Sublethal toxicity of carbofuran in cattle egret (Bubulcus ibis coromandus): hematological, biochemical, and histopathological alterations / Toxicidade subletal do carbofurano na garça-vaqueira (Bubulcus ibis coromandus): alterações hematológicas, bioquímicas e histopatológicas

Abstract This study was aimed to investigate Carbofuran (CF)-induced pathological changes in cattle egret. Two hundred cattle egrets were reared and equally divided into four groups and given different CF concentrations (0.03 mg/L, 0.02 mg/L, 0.01 mg/L and 0 mg/L (control group)). Hematology, serum biochemistry, histopathology, and immunological markers were studied. Our results confirm that CF induces anemic conditions, leukocytosis, elevated liver enzymatic activity, and alterations in renal biomarkers. Moreover, specific microscopic lesions such as multifocal necrosis, pyknotic nuclei, hemorrhages, congestion, and inflammatory cell proliferation were observed in the liver, kidney, spleen, and thymus. These findings suggest that CF can induce harmful effects, so the application of this pesticide in the field must be strictly monitored to mitigate the possibility of exposure to non-target species.

Resumo Este estudo teve como objetivo investigar as alterações patológicas induzidas por carbofurano (CF) em garças-vaqueiras. Duzentas dessas garças foram criadas e divididas igualmente em quatro grupos e receberam diferentes concentrações de CF: 0,03 mg/L; 0,02 mg/L; 0,01 mg/L; e 0 mg/L (grupo controle). Foram realizadas análises de hematologia, bioquímica sérica, histopatologia e marcadores imunológicos. Nossos resultados confirmaram que CF induz condições anêmicas, leucocitose, atividade enzimática hepática elevada e alterações nos biomarcadores renais. Além disso, lesões microscópicas específicas, como necrose multifocal, núcleos picnóticos, hemorragias, congestão e proliferação de células inflamatórias, foram observadas no fígado, rim, baço e timo. Esses achados sugerem que o CF pode causar efeitos nocivos, portanto a aplicação desse agrotóxico no campo deve ser rigorosamente monitorada para mitigar a possibilidade de exposição a espécies não alvo.

Postmortem Distribution and Postmortem Redistribution of Carbofuran-7-Phenyl Glucuronic Acid in Rabbits / 法医学杂志

OBJECTIVES@#To establish a carbofuran intragastric administration death model in rabbits, and to observe the postmortem distribution and postmortem redistribution of carbofuran-7-phenyl glucuronic acid (Glu-7PH) in rabbits.@*METHODS@#The postmortem distribution: Rabbits were given an administration of 1/2LD50, LD50, 2LD50 carbofuran. Dead rabbits were dissected immediately. Rabbits that had remained alive 2 hours were sacrificed by carbon dioxide (CO2) inhalation and dissected immediately. The myocardium, cardiac blood, liver, spleen, lung, kidney, brain and right hindlimb muscle were collected. The postmortem redistribution: After giving an administration of 4LD50 carbofuran, the myocardium, cardiac blood, liver, spleen, lung, kidney, brain, and right hindlimb muscle were collected at 0, 12, 24, 48, and 72 h postmortem in supine position at 15 ℃ room temperature. The quantity of Glu-7PH was determined by LC-MS/MS.@*RESULTS@#The postmortem distribution: Among the three dose groups, there were significant differences in the quantities of Glu-7PH in different tissues. The postmortem redistribution: There was no significant difference in the Glu-7PH quantities in cardiac blood, mycardium, spleen, kidney, brain and right hindlimb muscle, but there was a significant difference in the Glu-7PH quantities in the liver and lung.@*CONCLUSIONS@#The mycardium, cardiac blood, liver, lung, kidney, brain and hindlimb muscle of rabbits can be used as appropriate samples for Glu-7PH detection. However, it should be noted that Glu-7PH was redistributed postmortem in rabbit liver and lung.

