Some 2000 species of cyanobacteria (blue-green algae) occur globally in aquatic habitats. They are able to survive under a wide range of environmental conditions and some produce potent toxins. Toxin production is correlated with periods of rapid growth (blooms) and 25%-70% of blooms may be toxic. Anatoxin-a is an alkaloid neurotoxin that acts as a potent neuro-muscular blocking agent at the nicotinic receptor. Acute toxicity, following consumption of contaminated water, is characterized by rapid onset of paralysis, tremors, convulsions and death. Human exposures may occur from recreational water activities and dietary supplements, but are primarily through drinking water. The current studies were conducted to examine the effect of in utero exposure on postnatal viability, growth and neurodevelopment, to evaluate the potential of in vitro embryotoxicity, and to explore the synergistic relationship between anatoxin-a and the algal toxin microcystin-LR by the oral route. The results of preliminary studies on amphibian toxicity are also reported. Time-pregnant mice received 125 or 200 microg kg(-1) anatoxin-a by intraperitoneal injection on gestation days (GD) 8-12 or 13-17. Pup viability and weight were monitored over a 6-day period. Maternal toxicity (decreased motor activity) was observed at 200 microg kg(-1) in both treatment periods. There were no significant treatment-related effects on pup viability or weight on postnatal day (PND) 1 or 6. The GD 13-17 pups were evaluated on PND 6, 12 and 20 for standard markers of neurodevelopmental maturation (righting reflex, negative geotaxis and hanging grip time). No significant postnatal neurotoxicity was observed. In vitro developmental toxicity was evaluated in GD 8 mouse embryos exposed to 0.1-25 microm anatoxin-a for 26-28 h. Perturbations in mouse yolk sac vasculature were noted from the 1.0 microm concentration in the absence of significant embryonic dysmorphology. Potential algal toxin synergism was tested in mice receiving either 0, 500 or 1,000 microg kg(-1) microcystin-LR by gavage and approximately 50 min later receiving either 0, 500, 1,000 or 2,500 microg kg(-1) anatoxin-a by the same route. No deaths occurred at any dose and no definitive signs of intoxication were observed. Stages 17 and 25 toad embryos (Bufo arenarum) were exposed to 0.03-30.0 mg l(-1) of anatoxin-a for 10 days. Adverse effects included a dose-dependent transient narcosis, edema and loss of equilibrium. Most notable was the occurrence of 100% mortality at the high dose in both groups 6-13 days post-exposure. The observed delay between initial exposure and death is highly unusual for anatoxin-a.

Abstract: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 (LC 50 =3 904µg a.e./L; LC 50 =2 799µg a.e./L, respectively), while embryos and tadpoles of Hypsiboas crepitans (LC 50 =2 203µg a.e./L; LC 50 =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 (LC 50 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. Rev. Biol. Trop. 63 (1): 223-233. Epub 2015 March 01.

RESUMENEl Propanil es un herbicida empleado en el control de arvenses que puede afectar organismos no blanco como los anuros. El objetivo del trabajo fue evaluar los efectos letales (concentración letal media, CL 50 ) y subletales (retrasos en el desarrollo, longitud total y máxima distancia de natación) del Propanil (Propanil Trust ® 500EC) sobre embriones y renacuajos de tres especies de anuros bajo condiciones de laboratorio y microcosmos, que incluyen algunos componentes de campo (sedimentos y material vegetal). La especie más sensible fue Rhinella humboldti (embriones: laboratorio CL 50 = 9,14 mg/L y microcosmos CL 50 = 83,92 mg/ha; renacuajos: laboratorio CL 50 = 5,09 mg/L y microcosmos CL 50 = 44,52 mg/ha), y la más resistente Hypsiboas crepitans (embriones: laboratorio CL 50 = 19,58 mg/L y microcosmos CL 50 = 179,53 mg/ha; renacuajos: laboratorio CL 50 = 16,54 mg/L y microcosmos CL 50 = 190,72 mg/ ha). Engystomops pustulosus mostró una sensibilidad intermedia. En general, en laboratorio los CL 50 indicaron una letalidad alta y se encontraron cambios significantes en la longitud total y la máxima distancia de natación de los organismos expuestos al Propanil, contrario a los resultados en microcosmos, aunque el tiempo de desarrollo embrionario no mostró diferencias entre tratamientos. Al comparar los CL 50 se encontró que los renacuajos fueron más sensibles al herbicida que los embriones. En conclusión, el Propanil resultó tóxico para los embriones y renacuajos en condiciones de laboratorio pero tuvo un efecto menor en microcosmos. Esto demuestra que los componentes de campo de los microcosmos y la falta de renovación de las soluciones reducen la toxicidad del Propanil en los anuros de estudio.Palabras clave: agroquímicos, anfibios, CL 50 , Colombia, efectos subletales. ABSTRACTPropanil is an herbicide used to control weeds that can affect non-target organisms such as anurans. The aim of this study was to assess the lethal (median lethal concentration, LC 50 ) and sublethal effects (delays in development, total length and maximum swimming distance) of Propanil (Propanil Trust ® 500EC) on embryos and tadpoles of three species of anurans under laboratory and microcosm conditions, which include some field components (sediments and vegetal materials). The most sensitive species was Rhinella humboldti (embryos: laboratory LC 50 = 9.14 mg/L and microcosm LC 50 = 83.92 mg/ha; tadpoles: laboratory LC 50 = 5.09 mg/L and microcosm LC 50 = 44.52 mg/ha), whereas the most resistant was Hypsiboas crepitans (embryos: laboratory LC 50 = 19.58 mg/L and microcosm LC 50 = 179.53 mg/ha; tadpoles: laboratory LC 50 = 16.54 mg/L and microcosm LC 50 = 190.72 mg/ha). Engystomops pustulosus showed an intermediate sensitivity. In general, in laboratory the LC 50 indicated a high lethality and were found significant changes in the total length and maximum swimming distance of the organisms exposed to Propanil, as opposed to the microcosm results, although the time of embryonic development did not show differences between treatments. ...

