Performance of gas chromatography/tandem mass spectrometry in the analysis of pyrethroid insecticides in environmental and food samples

Pesticides in water and sediments from natural protected areas of Spain and their associated ecological risk

In the last years, issues related to intensive agriculture have been found in protected areas potentially harming wildlife. This study aimed to analyze a wide range of pesticides in water and sediments of two protected areas namely Doñana Natural Park (DNP) and Tablas de Daimiel National Park (TDNP) performing an environmental risk assessment in order to highlight potential risks to living organisms derived from pesticide burden. Higher pesticide load was found in DNP than TDNP with similar distribution profiles, with pyrethroid insecticides (PYRs) the main detected class. Particularly problematic are two PYRs, cyhalothrin and fenvalerate, which were detected at high concentrations that can pose a high risk to aquatic organisms. In addition, despite being detected at lower concentrations, the presence of chlorpyrifos, cypermethrin, and permethrin in water, and of chlorpyrifos, dicofol, and diflufenican in sediments, must be taken into account due to their potential risks for aquatic organisms. Moreover, some banned pesticides such as dimethoate, terbutryn, diazinon, and tricyclazol were detected in water at levels which deserve further investigation to assess their potential sources, including potential illegal practices.

Distribution and Elimination of Deltamethrin Toxicity in Laying Hens

Deltamethrin, an important pyrethroid insecticide, is frequently detected in human samples. This study aims to assess the potential effects of deltamethrin on human health and investigate the patterns of residue enrichment and elimination in 112 healthy laying hens. These hens were administered 20 mg·kg-1 deltamethrin based on their body weight. Gas chromatography-mass spectrometry (GC-MS) was used to investigate the residue enrichment pattern and elimination pattern of deltamethrin in the hens. The results indicated a significant increase in the concentration of deltamethrin in chicken manure during the treatment period. By the 14th day of administration, the concentration of deltamethrin in the stool reached 13,510.9 ± 172.24 μg·kg-1, with a fecal excretion rate of 67.56%. The pulmonary deltamethrin concentration was the second highest at 3844.98 ± 297.14 μg·kg-1. These findings suggest that chicken feces contain substantial amounts of deltamethrin after 14 days of continuous administration, and that it can easily transfer to the lungs. After 21 days of drug withdrawal, the residual concentration of deltamethrin in the fat of laying hens was 904.25 ± 295.32 μg·kg-1, with a half-life of 17 days and a slow elimination rate. In contrast, the lungs showed relatively low elimination half-lives of 0.2083 days, indicating faster elimination of deltamethrin in this tissue. These results highlight differences in the rate of deltamethrin elimination in different tissues during drug withdrawal. The fat of laying hens exhibited the highest residue of deltamethrin and the slowest elimination rate, while the lungs showed the fastest elimination rate. Moreover, deltamethrin was found to accumulate in the edible tissues of eggs and laying hens, suggesting that humans may be exposed to deltamethrin through food.

Pesticide contamination of bird species from Doñana National Park (southwestern Spain): Temporal trends (1999-2021) and reproductive impacts

Doñana National Park (DNP) is a protected area renowned for hosting a wide variety of birds. However, the agricultural practices in its surroundings might cause pesticide contamination of the park biota. This work aimed to assess temporal trends of a wide variety of pesticides, including organochlorine (OCPs), organophosphate (OPPs) and pyrethroid (PYRs) pesticides, in bird eggs collected for more than twenty years (1999-2021) in DNP. Twenty-six pesticides were detected, being 4,4'-DDE the most frequently detected and also the one with the highest concentrations (up to 2.55 μg g^-1 ww), exceeding in some cases the values usually reported to cause detrimental health and reproductive effects in avian species. An overall decreasing trend of OCPs was observed. In contrast, an apparent increase in PYRs was detected from 2013 onwards, especially for fenvalerate, whose median concentration was 3-5 orders of magnitude higher in the most recent samples. Moreover, other pesticides such as oxadiazon, oxyfluorfen and fenitrothion were first detected in 2021 samples. Finally, two variables estimating the cumulative impact of pesticides significantly decreased the breeding performance of a top predator such as the booted eagle. Therefore, it is essential to control the use of pesticides in the agricultural practices surrounding DNP and to study their potential negative impact on the bird populations breeding in this protected area.

Development of a fully automated analytical platform based on static headspace-gas chromatography-tandem mass spectrometry for the analysis of five N-nitrosamines in dried aquatic products of animal origin

BACKGROUND

The development of rapid and sensitive monitoring methods for trace N-nitrosamines (NAs) in foodstuffs is essential for mitigating the potential health risks to consumers. In the present study, an analytical platform based on one step fully automated static headspace sampling and gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed and validated for the analysis of N-nitrosamines in dried aquatic products of animal origin. The samples and sodium chloride solution mixture were incubated in a heated headspace vial for analyte evaporation, coupled to automatic sampling and online GC-MS/MS analysis. The proposed method requires minimal sample preparation and organic solvent consumption. Five N-nitrosamines including N-nitroso dimethylamine, N-nitroso methyl ethylamine, N-nitroso pyrolidine, N-nitroso piperidine and N-nitroso diphenylamine were selected as model compounds to optimize the significant factors by a using Box-Behnken design.