Avaliação do efeito combinado de carbofurano e temperatura para Ceriodaphnia dubia / Evaluation of the combined effect of carbofuran and temperature to Ceriodaphnia dubia

Desde 2008, o Brasil ocupa a posição de maior consumidor de agrotóxicos do mundo. Em 2001 o grupo dos agrotóxicos mais usados foi o grupo dos inseticidas. O Carbofurano é um inseticida carbamato sistêmico de amplo espectro, utilizado em todo o mundo. O Carbofurano possui meia vida no meio ambiente relativamente curta e sendo relativamente estável em condições neutras ou ácidas. Ele possui baixa tendência a volatilizar e é altamente móvel no solo, podendo lixiviar para águas subterrâneas e cursos d’água. O Carbofurano inibe a colinesterase, estimulando o sistema nervoso e causa efeitos cancerígenos, teratogênicos e genotóxicos. Estresses físicos como a mudança de temperatura podem afetar a susceptibilidade dos organismos à químicos, alterando a toxicodinâmica da interação química com o organismo, a toxicocinética, o metabolismo e estado fisiológico dos mesmos. As mudanças climáticas e o aquecimento global causados pela emissão de gases de efeito estufa, representam estressores que afetam a ocorrência de espécies levando à redução da biodiversidade. Acredita-se o aumento de 1,5-2,5oC nas temperaturas médias globais aumentam em 20-30% o risco de extinção de espécies e estudos indicam que um aumento na escala de 3oC é passível de ocorrer até o ano de 2100. Para a liberação e avaliação dos efeitos ambientais de agrotóxicos, são geralmente exigidos testes de toxicidade e o monitoramento através da avaliação ecotoxicológica é recomendado por diversos autores. Ceriodaphnia dubia é um microcrustáceos zooplanctônico muito utilizado como bioindicador, são filtradores, vivem em água doce e ocupam uma posição chave na cadeia alimentar. Dentre os fatores ambientais que influenciam as comunidades zooplanctônicas, a temperatura altera o ciclo de vida de muitos organismos, podendo modificar a taxa de reprodução e de filtração de várias espécies. Alterações nestes fatores podem influenciar a toxicidade de contaminantes para bioindicadores planctônicos. Diversos estudos encontraram relação entre o aumento da temperatura e o aumento da sensibilidade dos organismos e, consequentemente, da toxicidade dos contaminantes químicos. No entanto, esta toxicidade depende do contaminante testado. Não foram encontrados estudos sobre a avaliação do efeito combinado de Carbofurano e Temperatura sobre Ceriodaphnia dubia. O presente estudo visa avaliar este efeito combinado. Os resultados deste estudo, corroboraram com os de outros estudos, demostrando que temperaturas fora da faixa ótima influenciam a reprodução, desenvolvimento e alimentação de C. dubia, assim como influenciam negativamente na sensibilidade do organismo ao Carbofurano. Este efeito não pode ser observado apenas através de testes agudos, no entanto, os testes crônicos possibilitaram a observação do efeito combinado. Independente da temperatura, os resultados obtidos no presente estudo demonstram que as CL50 estão em concentrações inferiores às encontradas em ambientes naturais no Brasil e às estabelecidas pela OMS como padrão. Assim, conclui-se que os testes crônicos podem ser ferramentas interessantes para aplicação e uso rotineiro por agências ambientais. Esta avaliação deve ser realizada de acordo com as características ambientais locais e estes fatores devem ser levados em consideração durante a compilação de legislações, já que legislações nacionais podem não ser suficientes para evitar impactos a nível local.

Protective effect of secondary plant metabolites from Ipomoea aquatica Forsk. against carbofuran induced damages.

Plausible interactions between food contaminants and natural constituents in vivo and protective effect of polyphenols present in I. aquatica against carbofuran toxicity in Charles Foster rats were evaluated. Determinations based on antioxidant enzyme activities showed significant alterations in glutathione, glutathione peroxidase, superoxide dismutase and catalase in tissues (liver and brain) and plasma of pesticide treated group while polyphenolic extracts from I. aquatica (IAE) attenuated their activities when given alongwith carbofuran. IAE decreased enhanced lipid peroxidation levels in plasma and erythrocyte membrane and cholesterol levels in brain and plasma. IAE also minimized histopathological degenerative changes produced by carbofuran. While single cell gel electrophoresis showed that secondary metabolites in leafy vegetables produced a combinatorial effect with pesticide at cellular level, DNA fragmentation level in bone marrow cells showed a decline in the IAE treated rats. Food safety adversely affected by various chemical contaminants can be retained by plant polyphenols and secondary plant constituents that can be found together in bolus. Therefore, the present study gives an insight into the protective role of naturally found polyphenols against pesticide toxicity.

