Revista Ambiente & Água - An Interdisciplinary Journal of Applied Science

1-14

Authors: Denise Piccirillo Barbosa da Veiga* ; Manuel Enrique Gamero Guandique; Adelaide Cassia Nardocci

Land use influences the quality and availability of water resources, but Brazil has made little progress in integrated watershed management. This study therefore applied geoprocessing for land-use classification and evaluated the impact on the hydrological balance in order to contribute to the integrated management of water resources. Using GIS tools, two drainage areas from the water catchment points of two municipalities, Santa Cruz das Palmeiras and Piedade, were delimited; land-use mapping was carried out using the supervised classification method of satellite images, and the SWAT model was applied for hydrological simulation. The methods used were appropriate. The surface runoff was related to the absence of vegetation and the predominance of exposed soil. The relationship between land use/land cover and the hydrological balance was evidenced, especially the impact of agricultural activities and the lack of natural vegetation in the surface runoff.

1-16

Authors: José Carlos Marques Pantoja; Milton César Costa Campos* ; Alan Ferreira Leite de Lima; José Maurício da Cunha; Emily Lira Simões; Ivanildo Amorim de Oliveira; Laércio Santos Silva

The recognition of the influence of management practices on soil physical and chemical conditions is substantial for sustainable agriculture. For this reason, this study was developed for the purpose of evaluating the behavior of soil attributes under different uses in the region of Humaitá, AM, using multivariate statistical methods. The study was developed in 8 rural properties producing bananas, grassland, maize, coffee, cassava, vegetables, agroforestry system and a forest fragment. Samples of soils with preserved structure in the 0.0 - 0.10 and 0.10 - 0.20 m layers were randomly collected in 5 small trenches per area, totaling 32 samples in the management systems, to determine the physical and chemical attributes. The data were then submitted to univariate and multivariate statistical analysis. Exploratory data analysis (principal components and dendrogram) and frequency of environmental covariates was efficient in distinguishing production environments, so multivariate classification based on physical and chemical attributes of the soil can help in the proper planning of land use. The analysis of the principal components indicates that the BD presents direct dependence with the SPR, signaling the use of the soil with grassland the only one in the process of compaction. Soil acidity is the main limiting factor for crop development, requiring the adoption of pH corrective practices with improvements in nutrient supply. The conversion of the forest to grassland maintained the structural characteristics of the soil, while the other uses increased improvements in physical quality and soil fertility.

1-9

Authors: Gracieli Xavier Araújo; Raquel Dalla Costa da Rocha; Marcio Barreto Rodrigues*

Unlike organic contaminants, heavy metals are not biodegradable and tend to accumulate in living organisms; they are also recognized for being toxic or carcinogenic. The use of nanoparticles of zero-valent iron (nZVI) is reported as an alternative technique with high potential for in situ and ex situ remediation of contaminated matrices with this metal, mainly due to its large active surface area and significant adsorption capacity to consolidate into a simple and efficient method of treatment. In this study, ZVI particles were synthesized by the chemical reduction method using hydrated ferrous sulfate (FeSO4.7H2O) and sodium borohydride (NaBH4) with subsequent aggregation to powdered activated carbon (PAC), forming the adsorbent PAC-ZVI, which was characterized by the techniques of XRD and SEM, which revealed the integration of the catalyst to the activated carbon matrix. Finally, developed kinetic studies revealed that the adsorption kinetics was better adapted to a pseudo second order model, the isotherms were better represented by the Freundlich model and the thermodynamic results showed that the adsorption reaction occurred through a spontaneous process with endothermic interaction between Cr (VI) and PAC-ZVI with increase in the randomness of the system.

1-12

Authors: Fabiana de Amorim; Jaíza Ribeiro Mota e Silva* ; Ronaldo Fia; Luiz Fernando Coutinho de Oliveira; Cláudio Milton Montenegro Campos

