromatography methods with various detection techniques. These methods are very sensitive and discriminating, however they require sample pretreatment such as extraction, preconcentration and clean up, which are skilled techniques and high cost treatment and also time consuming. In this study, acetyl cholinesterase and butyrylcholinesterase based biosensors have emerged as a promising tool for the detection and characterization of pesticides which are inhibitors of these enzymes. Although the physiological function of butyrylcholinesterase in comparison with acetyl cholinesterase is ambiguous, it has larger substrate specificity towards choline esters. Therefore, the development of a more selective electrode against choline, can lead to more sensitive determination of the inhibitor being investigated. Hence in the present work, a method based on inhibition of butyrylcholinesterase was attempted for quantification of carbofuran on the basis of cholinesterase inhibition. Butyrylcholinesterase with an activity of 10.2 units/mg was immobilized on a solid surface by cross linking with glutaraldehyde. The immobilized system was calibrated by correlating the inhibition of the butyrylcholinesterase activity with varying concentrations of the butyryl choline chloride and carbofuran. The sensing mechanism was investigated for its response to carbofuran concentrations ranging from 125 to 1,000 ppm. The effects of butyryl choline chloride concentration on the response of the sensing strip were also determined. Through this work, a sensing element made up of a carbon based electrode, containing the immobilized butyrylcholinesterase, has been described. This element has certain practical advantages like smaller size, user friendly, easy portability and disposability.

The wide use of pesticides raises serious concerns regarding food safety and environmental impacts. There is increasing public concern about the potential health risks linked with exposure to pesticides. Regulation of maximum residue limits (MRL) of pesticide residues in food commodities has been established in many developed countries. For developing countries, like Thailand, this regulation often exists in law, but is not completely enforced in practice. Thus, pesticide residue levels in vegetables and fruits have not been thoroughly monitored. The present study aimed to examine potential health risks associated with pesticide exposure by determining the pesticide residues in two commonly consumed fruits, watermelon and durian. The fruit samples were purchased from markets in central provinces of Thailand and assayed for the content of 28 pesticides. Analysis of pesticides was performed by multiresidue extraction and followed by GC–MS/MS detection. Of 28 pesticides investigated, 5 were detected in 90.7 % of the watermelon samples (n = 75) and 3 in 90 % of durian samples (n = 30). Carbofuran, chlorpyrifos, diazinon, dimethoate and metalaxyl were found in watermelons, whereas dichlorvos, dimethoate and metalaxyl were detected in durians. However, their levels were much lower than the recommended MRL values. These pesticide levels detected in the fruits are unlikely to harm the consumers; therefore it is safe to eat watermelon and durian in Thailand. While our results found negligible risk associated with pesticide exposure from consuming these common tropical fruits, special precautions should be considered to decrease total exposure to these harmful pesticides from various foods.

A juvenile white-tailed sea eagle found alive on an island in the Baltic Sea died due to a secondary carbofuran poisoning. At necropsy, parts of a raven were found in the eagle’s gizzard, including the stomach containing seeds with carbofuran residues. Illegal persecution using poisoned baits often kill scavenging birds of prey. However, secondary poisoning of birds of prey has been rarely reported in Europe. The report aims to raise awareness to include toxicological analysis in forensic examinations in cases of otherwise healthy and well-feed birds found dead with no obvious cause of mortality.

Degradation and mineralization behavior of selected nematicides was studied in soil samples from fields cultivated with banana, potato, and coffee. Degradation assays in most of the studied soils revealed shorter half-lives for carbofuran (CBF) and ethoprophos (ETP) in samples with a history of treatment with these compounds, which may have been caused by enhanced biodegradation. A short half-life value for CBF degradation was also observed in a banana field with no previous exposure to this pesticide, but with a recent application of the carbamate insecticide oxamyl, which supports the hypothesis that preexposure to oxamyl may cause microbial adaptation towards degradation of CBF, an observation of a phenomenon not yet tested according to the literature reviewed. Mineralization assays for CBF and terbufos (TBF) revealed that history of treatment with these nematicides did not cause higher mineralization rates in preexposed soils when compared to unexposed ones, except in the case of soils from coffee fields. Mineralization half-lives for soils unexposed to these pesticides were significantly shorter than most reports in the literature in the same conditions. Mineralization rates for soils with a previous exposure to these pesticides were also obtained, adding to the very few reports found. This paper contributes valuable data to the low number of reports dealing with pesticide fate in soils from tropical origin.

