RESUMO
In recent years, the official authorities in Chile have reported transgressions in the maximum residue levels of pesticides in fresh vegetables. There is no official information about traceability, pesticide levels, and potential health risks. The aim of this study was to analyse pesticide residues and their corresponding dietary risk assessments in tomatoes from supermarkets in the Metropolitan Region. Pesticides were extracted using the Quick, Easy, Cheap, Effective, Rugged and Safe, QuEChERS method, and their concentrations were determined by using chromatography with HPLC-FL/UV and GC-MS/ECD/NPD, following the Analytical Quality Control and Method Validation Procedures for Pesticides Residues Analysis in Food and Feed, SANTE guide and ISO 17025:2017 standard. In addition, a dietary risk assessment was carried out by comparing Chilean data to international references. The results reported that 9% of the samples had pesticide residue levels above the maximum residue levels permitted in Chile. All the scenarios evaluated revealed the highest estimated daily intake and hazard quotients for methamidophos and chlorpyrifos. Both the active substances used were acetylcholinesterase inhibitors and were neurotoxic under chronic risk assessment. The results showed the highest chronic hazard index in the Chilean scenario for all age groups and genders. The evidence obtained revealed that methamidophos, methomyl, and chlorpyrifos should be restricted for their use in Chilean agriculture.
RESUMO
Over the last years, the detection of pesticide residues in the official food surveillance programs of Chile has been increased, mainly in fresh vegetables such as tomatoes and lettuces. The Metropolitana Region of Chile presents the highest detections in the country. The lack of evaluations of toxicological risks in human health have increased uncertainty of the potential effects of pesticides exposures in the Chilean population. This research aims to determinate health risks assessment of pesticide residues associated to tomatoes and lettuces produced in Metropolitana Region. The findings of this study reveal that tomatoes and lettuces cultivated in the MR show more than 50% of samples with one or multiple pesticides residues. From the total samples, 16% were over the Chilean Maximum Residue Levels (MRLs). The main pesticides detected in tomatoes and lettuces were methamidophos, methomyl, difenoconazole, cyprodinil and boscalid. The results obtained using the official data of the Ministry of Health of Chile (MINSAL) compared to the World Health Organization (WHO), describe relevant risks through the Estimated Daily Intakes (EDI), Hazard Quotients (HQ) and Hazard Index (HI) for the Chilean population due to high concentrations of methamidophos, methomyl and cyprodinil. More restrictions for the use of methamidophos, methomyl, difenoconazole, cyprodinil and boscalid and effective control programs should be implemented in order to mitigate the impacts on the Chilean population.
Assuntos
Monitoramento Ambiental/métodos , Fazendas/estatística & dados numéricos , Contaminação de Alimentos/análise , Lactuca/química , Resíduos de Praguicidas/análise , Medição de Risco/métodos , Solanum lycopersicum/química , HumanosRESUMO
Methamidophos (MET) is an organophosphate (OP) pesticide widely used in agriculture in developing countries. MET causes adverse effects in male reproductive function in humans and experimental animals, but the underlying mechanisms remain largely unknown. We explored the effect of MET on mice testes (5â¯mg/kg/day/4â¯days), finding that this pesticide opens the blood-testis barrier and perturbs spermatogenesis, generating the appearance of immature germ cells in the epididymis. In the seminiferous tubules, MET treatment changed the level of expression or modified the stage-specific localization of tight junction (TJ) proteins ZO-1, ZO-2, occludin, and claudin-3. In contrast, claudin-11 was barely altered. MET also modified the shape of claudin-11, and ZO-2 at the cell border, from a zigzag to a more linear pattern. In addition, MET diminished the expression of ZO-2 in spermatids present in seminiferous tubules, induced the phosphorylation of ZO-2 and occludin in testes and reduced the interaction between these proteins assessed by co-immunoprecipitation. MET formed covalent bonds with ZO-2 in serine, tyrosine and lysine residues. The covalent modifications formed on ZO-2 at putative phosphorylation sites might interfere with ZO-2 interaction with regulatory molecules and other TJ proteins. MET bonds formed at ZO-2 ubiquitination sites likely interfere with ZO-2 degradation and TJ sealing, based on results obtained in cultured epithelial cells transfected with ZO-2 mutated at a MET target lysine residue. Our results shed light on MET male reproductive toxicity and are important to improve regulations regarding the use of OP pesticides and to protect the health of agricultural workers.