RESULTS

The optimum conditions achieved limits of detections in the range 0.08-0.29 μg kg^-1 , with correlation coefficient over 0.998. Relative recoveries in dried aquatic product sample were in the range 76.9-92.4%, with relative SDs of 1.9-7.2%.

CONCLUSION

These results confirm the reliability of the developed method for further application in trace level monitoring of the target analytes in foodstuffs. © 2022 Society of Chemical Industry.

Simultaneous Determination of Pyrethroid Insecticides in Foods of Animal Origins Using the Modified QuEChERS Method and Gas Chromatography-Mass Spectrometry

Pyrethroid insecticides are used in agriculture to treat parasites in livestock. This study developed a simultaneous residue analysis method to measure seventeen pyrethroid insecticides in foods of animal origin, including beef, pork, chicken, milk, and eggs. The method, which comprises instrumental analysis using gas chromatography-tandem mass spectrometry and a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for pretreatment, was optimized to verify the applicability of the method. A mixture of acetonitrile, ethyl acetate, and original salt (MgSO4 4 g, NaCl 1 g) was used as the extraction solvent and salt. MgSO4 (150 mg) primary secondary amine (25 mg) and graphitized carbon black (25 mg) were selected for dispersive solid phase extraction (d-SPE). The method limit of quantitation was 0.01 mg/L, and the linearity of the matrix-matched calibration curves was reasonable (R2 > 0.99). Recovery tests were performed at three concentrations (LOQ, 10 LOQ, and 50 LOQ). Good recoveries (75.2109.8%) and reproducibility (coefficient of variation <10%) were obtained. The matrix effects were in the range of −35.8 to 56.0%. The established method was fully validated and can be used as an official analytical method for quantifying pyrethroid insecticides in animal commodities.

Priority and emerging organic microcontaminants in three Mediterranean river basins: Occurrence, spatial distribution, and identification of river basin specific pollutants

There is a worldwide growing use of chemicals by our developed, industrialized, and technological society. More than 100,000 chemical substances are thus commonly used both by industry and households. Depending on the amount produced, physical-chemical properties, and mode of use, many of them may reach the environment and, notably, the aquatic receiving systems. This may result in undesirable and harmful side-effects on both the human and the ecosystem's health. Mediterranean rivers are largely different from Northern and Central European rivers in terms of hydrological regime, climate conditions (e.g. air temperature, solar irradiation, precipitation), and socio-economics (e.g. land use, tourism, crop types, etc.), with all these factors leading to differences in the relative importance of the environmental stressors, in the classes and levels of the pollutants found and their environmental fate. Furthermore, water scarcity might be critical in affecting water pollution because of the lowered dilution capacity of chemicals. This work provides raw chemical data from different families of microcontaminants identified in three selected Mediterranean rivers (the Sava, Evrotas, and Adige) collected during two sampling campaigns conducted in 2014 and 2015 in three different matrices, namely, water, sediments, and biota (fish). More than 200 organic micropollutants were analyzed, including relevant groups like pharmaceuticals, personal care products, perfluorinated compounds, pesticides, pyrethroid insecticides, flame retardants, and persistent organic pollutants. Data obtained were summarized with some basic statistics for all compound families and matrices analyzed. Observed occurrence and spatial patterns were interpreted both in terms of compound physical-chemical properties and local environmental pressures. Finally, their spatial distribution was examined and their ecotoxicological risk in the water phase was assessed. This allowed locating, at each basin, the most polluted sites ("hot spots") and identifying the respective river basin specific pollutants (RBSPs), prioritizing them in terms of the potential ecotoxicological risk posed to the aquatic ecosystems.

