Pesticide effects on crabs: how environmental concentrations of endosulfan and chlorpyrifos affect embryos.

The objectives of this work were to evaluate the effects of environmentally relevant chlorpyrifos and endosulfan, concentrations in the incubation period, effective hatching and survival of embryos and neonates of the freshwater burrowing crab, Zilchiopsis collastinensis (Decapoda, Trichodactylidae). Both pesticides were prepared from commercial and technical grade products. The exposure to about 100, 200, and 400 ng endosulfan L(-1), and 48, 240, and 1,200 ng chlorpyrifos L(-1) did not cause differences in the incubation period or in effective hatching but decreased survival of neonates, especially in the concentrations prepared from the technical grade product. Even if these concentrations are below the median lethal concentration (LC50) values for embryos, these caused a significant decrease in the survival of neonates, i.e. when crabs are outside the egg and not protected by chorion. The decrease in the neonate population caused by these concentrations, which could be found in the environment, might impact aquatic communities.

Biochemical changes in certain enzymes of Lysapsus limellium (Anura: Hylidae) exposed to chlorpyrifos.

Different enzyme biomarkers (AChE: acetylcholinesterase, CbE: carboxylesterase, GST: glutathione-S-transferase, CAT: catalase) were measured in digestive tissues of Lysapsus limellum frogs collected from a rice field (RF: chlorpyriphos sprayed by aircraft) and a non-contaminated area (RS: reference site), immediately (24h) and 168 h after aerial spraying with chlorpyrifos (CPF). CPF degradation was also searched in water samples collected from RF and RS, and found that insecticide concentration was reduced to≈6.78% of the original concentration in RF at 168 h. A significant reduction of AChE and CbE activities was detected in L. limellum from RF in stomach and liver at 24 and 168 h, and in intestine only at 24h, with respect to RS individuals. CAT activity decreased in intestine of L. limellum from RF 24h and 168 h after exposure to CPF, whereas GST decreased in that tissue only at 24h. In stomach and liver, a decrease was observed only at 168 h in both CAT and GST. The use of biomarkers (AChE, CbE, GST, and CAT) provides different lines of evidences for ecotoxicological risk assessment of wild frog populations at sites contaminated with pesticides.

Induction of micronuclei and nuclear abnormalities in tadpoles of the common toad (Rhinella arenarum) treated with the herbicides Liberty® and glufosinate-ammonium.

The assessment of micronucleated erythrocytes (ME) in blood represents a widely used method for the detection of chromosomal damage by chemical agents, such as herbicides that may occur as water contaminants. We investigated the changes in some circulating blood-cell parameters of tadpoles of the common toad (Rhinella arenarum) that were exposed during 48 or 96 h to three sub-lethal concentrations (3.75, 7.5, and 15 mg/L) of a commercial formulation of a glufosinate-ammonium (GLA)-based herbicide (Liberty(®), LY(®)) as well as to the corresponding active ingredient GLA. The frequency of ME and other erythrocyte nuclear abnormalities (ENA, i.e., lobed nuclei, binucleates or segmented nuclei, kidney-shaped nuclei, notched nuclei, and picnotic nuclei) were evaluated and compared with positive (cyclophosphamide, CP, 40 mg/L) and negative (de-chlorinated tap water) controls. The results indicate that the exposure of R. arenarum tadpoles to LY(®) induces a concentration-dependent increase in ME frequency. The ENA frequency at 48 h was also significantly higher than that in the negative control group for all the chemicals assayed (CP, LY(®) and GLA) whereas at 96 h, increases in ENA over the negative control group were found only for CP and GLA (7.5 mg/L). Our study demonstrates that the commercial formulation of a GLA-based herbicide induces micronucleus formation in R. arenarum tadpoles, in contrast to the active ingredient. According to these results, the inert ingredients of the commercial formulation played an important role in the production of genotoxic damage in erythrocytes of amphibian tadpoles.

