Improvement of laboratory skills of Chemical and Civil Engineering students using an interdisciplinary service-learning project for water quality and supply assessment in low-income homes.

The University of Buenos Aires (UBA) develops the UBANEX program, focused on service-learning projects for students involving social, environmental and public health concerns. One of the proposals was a collaborative project between UBA and the National University of General Sarmiento. Based on the hypothesis that students' voluntary involvement in social concerns improves their attitudes towards themselves and learning, the aim was to focus on the development of social and professional skills by implementing an interdisciplinary work for water quality and supply assessment in low-income homes from a southern district of the Buenos Aires Metropolitan Area. Eighteen volunteers-Chemical and Civil Engineering students-were recruited during August-December 2016. Tasks were distributed according to their interests: survey making, sampling, lab analysis, infrastructure checking, etc. Volunteers were surveyed in social involvement, lab skills, data compilation and analysis, leading to a final report with recommendations for a proper water use. The survey results compiled their feedback: 72% admitted an update on water quality problems, 60% learned new lab techniques and were able to analyze results, 89% supported the University's involvement in social concerns and 56% expanded their opinion about the professional field. The students confirmed their interest in participating in the next UBANEX project.

Assessment of the acute toxicity of the organochlorine pesticide endosulfan in Cichlasoma dimerus (Teleostei, Perciformes).

The organochlorine insecticide endosulfan (ES) is widely used despite its high toxicity to fish (96-h LC(50) median value of 2.6 µg L(-1)). This study aimed to assess the acute toxicity, histological and physiological parameters after exposure to 0; 0.25; 1; 2; 3; 4 and 16 µg L(-1) ES for 96 h under semi-static conditions in a freshwater perciform fish, Cichlasoma dimerus. Prior to death, fish exhibited behavior indicative of neurotoxicity. No difference was found in brain AChE activity. A decrease in erythrocyte mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration in exposed fish suggests a state of anemia. Histological alterations observed in exposed fish included hyperplasia of the interlamellar epithelium, blood congestion in secondary lamellae, and mucous cells hyperplasia and hypertrophy in gills; pycnotic nuclei and hydropic degeneration in liver; testicular damage. These moderate pathological responses in major organs could become crucial during reproduction and under prolonged exposure periods.