The pollution profiles and human exposure risks of chlorinated and brominated PAHs in indoor dusts from e-waste dismantling workshops: Comparison of GC-MS, GC-MS/MS and GC × GC-MS/MS determination methods

The toxicities of some chlorinated and brominated polycyclic aromatic hydrocarbons (X-PAHs) are higher than their corresponding parent PAHs. However, the identification and quantitation of X-PAHs in environment are still changeable and limitedly reported. To develop a robust method for routine analysis of X-PAHs in environmental samples, the determination of 34 X-PAHs was performed and compared using different instruments, including gas chromatography-mass spectrometry (GC-MS), gas chromatography-tandem mass spectrometry (GC-MS/MS) in both electron ionization (EI) and negative chemical ionization (NCI) modes, and comprehensive two-dimensional gas chromatograph-tandem mass spectrometer (GC × GC-MS/MS). GC-EI-MS/MS possessed the highest sensitivity with method detection limits of 2.00-40.0 and 2.00-20.0 pg/g dry weight (dw) for Cl-PAHs and Br-PAHs, respectively. This validated method was then applied to analyze X-PAHs in indoor dusts from a typical e-waste dismantling workshop, and the concentrations of Σ₁₈Br-PAHs (8.80-399 ng/g dw) were higher than Σ₁₆Cl-PAHs (7.91-137 ng/g dw). The toxicity equivalency quantities (TEQs) of Cl-PAHs at e-waste dismantling workshop and Br-PAHs at raw materials crushing workshop showed the highest values of 176 and 453 pg·TEQ/g, respectively. Cl-PAHs and Br-PAHs posed a potential health risk to workers through dust ingestion in workshops. Further attention should be payed to the formation mechanism of X-PAHs and the health risk.

Exploring the degradation capability of Trametes versicolor on selected hydrophobic pesticides through setting sights simultaneously on culture broth and biological matrix

Pesticides introduced inadvertently or deliberately into environment by global agricultural practices have caused growing public concern, therefore the search of approaches for elimination of such xenobiotics should be motivated. The degradation of hydrophobic pesticides including chlorpyrifos, dicofol and cypermethrin were assayed with the white-rot fungus Trametes versicolor. Experiments were set at realistic concentration as 5 μg L^-1, and both culture medium and biologic matrix were analyzed for pollutants residues. Results showed that the first step was due to a fast adsorption, which also played an important role, accounting for more than 90% removal in average. Then mass balances proposal evidenced the biodegradation of the adsorbed pollutants, demonstrating efficient depletion as 94.7%, 87.9% and 93.1%, respectively. Additionally, the related degradation metabolites were identified using ultra performance liquid chromatography coupled to high resolution mass spectrometry. Two compounds, namely O,O-diethyl thiophosphate and diethyl phosphate were detected as transformation products of chlorpyrifos, whereas dicofol was degraded into benzaldehyde that is first time to be reported. It also confirms the degradation capability of T. versicolor. Our results suggest that T. versicolor is a potential microorganism for bioremediation of hydrophobic pesticide contaminated environments.

Chronic cypermethrin exposure alters mouse embryonic stem cell growth kinetics, induces Phase II detoxification response and affects pluripotency and differentiation gene expression

Worldwide uncontrolled use of synthetic pyrethroids contaminates water and soil leading to health hazards. Cypermethrin (CYP), the most used pyrethroid, induces detrimental effects on adults and embryos at different stages of development of several vertebrate species. In Mammals, CYP-induced alterations have been previously described in adult somatic cells and in post-implantation embryos. It remains unknown whether CYP has effects during pre-implantation development. Studies to access pre-implantation embryo toxicity are complicated by the restricted number of blastocysts that may be obtained, either in vivo or in vitro. Embryonic stem cells (ESCs) are an in vitro model study that overcomes these limitations, as millions of pluripotent cells are available to the analysis. Also, ESCs maintain the same pluripotency characteristics and differentiation capacity of the inner cell mass (ICM) present in the blastocyst, from which they derive. In this work, using mouse R1 ESCs, we studied CYP-induced cell death, ROS production, the activation of oxidative stress-related and detoxification responses and the population growth kinetics following 72 h exposure at the 0.3 mM LD50 dose. Also, the expression levels of pluripotency genes in exposed ESCs and of markers of the three germ layers after their differentiation into embryoid bodies (EBs) were determined. Two apoptotic waves were observed at 12-24 h and at 72 h. The increase of ROS production, at 24 h until the end of the culture period, was accompanied by the induction, at 48 h, of redox-related Cat, Sod1, Sod2, Gpx1 and Gpx4 genes. Up-regulation of Cyp1b1, but not of Cyp1a1, phase I gene was detected at 72 h and induction of Nqo1, Gsta1 and Ugt1a6 phase II genes began at 24 h exposure. The results show that exposed R1 ESCs activate oxidative stress-related and detoxification responses, although not sufficient, during the culture period tested, to warrant recovery of the growth rate observed in untreated cells. Also, CYP exposure altered the expression of Oct-4 and Nanog pluripotency genes in ESCs and, when differentiated into EBs, the expression of Fgf5, Brachyury and Foxa2, early markers of the ectoderm, mesoderm and endoderm germ layers, respectively. NIH/3T3 cells, a differentiated cell line of embryonic origin, were used for comparison.