Entomopathogenic nematodes and their interaction with chemical insecticide aiming at the control of banana weevil borer, Cosmopolites Sordidus Germar (Coleoptera: Curculionidae) / Nematoides entomopatogênicos e sua interação com inseticida químico Visando ao controle da broca-da-bananeira cosmopolites sordidus germar (coleoptera: curculionidae)

The banana weevil borer (Cosmopolites sordidus) is the main pest of banana crops, causing significant losses in productivity, being recommended control by chemical insecticides which cause several environmental impacts. On the other hand, entomopathogenic nematodes can be an alternative to the pest control, mainly because of their habits. Thus, this study aimed at evaluating isolated entomopathogenic nematodes under laboratory conditions and also their interaction with a chemical insecticide (carbofuran), aiming at their use for the weevil borer control. Sixteen Sterinernematidae and Heterorhabditidae isolates were evaluated, applied over the banana tree pseudo stem (100 JIs/cm²) and they were compared to one another concerning mortality caused in adults individual of C. sordidus. The most infective isolates were subjected to in vivo multiplication at the host Galleria mellonella and interaction with the insecticide carbofuran, including in this case, viability and infectivity analysis of the entomopathogenic nematodes exposed to the product, as well as the effect of the insecticide on the symbiotic bacteria of the entomopathogenic nematodes. The experiments at this stage were conducted in completely randomized design and the data were subjected to ANOVA, with application of the Tukey test (p 0.05). The most virulent isolates were IBCBn24 and IBCBn40 [...]

A broca-da-bananeira (Cosmopolites sordidus) é a principal praga dos cultivos de banana, acarretando perdas significativas na produtividade da cultura, sendo recomendados inseticidas químicos para seu controle, os quais causam impacto ambiental. Por outro lado, os nematoides entomopatogênicos podem ser uma alternativa para o controle da praga, principalmente devido aos seus hábitos. Assim, este trabalho teve como objetivo avaliar isolados de nematoides entomopatogênicos em condições de laboratório e a interação com inseticida químico (carbofurano), visando a sua utilização no controle da broca. Foram testados 16 isolados das famílias Sterinernematidae e Heterorhabditidae, aplicados sobre pseudocaule de banananeira (100 JIs/cm²) e comparados entre si quanto à mortalidade causada em indivíduos adultos de C. sordidus. Os isolados mais infectivos foram submetidos a experimentos de multiplicação in vivo no hospedeiro Galleria mellonella e de interação com o inseticida carbofurano incluindo, neste caso, análise de viabilidade e infectividade dos nematoides expostos ao produto, bem como o efeito do inseticida sobre as bactérias simbiontes dos nematoides entomopatogênicos. Os experimentos dessa fase foram conduzidos em delineamento inteiramente casualizado, sendo os dados submetidos à ANOVA, com aplicação do teste de Tukey (p 0,05). Os isolados mais virulentos foram o IBCBn24 [...]

Evaluación del riesgo ambiental de carbofurano en bioensayos con organismos no blanco / Environmental risk assessment of carbofuran in bioassays with non-target organisms

El carbofurano es uno de los plaguicidas más empleado en la agricultura peruana. El objetivo de este trabajo fue evaluar el riesgo ambiental del carbofurano en bioensayos de toxicidad, sobre once especies no destinatarias. La siguiente secuencia relativa de mayor a menor cocientes de riesgo (CR) del carbofurano para los 19 puntos finales de efecto en once especies fue encontrada: Daphnia magna (mortalidad) > Lemna minor (inhibición de formación de las hojas) > Paracheirodon innesi (nado extraño) = P. innesi (incremento del movimiento opercular) > Chironomus calligraphus (mortalidad) > L. minor (necrosis) > P. innesi (mortalidad) > L. minor (clorosis) > Tetrapygus niger (inhibición de la fecundación) > Coturnix japonica (mortalidad) > Oncorhynchus mykiss (incremento de coloración) > Ceraeochrysa cincta (no eclosión de huevos) > O. mykiss (mortalidad con oxígeno) > O. mykiss (mortalidad sin oxígeno) > Trichogramma pretiosum (mortalidad) > C. cincta (mortalidad) > T. pretiosum (no emergencia de adultos) > Trichogramma pintoi (mortalidad) > Beauveria bassiana (inhibición del crecimiento). Los cocientes de riesgo (CR) indicaron en todos los casos un alto riesgo del carbofurano principalmente en el ambiente acuático en comparación con el terrestre.

