A model based on a multivariate classification for assessing impacts on water quality in a DOCE river watershed after the Fundão tailings dam failure.

The main purpose of this study was to build multivariate classification models using water quality monitoring data for the hydrographic basin of the Gualaxo do Norte River, Minas Gerais state, Brazil, which was impacted in 2015 by the rupture of a containment structure for iron ore tailings. A total of 27 points were evaluated, covering areas affected and unaffected by the disaster, with monitoring of chemical, physical, and microbiological variables during the period from July 2016 to June 2017. Multivariate classification techniques were applied to the data, with the aim of developing models to determine when the impacted locations would present characteristics equivalent to those existing prior to the rupture. Classification models constructed using PLS-DA and LDA were able to predict three classes: unaffected main river, affected main river, and tributaries. The first technique was able to clearly differentiate the three classes for the data evaluated, achieving averages corresponding to 90% accuracy. The second method was consistent with the first, identifying the chloride content, conductivity, turbidity, and alkalinity as discriminatory variables, among those monitored, with the relationships among the parameters being coherent with the environmental conditions of the region. The model, with a correct classification rate of 91.67%, enabled identification of the behavior of new samples, using only these easily measured variables. In summary, application of the multivariate statistical tools allowed the development of models capable of providing information about the recovery process of an ecosystem impacted by the greatest environmental disaster to have occurred in Brazil.

Assessment of Gualaxo do Norte River water quality (Minas Gerais, Brazil) affected by the dam breach of Fundão utilizing exploratory multivariate techniques.

At the end of 2015, the Fundão dam belonging to the Samarco S.A. mining company was ruptured, releasing a flood of mud into the Gualaxo do Norte River, which advanced into the Doce River. The aim of the present study was to apply exploratory multivariate approaches to water quality data obtained during sampling campaigns at the Gualaxo do Norte River during the dry and rainy seasons, between July 2016 and June 2017. A total of 27 locations along the river were sampled, covering unaffected areas and regions influenced by the tailings waste from the dam. Determinations of chemical, physical, and microbiological water quality parameters were performed. Application of principal component analysis (PCA) resulted in the first two components together explaining 39.49% and 37.91% of the total variance for the dry and rainy season data, respectively. In both cases, the PCA groups were related to variables such as turbidity and total solids, which both presented higher values in regions affected by the mud flow. These results are in agreement with those obtained by the Kohonen neural network method, where two-dimensional maps confirmed the samples according to the affected and unaffected area by the disaster.

Proyecto MAPEC-Salta: una nueva modalidad de atención para pacientes hipertensos en el primer nivel de atención de la ciudad de Salta, Argentina / MAPEC-Salta Project: a new care model for hypertense patients in primary health care of Salta city, Argentine

RESUMEN Introducción: La hipertensión arterial (HTA) es la primera causa de morbimortalidad cardiovascular. A menudo es una enfermedad mal controlada porque los sistemas de salud están más orientados a atender enfermedades agudas. El Ministerio de Salud de Argentina propuso un nuevo modelo de atención para pacientes hipertensos conocido como MAPEC, basado en el Modelo de cuidados crónicos. Objetivo: Evaluar el impacto de la implementación del MAPEC en el control de la presión arterial (PA), el cuidado de las medidas higiénico-dietéticas, el conocimiento de la enfermedad y la adherencia al tratamiento en pacientes hipertensos asistidos en tres centros de atención primaria de la ciudad de Salta, Argentina. Material y Métodos: Se midió la PA con tensiómetro digital automático; se evaluó el conocimiento de la HTA y la adherencia al tratamiento con los test de Batalla y Morisky-Green-Levine, respectivamente. Resultados: Se estudiaron 232 pacientes. Hubo diferencias significativas (p <0,0001) luego de la intervención en el control de la PA, el conocimiento de la enfermedad, la adherencia al tratamiento y las medidas higiénico-dietéticas. También en los promedios de PA, con una disminución de 12,97 (IC95: 9,52-16,42) mmHg en la presión sistólica y de 6,93 (IC95: 4,70-9,16) mmHg en la presión diastólica. Conclusiones: Fue evidente la mejoría en los parámetros de salud analizados en los pacientes con la implementación del MAPEC. Este modelo es de fácil aplicación y bajo costo. Además, está en consonancia con los objetivos 25×25 de la OMS, mediante los que se busca una reducción del 25% de las muertes prematuras por enfermedades cardiovasculares hacia el año 2025.

