Eduardo Lorenzatti

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.

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.

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.

El estudio de casos en la enseñanza universitaria del quehacer profesional. La experiencia en contaminación y saneamiento del suelo

Fil: Lorenzatti, Eduardo Antonio. Universidad Nacional del Litoral. Facultad de Bioquimica y Ciencias Biologicas. Escuela Superior de Sanidad; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina

Acumulación y Persistencia del Insecticida Endosulfán en Soja, como Posible Factor de Contaminación Ambiental y Alimentaria

Fil: Lorenzatti, Eduardo Antonio. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Santa Fe. Instituto de Desarrollo Tecnologico para la Industria Quimica. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnologico para la Industria Quimica; Argentina

CONTAMINACIÓN POR COMPUESTOS CON ACCIÓN ANTILLAMA, USADOS EN POLIURETANO

Buscou-se determinar a origem da contaminacao com substâncias fosforadas, encontrada em camomila processada ( Camomilla setacciata ) e detectada em controles rotineiros de residuos de biocida. Estudos feitos por cromatografia em fase gasosa com diferentes detetores permitiram confirmar que alguns compostos organofosforados e de uso agricola podem ser confundidos, durante analise, com substância empregada como antichama na espuma rigida de poliuretano, que por sua vez e isolante termico. Na biblioteca do espectrometro de massa identificou-se o contaminante como sendo da familia do Fyrol, tambem usado como antichama ou retardador da chama. Estudando a migracao do composto em laboratorios, determinou-se que o mesmo e liberado com facilidade da matriz, difundindo-se no ar em funcao das variaveis temperatura e tempo de exposicao, o que o torna contaminante potencial em qualquer uma de suas aplicacoes.