Carbofuran is one of the most employed pesticides in Peruvian agriculture. This research aimed to evaluate the risk assessment in bioassays of carbofuran on eleven non-target species. The following relative sequence in decreasing ecotoxicity order in terms of RQ (Risk quotient) to carbofuran to 19 end points on 11 species was found: Daphnia magna (mortality) > Lemna minor (inhibition of new fronds) > Paracheirodon innesi (strange swim) = P. innesi (increase of opercula movement) > Chironomus calligraphus (mortality) > L. minor (necrosis) > P. innesi (mortality) > L. minor (chlorosis) > Tetrapygus niger (inhibition of fertilization)> Coturnix japonica (mortality) > Oncorhynchus mykiss (increase of coloration) > Ceraeochrysa cincta (not hatch of eggs) > O. mykiss (mortality without oxygen) > O. mykiss (mortality with oxygen) > Trichogramma pretiosum (mortality) > C. cincta (mortality) > T. pretiosum (not emergence of adults) > Trichogramma pintoi (mortality) > Beauveria bassiana (inhibition of growth). Risk quotient (RQ) indicated that carbofuran is highly risky mainly to aquatic environment than terrestrial.

Persistence and biochemical influence of carbosulfan and carbofuran on solanum tuberosum tubers under the Egyptian environmental conditions

Persistence of carbosul fan and carbofuran under the Egyptian normal field conditions when used for protecting Solanum tuberosum plant was studied. carbosulfan was used for foliar application but carbofuran was used as granulcs in soil against nematodes. The residue half life [RL50] values were 2.86 and 6.41 days for carbosulfan on plant leaves and in soil. respectively. As for carbofuran which was applied in soil. the RL50 value was 6.74 days in soil surface layer. The PHI for carbosulfan in tubers is more than 16 days after foliar application, but for carbofuran the PHI is about 30 days from tuber formation. Photo-decomposition study showed that carbosulfam degraded faster than carbofuran when exposed to direct sunlight or to short wave UV light, with RL50 of 8.14 and 20.38 hr in sunlight and 6.09. 89.41 hr in UV light for carbosulfan and carbofuran. respectively. The study included also the estimation of the amounts of carbofuran resulted from carbosulfan transformation under exposure to sunlight or to UV-light as major degradation product [or metabolite] for carbosulfan. The study of the biochemical effects on the composition of the tubers revealed that the two pesticide treatments attained no significant effect on total carbohydrates content or in total lipids content. A significant decrease in total nitrogen content anti consequently total crude protein was registered only after 7 days from carbosulfan application. Soluble protein content significantly decreased after 70 days from soil application with carbofuran but returned to the normal level after 7 days. The electrophoretic patterns of soluble protein extracted from tubers were also studied

Toxicidade aguda de alguns herbicidas e inseticidas utilizados em lavouras de arroz irrigado sobre o peixe Danio rerio / Acute toxicity of some herbicides and insecticides used in paddy rice on the fish Danio rerio

Este trabalho teve como objetivo determinar a CL50 48h de alguns herbicidas e inseticidas utilizados na cultura do arroz irrigado e estimar os coeficientes de risco (análise de risco determinístico), usando como organismo-teste o peixe paulistinha (Dario rerio). Os herbicidas 2,4-D, metsulfurom-metílico, carfentrazonaetílica, bentazona, quincloraque, clomazona, oxadiazona, oxifluoefem, bispiribaque-sódico, pirazossulfurom-etílico, apresentaram valores de CL50 48h em mg.L-1 (ingrediente ativo) de: 237,1; maior que 100,0; 2,5; 1150.0; 300,0; 13,8; 3,0; 1,2; maior que 100,0; 67,56, respectivamente. Os herbicidas betaciflutrina, carbofurano, fipronil e lambdacialotrina apresentaram valores de CL50 48h em mg.L (ingrediente ativo) de: 0,004; 1,3; 0,2 e 0,002, respectivamente. Os resultados deste trabalho indicaram que os herbicidas oxifluorfem, oxadiazona e clomazona e os inseticidas lambdacialotrina, betaciflutrina, carbofurano e fipronil apresentam maior potencial de risco de impacto ecológico sobre o bioindicador D. rerio. Os herbicidas metsulfurom, pirazossulfuron, bispiribaque, bentazona e quincloraque revelaram risco mínimo a leve de impacto sobre peixes da espécie D.rerio.

