Avaliação da dissipação do inseticida malation utilizado em nebulização a ultrabaixo volume no controle da dengue: avaliação ecotoxicológica e de risco ambiental / Evaluation of malathion insecticides dissipation used in ultra-low volume nebulization in dengue control ecotoxicological assessment and environmental risk

A dengue é um dos principais problemas de Saúde Pública da atualidade. É transmitida por mosquitos do gênero Aedes, sendo a espécie Aedes aegypti o vetor responsável pela transmissão no Brasil. O principal alvo de controle da doença é seu vetor, sendo o controle químico amplamente utilizado em todas as regiões atingidas. Como forma de prevenção ou em períodos de epidemia, torna-se necessária a eliminação dos mosquitos adultos, sendo indicada a nebulização a ultrabaixo volume (UBV) a frio do organofosforado malation por meio do uso de equipamentos pulverizadores acoplados a veículos. Este inseticida utilizado pode sofrer desvios durante e após a aplicação a UBV, caracterizando-se como um potencial agente de desequilíbrio ecológico, podendo atingir e gerar efeitos danosos em organismos não alvos aquáticos e terrestres. Este trabalho teve como objetivo desenvolver e validar um método de análise para o malation em cromatografia líquida de alta eficiência e obter recuperação do inseticida em níveis aceitáveis em água e solo, avaliar seu período de dissipação e tempo de meia vida (t1/2) nestas matrizes e classificá-lo quanto à toxicidade aguda e ao risco ambiental de acordo com diferentes autores, para o microcustáceo Daphnia magna, para a minhoca Eisenia foetida, para o peixe mato grosso (Hyphessobrycon eques) e para a macrófita Lemna minor. O método foi considerado adequado para análise do malation. A recuperação obtida para água foi de 97 por cento e para solo, 96 por cento...

Dengue is one of the major public health problems nowadays. It is transmitted by mosquitoes of the genus Aedes, and the Aedes aegypti specie is the vector responsible for transmission in Brazil. The main target to control the disease is its vector, and the chemical control is widely used in all affected regions. As a preventive measure or in epidemic periods, it becomes necessary to eliminate adult mosquitoes, being indicated the ultralow volume nebulization of malathion organophosphate in cold way through the use of sprinklers attached to vehicles. This used insecticide can suffer deviation during and after application ULV, characterizing itself as a potential agent of environmental imbalance, with the possibility of reach and generate harmful effects on aquatic and terrestrial non-target organisms. This work had the objective to develop and validate a method of analysis for malathion in high performance liquid chromatography and obtain recovery of insecticide in acceptable levels in water and soil, evaluate its dissipation period and half-life time in these matrices and classify it on acute toxicity and environmental risk according to different authors, to the microcrustacean Daphnia magna, to the earthworm Eisenia foetida, to the fish Hyphessobrycon eques and to the macrophyte Lemna minor. The method was considered appropriate for analysis of malathion. The obtained recovery for water was 97 per cent and for soil, 96 per cent . Toxic effects resulting from exposure to...

Malation vs. Aedes aegypti (Linnaeus) (Diptera: Culicidae) de diferentes regiones de Venezuela / Malathion vs. Aedes aegypti (Linnaeus, Diptera: Culicidae) from different regions of Venezuela

En Venezuela, el malation ha sido ampliamente usado en forma continua en programas de control de aedes aegypti. Por tal motivo se realizó un estudio en mosquitos provenientes de zonas urbanas con alta casuística de dengue de los estados: Amazonas, Aragua, Bolívar, Lara, Mérida y Zulia, para determinar el status de susceptibilidad en este vector al malatión, en comparación con la cepa susceptible referencial, Rockefeller (Rock). Se hicieron bioensayos en botellas tratadas con el insecticida malatión evaluando la dosis diagnóstica 100ug/mL en 30 minutos y ensayos bioquímicos en microplacas para determinar mecanismos metabólicos asociados al status frente al insecticida. Los resultados de los bioensayos mostraron que existe susceptibilidad a malatión, lo cual fue confirmado por pruebas bioquímicas. Sin embargo, se encontraron diferencias significativas entre todas las cepas evaluadas con valores de P<0,005 para esterasas alfa (α), esterasas beta (β) y acetilcolinesterasa normal (Ache) y acetilcolinesterasa inhibida (Achei). La prueba de comparación de medias de Bonferroni encontró similitud entre la cepa Rock, mazonas y Lara para esterasas α y β. Se encontró similitud de la cepa Rock con las cepas de Bolívar y Zulia para las pruebas con Ache y Achei. Este estudio concluye que el malatión mostró su potencial de uso en el control del vector del dengue de las localidades evaluadas.