The use of fast molecular descriptors and artificial neural networks approach in organochlorine compounds electron ionization mass spectra classification

Developing of theoretical tools can be very helpful for supporting new pollutant detection. Nowadays, a combination of mass spectrometry and chromatographic techniques are the most basic environmental monitoring methods. In this paper, two organochlorine compound mass spectra classification systems were proposed. The classification models were developed within the framework of artificial neural networks (ANNs) and fast 1D and 2D molecular descriptor calculations. Based on the intensities of two characteristic MS peaks, namely, [M] and [M-35], two classification criterions were proposed. According to criterion I, class 1 comprises [M] signals with the intensity higher than 800 NIST units, while class 2 consists of signals with the intensity lower or equal than 800. According to criterion II, class 1 consists of [M-35] signals with the intensity higher than 100, while signals with the intensity lower or equal than 100 belong to class 2. As a result of ANNs learning stage, five models for both classification criterions were generated. The external model validation showed that all ANNs are characterized by high predicting power; however, criterion I-based ANNs are much more accurate and therefore are more suitable for analytical purposes. In order to obtain another confirmation, selected ANNs were tested against additional dataset comprising popular sunscreen agents disinfection by-products reported in previous works.

Persistent and emerging pollutants assessment on aquaculture oysters (Crassostrea gigas) from NW Portuguese coast (Ria De Aveiro)

The study aim was to determine a range of relevant persistent and emerging pollutants in oysters produced in an aquaculture facility located in an important production area, to assure their safety for human consumption. Pollutants, including 16 PAHs, 3 butyltins (BTs), 29 flame retardants (FRs, including organophosphate and halogenated FRs), 35 pesticides (including 9 pyrethroid insecticides) and 13 personal care products (PCPs, including musks and UV filters), were determined in oysters' tissues collected during one year in four seasonal sampling surveys. The seasonal environmental pollution on the production site was evaluated by water and sediment analysis. Furthermore, oysters' nutritional quality was also assessed and related with the consumption of healthy seafood, showing that oysters are a rich source of protein with low fat content and with a high quality index all year around. Results showed that most analysed pollutants were not detected either in oyster tissues or in environmental matrixes (water and sediments). The few pollutants detected in oyster tissues, including both regulated and non-legislated pollutants, such as a few PAHs (fluorene, phenanthrene, anthracene, fluoranthene, pyrene and indenopyrene), FRs (TPPO, TDCPP, DCP, BDE-47, BDE-209 and Dec 602) and PCPs (galaxolide, galaxolidone, homosalate and octocrylene), were present at low levels (in the ng/g dw range) and did not represent a significant health risk to humans. The observed seasonal variations related to human activities (e.g. tourism in summer) highlights the need for environmental protection and sustainable resource exploration for safe seafood production.

Evaluation of flavour profiles in e-cigarette refill solutions using gas chromatography-tandem mass spectrometry

Many flavour compounds that are present in e-liquids for e-cigarettes are responsible for specific tastes and smoking sensations for users. Data concerning content and specific types of flavours is often limited and unknown to users. The aim of the research was to define and compare flavour profiles of e-liquids with the same group taste from different manufacturers. Gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) was used to separate and identify 90 popular compounds (98, including isomers) of interest. The developed method was validated in terms of accuracy (88-113%) for three spiking levels and the intra-day (0.2-13%) and inter-day precision (1-10%). Limits of quantitation were in the range of 10-816 ng/mL, while the matrix effects for 80% of the compounds were at negligible levels. The proposed method is rapid, simple and reliable and uses a green and modern GC-MS/MS technique. Twenty-five samples of five different flavours (tobacco, strawberry, cherry, menthol and apple) from five different producers were analysed, and the determined compounds were categorized and differentiated. The approach proposed in this study allowed for the evaluation of which compounds/group of compounds are responsible for taste and to distinguish common flavour compounds among the investigated brands for each flavour. Furthermore, the presented research can be considered in future toxicological studies.

Bioaccumulation of persistent and emerging pollutants in wild sea urchin Paracentrotus lividus

Marine pollution has been increasing as a consequence of anthropogenic activities. The preservation of marine ecosystems, as well as the safety of harvested seafood, are nowadays a global concern. Here, we report for the first time the contamination levels of a large set of 99 emerging and persistent organic contaminants (butyltins (BTs), polycyclic aromatic hydrocarbons (PAHs), pesticides including pyrethroids, pharmaceuticals and personal care products (PCPs) and flame retardants) in roe/gonads of sea urchin Paracentrotus lividus. Sea urchins are a highly prized worldwide delicacy, and the harvesting of this seafood has increased over the last decades, particularly in South West Atlantic coast, where this organism is harvested mainly for exportation. Sampling was performed in three harvesting sites of the NW Portuguese coast subjected to distinct anthropogenic pressures: Carreço, Praia Norte and Vila Chã, with sea urchins being collected in the north and south areas of each site. Butyltins and pharmaceuticals were not found at measurable levels. Several PAHs, four pyrethroids insecticides, four PCPs and eleven flame retardants were found in roe/gonads of sea urchins, though in general at low levels. Differences among harvesting sites and between areas within each site were found, the lowest levels of contaminants being registered in Carreço. The accumulation of contaminants in sea urchins' roe/gonads seemed to reflect the low anthropogenic pressure felt in the sampling sites. Nevertheless, taking into account the low accumulated levels of chemicals, results indicate that sea urchins collected in South West Atlantic coast are safe for human consumption.

