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Ferreira, F. F.

Publications and source records attributed to Ferreira, F. F..

2 recordsLinked to original sources
bioRxiv2020

Impacts of the Samarco tailing dam collapse on metals and arsenic concentration in freshwater fish muscle from Doce River, southeastern Brazil

On November 2015, Samarco tailings dam in Mariana MG, Brazil, collapsed, releasing 62 million tons of tailings that advanced through 668 km of the Doce River and adjacent floodplain. Although being the worst environmental disaster in Brazil, little is known about consequences to aquatic biota. Here we evaluate the effects of the tailings mudflow on metal and arsenic concentration in fish and how concentration correlates with water and fish characteristics. We quantified semitotal amounts of Ag, Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn in fish muscle tissue using ICP-MS in 255 individuals (34 species) sampled in unaffected and affected along the Doce River basin. Arsenic and Hg were higher in fish from affected sites, likely due to turbulent mixing of previously sedimented material by the giant tailings wave. Silver and Zn concentrations were higher in unaffected sites. Arsenic concentration in Geophagus brasiliensis decreased with increasing fish weight. Copper and Zn decreased with increasing fish weight considering the whole assembly of fish. The tailings mudflow increased water conductivity and conductivity increased Al concentration in fish, so we expected a larger Al concentration in fishes from affected sites. However, the observed Al concentration in fishes from affected sites was lower than expected by water conductivity. Thus, the tailings mudflow reduced Al uptake or accumulation in fishes. Mercury decreased with increasing water conductivity in both unaffected and affected sites considering all species and in G. brasiliensis alone. Despite the relatively low concentration range of metals and As found in fish, fishes from sites affected by the iron ore tailings mudflow showed higher As and Hg concentration, compared to fishes from unaffected sites. The higher As and Hg in affected sites require further detailed monitoring to ensure safeguards of human health by fishing activity along the Doce River.

ecology↗
bioRxiv2020

Effectiveness of active learning for ecology teaching: the perspective of students vs their grades

We evaluated the effectiveness of active learning for ecology teaching by comparing the perspective of students to their grades in exams. We estimated the perspective of the students through anonymous survey; we used students exam grades to estimate their ecology learning, and their effort and performance in the active learning tasks through their grades and proportion of intermediate steps for each active learning task. Active learning involved teachers stimuli for students active involvement, extra-class group task, individual online writing assessments, redoing exam in pairs, and classroom writing group assessments. We also evaluated the impact, unto the effectiveness of active learning, of several student characteristics, such as sex, age, individual study effort, and previous basic knowledge. We found that self-evaluated learning increased linearly with teachers attempts to stimulate students active involvement (P = 0.0003), extra-class group task (P = 0.0003), and previous basic knowledge (P = 0.02), while students grades increased asymptotically with extra-class group task (P < 2-16), and increased linearly with online writing assessments (P = 9.3-8) and classroom-based writing group assessments (P = 0.03). Our results showed that students perceive most part of the effectiveness of active-learning tasks and of teachers efforts. We showed that active learning tasks are complementary, so we recommend that teachers in both college and high school should implement simultaneous active-learning tasks, that include extra-class work in group, individual and group writing assessments, and should stimulate students engagement through respectful and non-authoritarian behavior of the teacher. Our results also showed that previous basic knowledge also plays a central role in driving effective learning, evidencing the importance of students instruction outside college. The applied teaching methodology is cheap and feasible for large classes. In these times of rising intolerance, prejudice, dismiss of environmental issues and disregard of science itself, we need an effective, pluralistic, respectful, and student-centred education, that fosters critical thinking, tolerance and respect for differing points of view.

ecology↗