ABSTRACT
Hot springs worldwide can be a source of extremophilic microorganisms of biotechnological interest. In this study, samplings of a hot spring in Hidalgo, Mexico, were conducted to isolate, identify, and characterize morphologically, biochemically, and molecularly those bacterial strains with potential industrial applications. In addition, a physicochemical and geochemical examination of the hot spring was conducted to fully understand the study region and its potential connection to the strains discovered. The hot spring was classified as sulfate-calcic according to the Piper Diagram; the hydrogeochemical analysis showed the possible interactions between minerals and water. Eighteen bacterial strains were isolated with optimal growth temperatures from 50 to 55 °C. All strains are Gram-positive, the majority having a rod shape, and one a round shape, and 17 produce endospores. Hydrolysis tests on cellulose, pectin, and xylan agar plates demonstrated enzymatic activity in some of the strains. Molecular identification through the 16S rDNA gene allowed classification of 17 strains within the Phylum Firmicutes and one within Deinococcus-Thermus. The bacterial strains were associated with the genera Anoxybacillus, Bacillus, Anerunibacillus, Paenibacillus, and Deinococcus, indicating a diversity of bacterial strains with potential industrial applications.
ABSTRACT
Acid mine drainage is one of the main environmental hazards to ecosystems worldwide and it is directly related to mining activities. In Ecuador, such acidic-metallic waters are drained to rivers without treatment. In this research, we tested a laboratory combined (Ca-Mg) Dispersed Alkaline Substrate (DAS) system as an alternative to remediate acid drainage from the Zaruma-Portovelo gold mining site, at El Oro, Ecuador. The system worked at low and high flow hydraulic rates during a period of 8 months, without signs of saturation.. Analysis of physico-chemical parameters and water composition (ICP-OES, ICP-MS) demonstrated that treatment effectively increased water pH and promoted the retention of about 80% of Fe, Al, Mn and Cu. Under acid conditions As, Cr and Pb concentrations decreased with Fe and possible precipitation of jarosite and schwertmannite. However, the homogeneous depletion of Cr at pH above 6 could be related to ferrihydrite or directly with Cr (OH)3 precipitation. After DAS-Ca, sulphate, phosphate and rare earth elements (REE) concentrations decreased to 1912, 0.85 and 0.07 mg/L respectively, while DAS-Mg contributed to form a complex model of minor carbonate and phosphate phases as main sink of REE. DAS-Mg also promoted the retention of most divalent metals at pH values over seven. Thus, this low cost treatment could avoid environmental pollution and international conflicts. Anyway, further investigations are needed to obtain higher Zn retention values. Graphical abstract.
Subject(s)
Environmental Monitoring , Environmental Restoration and Remediation/methods , Mining , Models, Chemical , Acids/analysis , Ecosystem , Ecuador , Ferric Compounds , Iron Compounds , Metals, Rare Earth/analysis , Minerals/analysis , Rivers/chemistry , Sulfates , Water Pollutants, Chemical/analysisABSTRACT
Drinking-water supply is one of the main issues that populations face in many coastlands. Shallow coastal aquifers are often characterized by the presence of lens-shaped freshwater floating on the saline groundwater plume of marine origin. These groundwater lenses are commonly associated with landforms, such as littoral ridges and dunes and in many cases they represent the main source of water supply in remote coastal areas. At the right side of the middle Río de la Plata estuary (Argentina) the aquifer system is generally saline. Elongated and thin sandy beach ridge systems emerging from the general flat morphology of the marsh-flood plain are capable of storing precipitations forming freshwater lenses, which to date are the main freshwater supply for inhabitants. The aim of this study is to identify and delimitate the presence of such valuable freshwater reserves in order to provide the first necessary guidelines for the water management plan in this area, which has never been implemented since, to the Authors' knowledge, no specific investigation had been carried out before this study. To achieve this goal, Vertical Electrical Sounding, groundwater electrical conductivity measurements, water balances and groundwater chemical analyses were performed and interpreted together. The whole dataset was processed to define the electro-stratigraphic model of the study area and to produce the map of the electrical conductivity of the shallow aquifer. In addition, a three-dimensional model of the fresh water reservoir has been implemented for a better understanding of the relationship between geomorphology and groundwater. Results point out that a total freshwater volume of 78,259,700m3 is stored into a continuous lens and the annual average recharge from precipitation amounts to 6,303,500m3. Although preliminary, this work provides the basic knowledge on the potential fresh groundwater lenses and provides important information for addressing a sustainable use of the freshwater resource.
