Navegando por Autor "FIGUEIREDO, Ricardo de Oliveira"

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Acesso aberto (Open Access)
Água e saúde no município de Igarapé-Açu, Pará
(Universidade Federal do Pará, 2016-12) SOUSA, Rafaela Sales de; FELIZZOLA, Juliana Feitosa; FIGUEIREDO, Ricardo de Oliveira; SÁ, Tatiana Deane de Abreu; GUERRA, Gutemberg Armando Diniz; MENEZES, Luciana Gonçalves Creão de
This article aims to analyze and understand the relationship between water and health in rural communities located in the watershed of Cumaru stream, in the municipality Igarapé-Açu, Northeast of Pará state. The harvesting and treatment of the water conducted by the rural population for human consumption were assessed, considering their practices of sanitary sewer, since these aspects have direct impact on their health. This study is based on field research with a quantitative approach. Closed questionnaire was used to raise the sources of water harvesting, rural sanitation, and use of agricultural inputs. We used participant observation, when focusing on the functioning of the agricultural establishment, to observe from various angles the relationship between water and health. We noted that the vulnerability of the water resources accessed by the population is a factor that contributes to the contamination of the sources, therefore a threat to the health of the rural population. However, the perception of the population is notable regarding deeper water sources, such as tube wells, which are priorities for water harvesting.
Acesso aberto (Open Access)
Evasion of CO2 and dissolved carbon in river waters of three small catchments in an area occupied by small family farms in the eastern Amazon
(Universidade Federal do Pará, 2017-08) FIGUEIREDO, Ricardo de Oliveira; MARKEWITZ, Daniel; KRUSCHE, Alex Vladimir; COSTA, Fabíola Fernandes; GERHARD, Pedro; ROSA, Maria Beatriz Silva da
CO2 effluxes from streams and rivers have been hypothesized to be a critical pathway of carbon flow from the biosphere back to the atmosphere. This study was conducted in three small Amazonian catchments to evaluate carbon evasion and dynamics, where land-use change has occurred on small family-farms. Monthly field campaigns were conducted from June 2006 to May 2007 in the Cumaru (CM), Pachibá (PB) and São João (SJ) streams. Electrical conductivity, pH, temperature, and dissolved oxygen measurements were done in situ, while water samples were collected to determine dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) concentrations, as well as carbon dioxide partial pressures (pCO2) and CO2 evasion fluxes. Instantaneous discharge measured by a current meter was used to calculate DOC fluxes. Considering all the sites, DOC, DIC, pCO2, and CO2 flux measurements ranged as follows, respectively: 0.27 - 12.13 mg L-1; 3.5 - 38.9 mg L-1; 2,265 - 26,974 ppm; and 3.39 - 75.35 μmol m-2 s-1. DOC annual flux estimates for CM, SJ and PB were, respectively, 281, 245, and 169 kg C ha-1. CO2 evasion fluxes had an average of 22.70 ± 1.67 μmol m-2 s-1. These CO2 evasion fluxes per unit area were similar to those measured for major Amazonian rivers, thus confirming our hypothesis that small streams can evade substantial quantities of CO2. As secondary vegetation is abundant as a result of family farming management in the region, we conclude that this vegetation can be a major driver of an abundant carbon cycle.
Acesso aberto (Open Access)
Ictiofauna de igarapés de pequenas bacias de drenagem em área agrícola do Nordeste Paraense, Amazônia Oriental
(Universidade Federal do Pará, 2012-06) CORRÊA, Jean Michel; GERHARD, Pedro; FIGUEIREDO, Ricardo de Oliveira
Stream fish communities can show spatial and temporal patterns, which can be revealed by species association or species groups as well as by species preference to certain habitats. The reduced number of studies and the scarce knowledge on the aquatic fauna in the Amazon results on an under-estimative upon stream fish fauna diversity. In this study, a survey at three small Amazonian catchments located in family agriculture areas, a total of 2,117 individuals were collected, belonging to seven orders, 13 families, 27 genera and 43 species. The most abundant species in all samples was Hyphessobrycon heterorhabdus, totaling 337 individuals, followed by Bryconops melanurus, with 326 individuals. The species richness was highest in a Pachibá stream reach, with 21 species. Simpson’s diversity index in a Cumaru stream reach showed the highest species dominance with a value of 0.43, while Shannon’s diversity index showed that the Pachibá stream lowest reach, had the greatest diversity with a value of 2.39. Iguanodectes rachovii was the most constant species, occurring in 50% of samples. Therefore, as a response to habitat size, the intermediate stream reaches presented the highest species diversity. Our study showed that agricultural catchments dominated by smallholder farmers can bear a reasonable stream fish diversity.
Acesso aberto (Open Access)
Retenção do dimetoato e sua relação com pH e teores de argila e matéria orgânica nos sedimentos da zona não-saturada de uma microbacia no nordeste paraense
(Instituto Nacional de Pesquisas da Amazônia, 2007-06) LIMA, Lilianne Maia; SOUZA, Eliene Lopes de; FIGUEIREDO, Ricardo de Oliveira
On smallholder farms of eastern Amazonia, in particular the northeast of the Pará state, heavy by pesticide applications at industrial half-perennial crops are very common. Due to their large use, mainly the dimethoate, in the catchment of the Cumaru stream, Igarapé-Açu county, we evaluated the retention process of this compound in samples of the non saturated zone, as well as verified the effects of soil pH and clay and organic mater contents in this process. Among the main pesticides the farmers use in this region, dimethoate was selected for this study, due to its larger leaching potential according to the GUS (Groundwater Ubiquity Score) index. A sorption experiment was carried out to evaluate the retention of the dimethoate in sediments in the non saturated zone. The experiment showed that the sorption of the dimethoate varied from 2.5% to 36.2% (initial concentration of 20 mg.l-1) and from 6.2% to 31.0% (initial concentration of 10 mg.l-1). These data demonstrate a high contamination potential of the groundwater by this compound, mainly due to its high mobility and low retention capacity. The dimethoate sorption rates were positively related to organic matter content in the sediments. On the other hand, values have an inverse relationship with the sorption rates of dimethoate, while clay content did not produce any effect on its retention.