Organophosphorus Insecticide Residues Research Articles

Optimization of an analytical method for carbaryl and chlorpyrifos residues determination by LC-MS/MS

The present study was aimed to optimize an analytical method for the quantification of carbamate and organophosphorus insecticide residues using Liquid Chromatography tandem Mass Spectrometry (LC-MS/MS). A series of experiments were conducted to select the parent ion and precusor ion and based on these findings, the analytical method for the determination of carbamate and organophosphorus insecticide residues using LC-MS/MS was developed. The electrospray ionization (ESI) mode was used to develop the method. The linearity of the developed analytical method was very good and it was 0.999 for carbaryl, while it was 0.998 for chlorpyrifos. The optimization of MS/MS parameters has been done properly for both of the selected pesticides through direct infusion of 100 ug/L pure analytical standard solutions. Asian Australas. J. Biosci. Biotechnol. 2022, 7 (3), 107-113

Impacts of dietary exposure to pesticides on faecal microbiome metabolism in adult twins

BackgroundDietary habits have a profound influence on the metabolic activity of gut microorganisms and their influence on health. Concerns have been raised as to whether the consumption of foodstuffs contaminated with pesticides can contribute to the development of chronic disease by affecting the gut microbiome. We performed the first pesticide biomonitoring survey of the British population, and subsequently used the results to perform the first pesticide association study on gut microbiome composition and function from the TwinsUK registry.MethodsDietary exposure of 186 common insecticide, herbicide, or fungicide residues and the faecal microbiome in 65 twin pairs in the UK was investigated. We evaluated if dietary habits, geographic location, or the rural/urban environment, are associated with the excretion of pesticide residues. The composition and metabolic activity of faecal microbiota was evaluated using shotgun metagenomics and metabolomics respectively. We performed a targeted urine metabolomics analysis in order to evaluate whether pesticide urinary excretion was also associated with physiological changes.ResultsPyrethroid and/or organophosphorus insecticide residues were found in all urine samples, while the herbicide glyphosate was found in 53% of individuals. Food frequency questionnaires showed that residues from organophosphates were higher with increased consumption of fruit and vegetables. A total of 34 associations between pesticide residue concentrations and faecal metabolite concentrations were detected. Glyphosate excretion was positively associated with an overall increased bacterial species richness, as well as to fatty acid metabolites and phosphate levels. The insecticide metabolite Br2CA, reflecting deltamethrin exposure, was positively associated with the phytoestrogens enterodiol and enterolactone, and negatively associated with some N-methyl amino acids. Urine metabolomics performed on a subset of samples did not reveal associations with the excretion of pesticide residues.ConclusionsThe consumption of conventionally grown fruit and vegetables leads to higher ingestion of pesticides with unknown long-term health consequences. Our results highlight the need for future dietary intervention studies to understand effects of pesticide exposure on the gut microbiome and possible health consequences.

Quinolone and Organophosphorus Insecticide Residues in Bivalves and Their Associated Risks in Taiwan.

Bivalves, such as freshwater clams (Corbicula fluminea) and hard clams (Meretrix lusoria), are the most extensive and widely grown shellfish in land-based ponds in Taiwan. However, few studies have examined the contamination of bivalves by quinolone and organophosphorus insecticides. Thus, we adapted an established procedure to analyze 8 quinolones and 12 organophosphorus insecticides using liquid and gas chromatography–tandem mass spectrometry. Surveys in Taiwan have not noted high residual levels of these chemicals in bivalve tissues. A total of 58 samples of freshwater or hard clams were obtained from Taiwanese aquafarms. We identified 0.03 mg/kg of enrofloxacin in one freshwater clam, 0.024 mg/kg of flumequine in one freshwater clam, 0.02 mg/kg of flumequine in one hard clam, 0.05 mg/kg of chlorpyrifos in one freshwater clam, 0.03 mg/kg of chlorpyrifos in one hard clam, and 0.02 mg/kg of trichlorfon in one hard clam. The results indicated that 5.17% of the samples had quinolone insecticide residues and 5.17% had organophosphorus residues. However, the estimated daily intake (EDI)/acceptable daily intake quotient (ADI) indicated no significant risk and no immediate health risk from the consumption of bivalves. These results provide a reference for the food-safety screening of veterinary drugs and pesticides in aquatic animals. Aquatic products should be frequently screened for residues of prohibited chemicals to safeguard human health.

Analytical Detection of Sulfonamides and Organophosphorus Insecticide Residues in Fish in Taiwan.

