Concentrations Of Chlorpyrifos Research Articles

A highly selective self-powered sensor based on the upconversion nanoparticles/CdS nanospheres for chlorpyrifos detection

Light sources are crucial for photoelectrochemical (PEC) self-powered sensing, where visible light is widely used. However, due to its high energy, it has some downsides as an irradiation source for overall system, so it is urgent to achieve effective near-infrared (NIR) light absorption because it makes up a significant portion of the solar spectrum. Herein, up-conversion nanoparticles (UCNPs) that could increase the energy of low-energy radiation were combined with semiconductor CdS as the photoactive material (UCNPs/CdS), which broadens the response range of solar spectrum. The NIR light-excited self-powered sensor could be produced via oxidizing H2O at photoanode and lowering dissolved oxygen at cathode under the NIR light without external voltage. Meanwhile, molecularly imprinted polymer (MIP) was added to photoanode as a recognition element to increase the sensor's selectivity. The open-circuit voltage of the self-powered sensor grew linearly as chlorpyrifos concentration climbed from 0.01 to 100 ng mL−1, showing good selectivity as well as reproducibility. This work provides valuable basis for the preparation of efficient and practical PEC sensor with NIR light response.

Combined cytotoxicity of ZnO nanoparticles and chlorpyrifos in the rainbow trout, Oncorhynchus mikyss, gonadal cell line RTG-2

The toxicity of ZnO nanoparticles (ZnO NPs) in aquatic organisms has been extensively studied, but little information is available on the effects associated with their interaction with other contaminants. In this context, the in vitro effects of co-exposure of chlorpyrifos (CPF) and ZnO NPs on fish-derived cells were investigated. A selection of concentrations was tested in single and binary exposures: CPF (0.312 - 75 mg/L) and ZnO NPs (10 - 100 mg/L). Cytotoxicity was measured using commonly used cellular endpoints: Alamar Blue/CFDA-AM for viability and plasma membrane integrity, NRU for lysosomal disruption and MTT for mitochondrial function. In addition, specific mechanisms of toxicity for CPF and ZnO NPs were tested: acetylcholinesterase (AChE) activity and ROS generation, respectively. AChE was by far the most sensitive assay for single exposure to CPF. There was no concentration-response relationship for ROS after single exposure to ZnO NPs, but 10 mg/L produced significant effects only for this cellular endpoint. Co-exposure of CPF with 10 m/L of ZnO NPs produced significant effects in almost all endpoints tested, which were enhanced by co-exposure with 100 mg/L of ZnO NPs. AChE testing of additional co-exposures with bulk ZnO, together with the application of the Independent Action (IA) prediction model, which allowed us to draw more in-depth conclusions on the toxicological behavior of the mixture. Synergism was observed at 0.625 mg/L CPF concentration and antagonism at 5 mg/L CPF in mixtures containing 100 mg/L of both ZnO NPs and bulk ZnO. However, more cases of synergism between CPF and ZnO NPs occurred at intermediate CPF concentrations, demonstrating that nano-sized particles have a more toxic interaction with CPF than bulk ZnO. Therefore it can be argued that in vitro assays allow the identification of interaction profiles of NP-containing mixtures by achieving multiple endpoints with a large number of concentration combinations.

Recovery of Ceratophrys ornata tadpoles exposed to environmental concentrations of chlorpyrifos: evaluation of biomarkers of exposure.

