RESUMO Com intenso consumo e lançamento contínuo em efluentes domésticos e industriais, a cafeína tem sido regularmente detectada em meios aquáticos por todo o mundo. Esse psicoativo é considerado um excelente indicador de contaminação na água, relacionada à atividade humana. No entanto, os impactos que pode ocasionar à saúde e ao ambiente ainda não são bem compreendidos. Dessa forma, o objetivo deste trabalho foi verificar a presença da cafeína em água bruta e tratada por uma estação de tratamento de água convencional, em diferentes períodos hidrológicos, e avaliar o risco potencial que ela representa ao ambiente aquático. A cafeína foi detectada em todas as amostras de água bruta. A maior concentração foi observada no período mais intenso de seca. Ela não foi detectada na água tratada. O composto é considerado como de alto risco ao ambiente aquático. Os resultados indicam a vulnerabilidade do manancial em questão.

ABSTRACT With an intense consumption and continuous release into domestic and industrial effluents, caffeine has been regularly detected in aquatic environments worldwide. This psychoactive is considered an excellent indicator of contamination in water, related to human activity. However, the impacts it can have on health and on the environment are still not well understood. Thus, the objective of this work was to verify the presence of caffeine in raw water treated by a conventional water treatment plant, in different hydrological periods, and to evaluate the potential risk that it represents to the aquatic environment. Caffeine was detected in all raw water samples. The highest concentration was observed in the most intense period of drought. It was not detected in the treated water. The compost is considered to be of high risk to the aquatic environment. The results indicate the vulnerability of the source in question.

Abstract The influence of Guarea guidonia (L.) Sleumer diaspore abundance on ants’ preference was studied in a secondary tropical forest area in Brazil. We offered seeds in stations with different abundances (one, two, five or 10 diaspores) for interactions with ants. The number of interactions and of ants were influenced by diaspore abundance during the observation period. Stations with 10 diaspores maintained a high number of interactions throughout the experiment. Incidence of seed cleaning differed among the four groups. Moreover, the number of interactions was positively related to the average percent of seeds cleaned. Diaspore abundance proved to be important for promoting more interactions with ants. Considering that the proportion of seeds cleaned increased with the number of interactions, further experiments should observe ant activity for a longer period. Furthermore, diaspore abundance should be considered in future studies of interactions with ants.

ABSTRACT Ants interact with seeds, and frequently remove their appendages. This work aimed to evaluate the effect of ants on the germination of Guarea guidonia (Meliaceae) seeds through removing the fleshy tissue of their integument (sarcotesta). The seeds were subjected to the following treatments: control (no sarcotesta removal), manual removal, and removal by ants. The results show that germination percentage and time varied among treatments, with removal by ants showing the highest percentage within the shortest possible time. The positive effect of sarcotesta removal by ants points to a possible action of anti-fungal substances. As germination is an essential step for recruitment, ant activity may be important to the regeneration of a deforested area. Further studies should consider germination experiments under natural conditions in order to increase the understanding on plant development.