A sensitive biosensor based on acetylcholinesterase (AChE) and carbon nanosphere (CNS) immobilized on a glassy carbon electrode was developed for the detection of pesticides by the inhibition of AChE activity. The inhibition effect of the pesticides resulted in a decrease of current response of the acetylthiocholine chloride that was used as a substrate to obtain an electrochemical signal. When applied to the pesticides carbofuran and fenitrothion, the designed biosensor exhibited high sensitivity and low detection limits. The inhibition ratio of carbofuran and fenitrothion were linearly proportional to their concentrations ranging from 0.40 to 4.79 and 6.26 to 125.31 μg/L, respectively. The theoretical detection limits were found to be 0.082 μg/L for carbofuran and 2.61 μg/L for fenitrothion. Furthermore, as the biosensor offers good reproducibility and stability, it could be used for trace detection of pesticides in real samples. Compared with other AChE biosensors, the proposed biosensor was convenient and it exhibited extreme sensitivity to pesticides.

A short term histological study was conducted to determine the impacts of technical grade synthetic pyrethroid insecticide, cypermethrin and carbamate pesticide, carbofuran on different phases of ovarian maturation of freshwater indigenous carp, Labeo rohita. Adult females of L. rohita were exposed to sublethal doses of carbofuran (0.06, 0.15 mg/L) and cypermethrin (0.16 and 0.40 μL/L) for 4 weeks during the pre-spawning (March), spawning (July) and post-spawning (November) phase. In the spawning phase, the carp showed maximum ovarian damage by both the pesticides while the pre-spawning phase was the next impaired stage. Considering all the phases of ovarian maturation, cypermethrin exhibited greater level of impact than carbofuran in both of its doses. Gonado-somatic indices for all these phases were also measured. In the reproductive cycle of fish, reduction in gonado-somatic index occurred by both the pesticides in all of its doses and the order was spawning > pre-spawning > post-spawning. It is concluded that ovarian maturation in Indian carp is affected by both the pesticides.

A method was developed using matrix solid-phase dispersion, together with liquid chromatography with ultraviolet diode array detector for determination of carbofuran, difenoconazole, β-cyfluthrin, spirodiclofen and thiophanate-methyl in stem of coconut palm. The best results were obtained using 2.0 g of stem, 1.6 g of Florisil as sorbent and cyclohexane:acetone mixture (4:1). The method was validated using stem samples spiked with pesticides at four concentration levels (0.05-2.0 μg/g). Average recoveries ranged from 70 % to 114.3 %, with relative standard deviations between 1.2 % and 19.2 %. Detection and quantification limits were in the ranges 0.02-0.03 and 0.05-0.1 μg/g, respectively.

We report on a multiplex bead-based competitive immunoassay using suspension array technology for the simultaneous detection of the pesticides triazophos, carbofuran and chlorpyrifos. Three hapten-protein conjugates were covalently bound to carboxylated fluorescent microspheres to serve as probes. The amount of conjugates and antibodies were optimized. The new multi-analyte assay has dynamic ranges of 0.02–50 ng mL−1, 0.5–500 ng mL−1 and 1.0–1000 ng mL−1 for triazophos, carbofuran and chlorpyrifos, respectively, and the detection limits are 0.024, 0.93 and 1.68 ng mL−1. This new multiplex assay is superior to the traditional ELISA in possessing a wider detection range, better reproducibility and the feature of multi-target detection. Cross-reactivity studies indicated that the bead-array method is highly selective for the three target pesticides, and that individual analyses have no significant influence between each other, also without cross-reactions from other structurally related pesticides. The method was applied to analyze vegetables spiked with the three pesticides, and the recoveries were in ranges of 78.5–112.1 %, 72.2–120.2 % and 70.2–112.8 %, respectively, with mean coefficients of variation of