This study evaluated the efficiency of a constructed wetland system (CWS) in removing total coliforms (TC) and thermotolerant coliforms (ThC) of swine wastewater, as a complementary treatment to an anaerobic system. At Stage 1, the experimental system was combined using a vertical flow constructed wetland system (VFCWS) cultivated with Tifton 85 grass in series with a horizontal subsurface flow constructed wetland system (HFCWS1) cultivated with Taboa. In HFCWS1, the hydraulic detention times (HDT) were 4.7, 3.1 and 2.3 days and the surface application rates (SAR) were 294, 319 and 397 kg ha-1 d-1 of COD, in Phases I, II and III, respectively. At Stage 2, the experimental system was combined using a horizontal subsurface flow constructed wetland system (HFCWS2) cultivated with Tifton 85 grass, HDT were 6.1, 2.0 and 0.5 days and the SAR were 850, 656 and 6.34 kg ha-1 d-1 of COD, in Phases I, II and III, respectively. In Stage 1, it was verified that the VFCWS was more efficient in coliform removal when compared to HFCWS1. When only HFCWS were compared, coliform removal in Stage 1 was between 1 and 2 log units in HFCWS1. In the stage 2, the HFCWS2 was more limited, with the highest removal efficiencies during Phase I of 1.6 and 0.8 log units for TC and ThC, respectively. In general, the association resulted in efficiencies that ranged from 96.4 to 99.0% for TC, 94.2 and 97.6% for ThC, equivalent to the average removal of 1.2 to 2 log units, considered satisfactory.

1-9

Authors: Patrícia dos Santos Nascimento; Lucylia Suzart Alves* ; Vital Pedro da Silva Paz

This work evaluated the development of colored cotton submitted to irrigation water of different salinity levels and organic matter doses from tanned manure. The experimental design was completely randomized in a 4 x 4 factorial scheme with 3 replications, totaling 48 experimental plots. The factors studied were 4 doses of organic matter (1, 4, 7 and 10%) and four levels of irrigation water salinity (0.26; 1, 2 and 4 dS m-1). The variables analyzed were plant height, stem diameter, number of leaves, number of fruits and fresh shoot mass. Significant effect of organic matter was observed on all studied variables, with a positive response on the increase of all variables as a function of increasing doses of organic matter. The isolated effect of salinity was significant for all parameters evaluated, except for the number of leaves, with significant reductions of 6.03; 3.27; 5.23; 6.94% in the parameters: plant height, stem diameter, number of fruits and shoot fresh weight respectively, for each unit increase of irrigation water salinity. The interaction between the variation sources studied had a significant effect only for fresh shoot mass, where the highest average for this parameter was observed at 10% organic matter dosage at irrigation water salinity level of 1.0 dS m-1.

1-17

Authors: Belize Leite* ; Magda Antunes de Chaves; Athos Aramis Thopor Nunes; Louise Jank; Gertrudes Corção

Wastes arising from human activities can reach water bodies and contribute significantly to the presence of antibiotic resistant bacterial populations in aquatic environments. The objective of this study was to evaluate the cultivable antibiotic resistant bacterial populations from a coastal lagoon impacted by agriculture and urbanization activities. Water samples were collected in low and peak season and characterized regarding physicochemical variables, microbiological indicators and the presence of antimicrobial residues. In order to analyze the presence of resistant bacterial populations, the samples were grown in the presence of nalidixic acid, ceftazidime, imipenem and tetracycline. Genes associated with β-lactamic resistance (blaCTX-M-like, blaGES-like, blaOXA-51, blaOXA-23-like, blaSHV-like, blaTEM-like and blaSPM-1), class I integron and efflux systems (tetA, tetB, acrA, acrB, tolC, adeA, adeB, adeR, adeS, mexB, mexD, mexF and mexY) were analyzed by conventional in vitro amplification. Although antimicrobials residues were below the detection limit, resistant bacteria and resistance determinants - blaGES, class I integron, adeS, acrA, acrB, tolC, mexB, mexF - were present at almost all points, in both seasons and for all antimicrobials assessed. The high numbers of resistant bacteria counts observed after the antibiotic treatment were positively correlated to the urbanization effects on the Lagoon. Some resistant populations were even higher in the low season samples, indicating the importance of a systematic evaluation of antibiotic resistance on water resources.

1-10

Authors: Gabriela Rezende de Souza* ; Italoema Pinheiro Bello; Luiz Fernando Coutinho de Oliveira; Flavia Vilela Corrêa

This study created thematic heavy rainfall maps for Brazil, with durations of 5-, 30-, 60- and 120 minutes and 5 years of return period (T). The intensity-duration-frequency (IDF) relationships used were compiled from studies found in the literature (798 locations) and derived for 4411 rainfall gauges available in the Hidroweb information system, totaling 5209 rainfall data collected. To derive IDF relationships, Gumbel's probability distributions were used, with parameters estimated by the method of moments. Distribution adequacy was verified by the Kolmogorov-Smirnov test. Rainfall-intensity values obtained by IDF relationships were spatialized in Geographic Information Systems, allowing elaboration of the thematic maps. Thematic maps enable obtain rainfall intensities for places without rain gauge data and/or precarious time-series data. Therefore, these maps are a great tool for the design of hydraulic structures related to urban and rural micro-drainage.