In Venezuela, malathion has been widely used continuously in control programs for Aedes aegypti. Therefore, a study in mosquitoes from urban areas with high dengue casuistry in the states of Amazonas, Aragua, Bolivar, Lara, Merida and Zulia was conducted to determine the status of this vector susceptibility to malathion, compared with the reference susceptible strain, Rockefeller. Bioassays were done on bottles treated with the insecticide malathion, 100ug/mL evaluating the diagnostic doses in 30 minutes and biochemical assays in microplates were performed to determine metabolic mechanisms associated with status against insecticide. The bioassay results showed that there is malathion susceptibility, which was confirmed by biochemical tests. However, significant differences were found among all strains assessed values of P<0.005 for esterases alpha (α), beta esterases (β) and standard acetylcholinesterase (AChe) and inhibited acetylcholinesterase (Achei). The mean comparison test of Bonferroni showed similarity between the strains Rock, Amazon and Lara for esterases α and β. Similarity was found between the strains Rock, Bolivar and Zulia for the Ache and Achei tests. This study concludes that malathion showed its potential use in controlling the dengue vector in the locations evaluated.

Determination of malathion in blood and urine using thin-layer chromatography.

Malathion is a broad-spectrum Organophosphorus insecticide generally used to control a variety of insects. Routinely it is analysed by Gas Liquid Chromatography & High Performance Liquid Chromatography. Now an attempt has been made to develop a new method for analysis of Malathion in biological samples using Thin Layer Chromatography (TLC) technique, which is inexpensive, accurate and non-destructive. Malathion was extracted from blood and urine using solvent extraction methods and then identified on the TLC plates. For chromatographic separation, various binary and tertiary solvent systems were used to demonstrate in the laboratory. For detection on developed plates, palladium chloride reagent was used which successfully increased the sensitivity without dispensing with the simplicity of the method. For the analysis, a total of 20 solvent systems were chosen. Out of these 20 solvent systems, the three best solvent systems namely Cyclohexane: Chloroform (60:40), Hexane: Acetone (80:20) and Acetone: Hexane: Toluene (40:40:20) were chosen for statistical analysis which included the calculation of mean Rf value, value of standard deviation and coefficient of variance. The method developed is simple, inexpensive, accurate and non-destructive that allows for sensitive and reproducible analysis of Malathion.

Determinación de Malathión 14C en arroz almacenado / Determination of malathion 14C in stored rice

Se investigó la permanencia de residuos de Malathión-14C en arroz en cáscara almacenado según procedimientos locales, durante un período de 9 meses. Los residuos de Malatión-14C fueron encontrados en mayor cantidad en el salvado (entre 22.04 y 408.15 ppm) y en la cáscara, entre (30.44 y 57.39 ppm), en contraste con los encontrados en la crióspside (entre 0.91 y 1.38). Los residuos superficiales y los residuos extraíbles disminuyeron a medida que transcurrió el tiempo, sucediendo lo contrario con los residuos no extraíbles. Fueron identificados el Malathión, el Malathión ácido monocarboxílico, el Malatión ácido dicarboxílico y una sustancia desconocida en los extractos metanólicos (residuos extraíbles) mediante cromatografía de capa fina y autoradiografía

Pesquisa de resíduos de malation em alimentos naturais e industrializados comercializados em Joäo Pessoa / Analysis of malathion residues in natural and processed food in Joäo Pessoa

O presente trabalho baseou-se em análises químicas de resíduos de Malation em amostras de alimentos naturais e industrializados, visando a obtençäo de dados sobre a presença ou ausência de resíduos e sua quantificaçäo, e compará-los com os limites máximos de tolerância permitidos, utilizando-se os parâmetros da FAO/OMS. Os resultados foram positivos para a presença de resíduos em 61,11% das amostras; 33,33% das amostras apresentaram limites acima dos permitidos e apenas 5,56% näo apresentaram resíduos