Perinatal Exposure to Low Levels of the Environmental Antiandrogen Vinclozolin Alters Sex-Differentiated Social Play and Sexual Behaviors in the Rat

In this study we examined the effects of exposure to the antiandrogenic fungicide vinclozolin (Vz) on the development of two sex-differentiated behaviors that are organized by the perinatal actions of androgens. Pregnant Long-Evans rats were administered a daily oral dose of 0, 1.5, 3, 6, or 12 mg/kg Vz from the 14th day of gestation through postnatal day (PND)3. The social play behavior of juvenile offspring was examined on PND22 and again on PND34 during play sessions with a same-sex littermate. After they reached adulthood, the male offspring were examined with the ex copula penile reflex procedure to assess erectile function. Vz did not produce any gross maternal or neonatal toxicity, nor did it reduce the anogenital distance in male pups. We observed no effects of Vz on play behavior on PND22. However, the 12-mg/kg Vz dose significantly increased play behavior in the male offspring on PND34 compared with controls. The most dramatic increases were seen with the nape contact and pounce behavior components of play. The Vz effect was more pronounced in male than in female offspring. As adults, male offspring showed a significant reduction of erections at all dose levels during the ex copula penile reflex tests. The 12-mg/kg dose was also associated with an increase in seminal emissions. These effects demonstrate that perinatal Vz disrupts the development of androgen-mediated behavioral functions at exposure levels that do not produce obvious structural changes or weight reductions in androgen-sensitive reproductive organs

Application of the RICEWQ-VADOFT model to simulate leaching of propanil in rice paddies in Greece

In recent years models have become an integral part of the pesticide registration processes. However, there are still no validated models which can adequately describe the specific conditions of rice paddies. Accordingly, this study aimed to evaluate the capability of a proposed model, the RICEWQ-VADOFT model, to simulate leaching of propanil. Model performance was evaluated with a data set derived from a field study (1993–1994) carried out in five paddy fields in the southern part of the Axios river basin. Predicted and measured concentrations of propanil leaching to the deeper soil layer were in good agreement. The Root Mean Square Error (RMSE) and Modeling Efficiency (EF) values calculated for three of the five studied fields varied between 39.4–46.1 and 0.813–0.867, respectively, indicating good model performance. However, little agreement between predicted and observed pesticide concentrations was evident in the remaining two paddies. This was attributed to the presence of preferencial flow mechanisms in these particular fields, which facilitated the rapid transport of high concentrations of propanil into the deeper soil layers, and which the model was not able to predict