Chlorpyrifos (CPF) is one of the most widely used insecticides worldwide despite the fact that many authors have warned about its effects in non-target biota. The effects of CPF on anurans are well known, but the process of recovery from these effects after exposure is less explored. The aim of this study was to evaluate the duration of sublethal effects induced by environmental concentrations of CPF on Ceratophrys ornata tadpoles after exposure. The experimental design consisted of an exposure phase (96 h) in which tadpoles were individually exposed to three concentrations of CPF (0, 0.01 and 0.02 mg CPF/L) and a post-exposure phase (72 h) in which exposed tadpoles were transferred to CPF-free media. Individuals that survived the exposure phase to CPF showed neither long-term lethal effects nor long-term swimming alterations and altered prey consumption after being transferred to CPF-free media. No morphological abnormalities were observed either. However, at the end of both phases, tadpoles emitted shorter sounds with a higher dominant frequency than the tadpoles in the control group, i.e., the tadpoles did not recover their normal sounds. Thus, for the first time in this species, we have shown that effects on sounds should be prioritized as biomarkers of exposure, as they not only provide longer detection times after cessation of exposure, but also involve non-destructive methods. The following order of priority could be established for the selection of biomarkers that diagnose the health status of individuals and precede irreversible responses such as mortality: alterations in sounds > swimming alterations > prey consumption.

Lethality and Acetylcholinesterase Inhibition in a Native Invertebrate Species Exposed to Water Samples of an Impacted Stream (Reconquista River Basin, Argentina).

The study of multiple biomarkers in bioindicator species is a useful tool to evaluate water quality in addition to physicochemical analysis. The aim of this work was to study the toxicity of water samples from two sites with different anthropogenic impacts (R: near a residential area and FP: close to horticultural farms and industrial waste treatment plants) from Las Catonas sub-basin (Reconquista River basin) in the native gastropod Biomphalaria straminea. Some physicochemical parameters and chlorpyrifos concentration were measured in water samples. Snails were exposed in laboratory conditions 48h to the water samples and neurotoxicity, behavior, lethality and acetylcholinesterase, carboxylesterase, glutathione S-transferase, glutathione reductase and catalase activities were measured. In water from FP, chlorpyrifos was detected and conductivity and pH were higher than in R. Lethality (60%) and a decrease (30%) in acetylcholinesterase were observed in snails exposed to FP indicating that water contamination causes high toxicity in B. straminea.

Pesticides exposure in pregnant Argentinian women: Potential relations with the residence areas and the anthropometric neonate parameters

Intrauterine environment is the first chemical exposure scenario in life, through transplacental transfer. In this study, the aim was to determine concentrations of organochlorine pesticides (OCPs) and selected current use pesticides in the placentas of pregnant women from Argentina. Socio-demographic information, the mother's lifestyle and neonatal characteristics were also analysed and related to pesticides residue concentrations. Thus, 85 placentas were collected at birth, from an area of intensive fruit production for the international market, in Patagonia Argentina. Concentrations of 23 pesticides including, trifluralin (herbicide), the fungicides chlorothalonil and HCB, and the insecticides chlorpyrifos, HCHs, endosulfans, DDTs, chlordanes, heptachlors, drins and metoxichlor, were determined by GC-ECD and GC-MS. Results were first analysed all together and then grouped by their residential settings, in urban and rural groups. Total mean pesticide concentration was 582.6 ± 1034.4 ng/g lw, where DDTs (325.9 ± 950.3 ng/g lw) and chlorpyrifos (188.4 ± 365.4 ng/g lw) showed a high contribution. Pesticide levels found exceeded those reported in low, middle and high income countries from Europe, Asia and Africa. In general, pesticides concentrations were not associated with neonatal anthropometric parameters. When the results were analysed by residence place, significantly higher concentrations of total pesticides and chlorpyrifos (Mann Whitney test p = 0.0003 and p = 0.032, respectively) were observed in placentas collected from mothers living in rural settings compared to urban areas. Rural pregnant women presented the highest pesticide burden (5.9 μg), where DDTs and chlorpyrifos were the major constituents. These results suggested that all pregnant women are highly exposed to complex pesticide mixtures, including banned OCPs and the widely used chlorpyrifos. Based on the pesticide concentrations found, our results warn of possible health impacts from prenatal exposure through transplacental transfer. This is one of the first reports of both chlorpyrifos and chlorothalonil concentrations in placental tissue, and contributes to the knowledge of current pesticide exposure in Argentina.