Plaguicidas organoclorados en leche materna en Santa Fé, Argentina / Organochlorine pesticides in breast milk in Santa Fé, Argentina

Se estudió el nivel de contaminación por plaguicidasorganoclorados en leche materna de un grupo de mujeres que viven en Santa Fé, Argentina. Se analizaron cincuenta y dos muestras de leche materna recolectadas en hospitales públicos regionales, para determinar la concentración de 12 compuestos usados en el control de plagas. Con el mismo objetivo se estudiaron cinco marcas comerciales de leche en polvo maternizadas. Se empleó un método miniaturizado de extracción, seguido de limpieza de extractos, concentración y posterior uso de cromatografía gaseosa con detectores ECD Ni63. Los resultados analíticos señalan que el 86 por ciento de las muestras tuvo residuos de al menos un plaguicida, sindo los más frecuents hallados, heptacloro epóxido, aldrín, pp DDe y pi-CH. En menos del 15 por ciento de las muestras se detectó endrín, HCB, pp DDt, dieldrin y alfa HCH. El estudio permite conocer el grado de exposición humana, analizar las posibles relaciones con el uso de biocidas como control de plagas, con la ingesta alimenticia por bioacumulación en la cadena alimentaria y a la vez sienta las bases para futuras investigaciones. Comparándolo con estudios anteriores realizados en Argentina, en América Latina y en otros continentes, los niveles de contaminación hallados muestran concentraciones inferiores a aquellos

Plaguicidas organoclorados en leche materna en Santa Fé, Argentina / Organochlorine pesticides in breast milk in Santa Fé, Argentina

Se estudió el nivel de contaminación por plaguicidasorganoclorados en leche materna de un grupo de mujeres que viven en Santa Fé, Argentina. Se analizaron cincuenta y dos muestras de leche materna recolectadas en hospitales públicos regionales, para determinar la concentración de 12 compuestos usados en el control de plagas. Con el mismo objetivo se estudiaron cinco marcas comerciales de leche en polvo maternizadas. Se empleó un método miniaturizado de extracción, seguido de limpieza de extractos, concentración y posterior uso de cromatografía gaseosa con detectores ECD Ni63. Los resultados analíticos señalan que el 86 por ciento de las muestras tuvo residuos de al menos un plaguicida, sindo los más frecuents hallados, heptacloro epóxido, aldrín, pp DDe y pi-CH. En menos del 15 por ciento de las muestras se detectó endrín, HCB, pp DDt, dieldrin y alfa HCH. El estudio permite conocer el grado de exposición humana, analizar las posibles relaciones con el uso de biocidas como control de plagas, con la ingesta alimenticia por bioacumulación en la cadena alimentaria y a la vez sienta las bases para futuras investigaciones. Comparándolo con estudios anteriores realizados en Argentina, en América Latina y en otros continentes, los niveles de contaminación hallados muestran concentraciones inferiores a aquellos(AU)

Contaminación por compuestos con acción antillama, usados en poliuretano / Contamination by substances with antiflame used in polyurethane

Buscou-se determinar a origem da contaminaçäo com substância forsforada, encontrada em camomila processada (Camomilla setacciata) e detectada em controles rotineiros de resíduos de biocidas. Estudos feitos por cromatografia em fase gasosa com diferentes detectores permitiram confirmar que alguns compostos organofosforados e de uso agrícola podem ser confundidos, durante análise, com substância empregada como antichama na espuma rígida de poliuretano, que por sua vez é isolante térmico. Na biblioteca do espectrômetro de massa identificou-se o contaminante como sendo da família do Fyrol, também usado como antichama ou retardador da chama. Estudando a migraçäo do composto em laboratório, determinou-se que o mesmo é liberado com facilidade da matriz, difundindo-se no ar em funçäo das variáveis temperatura e tempo de exposiçäo, o que o torna contaminante potencial em qualquer uma de suas aplicaçöes

Monitoreo de insecticidas organoclorados y organofosforados en el rio Paraná (Km 600) / Monitoring organochlorine and organophosphorus insecticide in Paraná river

Analisa os resíduos de inseticidas organoclorados e organofosforados, na água e materiais em suspensäo de amostras retiradas da Bacia do Rio Paraná (próximo ao Km 600), durante os anos de 1995 e 1996. Verifica o transporte de material em suspensäo e a relaçäo entre o transporte dos inseticidas dissolvidos e adsorvidos. Compara as condiçöes ambientais atuais com dados obtidos nos anos 1983-84. Usa a cromatografia em fase gasosa para as determinaçöes qualitativas e quantitativas dos inseticidas Alfa+gama Hexaclorohexano, Aldrin, heptacloro, Paration metílico. Conclui que as concentraçöes máximas säo obtidas nos meses de primavera e veräo, os quais coincidem com as épocas de aplicaçäo dos inseticidas. Em geral o máximo de inseticidas adsorvidos se apresentam com um "lag" de 60 dias em relaçäo aos dissolvidos. Considerando os limites internacionais estabelecidos para água potável e desenvolvimento da vida aquática, o Rio Paraná (Km600) e suas áreas de influência continuam em condiçöes perigosas para a fauna íctica, embora tenha sido registrada diminuiçäo nos índices de concentraçäo