Pyrethroids in chicken eggs from commercial farms and home production in Rio de Janeiro: Estimated daily intake and diastereomeric selectivity

In this study, pyrethroids were determined in chicken eggs from commercial farm (n = 60) and home egg production (n = 30). These pyrethroids were investigated: bifenthrin, phenothrin, permethrin, cyfluthrin, cypermethrin and fenvalerate, including most diastereomers. Quantification was done using GC-MS in a negative chemical ionization mode. Pyrethroids residues were found in 79% of the analyzed samples. Cypermethrin presented the highest occurrence, being quantified in 62 samples (69%) in concentrations (lipid weight - l w.) varying between 0.29 and 6408 ng g^-1, followed by phenothrin (24%), 21-3910 ng g^-1, permethrin (14%), 2.96-328 ng g^-1, and bifenthrin (11%), 3.77-16.7 ng g^-1. Cyfluthrin and fenvalerate were not detected. Home-produced eggs had a higher occurrence of pyrethroids (97%), with a greater predominance of phenothrin. In commercial production, 70% of the samples presented pyrethroid residues (predominantly cypermethrin). This is the first report about the presence of pyrethroids in home-produced eggs and the first description of a selectivity pattern with the predominance of cis diastereomers in chicken eggs. In general, estimated daily intake does not present a risk to human consumption, according to Brazilian and international standards (FAO/WHO). However, one third of the samples (30 eggs) had concentrations above the maximum residue limits (MRLs). The maximum cypermethrin concentration was 66 times the MRL, while the maximum phenothrin concentration was 11 times the limit. Further studies about transfer dynamics, bioaccumulation and metabolic degradation of stereoisomers are required, as well as determining if this selectivity pattern in food can increase consumer's health risk.

Pyrethroid insecticides in wild bird eggs from a World Heritage Listed Park: A case study in Doñana National Park (Spain)

Recent studies demonstrated that the common pyrethroid insecticides are present in aquatic biota tissues. In this study, 123 samples of unhatched eggs of 16 wild bird species collected from 2010 to 2012 in Doñana National and Natural Park were analysed to determine 13 pyrethroids. This study represents the first time that pyrethroids are detected in tissues of terrestrial biota, 93% of these samples being positive to those pollutants. Levels of total pyrethroids ranged from not detected to 324 ng g^-1 lw. The samples were characterized by stable isotope analysis. Species with diets based on anthropogenic food showed higher levels of pyrethroids and lower values of δ¹⁵N. Finally, we characterized the isomers of pyrethroids and discerned some isomeric- and enantiomeric-specific accumulations. In particular, tetramethrin and cyhalothrin showed an enantiomeric-selective accumulation of one enantiomer, highlighting the need to assess toxicological effects of each enantiomer separately to be able to make a correct risk assessment of pyrethroids in birds.

Insecticide pyrethroids in liver of striped dolphin from the Mediterranean Sea

Pyrethroid pesticides were analysed in liver of striped dolphin (Stenella coeruleoalba) from the Alboran Sea (south of Spain, Mediterranean Sea). The occurrence and bioaccumulation of pyrethroid insecticides in marine mammal tissues from the northern hemisphere had never been determined before. Pyrethroids were detected in 87% of the specimens with a mean total concentration of 300 ng g^-1 lw ± 932 (range 2.7-5200 ng g^-1 lw). Permethrin and tetramethrin were the main contributors to the pyrethroid profiles, with enantiospecific accumulation for the first and isomer specific accumulation for the latter. Bioaccumulation of pyrethroids was unlike that of persistent organic pollutants (POPs), as pyrethroid concentrations were not correlated to the maturity stage of the specimens. Concentrations slightly increased from calves to juveniles, whereas juveniles presented similar concentrations to adults. Metabolization of pyrethroids after achieving sexual maturity might account for this pattern.