ABSTRACT
The Negro river, on the shoreline of the city of Manaus, receives an input of industrial and domestic wastes from its urban tributaries, which varying composition has been changing the natural characteristics of its waters. Aiming to assess the effect of the human action on the Negro River water samples were collected, and pH, Eh, electric conductivity and alkalinity (by potentiometry); dissolved oxygen (titrimetry); ammonia and nitrite (spectrophotometry); cations Ca, Mg, Na and K, and the metals Cd, Cu, Cr, Fe, Mn, Ni, Pb and Zn (by atomic absorption spectroscopy, AAS) were analyzed. The results for pH, electric conductivity, dissolved oxygen, ammoniacal nitrogen and nitrite values, indicated a worsening water quality in the Negro river, at the mouths of the São Raimundo (FISR) and Educandos (FIE) streams, which are the two major urban tributaries and receptors of domestic wastes and industrial effluents and downstream from them (JIE). Metals predominate in the dissolved phase and, apart from copper and zinc, are mostly above the maximum desirable limit allowed by the Health Ministry for human consumption. This study showed that in spite of the human contribution from its urban tributaries, the Negro river, still maintains its ability for diluting pollutants, mainly during the period of high water.
O rio Negro, na orla de Manaus, recebe de seus tributários urbanos resíduos domésticos e industriais, cuja composição variada vem modificando as características naturais de suas águas. Com o intuito de avaliar o efeito da ação antrópica sobre o rio Negro foram coletadas amostras de água e analisadas as variáveis: pH, Eh, condutividade elétrica e alcalinidade (por potenciometria); oxigênio dissolvido (titrimetria); nitrogênio amoniacal e de nitritos (espectrofotometria); os cátions Ca, Mg, Na e K, e os metais Cd, Cu, Cr, Fe, Mn, Ni, Pb e Zn (por espectroscopia de absorção atômica - EAA). Os resultados obtidos para pH, condutividade, oxigênio dissolvido, nitrogênio amoniacal e nitritos mostram piora na qualidade da água do rio Negro, na foz dos igarapés São Raimundo (FISR) e Educandos (FIE) e a jusante destes (JIE), que são os dois maiores tributários urbanos e receptores de esgotos domésticos e efluentes industriais. Os metais predominaram na fase dissolvida e, a maior parte, está acima do limite máximo desejável, preconizado pelo ministério da saúde para águas destinadas ao abastecimento público, exceto cobre e zinco. O estudo mostrou que apesar da contribuição antrópica dos tributários urbanos, o rio Negro mantém, ainda, sua capacidade de diluir os poluentes, principalmente, no período de maior volume de água.
ABSTRACT
The Negro river, on the shoreline of the city of Manaus, receives an input of industrial and domestic wastes from its urban tributaries, which varying composition has been changing the natural characteristics of its waters. Aiming to assess the effect of the human action on the Negro River water samples were collected, and pH, Eh, electric conductivity and alkalinity (by potentiometry); dissolved oxygen (titrimetry); ammonia and nitrite (spectrophotometry); cations Ca, Mg, Na and K, and the metals Cd, Cu, Cr, Fe, Mn, Ni, Pb and Zn (by atomic absorption spectroscopy, AAS) were analyzed. The results for pH, electric conductivity, dissolved oxygen, ammoniacal nitrogen and nitrite values, indicated a worsening water quality in the Negro river, at the mouths of the São Raimundo (FISR) and Educandos (FIE) streams, which are the two major urban tributaries and receptors of domestic wastes and industrial effluents and downstream from them (JIE). Metals predominate in the dissolved phase and, apart from copper and zinc, are mostly above the maximum desirable limit allowed by the Health Ministry for human consumption. This study showed that in spite of the human contribution from its urban tributaries, the Negro river, still maintains its ability for diluting pollutants, mainly during the period of high water.
O rio Negro, na orla de Manaus, recebe de seus tributários urbanos resíduos domésticos e industriais, cuja composição variada vem modificando as características naturais de suas águas. Com o intuito de avaliar o efeito da ação antrópica sobre o rio Negro foram coletadas amostras de água e analisadas as variáveis: pH, Eh, condutividade elétrica e alcalinidade (por potenciometria); oxigênio dissolvido (titrimetria); nitrogênio amoniacal e de nitritos (espectrofotometria); os cátions Ca, Mg, Na e K, e os metais Cd, Cu, Cr, Fe, Mn, Ni, Pb e Zn (por espectroscopia de absorção atômica - EAA). Os resultados obtidos para pH, condutividade, oxigênio dissolvido, nitrogênio amoniacal e nitritos mostram piora na qualidade da água do rio Negro, na foz dos igarapés São Raimundo (FISR) e Educandos (FIE) e a jusante destes (JIE), que são os dois maiores tributários urbanos e receptores de esgotos domésticos e efluentes industriais. Os metais predominaram na fase dissolvida e, a maior parte, está acima do limite máximo desejável, preconizado pelo ministério da saúde para águas destinadas ao abastecimento público, exceto cobre e zinco. O estudo mostrou que apesar da contribuição antrópica dos tributários urbanos, o rio Negro mantém, ainda, sua capacidade de diluir os poluentes, principalmente, no período de maior volume de água.