Effect of chlorpyrifos and its metabolites on skeletal system development of chick embryo.

Chlorpyrifos is an organophosphate insecticide used primarily to control pests on a variety of food and feed crops. Humans are directly or indirectly exposed to this pesticide through food, air, and occupation. The ill effects of chlorpyrifos on various organ systems of human has been widely documented, but less is known about its influence on human bones. To analyze the effect of chlorpyrifos and its metabolites 3,5,6-trichloro-2-pyridinol (TCPy) on the skeletal system of the chick embryo. Fertilized chick eggs were exposed to different concentrations of chlorpyrifos and its metabolite 3,5,6-TCPy on 1.5 days of incubation. The proximal phalanx of 18-day-old embryos was analyzed for defects in growth and ossification through histopathology, immunohistochemistry, angiogenesis assay, and gene expression study. Dose-dependent variations in developing bone of chick embryo were observed. Histochemical and histomorphometry studies of proximal phalanx showed increased in the growth plate length (F(9, 59)=228.9509, p=.00001) with a reduction in the total length of the phalanx (F(9, 59)=109.9905, p=.00001), decreased mineralization (F(9, 59)=224.6872, p=.00001), decreased blood islands in the bone marrow (F(9, 59)=7.7083, p=.0001) of chlorpyrifos, and 3,5,6-TCPy-exposed group. Significant downregulations in the expression patterns of the transcription factors, such as SOX9, RUNX2, and ALP, were also observed. Chlorpyrifos and its metabolite 3,5,6-TCPy exposure alters the chondrogenesis in the growth plate cartilage of long bone in chick embryo. The pesticide and its metabolite also interfere in ossification.

Assessment Of Acute Toxicity Of Chlorpyrifos And Its Sub-Lethal Effects On Protein Patterns Of Cyprinus Carpio(L.) By Using SDS-PAGE

The present study was focused on investigating the acute toxicity of chlorpyrifos and its impact on electrophoretic protein patterns in the tissues of Cyprinus carpio, an acute toxicity bioassay was conducted in the semi-static system and the fingerlings of C. carpio were exposed to various chlorpyrifos(50%EC)concentrations ranging from 0.1mg/L to 0.7mg/L for 96 h, and acute toxicity was determined as 0.318mg/L. Based on the LC50 value, the Cyprinus carpio were exposed to two sub-lethal concentrations viz., SL-1 (1/5th of LC50, 0.0636mg/l) and SL-2 (1/10th of LC50,0.0318 mg/l)  of chlorpyrifos. Proteins have a unique role in cell metabolism and proteomic analysis provides valuable information when variations that occur within the proteome of organisms are compared as a consequence of biological perturbations or external stimuli. The study's goal was to investigate the influence of chlorpyrifos on electrophoretic protein patterns by performing SDS-PAGE on muscle, liver, gill, and brain tissues after exposing fish to two sublethal concentrations  in a semi-static system for 3 weeks. The intensity of protein subunits in exposed tissues decreased, and some subunits disappeared, CPF influences both high-intensity protein bands and low intensity as well in both the sub-lethal concentrations. The study has suggested that the changes in the protein banding are more prominent in the SL-1 concentration of chlorpyrifos.The variations in protein subunits band patterns are due to protein deprivation of various proteins, proteolysis, or maybe insufficient amino acid incorporation into the polypeptide chain due to induced stress imposed by the toxicant.   &nbsp

Pesticide Exposure among Latinx Children in Rural Farmworker and Urban Non-Farmworker Communities: Associations with Locality and Season.