Biossensor amperométrico para detecção screening de inseticidas carbamatos em águas de abastecimento / Amperometric biosensor to detect screening of carbamate insecticides in drinking water

Biossensor amperométrico, baseado em enzimas colinesterases (AChE) imobilizadas em eletrodo do tipo screen-printing, foi utilizados na investigação de teores de pesticidas carbamatos (carbofuran e carbaril) em amostras de águas de abastecimento. Inicialmente, efetuou-se o estudo dos constantes de inibição dos pesticidas carbaril (1x10 elevado à sétima potência) e carbofuran (5x10 elevado à quarta potência). Utilizou-se sistema com eletrodo de dois canais, composto de grafite modificada com TCNQ e Ag/AgCl, como eletrodos de trabalho e referência, respectivamente. Dois processos, visando otimização do biossensor. A metodologia de fotopolimerização com álcool polivinílico modificado com grupos estirilpiridínicos (PVS-SbQ) e a de glutaraldeido foram selecionadas para o estudo, sendo que a imobilização com PVS-SbQ apresentou melhores resultados (CV=6,5por cento). Curvas analíticas foram plotadas após os ensaios de inibição com os pesticidas e os limites de detecção (LD) determinados. Carbaril apresentou curva linear (LD de 18 ug L -1), enquanto o carbofuran demonstrou curva com comportamento logarítmico (LD de 0,05 ug L-1). Para avaliar a precisão, amostras de água de abastecimento foram fortificadas com os pesticidas estudados em três níveis de fortificação. As recuperações variaram de 93,3 por cento a 102,7 por cento. Os biossensores a base de AChE atenderam às exigências analíticas para a direta aplicação de sensores descartáveis em amostras reais

Integrated application of some compatible biocontrol agents along with mustard oil seed cake and furadan on Meloidogyne incognita infecting tomato plants / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Experiments were carried out to study the effect of two fungal bioagents along with mustard oil cake and furadan against root knot nematode Meloidogyne incognita infecting tomato under greenhouse condition. Bioagents viz., Paecilomyces lilacinus and Trichoderma viride alone or in combination with mustard cake and furadan promoted plant growth, reduced number of galls/plant, egg masses/root system and eggs/egg mass. The fungal bioagents along with mustard cake and nematicide showed least nematodes reproduction factor as compared to untreated infested soil.

Effect of the pesticides carbofuran [Carbamate] and Profenophos [Organophosphorus] on Biomphalaria alexandrina and on its infection with Schistosoma mansoni miracidia

Carbofuran [carbamate pesticide] and Profenophos [organophosphorus pesticide] showed molluscicidal effect on Biomphalaria alexandrina snails, with the LC[50] 1.42 ppm and 1.29 ppm, respectively Maintaining Biomphalaria alexandrina at sublethal concentrations of these compounds [0.5, 0.75, and 1.0 ppm] reduced the snail survival rate and net reproductive rate [R[0]] [E L[x]M[x]] compared with the control snail group. The percentage reduction in R[0] was 86.9, 90.8, and 93.9 for the tested concentrations of Carbofuran and 86.8, 82.9 and 88.5 for the tested concentrations of Profenophos, respectively. The susceptibility of Biomphalaria snails to infection with Schistosoma mansoni miracidia and further infectivity of this parasite were also reduced. Increasing the pesticide concentration increased the magnitude of reduction reaching 80.7% and 89.3% for the two pesticides, respectively. Pesticide may be considered one of the factors contributing in the disappearance of snail vectors on reaching water bodies as residues from pesticidal activities and consequently hindering schistosomiasis transmission