Exposure to residues of antibiotics (e.g., sulfonamides) and insecticides (e.g., organophosphorus insecticides) in aquacultured food can adversely affect humans and animals and thus affect public health globally. Here, using a validated method, we examined the levels of residues of 12 sulfonamides as well as 18 organophosphorus insecticides in aquacultured fish in Taiwan. A total of 52 fish samples (i.e., 20 tilapia, 16 milk fish, and 16 perch samples) were obtained from Taiwanese aquafarms from June 2018 to October 2019. We detected 0.02 and 0.03 mg/kg of sulfamethazine (a sulfonamide) in one tilapia and one milk fish, respectively, and 0.02, 0.05, and 0.03 mg/kg of chlorpyrifos (an organophosphorus insecticide) in one tilapia, one milk fish, and one perch, respectively; thus, among the samples, 3.85% and 5.77% contained sulfonamides and organophosphorus insecticide residues, respectively. Furthermore, we assessed human health risk based on the estimated daily intakes (EDIs) of these residues: EDIs of sulfonamide and organophosphorus insecticide residues were <1.0% of the acceptable daily intake recommended by the Joint Food and Agriculture Organization of the United Nations/World Health Organization Expert Committee on Food Additives. The risk of exposure to sulfonamide and organophosphorus insecticide residue by consuming aquacultured fish in Taiwan was thus negligible, signifying no immediate health risk related to the consumption of fish. Our findings can constitute a reference in efforts geared toward ensuring food safety and monitoring veterinary drug and insecticide residue levels in aquacultured organisms. Residue levels in fish must be continually monitored to further determine possible effects of these residues on human health.

Cover Image, Volume 43, Issue 8

The cover image is based on the Original Article Storage stability improvement of organophosphorus insecticide residues on representative fruit and vegetable samples for analysis by Jiannan Dong et al., DOI 10.1111/jfpp.14048

Storage stability improvement of organophosphorus insecticide residues on representative fruit and vegetable samples for analysis

Accuracy of data for pesticide residues analysis is particularly important because analytical results are the basis for risk assessment and taking regulatory action. We, therefore, investigated the storage stability of eight organophosphorus pesticides on seven different kinds of matrices under different conditions; and the improvement measures of the stability of five pesticides on cabbage and potato were studied. The results confirmed the reduction of pesticide residue levels over time due to the storage conditions, the properties of the pesticide and characteristics of the matrices. It was found temperature was most important for stability and had the greatest effect on diazinon, pirimiphos-methyl, and methidathion. Another promising finding was that adding the copper ion, sulfur powder, methanol, dichloromethane, and adjusting pH to acidity could improve the stability of the five pesticides. The results indicated that methods to apply some extra substrates need to be identified and intensively studied to improve storage stability of organophosphorus pesticides. Practical applications Undesired loss of pesticides at the sample storage stage and subsequent analytical steps will result in an underestimate of residue levels with possible implications on MRL compliance monitoring, risk assessments, and measurement uncertainty. Regulatory agencies can no longer afford to ignore the contribution of storage stability to the uncertainty results owning to the high risks involved. Our research topic is how to improve storage stability. These measures can be applied to actual production and have important significance for the evaluation of unstable pesticides during storage. This also provides data support and research basis for future storage stability studies.

Phthalates and organophosphorus insecticide residues in shrimp determined by liquid/gas chromatography–Tandem mass spectrometry and a health risk assessment

Shrimps are the most widely and increasingly cultured crustaceans in land-based ponds in Taiwan. However, few studies have investigated the phthalate contamination of and insecticide residues in shrimp. In this study, we applied a validated method to analyze the phthalate and 18 insecticides residues in shrimp. A total of 46 samples of whiteleg, grass, or giant river shrimp were collected from aquafarms and production areas in Taiwan. We detected 0.02–0.70 mg/kg of di-2-ethylhexyl phthalate (DEHP) in three shrimps; 0.02–0.03 mg/kg of chlorpyrifos in three shrimps, and 0.03 mg/kg of trichlorfon in one shrimp, indicating that 6.52% and 8.70% of the samples contained phthalate and insecticide residues, respectively. Furthermore, the assessed risk was negligible and indicated no immediate health risk associated with shrimp consumption. Continual monitoring of the residues in shrimps is critical for further assessment of possible effects on human health.

