Acute toxicity and sublethal effects of the mixture glyphosate (Roundup® Active) and Cosmo-Flux®411F to anuran embryos and tadpoles of four Colombian species / Toxicidad aguda y efectos subletales de la mezcla glifosato (Roundup® Activo) y Cosmo-Flux®411F en embriones y renacuajos de cuatro especies de anuros colombianos

Glyphosate is the most widely used herbicide in the world with application in agriculture, forestry, industrial weed control, garden and aquatic environments. However, its use is highly controversial for the possible impact on not-target organisms, such as amphibians, which are vanishing at an alarming and rapid rate. Due to the high solubility in water and ionic nature, the glyphosate requires of surfactants to increase activity. In addition, for the control of coca (Erythroxylum coca) and agricultural weeds in Colombia, formulated glyphosate is mixed and sprayed with the adjuvant Cosmo-Flux®411F to increase the penetration and activity of the herbicide. This study evaluates the acute toxic and sublethal effects (embryonic development, tadpole body size, tadpole swimming performance) of the mixture of the formulated glyphosate Roundup® Active and Cosmo-Flux®411F to anuran embryos and tadpoles of four Colombian species under 96h laboratory standard tests and microcosms, which are more similar to field conditions as they include soil, sand and macrophytes. In the laboratory, embryos and tadpoles of Engystomops pustulosus were the most tolerant (LC50=3 904µg a.e./L; LC50=2 799µg a.e./L, respectively), while embryos and tadpoles of Hypsiboas crepitans (LC50=2 203µg a.e./L; LC50=1 424µg a.e./L, respectively) were the most sensitive. R. humboldti and R. marina presented an intermediate toxicity. Embryos were significantly more tolerant to the mixture than tadpoles, which could be likely attributed to the exclusion of chemicals by the embryonic membranes and the lack of organs, such as gills, which are sensitive to surfactants. Sublethal effects were observed for the tadpole body size, but not for the embryonic development and tadpole swimming performance. In microcosms, no toxicity (LC50 could not be estimated), or sublethal responses were observed at concentrations up to fourfold (14.76kg glyphosate a.e./ha) the highest field application rate of 3.69kg glyphosate a.e./ha. Thus, toxicity was less in the microcosms than in laboratory tests, which may be attributed to the presence of sediments and organic matter which rapidly adsorb glyphosate and surfactants such as POEA. It is concluded that the mixture of glyphosate (Roundup® Active) and Cosmo-Flux®411F, as used in the field, has a negligible toxic effect to embryos and tadpoles of the species tested in this study.

El glifosato es el herbicida más usado en el mundo con aplicaciones para la agricultura, control de malezas forestales, industriales, en jardines y ambientes acuáticos. Sin embargo, su uso es altamente controversial por el posible impacto sobre organismos no blanco, como los anfibios, los cuales están desapareciendo a una tasa alarmantemente rápida. Debido a su alta solubilidad en agua y naturaleza iónica, el glifosato requiere de surfactantes para incrementar su actividad. Además, para el control de Erythroxylum coca y de malezas en la agricultura en Colombia, el glifosato formulado es mezclado y rociado con el coadyuvante Cosmo-Flux®411F para incrementar la penetración y actividad del herbicida. Este estudio evalúa los efectos tóxicos agudos y subletales (desarrollo embrionario, tamaño corporal y desempeño natatorio de los renacuajos) de la mezcla del glifosato formulado Roundup® Activo con el Cosmo-Flux®411F en embriones y renacuajos de cuatro especies de anuros colombianos, bajo pruebas de 96h en condiciones estándar de laboratorio y microcosmos, que son más similares a las condiciones de campo al incluir tierra, arena y macrófitas. En laboratorio, los embriones y renacuajos de Engystomops pustulosus fueron los más tolerantes (CL50=3 904µg a.e./L; CL50=2 799µg a.e./L, respectivamente), mientras que los embriones y renacuajos de Hypsiboas crepitans fueron los más sensibles (CL50=2 203µg a.e./L; CL50=1 424µg a.e./L, respectivamente). R. humboldti y R. marina presentaron una toxicidad intermedia. Los embriones fueron más tolerantes a la mezcla que los renacuajos, lo cual podría ser atribuido a la exclusión de los químicos por las membranas embrionarias y a la falta de órganos, como las branquias, que son más sensibles a los surfactantes. Se observaron efectos subletales en el tamaño corporal de los renacuajos, pero no en el desarrollo embrionario ni el desempeño natatorio de los renacuajos. En microcosmos no se observaron efectos tóxicos ni respuestas subletales a concentraciones hasta cuatro veces (14.67kg glifosato a.e./ha) la tasa de aplicación más alta de 3.69kg glifosato a.e./ha. Por lo tanto, la toxicidad fue menor en los microcosmos que en las pruebas de laboratorio, lo que puede ser atribuido a la presencia de sedimentos y materia orgánica que absorbe rápidamente el glifosato y surfactantes como el POEA. Se concluye que la mezcla del glifosato (Roundup® Activo) y Cosmo-Flux®411F, como se aplica en campo, tiene un efecto tóxico bajo en los embriones y renacuajos de las especies estudiadas.