Studies on the management of root-knot nematode, Meloidogyne incognita-wilt fungus, Fusarium oxysporum disease complex of green gram, Vigna radiata cv ML-1108 / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Studies were conducted under pot conditions to determine the comparative efficacy of carbofuran at 1 mg a.i./kg soil, bavistin at 1 mg a.i./kg soil, neem (Azadirachta indica) seed powder at 50 mg/kg soil, green mould (Trichoderma harzianum) at 50.0 ml/kg soil, rhizobacteria (Pseudomonas fluorescens) at 50.0 ml/kg soil against root-knot nematode, Meloidogyne incognita-wilt fungus, Fusarium oxysporum disease complex on green gram, Vigna radiata cv ML-1108. All the treatments significantly improved the growth of the plants as compared to untreated inoculated plants. Analysis of data showed that carbofuran and A. indica seed powder increased plant growth and yield significantly more in comparison to bavistin and P. fluorescens. Carbofuran was highly effective against nematode, bavistin against fungus, A. indica seed powder against both the pathogens and both the bioagents were moderately effective against both the pathogens.

Construction of multifunctional genetically engineered pesticides-degrading bacteria by homologous recombination / 生物工程学报

Construction of multifunctional pesticides-degrading genetically engineered microorganisms (GEMs) is increasing important in the bioremediation of various pesticides contaminants in environment. However, construction of genetically stable GEMs without any exogenous antibiotic resistance is thought to be one of the bottlenecks in GEMs construction. In this article, homologous recombination vectors with the recipient's 16S rDNA as homologous recombination directing sequence (HRDS) and sacB gene as double crossover recombinants positive selective marker were firstly constructed. The methyl parathion hydroalse gene (mpd) was inserted into the 16S rDNA site of the carbofuran degrading strain Sphingomonas sp. CDS-1 by homologous recombination single crossover in the level of about 3.7 x 10-(7) - 6.8 x 10(-7). Multifunctional pesticides-degrading GEMs with one or two mpd genes inserted into the chromosome without any antibiotic marker were successfully constructed. The homologous recombination events were confirmed by PCR and southern blot methods. The obtained GEMs were genetically stable and could degrade methyl parathion and carbofuran simultaneously. The insertion of mpd gene into rrn site did not have any significant effect on recipient' s physiological and original degrading characteristics. The methyl parathion hydrolase (MPH) was expressed at a relatively high level in the recombinants and the recombinant MPH specific activity in cell lysate was higher than that of original bacterium (DLL-1) in every growth phase tested. The highest recombinant MPH specific activity was 6.22 mu/tg. In this article, we describe a first attempt to use rRNA-encoding regions of Sphingomonas strains as target site for expression of exogenous MPH, and constructed multifunctional pesticides degrading GEMs, which are genetically stable and promising for developing bioremediation strategies for the decontamination of pesticides polluted soils.

First ovarian maturity and recovery response in common carp, Cyprinus carpio after exposure to carbofuran.

The present study embodies the observations on duration (45, 75 and 105 days) dependent effects of toxicologically low concentration (16 ppm) of a carbamate pesticide, carbofuran, on first ovarian maturity with correlative recovery response by withdrawal of treatment for 30 days in virgin yearlings of common carp, Cyprinus carpio var. Communis. In control fish histological organization of ovary and changes in gonado-somatic index (GSI) revealed the initiation of oocyte differentiation and development at the commencement of experiment in December-January and peak of maturation with fully grown yolky oocytes was attained by the time of termination of experiment in the end of March. In carbofuran exposed groups ovaries exhibited retardation of development and growth evident by significantly decreased GSI and predominace of immature oocytes passing through nuclear-cytoplasmic degeneration of variable magnitude. Severity of degenerative changes was more pronounced with prolonged duration. In recovery group ovaries had experienced regeneration as clued by the presence of oocytes of differential stages including vitellogenic and fully grown oocytes. In liver histopathological changes coupled with significant decrease in hepato-somatic index (HSI) attributed hepatic inactivation in all exposure groups whereas in recovery group an increase in HSI value with marked sign of hepatic reactivation was evidenced. No significant change in values of condition (CF) and somatic condition (SCF) factors substantiated the over all normal health of fish. Lipid and water content of ovary, liver and muscle registered the significant decrease at 105th day of exposure with concomitant augmented value for recovery group. These observations suggest that the commercial formulation of carbofuran, even at this toxicologically low concentration, is equally capable of affecting the first ovarian maturity with associated physiological implications but with reversibility in toxicity by withdrawal of pesticide exposure attributing regeneration in affected organs in due course time.