The degradation of two pesticides, carbofuran (CBF) and ioprodine (IPR), was studied by the photolytic decomposition of hydrogen peroxide (UV/H2O2). The influence of two experimental parameters, H2O2 concentration and initial pH, as well as their interactions, was investigated. Optimization was carried out where experimental parameters were determined for the treatment of each pesticide. Both pesticides were totally eliminated by UV/H2O2 system under optimal conditions. However, significant differences were found: CBF degradation was influenced by both parameters and their interactions, while IPR degradation was not statistically affected by initial pH. Interestingly, analysis of degradation pathways showed a major influence of photolysis process and oxidation due to hydrogen peroxide for the CBF degradation, while the synergistic combination between both of them played the most relevant role during IPR degradation. A mixture of both pesticides was also submitted to UV/H2O2 action in which a lower rate was observed for IPR elimination while CBF was not affected. A 90 % of chemical oxygen demand (COD) was removed and 75 % of mineralization was achieved after the treatment of the mixture. Almost 92 % of the toxicity was eliminated making this technique a promising process to treat toxic mixtures of these pesticides.

Pesticide residues in groundwater have caused health and environmental concerns in regions in which the water is used for drinking and irrigation purposes. In this study, seven pesticide residues were studied in groundwater of a condensed agricultural area in the Al-Qassim region, Kingdom of Saudi Arabia using multiresidue gas chromatography coupled with mass spectrometry. Diazinon followed by chlorpyrifos and carbofuran was the most frequently detected pesticide in the collected water samples. In most locations, pesticide residues detected in groundwater samples were above the maximum acceptable levels of total and individual pesticide contamination of 0.5 and 0.1 μg L−1, respectively. The spatial distribution of the detected pesticides showed extremely high concentrations in intensified agricultural areas 55 km southwest of Buraydah. The results of the present study are expected to provide adequate information to enable the formulation of guidelines for permissible pesticide residues in water. Additionally, a regular monitoring program for pesticide residues in water is suggested based on the strict guidelines for pesticidal use.

We have developed a simple method for the microextraction of the carbamate pesticides carbofuran, pirimicarb, and carbaryl. It is termed ionic liquid magnetic bar microextraction (ILMB-ME) and based on an ionic liquid deposited on a magnetic stirrer bar placed in a sealed short PCR tube into which microholes where pinned. When placed in a vial containing the aqueous sample solution, the ILMB tumbles freely in the aqueous solution and the carbamates are extracted into the ionic liquid phase which then was determined by HPLC. The enrichment factors for carbofuran, pirimicarb, and carbaryl are 107, 94, 95, respectively. The limits of detection, calculated as three times the signal-to-noise ratio (S/N), are 1.4 μg L−1 for carbofuran, 3.4 μg L−1 for pirimicarb, and 1.7 μg L−1 for carbaryl. The repeatability, carried out by extracting water samples spiked with carbamate levels of 200 μg L−1, yielded relative standard deviations between 2.9 and 6.0 %, (for n = 5). The recoveries of all the three fungicides from tap, lake and rain water samples at spiking levels of 5 and 50 μg L−1 are in the range from 86 to 98 %, and from 80 to 96 %, respectively. We conclude that this is a simple, practical and efficient method for the determination of fungicide residues in real water samples.

In this work, a highly sensitive acetylcholinesterase (AChE) inhibition-based amperometric biosensor has been developed. Firstly, a glassy carbon electrode (GCE) was modified with chitosan (Chits). Then, hollow gold nanospheres (HGNs) were absorbed onto the surface of chitosan based on the strong affinity through electrostatic adsorption. After that, L-cysteine (L-cys) was assembled on HGNs through Au-S bond. The hollow gold nanospheres were prepared by using Co nanoparticles as sacrificial templates and characterized by scanning electron microscopy, transmission electron microscopy and ultraviolet spectra, respectively. Finally, AChE was immobilized with covalent binding via -COOH groups of L-cysteine onto the modified GCE. The AChE biosensor fabrication process was characterized by cyclic voltammetry and electrochemical impedance spectroscopy methods with the use of ferricyanide as an electrochemical redox indicator. Under optimum conditions, the inhibition rates of pesticides were proportional to their concentrations in the range of 0.1-150 and 0.1-200 μg L(-1) for chlorpyrifos and carbofuran, respectively, the detection limits were 0.06 μg L(-1) for chlorpyrifos and 0.08 μg L(-1) for carbofuran. Moreover, the biosensor exhibited a good stability and reproducibility and was suitable for trace detection of pesticide residues in vegetables and fruits.