El insecticida cipermetrina (CY) es usado en la agricultura para el control de plagas; sin embargo, por su acción neurotóxica puede afectar organismos no blanco como los anuros. El objetivo del trabajo fue determinar la toxicidad (concentración letal media: CL50, y algunos efectos subletales: retrasos en el desarrollo, capacidad de natación y longitud total de las larvas) del insecticida CY (Cypermon® 20EC) expuesto durante 96 horas en embriones y renacuajos de cuatro especies de anuros bajo pruebas de laboratorio y microcosmos. Los embriones de Rhinella humboldti fueron los más sensibles en condiciones de laboratorio (CL50= 6,27 mg/L) y Boana xerophylla en microcosmos (CL50= 88,32 mg/ha), mientras que los de Engystomops pustulosus fueron los más resistentes (laboratorio: CL50= 11,80 mg/L; microcosmos: CL50= 112,37 mg/ha). Rhinella marina mostró una sensibilidad intermedia. En los renacuajos no fue posible calcular los valores CL50 debido a la alta mortalidad registrada en las concentraciones experimentales en laboratorio y microcosmos, las cuales fueron 40 y 122 veces menores al valor de aplicación del insecticida (500 mg/L y 1,52 mg/ha, respectivamente). Por otra parte, se encontró una reducción significante en la longitud total y la capacidad de natación de las larvas obtenidas de los embriones expuestos a la CY, pero no en el tiempo de desarrollo. En conclusión, la exposición a la cipermetrina provocó una letalidad alta en los renacuajos y efectos subletales en estadíos tempranos del desarrollo, por lo que a las concentraciones recomendadas de aplicación, este insecticida es tóxico para las especies de estudio.

RESUMEN El Roundup® Activo es un herbicida elaborado a base de glifosato ampliamente utilizado en Colombia para el control de malezas. Sin embargo, para su aplicación requiere ser mezclado con un coadyuvante que facilite su acción, tal como el Cosmo-Flux ® 411F el cual mejora la adherencia y fijación del herbicida en las hojas de las plantas. El objetivo de este estudio fue determinar la concentración letal media (CL 50 ) y algunos efectos subletales (cambios en el tamaño corporal y en el desempeño natatorio) del Roundup ® Activo y del Cosmo-Flux ® 411F en renacuajos de cuatro especies de anuros colombianos expuestos bajo condiciones controladas de laboratorio y en microcosmos. La especie más sensible a la exposición del Roundup ® Activo fue Hypsiboas crepitans (Laboratorio: CL 50 = 1414 µg a.e. de glifosato/L y microcosmos: CL 50 = 4 kg a.e. de glifosato/ha) y para el Cosmo-Flux Palabras clave: anfibios, CL 50 , efectos subletales, glifosato. ABSTRACT Roundup® Active is an herbicide based on glyphosate widely used in Colombia for control of illicit crops and weeds. However, it must be mixed with an adjuvant that facilitates its action, such as the Cosmo-Flux ® 411F which improves the adhesion and fixation of the herbicide into the leaves of the plants. The aim of this study was to determine the median lethal concentration (LC 50 ) and some sublethal effects (changes in body size and swimming performance) of the Roundup ® Active and the Cosmo-Flux ® 411F to tadpoles of four Colombian anuran species exposed under laboratory and microcosm conditions. The most sensitive species to exposure of Roundup ® Active was Hypsiboas crepitans (Laboratory: LC 50 = 1414 µg a.e. glyphosate/L; microcosm: LC 50 = 4 kg a.e. glyphosate/ ha), and for Cosmo-Flux ® 411F was Rhinella humboldti (Laboratory: LC 50 = 319 mg/L; microcosm: LC 50 = 632.3 L/ha). In laboratory and microcosms, Roundup ® Active did not alter the tadpole body size nor the swimming performance, while the Cosmo-Flux ® 411F generated changes in the body size but not in the swimming performance. Comparing the LC 50 of the two agrochemicals with respect to concentrations used in field, the Roundup ® Active exerted a moderate risk whereas the Cosmo-Flux ® 411F was not lethal. In addition, the Roundup ® Active was notably more toxic than the Cosmo-Flux ® 411F.