This study uses repeated measures to document the pesticide exposure of rural and urban Latinx children (age eight at baseline), and to compare these children in terms of the frequency and concentration of their exposure to a large set of pesticides, accounting for season. We used silicone wristbands worn for one week up to ten times at quarterly intervals from 2018 to 2022 to assess pesticide exposure in children from rural farmworker (n = 75) and urban non-farmworker (n = 61) families. We determined the detection and concentrations (ng/g) of 72 pesticides and pesticide degradation products in the wristbands using gas chromatography electron capture detection and gas chromatography mass spectrometry. The most frequently detected pesticide classes were organochlorines, pyrethroids, and organophosphates. Controlling for season, organochlorine or phenylpyrazole detections were less likely for rural children than for urban children. Detections of organochlorines, pyrethroids, or organophosphates were lower in spring and summer versus winter. Controlling for season, urban children had greater concentrations of organochlorines, while rural children had greater concentrations of pyrethroids and Chlorpyrifos. Pesticide concentrations were lower in winter and spring compared with summer and fall. These results further document that pesticides are ubiquitous in the living environment for children in vulnerable, immigrant communities.

Assessing acetamiprid and chlorpyrifos pesticide concentrations in water and sediments across macadamia orchard and communal area small reservoirs

ABSTRACT Pesticides are well known for their persistence in the environment their slow degradation and high toxicity. Aquatic environments, while not the target of many pesticide applications, often receive these chemicals from their catchments through runoff dynamics. Here, we assessed pesticide concentrations of acetamiprid and chlorpyrifos in water and sediment across macadamia orchard and communal area reservoirs in the Levubu area, South Africa, using liquid chromatography tandem mass spectrometry. Analysis of acetamiprid and chlorpyrifos associated with sediments in macadamia orchard reservoirs revealed mean pesticide concentrations of 14.48 µg L−1 and 5.67 µg L−1, respectively, whereas, in communal area reservoirs both pesticides were not detected. Acetamiprid was not detected across reservoir water, whereas the mean pesticide concentration of chlorpyrifos of 6.51 µg L−1 (macadamia orchard) and 0.13 µg L−1 (communal area) were detected. Significant differences were observed for chlorpyrifos concentrations in water samples between macadamia orchard and communal area reservoirs, whereas acetamiprid and chlorpyrifos indicated non-significant differences in sediments. The results indicate that macadamia orchard reservoirs are highly contaminated by acetamiprid and chlorpyrifos. Consequently, these pesticides can alter water quality and ecosystem functioning by reducing species diversity, adjusting community structure, altering energy flow and nutrient recycling.

Prediction of in vivo prenatal chlorpyrifos exposure leading to developmental neurotoxicity in humans based on in vitro toxicity data by quantitative in vitro-in vivo extrapolation.

Introduction: Epidemiological studies in children suggested that in utero exposure to chlorpyrifos (CPF), an organophosphate insecticide, may cause developmental neurotoxicity (DNT). We applied quantitative in vitro-in vivo extrapolation (QIVIVE) based on in vitro concentration and non-choline esterase-dependent effects data combined with Benchmark dose (BMD) modelling to predict oral maternal CPF exposure during pregnancy leading to fetal brain effect concentration. By comparing the results with data from epidemiological studies, we evaluated the contribution of the in vitro endpoints to the mode of action (MoA) for CPF-induced DNT. Methods: A maternal-fetal PBK model built in PK-Sim® was used to perform QIVIVE predicting CPF concentrations in a pregnant women population at 15weeks of gestation from cell lysate concentrations obtained in human induced pluripotent stem cell-derived neural stem cells undergoing differentiation towards neurons and glia exposed to CPF for 14days. The in vitro concentration and effect data were used to perform BMD modelling. Results: The upper BMD was converted into maternal doses which ranged from 3.21 to 271mg/kg bw/day. Maternal CPF blood levels from epidemiological studies reporting DNT findings in their children were used to estimate oral CPF exposure during pregnancy using the PBK model. It ranged from 0.11 to 140μg/kg bw/day. Discussion: The effective daily intake doses predicted from the in vitro model were several orders of magnitude higher than exposures estimated from epidemiological studies to induce developmental non-cholinergic neurotoxic responses, which were captured by the analyzed in vitro test battery. These were also higher than the in vivo LOEC for cholinergic effects. Therefore, the quantitative predictive value of the investigated non-choline esterase-dependent effects, although possibly relevant for other chemicals, may not adequately represent potential key events in the MoA for CPF-associated DNT.