Determination of organophosphorus and carbamate insecticide residues in food and water samples by solid phase extraction coupled with capillary liquid chromatography

A method was established for the simultaneous separation and determination of one organophosphorus and three carbamate insecticide residues in food and water samples by solid phase extraction (SPE) followed by analysis using a home-made capillary liquid chromatogram. Various parameters possibly affecting the efficiencies of capillary liquid chromatography (CLC) and SPE were investigated in detail, such as type of SPE column, pH value of samples, type and volume of elution solvent, flow rate of loading sample, salt effect, loading volume, detection wavelength, and type and ratio of mobile phases. Under the optimized experimental conditions, the four insecticides were separated completely within 6 min. The limits of detection and limits of quantification were 0.35-1.20 μg/kg and 1.17-4.00 μg/kg, respectively. Satisfactory recoveries of the SPE-CLC method were achieved for spiked food samples of tomato, cucumber and apple ranging from 72.41% to 107.15% with the relative standard deviations (RSDs) no more than 8.12%, and for spiked tap/lake water samples ranging from 71.45% to 109.25% with the RSDs no more than 9.28%. The method can meet the requirements for multi-residue analysis of insecticides.

Determination of Organophosphorus Insecticide Residues in Country Bean Collected from Different Markets of Dhaka

The study was conducted to analyze pesticide residues in country bean collected from different areas of Dhaka city from January 2016 to September 2016. A simple and efficient multiple pesticide residue analytical method using Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) extraction technique and Gas Chromatography (GC) coupled with Flame Thermionized Detector (FTD) were used for the determination of pesticide residues in 50 country bean samples. Among the 50 analyzed samples of country bean, 10 samples (20%) contained residues of Dimethoate and Quinalphos, of which 5 samples were above the maximum residue limits (MRLs). Most of the contaminated samples (8 samples) contain residue of Dimethoate. This study reflects the overall scenario of pesticide contamination in vegetables, especially in country bean collected from the local markets of Dhaka city, which will help the consumer to be aware of their health and safety.

Residues of organophosphorus insecticides in sediment around a highly eutrophic lake, Eastern China

Purpose Organophosphorus pesticides (OPs) are significant stressors in the aquatic ecosystem of lakes due to their extensive use in agriculture. To understand the potential ecotoxicological risk of OPs, we examined the occurrence, distribution, and sources of 12 selected OPs in surface and core sediment samples collected around Chaohu Lake, one of the most eutrophic lakes in Eastern China.

Organophosphorus Insecticide Residues in Honey Produced in Turkey

In this study, a number of 15 organophoshorus (OP) insecticides were investigated in 275 honey samples in 33 different cities of Turkey, using gas chromatography electron capture detector. The limit of determination values was detected between 0.25 and 9.55 ng g(-1). The correlation coefficients obtained from calibration curves of the OP standards were found to be between 0.992 and 0.999. No insecticide residue was detected in the samples analyzed. This result is highly significant because of its impacts on public health and food safety.

Dialkylphosphates (DAPs) in Fruits and Vegetables May Confound Biomonitoring in Organophosphorus Insecticide Exposure and Risk Assessment

Trace residues of organophosphorus (OP) pesticides are associated with fruits and vegetables that have been sprayed with those OP pesticides to guard against insect pests. Human dietary exposure to these OP pesticides is commonly estimated by measuring the amount of OP metabolites in urine, assuming a stoichiometric relationship between a metabolite and its parent insecticide. Dialkylphosphates (DAPs) are the OP metabolites that are most often used as markers in such biomonitoring studies. However, abiotic hydrolysis, photolysis, and plant metabolism can convert OP chemicals (OP residues) to DAP residues on or in the fruits and vegetables. To evaluate the extent of these conversions, OPs and DAPs were measured in 153 produce samples. These samples from 2 lots were known to contain OP insecticide residues based on routine monitoring by California producers and shippers. A total of 12 OPs were quantified, including mevinphos, naled, acephate, methamidophos, oxidemeton-methyl, azinphos-methyl, dimethoate, malathion, methidathion, phosmet, chlorpyrifos, and diazinon. All OP insecticide residues were below their respective residue tolerances in 2002-2004. A total of 91 of 153 samples (60%) contained more DAP residues than parent OPs. The mean mole fractions [DAPs/(DAPs + OPs)] for the first and second lots of produce were 0.62 and 0.50, respectively, and the corresponding geometric means were 0.55 and 0.34. The corresponding mean mole ratios (DAPs/OP) were 7.1 and 3.4, with geometric means of 2.1 and 0.9. Any preformed DAPs ingested in the diet that are excreted in urine may inflate the estimated absorbed OP insecticide doses in occupational and environmental studies. In subsequent prospective studies, time-dependent production of dimethylphosphate (DMP) and dimethylthiophosphate (DMTP) in strawberries and leaves following malathion sprays occurred concomitant with the disappearance of the parent insecticide and its oxon. DAPs are more persistent in plants and produce at routinely measured levels than their parent OP insecticides.