Bioresidual efficacy and phytotoxicity of certain systemic nematicides against root-knot nematode infesting tomato plants

The bioresidual efficacy and phytotoxic effects of four systemic nematicides: akldicarb, carbofluran, oxamyl and fenamiphos against root-knot nematodes infesting tomao plants were evaluated in laboratory and greenhouses. The obtained results indicated the important role of nematicide type on the studied nematodes and tomato plants. Fenamiphos proved more effectiveness than the other nematicides tested against the root-knot nematode larvae, followed by akldicarb. The highest inhibition of gall formation was obtained by fenamiphos, while oxamyl was the lowest inhibitor. General, for all tested nematicides at the evaluated concentrations, the best inhibition was achieved when the nematicide was applied at the time of inoculation. The nematicides tested except fenamiphos showed clear phytotoxic symptoms on treated tomato plants characterized by significantly reduction in the dry weight of plant roots and shoots. Among the tested nematicides only carbofuran decreased significantly the height of treated tomato plants

Avaliaçäo do potencial de lixiviaçäo de pesticidas em latossolo da regiäo de Guaíra, SP / Assessing leaching potential of pesticides in oxisol from Guaíra region, state of Säo Paulo, Brazil

Os potenciais de lixiviaçäo de dezenove pesticidas nos primeiros 60 cm de latossolo da regiäo de Guaíra, Estado de Säo Paulo, foram estimados mediante fator deatenuaçäo (AF). O modelo aplicado considerou propriedades do pesticida e do solo, assim como a taxa de recarga hídrica líquida. Os pesticidas com maior potencial de lixiviaçäo foram manocrotofós>carbofuranmetalaxil>aldicarb>metolactor>metamidofós. Para todos os pesticidas estudados naquele latossolo, o tratamento da lixiviaçäo devido à volatilizaçäo foi muito pequeno quando comparado com o retardamento devido à sorçäo:Todos os pesticidas que apresentaram os mais altos potenciais delixiviaçäo foram os mais solúveis em água, com valores do coeficiente de partiçäo (Koc) iguais ou menores que 200 mL/g. Além disso, a meia-vida da maioria destes pesticidas excedeu 30 dias. Os resultados obtidos permitiram estimar que 15,2 por cento do Monocrotofós, 5,7 por cento do Carbofuran e 2,5 por cento do Metalaxil que atinge a superfície do solo ultrapassariam os primeiros 60 cm do perfil do solo, sendo que cerca de 8 mg para cada 100g de Monocrotofós aplicados na superfície do solo passariam através dos primeiros 3m. Com base nos baixos valores de AF calculdados, o potencial de lixiviaçäo dos pesticidas que tem sido usados em áreas agrícolas de Guaíra (SP) sobre latossolos apresenta-se baixo, assim como o consequente risco de contaminaçäo da água subterrânea

Carbofuran induced impairment in the hypothalamo-neurohypophyseal-gonadal complex in the teleost, Channa punctalus (Bloch).

The effect of chronic exposure to carbofuran (4.5 ppm in static water) for six months on the gonadal histophysiology and hypothalamo-neurohypophyseal complex was studied in Channa punctatus. Experimental observations revealed significant inhibition of gonadal development with associated degenerative abnormalities as evidenced by ovarian and testicular histology and reduced gonadosomatic index. Degenerative changes in ovary were exihibited by stage I (oogonium) and stage II (immature/non-vitellogenic) oocytes as marked by perinuclear ooplasmic lysis, clumping and dissolution resulting in disintigration of nuclear material altogether attributed to complete degeneration of such oocytes. Testicular deleterious changes included degeneration of spermatogenic elements and necrosis of interstitial cells of Leydig. Correlative histophysiological changes were also observed in the pituitary gonadotrophs and hypothalamic, nucleus pre-opticus, neurons that were smaller, inactive and less in number with associated necrosis. Corresponding to the changes in nucleus pre-opticus neurons, significant inhibition of brain monoamine oxidase enzyme activity was also recorded in treated group. These observations suggest that carbofuran even at low concentration level under long-term exposure is capable of inducing retardation of gonadal development which might have been mediated through the impairment of the hypothalamo-neurohypophyseal-gonadal axis in this species.