Assuntos
Barreira Hematotesticular/efeitos dos fármacos , Inseticidas/farmacologia , Organofosfatos/farmacologia , Compostos Organotiofosforados/farmacologia , Proteína da Zônula de Oclusão-2/metabolismo , Animais , Barreira Hematotesticular/metabolismo , Claudinas/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos ICR , Ocludina/metabolismo , Fosfoproteínas/metabolismo , Fosforilação/efeitos dos fármacos , Túbulos Seminíferos/efeitos dos fármacos , Túbulos Seminíferos/metabolismo , Espermatogênese/efeitos dos fármacos , Junções Íntimas/efeitos dos fármacos , Junções Íntimas/metabolismo , Proteína da Zônula de Oclusão-1/metabolismoRESUMO
Although evidence indicates that exposure to organophosphorus (OP) pesticides induces neurobehavioral disorders, little is known about the effects of OP on aggressive behaviour. Our study investigated the effects of repeated exposure to an OP pesticide, methamidophos, on the isolation-induced aggressive behaviour in mice. Forty seven male mice were individually housed for a month. Socially isolated animals were then confronted with a standard non-isolated opponent for 15 min (pre-treatment trial), and the latency and frequency of aggressive and general exploratory behaviours were recorded. Based on the presence of attack behaviour in the pre-treatment trial, mice were classified as isolation-induced aggressive and non-aggressive. All mice were then treated for 7 days with methamidophos (3.5 mg/kg/day, n = 22, intraperitoneal (i.p.)) or saline (1 mL/kg/day, control group, n = 25, i.p.), and a second trial was performed. Repeated exposure to methamidophos induced attack behaviour in non-aggressive mice. The treatment with methamidophos also decreased plasma butyrylcholinesterase and brain acetylcholinesterase activity. These results suggest that methamidophos has a pro-aggressive effect on socially isolated mice.
Assuntos
Agressão/efeitos dos fármacos , Inseticidas/toxicidade , Compostos Organotiofosforados/toxicidade , Acetilcolinesterase/metabolismo , Agressão/fisiologia , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/enzimologia , Butirilcolinesterase/sangue , Injeções Intraperitoneais , Masculino , Camundongos , Atividade Motora/efeitos dos fármacos , Atividade Motora/fisiologia , Testes Psicológicos , Isolamento SocialRESUMO
Previous studies have shown that organophosphate pesticide (OP) exposure is associated with oxidative stress. Methamidophos (MET) is an OP widely used in agriculture, which is regarded as a highly toxic pesticide and it is a potent inhibitor of acetylcholinesterase. The aim of this study was to evaluate whether MET can induce oxidative stress at low concentrations in primary cultures of human peripheral blood mononuclear cells (PBMCs). PBMCs from healthy individuals were exposed to MET (0-80 mg/L) for 0-72 h. We performed the MTT and neutral-red assays to assess the cytotoxicity. As indicators of oxidative stress, the levels of reactive oxygen species (ROS) were assessed using flow cytometry, and the malondialdehyde (MDA) and reduced glutathione (GSH) levels were determined. MET decreased the viability of PBMCs in a dose-dependent manner. At concentrations of 3, 10, or 20 mg/L for 24 h, MET increased the ROS production significantly compared with the vehicle control. Similarly, MET increased the levels of MDA at the same concentrations that increased ROS (10 and 20 mg/L); however, no changes in GSH levels were observed. These results suggest that MET increased the generation of oxidative stress in PBMCs. © 2015 Wiley Periodicals, Inc. Environ Toxicol 32: 147-155, 2017.