Concentration evaluation and risk assessment of pesticide residues in selected vegetables sold in major markets of Port Harcourt South-South Nigeria

Abstract Concentration levels and health risk assessment of residues of organochlorine and organophosphate pesticides in four commonly vegetables (Cucumber, carrot, cabbage, and eggplant) collected from major markets of Port Harcourt city, South-south Nigeria were assessed. The collected samples were analysed using QuEChERS (quick, easy, cheap, effective, rugged, and safe) extraction method by gas chromatography coupled with Electron Capture Detector (ECD). Pesticide concentrations were compared with UK/EU maximum residual limits (MRLs). Health risk estimates were analysed using estimated daily intake (EDI), hazard quotient (HQ), and hazard ratio (HR) for children (16.7 kg) and adults (60 kg) weight groups. The results of this study showed that 80% of the vegetable samples contained detectable pesticide residues, of which 70% had residues that exceeded MRLs while 20% had residues below detectable levels. The highest concentrations of HCH residues are present in cabbage with a concentration of 0.25 ± 0.15 mg/kg for α-HCH while the least are present in eggplant with concentration of 0.038 ± 0.025 mg/kg in lindane. Pirimophos-methyl was detected in cucumber at 0.017 mg/kg while parathion and isofenfos was detected only in eggplants at concentration of 0.042 mg/kg and 0.022 mg/kg respectively. Concentrations of parathion, chlorpyrifos, and pirimophos-methyl residues were lower than MRLs in all the detected vegetable samples analysed. Non-carcinogenic health risk estimates for the children consumer groups showed that mevinfos, p, pʹ DDD, aldrin, and heptachlor epoxide detected in eggplant, carrot, and cabbage had HQ > 1. While for adults, only p, pʹ DDD and heptachlor epoxide revealed non-carcinogenic effect in cabbage. Risk was highest for child consumers. However, most of the pesticide residues were less than 1 for the HQs value which is indicative of insignificant health risk. Human risk estimations for the carcinogenic health effect for the studied vegetables showed that lindane and delta HCH could pose carcinogenic health risks to adult, while aldrin, dieldrin, heptachlor, α HCH, β HCH, delta HCH, and heptachlor epoxide could pose carcinogenic health risks to children. The HRI values in some of the detected residues indicate that the cancer benchmark concentrations exceeded the EDI for the respective organochlorine pesticide in the vegetable samples, thus raising serious concerns of possible carcinogenicity. Non carcinogenic and carcinogenic risk assessment of organochlorine pesticide residues in the studied vegetable indicates health threat. Hence, strict monitoring and control of pesticide residues in agricultural products is being suggested, to protect consumers, especially the children who are vulnerable to the adverse effects of pesticides.

Effect of chlorpyrifos on the expression and regulation of salivary gland protein of Haemaphysalis longicornis

ABSTRACT The aim of this study is to explore the detoxification and homoeostasis functions of salivary glands, and to look for possible target proteins of new drugs for tick prevention and treatment. Different concentrations of chlorpyrifos to deal with the semi-engorged female Haemaphysalis longicornis, through the DIA quantitative proteomics method to quantitatively determine of all the proteins in the salivary glands, and through a variety of the depth of the bioinformatics methods for protein analysis and function mining, explain the molecular mechanism of detoxification function of salivary glands. Quantitative information from 5 normal groups and 8 different treatment groups showed that a total of 3152 proteins were identified. The expression levels of these proteins changed with the chlorpyrifos different concentration and treatment times. However, after the overall analysis, it was found that after the action of chlorpyrifos, the proteins involved in detoxification, such as glutathione S-transferase and glutamine synthetase, the heat shock proteins involved in stress, and the acid sphingomyelinase involved in maintaining the body’s homoeostasis had corresponding changes. We found and explained the functions of detoxification, stress, and homoeostasis of salivary glands. The regulatory strategies of proteins that played a key role in these functions were explored.