Variability of organophosphorus insecticide residues in large size crops grown in commercial farms in Brazil

Field trials were conducted in commercial agricultural areas in Brazil to determine the variability of residues of parathion methyl, diazinon and methidathion in individual units of large crops treated twice with a mixture of the three pesticides. Over 120 random samples were collected, extracted with ethyl acetate and residues determined by GC/FPD. The recoveries and their coefficient of variation were, in general, within the acceptable levels during sample analyses. Residues in papaya and mango were not affected by the position of the fruits in the plant, apparently more or less exposed to the pesticides. Variability factor υ, defined as the 97.5th percentile divided by the mean of residues in all samples taken from a field ranged from 2.0–2.6. The variability of residues within the plant contributed to about 34–61% of the field variability. The results found in this study support the variability factor of 3 adopted by the FAO/WHO for the deterministic estimation of dietary acute intake of pesticides.

Immunochemical determination of four organophosphorus insecticide residues in olive oil using a rapid extraction process

Sensitive, simple and rapid ELISA methods have been developed for the determination of four organophosphorus pesticides in extra virgin olive oil. The analytical procedure involves simultaneous extraction of the analytes from oil matrix with methanol and a freezing clean-up step (−80 °C), followed by immunoassay determination using standards in matrix. The methodology is specific for diazinon, fenthion, malathion and chlorpyrifos showing little or no cross-reactivity against other organophosphorus compounds. Limits of detection for the pesticides in olive oil are from 46 ng ml −1 for diazinon to 10 ng ml −1 for fenthion, all of them under the established MRLs for olives. The excellent recoveries (between 94 and 122%) obtained by the complete analytical protocol confirm the potential of this approach for detecting these compounds in olive oil, being useful as screening and complementary method in pesticide regulatory and food safety programs. The proposed methodology also correlates well with the reference chromatographic (GC–MS) methods.

A Gas Chromatographic Determination of Residues of Eleven Insecticides and Two Metabolites on Olive Tree Leaves

A gas chromatographic (GC) method was developed and statistically validated for the simultaneous determination of residues of pyrethroid, endosulfan, and organophosphorus insecticides and some of their metabolites on olive tree leaves. Pesticide residues were extracted by static extraction with acetone-dichloromethane. After evaporation of the extract to dryness and redissolution in acetone, the organophosphorus insecticides were determined by GC with nitrogen-phosphorus detection. Another portion of the extract, after solvent change to acetonitrile, was cleaned up on an Alumina-N cartridge and analyzed for insecticides sensitive to electron-capture detection (ECD), i.e., pyrethroids and endosulfan and its metabolite. Recoveries of the organophosphorus insecticides ranged from 80.7 to 93.3% with relative standard deviations (RSDs) of < or = 7.2%; recoveries of the ECD-sensitive insecticides ranged from 71.6 to 89.5% with RSDs of < or = 11.6%. The method was used to analyze 26 samples of olive tree leaves from organic olive groves all over Greece, and the results confirmed the viability of the method for routine analysis. Residues of fenthion and fenthion sulfoxide were found in one and 3 samples, respectively, and their identities were confirmed by GC with mass spectrometry.

Optimization of headspace solid-phase microextraction conditions for the determination of organophosphorus insecticides in olive oil

A method based on headspace solid-phase microextraction (HS-SPME) technique followed by gas chromatography with flame thermionic detection was developed for the determination of seven organophosphorus (OP) insecticide residues in olive oil samples. The extraction capacity of four fiber coatings, polyacrylate (PA 85 µm), poly(dimethylsiloxane) (PDMS 100 µm), carbowax-divinylbenzene (CW-DVB 65 µm) and poly(dimethylsiloxane)divinylbenzene (PDMS-DVB 65 µm), have been studied and compared. The method was developed using spiked olive oil samples in the concentration range 0.025 to 0.5 mg/L. The PDMS 100-µm fiber showed good extraction efficiency for the target compounds. An increase in the extraction efficiency of OP insecticides was observed when the parameters affecting the HS-SPME process such as temperature, extraction time, salt additives and stirring rate were optimized. Good linearity was observed for the compounds in the tested concentration range. The limits of detection were between 0.005 and 0.01 µg/L.