LC- and GC-QTOF-MS as Complementary Tools for a Comprehensive Micropollutant Analysis in Aquatic Systems

Efficient strategies are required to implement comprehensive suspect screening methods using high-resolution mass spectrometry within environmental monitoring campaigns. In this study, both liquid and gas chromatography time-of-flight mass spectrometry (LC-QTOF-MS and GC-QTOF-MS) were used to screen for >5000 target and suspect compounds in the Sacramento-San Joaquin River Delta in Northern California. LC-QTOF-MS data were acquired in All-Ions fragmentation mode in both positive and negative electrospray ionization (ESI). LC suspects were identified using two accurate mass LC-QTOF-MS/MS libraries containing pesticides, pharmaceuticals, and other environmental contaminants and a custom exact mass database with predicted transformation products (TPs). The additional fragment information from the All-Ions acquisition improved the confirmation of the compound identity, with a low false positive rate (9%). Overall, 25 targets, 73 suspects, and 5 TPs were detected. GC-QTOF-MS extracts were run in negative chemical ionization (NCI) for 21 targets (mainly pyrethroids) at sub-ng/L levels. For suspect screening, extracts were rerun in electron ionization (EI) mode with a retention time locked method using a GC-QTOF-MS pesticide library (containing exact mass fragments and retention times). Sixteen targets and 42 suspects were detected, of which 12 and 17, respectively, were not identified by LC-ESI-QTOF-MS. The results highlight the importance of analyzing water samples using multiple separation techniques and in multiple ionization modes to obtain a comprehensive chemical contaminant profile. The investigated river delta experiences significant pesticide inputs, leading to environmentally critical concentrations during rain events.

Toxic heritage: Maternal transfer of pyrethroid insecticides and sunscreen agents in dolphins from Brazil

Pyrethroids (PYR) and UV filters (UVF) were investigated in tissues of paired mother-fetus dolphins from Brazilian coast in order to investigate the possibility of maternal transfer of these emerging contaminants. Comparison of PYR and UVF concentrations in maternal and fetal blubber revealed Franciscana transferred efficiently both contaminants to fetuses (F/M > 1) and Guiana dolphin transferred efficiently PYR to fetuses (F/M > 1) different than UVF (F/M < 1). PYR and UVF concentrations in fetuses were the highest-ever reported in biota (up to 6640 and 11,530 ng/g lw, respectively). Muscle was the organ with the highest PYR and UVF concentrations (p < 0.001), suggesting that these two classes of emerging contaminants may have more affinity for proteins than for lipids. The high PYR and UVF concentrations found in fetuses demonstrate these compounds are efficiently transferred through placenta. This study is the first to report maternal transfer of pyrethroids and UV filters in marine mammals.

Acute toxicity of cypermethrin on the freshwater mussel Unio gibbus

Cypermethrin is a synthetic pyrethroid insecticide used worldwide in agriculture, home pest control, food stuff protection and disease vector control. We investigate the potential of cypermethrin to induce oxidative stress and enzyme activities within the gills of freshwater mussel Unio gibbus. This study was carried out under laboratory conditions using two nominal cypermethrin concentrations C1 (100µg/L) and C2 (150µg/L) during 96h. The measured concentrations of cypermethrin using GC-MS-MS in the treatment aquariums were respectively 59.7 µg/L and 97.5µg/L. Antioxidant enzyme activities (superoxide dismutase (SOD) and catalase (CAT)) as well as H2O2, malondialdehyde (MDA) and protein carbonyl (PCO) levels were assessed. An exposure during 96h induced the SOD activity at the highest concentration. The CAT activity and H2O2 level were increased significantly (P<0.05) in gills following a dose-dependent profile. Cypermethrin also generated an increase in malondialdehyde (MDA) levels reaching the highest value at the high concentration. The considered parameters can be used as biomarkers of exposure to cypermethrin. Freshwater mussel U. gibbus can be potentially employed in biomonitoring surveys of such threatened ecosystems.

First report of pyrethroid bioaccumulation in wild river fish: a case study in Iberian river basins (Spain)

For the first time, this work described pyrethroid bioaccumulation in edible river fish samples. We analyzed 42 whole fish samples collected in 4 different Iberian rivers. All samples were positive to these insecticides. Levels of concentration ranged from 12 to 4938ngg(-1) lipid weight (lw). Moreover, isomeric characterization was carried out. Our results remarked a general preference of cis isomers in bioaccumulation. Finally, the enantiomeric evaluation showed that there was an enantioselective bioaccumulation of some pyrethroids, depending on the studied species. Pyrethroid concentrations were compared with levels obtained for other common pollutants, such as flame retardants, personal care products, hormones and pharmaceuticals. The highest values corresponded to pyrethroid insecticides, even though, pyrethroid levels are safe for human consumption taken into account the current regulations.