Experimental detection of chlorpyrifos by MoS2 coated planar polymer waveguide sensor utilizing common path interferometric principle

A common path Mach-Zehnder interferometer is fabricated using a planer polymer waveguide having MoS2 as an adlayer for chlorpyrifos detection. The dispersion characteristic and cutoff condition of proposed waveguide are obtained theoretically and hence the cutoff film thickness is optimized to get TE0 and TM0 propagating modes. Variations between the phase shift of propagating modes with the concentration of pure chlorpyrifos and its commercial sample are obtained. A good linear variation between phase shift and concentration of chlorpyrifos is obtained in our fabricated waveguide for all considered temperatures. The obtained maximum sensitivity, minimum limit of detection, and limit of quantification of chlorpyrifos are 5.66 degree/μM, 1.57 μM, and 5.24 μM respectively, at 45° C. The capability of the fabricated sensor to generate distinct response for a pure and commercial sample of chlorpyrifos at different concentration and temperature were confirmed by principal component analysis. Since the response of sensor is better for commercial samples at a lower temperature, therefore it is recommended that the concentration of chlorpyrifos in commercial samples should be measured at low temperatures.

Protection of Mitochondrial Potential and Activity by Oxyprenylated Phenylpropanoids.

A series of five naturally occurring oxyprenylated phenylpropanoids, namely, the coumarins auraptene (7-geranyloxycoumarin) 1 and 7-isopentenyloxycoumarin 2, and the coumaric acid and ferulic acid derivatives, 4'-isopentenyloxycoumaric acid 3, boropinic acid 4, and 4'-geranyloxyferulic acid 5 were tested for their effects on mitochondrial functionality using the organophosphate pesticides glyphosate and chlorpyrifos, and resveratrol, as the reference. While not showing an appreciable in vitro antioxidant activity, and virtually no or a little effect on the viability of non-cancer cell lines BEAS-2B and SHSY-5Y, all phytochemicals exhibited a marked protective effect on mitochondrial potential and activity, with values that were comparable to resveratrol. Auraptene 1 and 7-isopentenyloxycoumarin 2 were seen to be the most effective secondary metabolite to this concern, in particular in being able to completely abolish the decrease of mitochondrial potential induced by increasing concentration of both glyphosate and chlorpyrifos. All the compounds tested also exhibited a protective effect on mitochondrial activity. The potency displayed will shed more light on the molecular basis of the beneficial effects of auraptene, 7-isopentenyloxycoumarin, and structurally related oxyprenylated phenylpropanoids reported to date in the literature.

In Vitro Compatibility of Three Native Isolates of Trichoderma with the Insecticide Chlorpyrifos

The compatibility between biocontrol agents and pesticides seems to be a sustainable control strategy in agriculture. Therefore, the in vitro compatibility of three native isolates of Trichoderma was evaluated in three concentrations of chlorpyrifos (960, 1200, and 1440 mg/L), by determining the effect on spore germination, mycelial growth, and the antagonistic capacity. The isolates correspond to Trichoderma asperellum TCA 3, Trichoderma asperellum TCA 21 and Trichoderma harzianum TCA 23. Both spore germination and mycelial growth were performed using the poisoned medium method, while the antagonistic capacity was evaluated against Botrytis sp. in a dual culture. The results showed that TCA 21 strain had a higher germination percentage (79.46, 59.79, and 37.43%) than the TCA 3 and TCA 23 strains, in the three concentrations of chlorpyrifos. Regarding the mycelial growth of the three native strains in chlorpyrifos are affected when concentration of chlorpyrifos increase (p < 0.05). Finally, the antagonistic capacity of the three strains was not affected by any concentration of chlorpyrifos, where strains TCA 21 and TCA 23 presented a degree of antagonism of one, while TCA 3 presented a degree of two, according to the scale used by Bell. In conclusion, T. asperellum TCA 21 was the one that presented the best in vitro compatibility with chlorpyrifos at concentrations of 960 and 1200 mg/L, compared to T. asperellum TCA 3 and TCA 23. These results are favorable for field application since these native strains can also have the ability to degrade the insecticide, representing a sustainable and eco-friendly alternative to the environment.