ABSTRACT Background: blood hypertension is the first cause of worldwide cardiovascular morbidity and mortality. Nevertheless, it is a poorly controlled disease, largely because health care systems are oriented to the attention of acute diseases. The Argentine Ministry of Health proposed a new care model for hypertensive patients called MAPEC, based on the Chronic Care Model. Objective: to evaluate the impact made by the implementation of MAPEC to improve the blood pressure control, the treatment adherence and changes in life style, and disease awareness, in three primary health centers of Salta city Argentine. Methods: the blood pressure was measured with automated device, Batalla and Morisky-Green-Levine were used to evaluate the disease awareness and treatment adherence, respectively. Results: 232 patients were included. After model implementation, significant difference (p<0,0001) were found in blood pressure control, disease awareness, treatment adherence and changes in life style. There was a decrease in blood pressure average with reduction of 12,97 (IC 95: 9,52-16,42) mm Hg and 6,93 (IC 95: 4,70-9,16) mm Hg in sistolic and diastolic pressure, respectively. Conclusions: there was evident improvement in the analyzed health parameters after MAPEC implementation. This can be easily adapted for primary health centers and with low cost. This is in order with WHO 25×25 target to reduce 25% cardiovascular premature deaths in 2025.

Adsorption/desorption of arsenic by tropical peat: influence of organic matter, iron and aluminium.

The objective of this work was to investigate the interaction of arsenic species (As(III) and As(V)) with tropical peat. Peat samples collected in Brazil were characterized using elemental analysis and 13C NMR. Adsorption experiments were performed using different concentrations of As with peat in natura and enriched with Fe or Al, at three different pH levels. Peat samples, in natura or enriched with metals, were analysed before and after adsorption processes using Fourier transform infrared spectroscopy (FTIR) spectroscopy. The adsorption kinetics was evaluated, and the data were fitted using the Langmuir and Freundlich models. The results showed that interaction between As and peat was dependent on the levels of organic matter (OM) and the metals (Fe and Al). As(III) was not adsorbed by in natura peat or Al-enriched peat, although small amounts of As(III) were adsorbed by Fe-enriched peat. Adsorption of As(V) by the different peat samples ranged from 21.3 to 52.7 µg g(-1). The best fit to the results was obtained using the pseudo-second-order kinetic model, and the adsorption of As(V) could be described by the Freundlich isotherm model. The results showed that Fe-enriched peat was most effective in immobilizing As(V). FTIR analysis revealed the formation of ternary complexes involving As(V) and peat enriched with metals, suggesting that As(V) was associated with Al or Fe-OM complexes by metal bridging.

Approach combining on-line metal exchange and tangential-flow ultrafiltration for in-situ characterization of metal species in humic hydrocolloids.

This paper deals with the development and optimization of an analytical procedure using ultrafiltration and a flow-injection system, and its application in in-situ experiments to characterize the lability and availability of metal species in humic-rich hydrocolloids. The on-line system consists of a tangential flow ultrafiltration device equipped with a 3-kDa filtration membrane. The concentration of free ions in the filtrate was determined by atomic-absorption spectrometry, assuming that metals not complexed by aquatic humic substances (AHS) were separated from the complexed species (M-AHS) retained by the membrane. For optimization, exchange experiments using Cu(II) solutions and AHS solutions doped with the metal ions Ni(II), Mn(II), Fe(III), Cd(II), and Zn(II) were carried out to characterize the stability of the metal-AHS complexes. The new procedure was then applied in-situ at a tributary of the Ribeira do Iguape river (Iguape, São Paulo State, Brazil) and evaluated using the ions Fe(III) and Mn(II), which are considered to be essential constituents of aquatic systems. From the exchange between metal-natural organic matter (M-NOM) and the Cu(II) ions it was concluded that Cu(II) concentrations >485 microg L(-1) were necessary to obtain maximum exchange of the complexes Mn-NOM and Fe-NOM, corresponding to 100% Mn and 8% Fe. Moreover, the new analytical procedure is simple and opens up new perspectives for understanding the complexation, transport, stability, and lability of metal species in humic-rich aquatic environments.

In situ application of a cellulose bag and an ion exchanger for differentiation of labile and inert metal species in aquatic systems.

This work involved the development and application of a new analytical procedure for in-situ characterization of the lability of metal species in aquatic systems by using a system equipped with a diffusion membrane and cellulose organomodified with p-aminobenzoic acid groups (DM-Cell-PAB). To this end, the DM-Cell-PAB system was prepared by adding cellulose organomodified with p-aminobenzoic acid groups (Cell-PAB) to pre-purified cellulose bags. After the DM-Cell-PAB system was sealed, it was examined in the laboratory. The in-situ application involved immersing the DM-Cell-PAB system in two different rivers, enabling us to study the relative lability of metal species (Cu, Cd, Fe, Mn, and Ni) as a function of time and quantity of exchanger. The procedure is simple and opens up a new perspective for understanding environmental phenomena relating to the complexation, transport, stability, and lability of metal species in aquatic systems rich in organic matter.