Assuntos
Sobrevivência Celular/efeitos dos fármacos , Inseticidas/toxicidade , Monócitos/efeitos dos fármacos , Compostos Organotiofosforados/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Relação Dose-Resposta a Droga , Glutationa/metabolismo , Humanos , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Malondialdeído/metabolismo , Cultura Primária de Células , Espécies Reativas de Oxigênio/metabolismo , Adulto JovemRESUMO
Methamidophos (MET) is a highly toxic organophosphate (OP) pesticide that is widely used in developing countries. MET has male reproductive effects, including decreased fertility. We evaluated MET effects on sperm quality, fertilization and DNA integrity, exploring the sensitivity of different stages of spermatogenesis. Adult male mice received MET (3.75 or 5mg/kg-bw/ip/day/4 days) and were euthanized 1, 28 or 45 days post-treatment (dpt) to evaluate MET's effects on epididymal maturation, meiosis or mitosis, respectively. Spermatozoa were obtained from the cauda epididymis-vas deferens and were evaluated for sperm quality, acrosome reaction (AR; Coomassie staining), mitochondrial membrane potential (by JC-1), DNA damage (comet assay), oxidative damage (malondialdehyde (MDA) production), in vitro fertilization and protein phosphorylation (immunodetection), and erythrocyte acetylcholinesterase (AChE) activity. At 1-dpt, MET inhibited AChE (43-57%) and increased abnormal cells (6%). While at 28- and 45-dpt, sperm motility and viability were significantly reduced with an increasing MET dose, and abnormal morphology increased at 5mg/kg/day/4 days. MDA and mitochondrial activity were not affected at any dose or time. DNA damage (OTM and %DNA) was observed at 5mg/kg/day/4 days in a time-dependent manner, whereas both parameters were altered in cells from mice exposed to 3.75 mg/kg/day/4 days only at 28-dpt. Depending on the time of collection, initial-, spontaneous- and induced-AR were altered at 5mg/kg/day/4 days, and the fertilization capacity also decreased. Sperm phosphorylation (at serine and tyrosine residues) was observed at all time points. Data suggest that meiosis and mitosis are the more sensitive stages of spermatogenesis for MET reproductive toxicity compared to epididymal maturation.
Assuntos
Replicação do DNA/efeitos dos fármacos , Inseticidas/toxicidade , Compostos Organotiofosforados/toxicidade , Espermatogênese/efeitos dos fármacos , Espermatozoides/efeitos dos fármacos , Acetilcolinesterase/metabolismo , Reação Acrossômica/efeitos dos fármacos , Animais , Peso Corporal/efeitos dos fármacos , Ensaio Cometa , Feminino , Fertilização/efeitos dos fármacos , Técnicas In Vitro , Infertilidade Masculina/induzido quimicamente , Infertilidade Masculina/patologia , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos ICR , Oócitos/efeitos dos fármacos , Tamanho do Órgão/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Fosforilação , Reprodução/efeitos dos fármacosRESUMO
The earthworm Eisenia foetida (Annelida, Oligochaeta) is an excellent biosentinel model organism for assessing potential toxicological risks by xenobiotics in terrestrial ecosystems. Methamidophos is an organophosphorous insecticide widely used to control agricultural pests. Its main action is due to inhibition of the enzyme acetylcholinesterase. The aim of this study was to evaluate the toxicity of methamidophos on the morphology and male parameters in Eisenia foetida. After determining the LD50 for methamidophos (85.34 mg/kg soil), five groups were formed, including control subjects, and sprayed with tap water. Methamidophos treated groups were subjected to doses of 1/10, 1/6, 1/3 and 2/3 of the LD50. Each group was analyzed at day 1, 6, 14 and 30 post-treatment. The results show a significant decrease in the weight of all individuals treated with methamidophos, besides showing a coiled body in 100 percent of them. Sperm count showed a significant increase in the treated groups after 1, 6 and 14 days post exposure and a significant decrease by day 30. Using the technique of acridine orange, a significant increase in abnormal metachromatic sperm (red fluorescence) in treated animals was shown. Methamidophos alters the overall behavior in earthworms and the male reproductive parameters of Eisenia foetida possibly altering the structure and conformation of DNA.