Influence of hexaconazole, carbofuran and ethion on soil microflora and dehydrogenase activities in soil and intact cell.

Total microbial count was highly affected (up to 61% at 1000 micrograms level) in presence of hexaconazole and persisted up to 21 days. Bacteria were more susceptible than actinomycetes. Carbofuran and ethion were moderately toxic to soil microflora. Inhibitory effects of all the three pesticides gradually decreased after 21 days as was evident by increase in total microbial count except in carbofuran. GDH activity in soil was also affected initially (up to 14 days) by all the three pesticides (60.3% in hexaconazole at 1000 micrograms level) and inhibition gradually decreased to zero except in carbofuran (15-20% toxicity persisted up to 35 days). GDH and LDH activity in presence of hexaconazole was strongly affected in intact cells of some standard culture of bacteria like Rhizobium sp. (host Dolichos sp., 32.1 and 72.5%), Bacillus subtilis Cohn (86.75 and 76.5%), Azotobacter sp. (36.9 and 55.4%) and B. sphaericus (67.6% GDH) respectively. Carbofuran inhibited the enzyme activity in B. subtilis (55.55 and 35.3%) and to some extent in B. sphaericus. Ethion moderately inhibited LDH activity in Rhodococcus sp. AK1 (17.1 and 33.3%), Rhizobium (27.6% LDH), E. coli HB 101 (34.2% LDH) as evidenced by formazan formation. From the result, it might be concluded that among the above three pesticides tested hexaconazole strongly inhibited the dehydrogenase system in bacteria including nitrogen fixing bacteria of soil and thus may affect soil fertility. It was concluded that hexaconazole was more toxic than ethion to dehydrogenase enzymes.

Impactos ao ambiente e riscos potenciais à saúde, decorrentes do uso de carbofuran em área de produçäo de arroz, Taubaté, Säo Paulo / Environmental impacts and potential risk for the health, resultants of carbofuran use in rice-producing area, Taubaté, São Paulo

Objetivos: Averiguar a presença de resíduos do inseticida - nematicida carbofuran e seu metabólito 3 - hydroxycarbofuran, na água destinada ao abastecimento, nos locais de captação e após o tratamento efetuado pela SABESP, na região do Vale do Paraíba. Verificar a presença de resíduos em amostras de águas de irrigação na cultura de arroz em várzeas sistematizadas, no solo e sedimento de tabuleiros e água do Rio Paraíba do Sul. Métodos: A extração em amostras de água foi realizada em fase sólida empregando cartuchos de C18. Estes foram ativados com acetonitrila (CH3CN) e água deionozada. Os compostos absorvidos foram eluídos com 3 mL de acetonitrila. A extração em solo e sedimento foi realizada com acetonitrila. Todas as amostras foram concentradas em N2 até 0,9 mL e adicionadas de água grau HPLC até o volume de 2,0 mL para reconstituição da proporção da fase móvel. As amostras foram analisadas por cromatografia líquida de alta eficiência (HPLC ou CLAE), injetando-se o volume de 50uL em coluna de fase reversa, usando-se fase móvel acetonitrila: água (45:55) e detector de fluorescência. Resultados: As concentrações de carbofuran ficaram abaixo do estabelecido pela USEPA como padrão para água potável ( 40ug/L) e pelas agências internacionais para águas ambientais (6000ug/L). O nível máximo de resíduos de cabofuran detectado foi 20ug/L, cinco dias após a aplicação, sendo detectados resíduos de 0,8 a 1,4 ug/L, quarenta e nove dias após a aplicação de carbofuran. Nas amostras em que foram detectados resíduos, as concentrações estiveram acima do estabelecido pela CEE para pesticidas individuais (0,1ug/L) em água potável. Não foram detectados resíduos de carbofuran em solo superficial e sedimento e 3 - hydroxycarbofuran não foi detectado em nenhuma amostra. Conclusões: A persistência de carbofuran é relativamente curta no ambiente e em solos com história de uso anterior é degradado mais rapidamente. A subdosagem, prática usual na região, pode induzir a resistência da bicheira do arroz Oryzophagus oryzae, tornando-se necessário usar doses cada vez mais altas ou outros produtos, comprometendo o ambiente