Post-treatment with plant extracts used in Brazilian folk medicine caused a partial reversal of the antiproliferative effect of glyphosate in the Allium cepa test

Species of the genus Psychotria are used for multiple purposes in Brazilian folk medicine, either as water infusions, baths or poultices. This study was aimed to evaluate the genotoxic and antiproliferative effects of infusions of Psychotria brachypoda and P. birotula on the Allium cepa test. Exposure to distilled water was used as a negative control, while exposure to glyphosate was used as a positive control. The interaction of extracts (as a post-treatment) with the effects of glyphosate was also studied. Results showed that glyphosate and the extracts of both P. brachypoda and P. birotula reduced the mitotic index as compared with the negative control (distilled water). Surprisingly, however, both extracts from P. brachypoda and P. birotula caused a partial reversal of the antiproliferative effect of glyphosat e when used as a post-treatment. Glyphosate also induced the highest number of cells with chromosomal alterations, which was followed by that of P. birotula extracts. However, the extracts from P. brachypoda did not show any significant genotoxic effect. Post-treatment of glyphosate-treated samples with distilled water allowed a partial recovery of the genotoxic effect of glyphosate, and some of the Psychotria extracts also did so. Notably, post-treatment of glyphosate-treated samples with P. brachypoda extracts induced a statistically significant apoptotic effect. It is concluded that P. brachypoda extracts show antiproliferative effects and are not genotoxic, while extracts of P. birotula show a less potent antiproliferative effect and may induce chromosomal abnormalities. The finding of a partial reversion of the effects of glyphosate by a post-treatment with extracts from both plants should be followed up.

Leaf anatomy and morphometry in three eucalypt clones treated with glyphosate / Anatomia e morfometria foliar em clones de eucalipto tratados com glyphosate

This work aimed to evaluate the effects of simulated drift of glyphosate on the morphoanatomy of three eucalypt clones and to correlate the intoxication symptoms on a microscopic scale with those observed in this visual analysis. The effects of glyphosate drift were proportional to the five doses tested, with Eucalyptus urophylla being more tolerant to the herbicide than E. grandis and urograndis hybrid. The symptoms of intoxication which were similar for the different clones at 7 and 15 days after application were characterized by leaf wilting, chlorosis and curling and, at the highest rates, by necrosis, leaf senescence and death. Anatomically glyphosate doses higher than 86.4 g.ha-1 caused cellular plasmolysis, hypertrophy and hyperplasia, formation of the cicatrization tissue and dead cells on the adaxial epidermis. The spongy parenchyma had a decrease, and the palisade parenchyma and leaf blade thickness had an increase. The increased thickness in leaf blade and palisade parenchyma may be related to the plant response to glyphosate action, as a form of recovering the photosynthetically active area reduced by necroses and leaf senescence caused by the herbicide.

Este trabalho teve como objetivo avaliar os efeitos da deriva simulada de glyphosate na morfoanatomia de três clones de eucalipto e correlacionar os sintomas de intoxicação em escala microscópica com aqueles observados à vista desarmada. Os efeitos da deriva do glyphosate foram proporcionais às doses testadas, sendo Eucalyptus urophylla mais tolerante ao herbicida que E. grandis e o híbrido urograndis. Os sintomas de intoxicação foram semelhantes para os diferentes clones testados, tanto aos 7 quanto aos 15 dias após a aplicação, sendo caracterizados, morfologicamente, por murcha, clorose e enrolamento foliar e, no caso das maiores doses, por necrose, senescência foliar e morte das plantas de eucalipto. Anatomicamente, doses de glyphosate superiores a 86,4 g.ha-1 provocaram plasmólise, hipertrofia e hiperplasia celular, formação de tecido de cicatrização e morte das células da face adaxial da epiderme. Observou-se diminuição na espessura do parênquima lacunoso e aumento na espessura do parênquima paliçádico e da lâmina foliar. O aumento na espessura da folha e do parênquima paliçádico podem estar relacionados à resposta das plantas ao glyphosate, como forma de compensar a área fotossinteticamente reduzida pelas necroses e senescência causadas pelo herbicida.

Valores de referência do ácido hipúrico urinário na regiäo metropolitana de Belo Horizonte / Urinary hippuric acid reference values in Belo Horizonte metropolitan area, Brazil

Objetivando estabelecer a faixa de valor referência para o ácido hipúrico na regiäo metropolitana de Belo Horizonte, urinas de indivíduos näo expostos ocupacionalmente ao tolueno foram analisadas por cromatografia em fase gasosa, utilizando-se detector de ionizaçäo de chama. Os valores encontrados experimentalmente (n=281) variaram de <0,1 a 2,79 g/L, mas a aplicaçäo de estudo estatístico delimita como faixa de referência,a nível de significância de 95 porcento, os valores de 0,361 a 0,481 g/L. Säo descritas, também, as condiçöes analíticas padronizadas para a determinaçäo cromatográfica do ácido hipúrico urinário