La Lombriz de tierra, Eisenia foetida (Annelida, Oligochaeta), constituye un excelente modelo de organismo biocentinela para evaluar los riesgos tóxicos de xenobióticos, en ecosistemas terrestres. Metamidofos es un insecticida organofosforado de amplio uso para controlar plagas agrícolas. Su acción principal se debe a la inhibición de la enzima acetilcolinesterasa. El objetivo de este estudio fue evaluar la toxicidad de metamidofos sobre la morfología y parámetros espermáticos de Eisenia foetida. Una vez determinada la LD50 para metamidofos (85,34 mg/kg de tierra), se tomaron 5 grupos, entre ellos los individuos del grupo control, los cuales fueron asperjados con agua potable. Los grupos tratados con metamidofos fueron sometidos a dosis de 1/10, 1/6, 1/3 y 2/3 de la LD50. Cada grupo fue analizado al día 1, 6, 14, y 30 post tratamiento. Los resultados muestran una baja significativa en el peso de todos los individuos tratados con metamidofos, además de presentar enrrollamiento corporal, en el 100 por ciento de ellos. El recuento espermático presenta un aumento significativo en los grupos tratados a 1,6 y 14 días, para luego decaer significativamente el día 30. El uso de la técnica del naranja de acridina, mostró un aumento significativo de espermatozoides metacromáticos anormales en los animales tratados (fluorescencia de color rojo). Se concluye que Metamidofos altera el comportamiento general de la lombriz de tierra y los parámetros reproductivos espermáticos de Eisenia foetida posiblemente alterando la conformación y estructura del ADN.
Assuntos
Animais , Compostos Organotiofosforados/administração & dosagem , Inseticidas/administração & dosagem , Oligoquetos , Reprodução , Peso Corporal , Sêmen , Fatores de TempoRESUMO
Infrared, Raman and SERS spectra of O,S-Dimethyl phosphoramidothioate, metamidophos, MAP, have been recorded. Density Functional Theory, DFT, with the B3LYP functional was used for the optimization of the ground state geometry and simulation of the infrared and Raman spectra of this molecule. Calculated geometrical parameters fit very well with the experimental ones. Combining the recorded data, the DFT results and a Normal Coordinate Analysis based on a scaled quantum mechanical (SQM) force field approach, a complete vibrational assignment was made for the first time. The comparison of SERS spectra obtained by using colloidal silver nanoparticles, with the corresponding Raman spectrum reveals enhancement and shifts in bands as well as information about the orientation of MAP on the nm-sized metal structures and the importance of the S atom on the SERS effect. DFT modelling of the SERS effect and Molecular Electrostatic Potentials (MEP) confirms the experimental information.
Assuntos
Compostos Organotiofosforados/química , Praguicidas/química , Modelos Moleculares , Teoria Quântica , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral RamanRESUMO
We examined the cytogenetic and genotoxic effects of the neonicotinoid insecticide imidacloprid and the organophosphate insecticide methamidophos, when administered alone or in combination. These insecticides were tested with the bone marrow chromosome aberration assay and micronucleus test in rats and by the bacterial mutation assay (Salmonella/microsome mutagenicity assay). Wistar albino rats were orally fed daily with laboratory chow treated with various concentrations of insecticides, 50 and 100 mg/kg imidacloprid, 2.5 and 5 mg/kg methamidophos, and 2.5 and 5 mg/kg imidacloprid plus methamidophos, respectively, for 90 days. Numerical and structural chromosomal aberrations were evaluated. Significant differences were detected between all the insecticide-administered groups versus the control group and between the two concentrations of the pesticide-treated groups. Both concentrations of the insecticides induced a dose-related increase in the micronucleus frequency (P < 0.05). Dose-related increases in the number of revertants were observed with the two Salmonella strains (TA98 and TA100). All tested doses of the insecticides demonstrated mutagenic activity in the presence of S9 mix. These results lead us to the conclusion that the synergistic effect of methamidophos and imidacloprid causes an increase in potential damage to non-target organisms.