A new sampling system has been developed for the measurement of time-averaged concentrations (TWA) and diffusion coefficients of organic micropollutants in aquatic environments. The system is based on the diffusion of targeted organic compounds through a rate-limiting membrane and the subsequent accumulation of these species in a bound, hydrophobic solid-phase material. Two separate prototype systems are described. One is suitable for the sampling of carbamates such as carbaryl, carbofuran, 3-hydroxycarbofuran, baygon, propham, clorpropham, and the other one for s-triazines such as atrazine, prometryn, propazine, simazine, terbuthylazine, terbutryn, metribuzin, cyanazine, and metamitron pesticides. The systems use solid-phase material (47-mm C18 Empore disk) as the receiving phase but are fitted with rate-limiting membranes of either polysulfone or polycarbonate. For the two designs investigated, the cumulative uptake of all target analytes was considered over exposure periods of 7 days. The determined sampling rates ranged from 0.1323 to 0.0465 L day−1 with both membranes. The best system was the one with the polysulfone membrane allowing a better cumulative uptake.

Organophosphate (OP) and carbamate (CP) pesticides act by the inhibition of acetylcholinesterase (AChE). This enables the use of this enzyme for the detection of these pesticides in the environment. While many studies have looked at the effect of single pesticides on AChE, the effect of mixtures of pesticides still requires extensive investigation. This is important to evaluate the cumulative risk in the case of simultaneous exposure to multiple pesticides. Therefore we examined the effect of five different pesticides (carbaryl, carbofuran, parathion, demeton-S-methyl, and aldicarb) on AChE activity to determine whether combinations had an additive, synergistic, or antagonistic inhibitory effect. Results indicated that the mixtures had an additive inhibitory effect on AChE activity. The data from the assays of the mixtures were used to develop and train an artificial neural network (ANN) which was then utilised successfully for the identification of pesticides and their concentrations in mixtures. This study is significant because it evaluated mixtures of OPs and CPs where previous studies focused on either OPs or CPs. Previous studies have only examined up to three pesticides while this study evaluated mixtures of five pesticides simultaneously. This is also the first study where an ANN was able to utilise data from the inhibition of a single enzyme to differentiate five different pesticides and their concentrations from mixtures.

We report the presence of organophosphorus and carbamate residues in 24 surface water samples and five ground water samples from Pirgacha Thana, Rangpur district, Bangladesh using high-performance liquid chromatography. A number of samples of surface water from paddy fields were found to contain chlorpyriphos, carbofuran and carbaryl at concentrations ranging from 0-1.189, 0-3.395 and 0-0.163 μg/L, respectively. Surface water from the lakes had chlorpyriphos, carbofuran and carbaryl at concentrations ranging from 0.544-0.895, 0.949-1.671 and 0-0.195 μg/L, respectively. This result indicates that the general public living in the area of Rangpur is at high risk of pesticide exposure from contaminated waters in the environment.

Disturbed soil columns, 5.8 cm in diameter and 25 cm in length, were used as a basic model to simulate the movement of carbofuran in rice field soil under saturated conditions. Bioaugmentation using a specific carbofuran degrader, Burkholderia sp. PCL3, in free and immobilized cell forms and biostimulation using rice straw as organic amendment were applied with the aim of enhancing the degradation of carbofuran in soil and to prevent the movement of carbofuran along with the flow through. In the abiotic control and the treatment with only indigenous microorganisms, the mass recovery percentage of carbofuran in the effluent was 52.1 and 22.5%, respectively. The application of bioaugmentation or biostimulation significantly enhanced carbofuran degradation in soil and reduced the movement of carbofuran as indicated by a low mass recovery percentage of carbofuran in the effluent of 14.6-15.5%. A low efficiency of carbofuran removal was obtained from the soil column with bioaugmentation together with biostimulation treatments in which the mass recovery percentage of carbofuran in the effluent was in the range of 22.1-22.6%. Sorption of carbofuran to soil, rice straw and corncob, formation of carbofuran metabolite and colony forming unit (CFU) and pH variation with the time were also investigated during column operation.