Oxidative stress in Arthrospira platensis by two organophosphate pesticides.

Although it is known that organophosphate insecticides are harmfull to aquatic ecosystems, oxidative damages caused by Dimethoate and Chlorpyrifos are not studied on Arthrospira platensis Gomont. In this study, various Chlorpyrifos (0-150 µg mL-1) and Dimethoate (0-250 µg mL-1) concentrations were added to the culture medium in laboratory to evaulate growth rate, chlorophyll-a content and antioxidant parameters of A. platensis. Optical Density (OD560) and chlorophyll-a decreased compared to the control for seven days in both pesticide applications. Superoxide dismutase (SOD) activity increased at 50 µg mL-1 Chlorpyrifos concentration but it decreased at all concentrations. Although Ascorbate peroxidase (APX) and glutathione reductase (GR) activities increased with Chlorpyrifos application, they did not change with Dimethoate application. Malondialdehyde (MDA) amount decreased at 150 µg mL-1 Chlorpyrifos concentration but it increased in Dimethoate application. The H2O2 content were increased in both applications. Proline decreased in 50 and 75 µg mL-1 Chlorpyrifos concentrations and increased at 150 µg mL-1 concentration, while it increased at 25 µg mL-1 Dimethoate concentration. The results were tested at 0.05 significance level. These pesticides inhibit A. platensis growth and chlorophyll-a production and cause oxidative stress. The excessive use may affect the phytoplankton and have negative consequences in the aquatic ecosystem.

Combined Effect of Pesticides Containing Active Ingredients of Chlorpyrifos and Mancozeb on the DNA Damage of Chlorella Sorokiniana Shihira and Krauss

The intensive use of pesticides in agricultural areas can leave residues of pesticide mixtures on the soil surface. Surface run-off can carry pesticide residues, enter water bodies, and then may affect non-target organisms. Chlorpyrifos and mancozeb are active ingredients commonly contained in pesticides applied in shallot farming. This study aims to evaluate the combined effect of pesticides containing active ingredients of chlorpyrifos and mancozeb on the growth and DNA damage of the microalgae Chlorella sorokiniana. The test organism was exposed to the combined concentration of chlorpyrifos:mancozeb, i.e., 0:0, 20%:20%, 20%:80%, 80%:20%, and 80%:80% of the individual EC50 of each pesticide with sampling time at hours 0, 6, 24, and 48. Microalgae growth was estimated by cell counting method, and DNA damage was analyzed by alkaline comet assay method with parameters, i.e., Tail Intensity (TI%), Head Intensity (HI%), Tail Moment (TM), Olive Tail Moment (OTM), and Tail Factor (TF). The results showed that the combined pesticides inhibited the growth of C. sorokiniana, with the highest growth inhibition being at a combined concentration of 80%:80%. The TM and OTM values of C. sorokiniana increased with the increase of combined concentrations at an exposure period of up to 24 hours. In conclusion, the combined exposure could induce growth inhibition and DNA damage of Chlorella sorokiniana, mainly in the first 24 hours. The TM and OTM can be used as sensitive biomarkers for biomonitoring pesticide pollution.