Headspace solid-phase microextraction in combination with gas chromatography–mass spectrometry for the rapid screening of organophosphorus insecticide residues in strawberries and cherries

A headspace solid-phase microextraction (HS-SPME) method in combination with GC–MS was used for the extraction and quantification of diazinon, fenitrothion, fenthion, parathion ethyl, bromophos methyl, bromophos ethyl and ethion. The method was developed using a 100-μm poly(dimethylsiloxane) fiber. The obtained results showed higher responses of the insecticides after addition of aliquots of water and solvent to the fruit samples. Calibration curves that were constructed for the analytes spiked into strawberry and cherry samples followed linear relationships with good correlation coefficients ( R 2>0.986). Linearity range was between 50 and 500 μg/kg and the precision was found to be lower than 15% when applying the optimized HS-SPME procedure to fruit samples. Limits of detection in both strawberry and cherry samples using GC–MS (selected ion monitoring mode) were below 13 μg/kg. Moreover, the HS-SPME method was applied to the analysis of fruit samples and compared with liquid–liquid extraction. Results obtained in this study were in good agreement with those obtained using liquid–liquid extraction demonstrating that the recommended procedure was a fast, accurate and stable sample pretreatment method obtaining good efficiency for the extraction of organophosporus insecticides from strawberries and cherries.

Headspace solid phase microextraction applied to the analysis of organophosphorus insecticides in strawberry and cherry juices.

A method based on a headspace solid phase microextraction (HS-SPME) technique followed by gas chromatography with flame thermionic and mass spectrometric detection was developed for the determination of seven organophosphorus (OPs) insecticide residues in strawberry and cherry juice samples. The extraction capacities of four fiber coatings, polyacrylate (PA 85 microm), poly(dimethylsiloxane) (PDMS 100 microm), carbowax-divinylbenzene (CW-DVB 65 microm), and poly(dimethylsiloxane)-divinylbenzene (PDMS-DVB 65 microm), have been studied and compared. The method was developed using spiked strawberry and cherry juices in a concentration range of 0.5-50 microg/L. The PDMS 100 microm fiber showed good extraction efficiency for the target compounds. An increase in the extraction efficiency of OP insecticides was observed when the parameters affecting the HS-SPME process such as temperature, extraction time, salt additives, stirring rate, pH, and effect of dilution were optimized. Good linearity of compounds was observed in the tested concentration range. The relative standard deviations were found to be <20%. The limits of detection were between 0.025 and 0.050 microg/L. The mean relative recoveries ranged from 82 to 102%.

Investigations into the causes of residue variability on carrots in the UK

A pilot study was established to determine whether the preferential flow of water and thus insecticide in carrot beds might be responsible for the high residues of organophosphorus insecticides detected in individual carrot roots grown in the UK. A field site typical of UK carrot growing conditions was selected on a sandy soil with a low organic carbon content. Brilliant blue dye was applied in water to a small number of field plots located in the carrot beds to trace water movement through the bed and not to simulate insecticide application or irrigation. The plots were excavated following sufficient time for infiltration and drainage. Horizontal and vertical cross-sections through the soil profile were cut and descriptions of the dye presence in relation to soil features and the position of the carrot roots were made. Dye tracing and soil analyses showed there was a clear mechanical cultivation effect which generated a preferential movement of dye and water within the bed. The subsequent growth of carrots also created additional pathways of preferential movement due to stemflow or canopy drip. A second study which increased replication of samples and allowed analysis of triazophos and chlorfenvinphos residues in the carrots could not identify any single factor which was conclusively responsible for initiating high residues in individual roots.

Presence of Pesticides throughout Trophic Compartments of the Food Web in the Mar Menor Lagoon (SE Spain)

The main paths of some pesticides and their levels in the trophic compartments of the benthic food web of the Mar Menor, an oligotrophic coastal lagoon located in the SE of Spain, are studied in this paper. A total of 78 samples of water, sediment and benthic organisms were analysed. The analytical determination of organochlorine and organophosphorus insecticides was realized through gas–liquid chromatography with specific detectors (ECD and NPD, respectively). For triazine herbicides determination we used inmunoenzymatic technique. Residues of organochlorine insecticides and/or any of their analysed metabolites were detected in 70.5% of the controlled samples, though at small concentrations. In any case, residues of organophosphorus insecticides were detected and only traces of triazine herbicides were found in sediments (0.1–1 ng g −1). Between the detected compounds stand out the presence of endosulfan in 51.3% of the analysed samples followed by HCH (47.4%) and endrin (18%). The highest concentrations are reached in organisms (in the green algae Chaetomorpha linum and in the isopod Idotea basteri, with 1475 and 603 ng g −1 of endrin, respectively) followed by sediments (662 ng g −1 of endosulfan) and water (13 μg l −1 of endosulfan). Inputs of pesticides into the trophic web take place mainly through plants to the herbivorous–detritivorous compartment. The maximum bioconcentration factor is shown by the gammarids for heptachlor compounds (30 980 times the concentrations in water).