We report on a new method for sample pretreatment. It is based on solid-phase extraction combined with dispersive liquid-liquid microextraction (SPE-DLLME) and was applied to the determination of carbamates in apple and cucumber. The carbamates carbofuran, carbaryl, and pirimicarb were first extracted from samples by SPE. The analytes were then eluted from the sorbent with acetonitrile, and the DLLME technique was then applied to the resulting eluate. Finally, the analytes in the extraction solvent were determined by HPLC. Several parameters affecting the SPE-DLLME process were optimized. The new method provides enrichment factors that range from 5,400 to 7,650. Calibration plots are linear in the range from 0.25 to 100 μg kg−1 for carbofuran and carbaryl, and from 0.10 to 100 μg kg−1 for pirimicarb, with correlation coefficient (r2) ranging from 0.9980 to 0.9997. The limits of detection range from 5 to 60 pg kg−1 (at S/N = 3). The method was successfully applied to the extraction and sensitive determination of carbamates in apple and cucumber samples.

The increasing number of incidences of alleged wildlife poisoning with Furadan in Kenya has sparked off a strong lobby fronted by wildlife conservationists against Furadan use in the country and prompted this study. The worst-case scenario was in 2004 in Athi River, where a massive number of 187 African white-backed vultures (Gyps africanus) and hyenas were found dead at a spot where poisoning was suspected to have occurred through a Furadan-laced camel carcass bait. This study was initiated by the Peregrine Fund—Africa Project, and the objective was to provide evidence for Furadan exposure, its misuse and involvement in vulture poisoning and potential impact on areas near two wildlife conservancies in two most affected districts. The study found evidence for ready availability of Furadan 5G in local veterinary retail shops and its illegal misuse by pastoralists and farmers against wildlife to protect their animals and crops. Analysis of soil, water and plants taken from the farms and water sources by high-perfomance liquid chromatography (HPLC) and gas liquid chromatography–mass spectrometry (GC–MS) found residues of carbofuran, 3-hydroxycarbofuran and 3-ketocarbofuran, indicating that Furadan was used extensively in farming causing residual environmental distribution and contamination and posing risks to small birds and mammals. Forensic analysis of residues in beaks, feet and crop content of the dead vultures as well as in a laced camel carcass bait and soil samples from one site of poisoning also showed carbofuran and its two metabolites supporting allegations of Furadan involvement in wildlife poisoning and high-mortality cases of African white-backed vultures (Gyps africanus) in Kenya.

A novel yeast named HQ-C-01 was isolated from activated sludge and identified as Pichia anomala based on the morphology and 18S rDNA sequence analysis. The HQ-C-01 strain degraded 95.2% of carbofuran when the insecticide was used as the only C source and added at 50 mg/L in a mineral salts medium within 48 h. The optimal concentration, temperature, and pH of medium for degradation of carbofuran were 50 mg/L, 30°C, and pH 7.5, respectively. Strain HQ-C-01 could also effectively degrade other carbamate insecticides including carbaryl, indoxacarb, and fenobucarb, and the degradation rates were 99%, 85%, and 67%, respectively. Gas chromatography–mass spectrometry analysis showed that the strain metabolized carbofuran to produce benzofuranol as the intermediate metabolite, which was further degraded. Degradation of carbofuran added at 50 mg/kg of soil was higher in yeast-inoculated soil than in the control. These results indicated that strain HQ-C-01 may potentially be used in bioremediation of carbofuran-contaminated soil.

Pesticides are toxic chemicals used for agricultural as well as non-agricultural purposes. The toxicity of pesticides does not remain limited to the site of application but they also cause toxicity to non-target organisms in terrestrial as well as in aquatic environments. This study discusses the comparative toxicity of a carbamate (carbofuran) and an organophosphorus (malathion) pesticide to the freshwater flagellate Euglena gracilis during short- and long-term exposures. To evaluate the toxicity of the pesticides, different parameters of the flagellate, like cell density, motility, swimming velocity, cell shape, gravitactic orientation, photosynthetic efficiency, and concentration of light harvesting pigments, were used as end points. Carbofuran was found to be more toxic to E. gracilis than malathion and adversely affected almost all the tested parameters in short- and long-term experiments. The only significant adverse effect by malathion could be demonstrated on the swimming velocity of cells in short-term experiments. The adverse effects of the pesticides were more pronounced during short-term than during long-term exposure.