Solid-state electrochemiluminescence sensor based on the carbon fibers derived from ZIFs-containing electrospun fibers for chlorpyrifos detection

Carbon fiber containing zeolite imidazole framework-67 (ENCF-67) combined with graphene oxide (GO) and ruthenium bipyridine [Ru(bpy)32+] was first applied in the field of electrochemiluminescence (ECL). ENCF-67, GO@Ru(bpy)32+ and Nafion were successively modified on the electrode surface by layer-by-layer assembly method to fabricate a simple and sensitive solid-state ECL sensor. ENCF-67 prepared by electrostatic spinning combined with high temperature pyrolysis can not only fix Ru(bpy)32+, but also shorten the electron transport distance and promote the system electron transport due to the large specific surface area and porous structure. GO, which has a large specific surface area, worked with ENCF-67 to immobilize Ru(bpy)32+ and promote electron transfer in the system. The constructed sensor can obtain a significant ECL phenomenon under neutral condition. Chlorpyrifos can obviously quench the ECL signal of the constructed sensor, and the quenching value was associated with the concentration of chlorpyrifos. From 1.0 × 10–13 M to 1.0 × 10–6 M, the quenching value was positively correlated with the logarithm value of the concentration, which can be used for the quantitative detection of chlorpyrifos residues. This work not only expanded the application range of carbon fibers, but also provided an effective way for ECL signal amplification.

Effects of Pesticides on the Survival of Shredder Nectopsyche sp. (Trichoptera) and Leaf Decomposition Rates in Tropical Andes: A Microcosm Approach.

Andean streams are becoming increasingly impacted by agricultural activities. However, the potential effects of pesticides on their aquatic biodiversity remain unassessed. In order to address this knowledge gap, we conducted an experiment over 37 days in microcosms to assess the effect of two pesticides commonly used in Ecuador (Engeo and Chlorpyrifos) on the aquatic insect Nectopsyche sp. (Trichoptera: Leptoceridae) at 0, 0.10, 5 and 10 μg L-1 concentrations. The highest concentration corresponds to the maximum concentration allowed by the Equatorian legislation. We assessed insect mortality every 24 h, with leaf litter decomposition rates of organic matter determined by deploying Andean alder (Alnus acuminata) dry leaf packs in the microcosms. We found significant mortality of Nectopsyche sp. at high concentrations of Chlorpyrifos, whereas leaf litter was not significantly affected by any of the treatments. We conclude that the environmental legislation of Ecuador might not be fully protecting aquatic biodiversity from pesticide pollution. Further studies are needed, especially when considering that the maximum permitted concentration is very likely exceeded in many areas of the country. We also suggest that the maximum permissible values should be reviewed, considering each pesticide individually.

Multi-and transgenerational synergistic effects of glyphosate and chlorpyrifos at environmentally relevant concentrations in the estuarine rotifer Proales similis

We evaluated the multi-and transgenerational effects of single and combined environmentally relevant concentrations of glyphosate (GLY) and chlorpyrifos (CPF) in the estuarine rotifer Proales similis. The acute and chronic toxicities of GLY and CPF were determined as individual compounds and as a mixture. Rotifers were exposed to environmental concentrations of GLY (1, 10, 100, and 1000 μg/L) and CPF (0.1, 1, 5, and 10 μg/L). The main findings were as follows: (i) the LC50 values were 33.91 mg/L (GLY) and 280 μg/L (CPF); (ii) the toxic unit (TU50) of the mixture was 0.30, corresponding to 10.17 mg/L GLY and 83 μg/L CPF; (iii) the multigenerational study indicated that the tested concentrations of GLY and CPF, both single and combined, significantly and consistently decreased the growth rates of P. similis from the F0 to F6 generations; (iv) in most cases, GLY and CPF mixtures induced a strong synergistic effect; and (v) transgenerational effects were detected in the F4 generation, especially GLY and CPF in higher equitoxic proportions. These effects seem to dissipate in F5. Across multigeneration, a slight recovery could indicate population resilience to pollution. Our findings suggest that a mixture of GLY and CPF at environmental concentrations is likely to occur under real field conditions, increasing the risk to marine and estuarine invertebrates such as rotifers.