Picogram per liter detections of pyrethroids and organophosphates in surface waters using passive sampling

Pyrethroids and organophosphates are among the most toxic insecticides for aquatic organisms, leading to annual-average environmental quality standards (AA-EQS) in the picogram per liter range in surface waters. For monitoring purposes, it is therefore crucial to develop very sensitive analytical methods. Until now, it is very difficult to reach detection limits at or below given AA-EQSs. Here, we present a passive sampling method using silicone rubber (SR) sheets for the sampling of ten pyrethroids and two organophosphates in surface waters. An analytical method was developed, optimized and validated for the extraction of the insecticides from the SR sheets by accelerated solvent extraction followed by clean-up on C18 and silica gel and detection with GC-MS/MS in positive ionization mode. Good precision (<20%) and absolute recovery (>50%) was observed for all substances, accuracy was between 66% and 139%. Limits of detection between 6 and 200 pg/L were achieved for all substances in surface waters using average sampling rates for PCBs and PAHs. The lack of substance-specific sampling rates and missing performance reference compounds led to an uncertainty in the concentration estimation of factor three in both directions. In a large field study, comprising 40 environmental samples from nine Swiss rivers, eight out of 12 substances were detected (most frequently: chlorpyrifos, cypermethrin). Most of the estimated organophosphate concentrations were between 0.1 and 1 ng/L, most pyrethroid detections below 0.1 ng/L. Four substances (chlorpyrifos-methyl, cypermethrin, deltamethrin and lambda-cyhalothrin) showed exceedances of their respective AA-EQS in multiple samples, also when the uncertainties in the concentration estimation were considered. As pyrethroid and organophosphate detection by SR passive sampling is very practicable and allows sensitive analysis, it has the potential to become a new tool in the monitoring of non-polar pesticides.

High-resolution mass spectrometry associated with data mining tools for the detection of pollutants and chemical characterization of honey samples

Analytical methods for food control are mainly focused on restricted lists of well-known contaminants. This paper shows that liquid chromatography-high-resolution mass spectrometry (LC/ESI-HRMS) associated with the data mining tools developed for metabolomics can address this issue by enabling (i) targeted analyses of pollutants, (ii) detection of untargeted and unknown xenobiotics, and (iii) detection of metabolites useful for the characterization of food matrices. A proof-of-concept study was performed on 76 honey samples. Targeted analysis indicated that 35 of 83 targeted molecules were detected in the 76 honey samples at concentrations below regulatory limits. Furthermore, untargeted metabolomic-like analyses highlighted 12 chlorinated xenobiotics, 1 of which was detected in lavender honey samples and identified as 2,6-dichlorobenzamide, a metabolite of dichlobenil, a pesticide banned in France since 2010. Lastly, multivariate statistical analyses discriminated honey samples according to their floral origin, and six discriminating metabolites were characterized thanks to the MS/MS experiments.

Ethylene vinyl acetate polymer as a tool for passive sampling monitoring of hydrophobic chemicals in the salmon farm industry

Current monitoring programs are focused on hydrophobic chemicals detection in aquatic systems, which require the collection of high volumes of water samples at a given time. The present study documents the preliminary use of the polymer ethylene vinyl acetate (EVA) as a passive sampler for the detection of a hydrophobic chemical used by salmon industries such as cypermethrin. Initially, an experimental calibration in laboratory was performed to determine the cypermethrin equilibrium between sampler and aquatic medium, which was reached after seven days of exposure. A logarithm of partitioning coefficient EVA-water (logKEVA-W) of 5.6 was reported. Field deployment of EVA samplers demonstrated average concentrations of cypermethrin in water to be 2.07 ± 0.7 ng L(-)(1) close to salmon cages, while near-shore was 4.39 ± 0.8 ng L(-)(1). This was a first approach for assessing EVA samplers design as a tool of monitoring in water for areas with salmon farming activity.

Pyrethroids: a new threat to marine mammals?

The present study constitutes the first investigation to demonstrate pyrethroid bioaccumulation in marine mammals, despite the assumption that these insecticides are converted to non-toxic metabolites by hydrolysis in mammals. Twelve pyrethroids were determined in liver samples from 23 male franciscana dolphins from Brazil. The median concentration values for total pyrethroids were 7.04 and 68.4 ng/g lw in adults and calves, respectively. Permethrin was the predominant compound, contributing for 55% of the total pyrethroids. Results showed a distinct metabolic balance of pyrethroids through dolphin life. High loads are received at the beginning of their lives and, when they reach sexual maturity, these mammals seem to degrade/metabolize pyrethroids. Maternal transfer of these compounds was also evaluated through the analysis of breast milk and placenta samples. Pyrethroids were detected in both matrices, with values between 2.53-4.77 ng/g lw and 331-1812 ng/g lw, respectively. Therefore, for the first time, a study shows mother-to-calf transfer of pyrethroids by both gestational and lactation pathways in dolphins.

Pyrethroids in human breast milk: occurrence and nursing daily intake estimation

There is an assumption that pyrethroid pesticides are converted to non-toxic metabolites by hydrolysis in mammals. However, some recent works have shown their bioaccumulation in human breast milk collected in areas where pyrethroids have been widely used for agriculture or malaria control. In this work, thirteen pyrethroids have been studied in human breast milk samples coming from areas without pyrethroid use for malaria control, such as Brazil, Colombia and Spain. The concentrations of pyrethroids ranged from 1.45 to 24.2 ng g⁻¹ lw. Cypermethrin, λ-cyhalothrin, permethrin and esfenvalerate/fenvalerate were present in all the studied samples. The composition of pyrethroid mixture depended on the country of origin of the samples, bifenthrin being the most abundant in Brazilian samples, λ-cyhalothrin in Colombian and permethrin in Spanish ones. When the pyrethroid concentrations were confronted against the number of gestations, an exponential decay was observed. Moreover, a time trend study was carried out in Brazil, where additional archived pool samples were analyzed, corresponding to years when pyrethroids were applied for dengue epidemic control. In these cases, total pyrethroid levels reached up to 128 ng g⁻¹ lw, and concentrations decreased when massive use was not allowed. Finally, daily intake estimation of nursing infants was calculated in each country and compared to acceptable WHO levels. The estimated daily intakes for nursing infants were always below the acceptable daily intake levels, nevertheless in certain samples the detected concentrations were very close to the maximum acceptable levels.

Validated TLC-densitometry method for the simultaneous analysis of pyrethroid insecticides in agricultural and domestic products

Background

Pyrethroids are widely used for the control of pests and insects, as pyrethroids are believed to pose little risk to human health and environment. However, exposure to the pyrethroids exceeding the label directions might adversely affect human health and environment. Hence a careful selection of environment friendly household product is required that must contain exactly the label claimed pyrethroids amount.

Results

A sensitive and robust TLC-densitometric method for simultaneous quantification of commonly used synthetic pyrethroids including esbiothrin, alpha-cypermethrin and cis/trans permethrin in agricultural and domestic products has been developed and validated. TLC aluminum sheets, precoated with 0.2 mm thick layer of silica gel 60 F-254, were used for chromatographic process. Densitometric analysis of chromatoplates was carried out in absorbance mode at corresponding λ_max of each pyrethroid. Equally valid common mobile phase for all pyrethroids consisted of hexane-dichloromethane-ethylacetate-formic acid (8:1.5:0.4:0.1 v/v/v/v) which provided sharp and symmetrical peaks of esbiothrin, alpha-cypermethrin, trans-permethrin and cis-permethrin, at R_f 0.31, 0.53, 0.6 and 0.65, respectively. Linear regression data for respective calibration curves showed a good linearity for all pyrethroids with r = 0.991-0.996. Limits of detection (LOD) and limits of quantification (LOQ) for all pyrethroids were found in the range of 1.6-2.8 and 4.9-8.5 ng/spot, respectively.

Conclusions

The developed method is applicable for separating the mixture of pyrethroids and at the same time, it is also valid for separating their isomers. The method is reproducible, precise and accurate for the quantitative determination of pyrethroids in agricultural and domestic products.

Pyrethroid use-malaria control and individual applications by households for other pests and home garden use

Presence of pyrethroid insecticides in human breast milk and in thatch wall material of dwellings from Southern Africa subtropical area (Manhiça, Mozambique) was investigated to assess potential pyrethroid route of human exposure. Human breast milk samples were collected during 2002 when pyrethroids were widely used as insecticides for mosquito bed nets in Mozambique for malaria control. The median concentration value of total pyrethroids ranged between 87 and 1200ng/glw, with λ-cyhalothrin being the most predominant pyrethroid in human breast milk contributing for 35% of the total amount. Moreover, and for the first time, an isomer-specific enrichment was found in human breast milk, showing a selective isomeric accumulation or metabolism in the human body. Based on the calculated pyrethroid concentrations in human breast milk, the daily ingestion rate of pyrethroid was estimated. The nursing infant dietary intake ranged from 0.67 to 9.0μg(kg of body weight)(-1)day(-1). In addition, thatch materials collected after the reintegration of dichlorodiphenyltrichloroethene (DDT) as insecticide residual spraying (IRS) in Mozambique, showed the presence of pyrethroids with concentration values ranging between 6.9 and 700ng/gdw. In thatch material as well as in human breast milk, pyrethroid contamination was mainly attributed to the agriculture usage of this insecticide knowing that agriculture represent the 80% of the economy in Mozambique. However, a possible usage of this insecticide as IRS in Mozambique cannot be excluded despite their low efficiency for malaria control. The continued use of these compounds (both for agriculture and malaria prevention) and the ingestion rates calculated from the breast milk concentrations indicate that these insecticides cannot be overlooked for the assessment of the lactation risks of breastfeeding infants from the Manhiça region.