Application of Sustainable Remediation Techniques for Heavy Metal Reduction in Polluted Rivers in Mining Zones: Study Area Ponce Enriquez

Mining activity in Ecuador is primarily artisanal and small-scale. Rivers near the mining county of Camilo Ponce Enriquez have been severely affected by this type of mining. A field study was conducted encompassing 29 sites on the rivers Siete, Fermin, and Pagua during sampling campaigns that took place in both dry (December) and wet seasons (February). Physiochemical parameters and heavy metal concentrations were measured to enable environmental characterization of the rivers. Results revealed that most of the sampled sites had bad water quality and exceeded the environmental limits of heavy metal concentrations set by the Ecuadorian government. A parallel pilot investigation was performed for reducing the heavy metal concentrations in water ecosystems polluted by mining activities using bioremediation techniques. The bioremediation technique applied in the study used bacteria from a wastewater digestor and sugarcane bagasse as a carbon source to support the bacterial community. Sulfide was measured to monitor bacterial activity in experimental bioreactors containing local acid mine drainage (AMD). The results obtained were encouraging, as a significant decrease in heavy metal concentration was observed to nearly the level of Ecuadorian environmental regulations for Al, Cd, Cu, Fe, Pb, and Zn concentrations in freshwater in a set of bioreactors. Keywords: acid drainage, artisanal mining, bioremediation, heavy metals, pollution. Resumen La actividad minera en el Ecuador es principalmente artesanal y de pequeña escala. Los ríos cercanos al área minera de Camilo Ponce Enríquez se han visto severamente afectados por este tipo de minería. Se realizó un estudio de campo en 29 sitios sobre los ríos Siete, Fermín y Pagua durante campañas de muestreo que se realizaron tanto en la época seca (diciembre) como en época húmeda (febrero). Se midieron parámetros fisicoquímicos y concentraciones de metales pesados para permitir la caracterización ambiental de los ríos. Los resultados revelaron que la mayoría de los sitios muestreados tienen agua de mala calidad y excedieron los límites ambientales de concentración de metales pesados establecidos por el gobierno ecuatoriano. También se realizó una investigación piloto paralela destinada a reducir las concentraciones de metales pesados en ecosistemas acuáticos contaminados por actividades mineras utilizando técnicas de biorremediación. La técnica de biorremediación aplicada en el estudio utilizó bacterias de un digestor de aguas residuales y bagazo de caña de azúcar como fuente de carbono para apoyar a la comunidad bacteriana. Se midió el sulfuro para controlar la actividad bacteriana en biorreactores experimentales que contenían drenaje ácido minero (AMD) local. Los resultados obtenidos son alentadores ya que en un conjunto de biorreactores se observó una disminución significativa de las concentraciones de algunos metales pesados alcanzando casi en su mayoría el nivel permisible según las regulaciones ambientales ecuatorianas para las concentraciones de Al, Cd, Cu, Fe, Pb y Zn en agua dulce. Palabras Clave: drenajes ácidos, minería artesanal, biorremediación, metales pesados, contaminación

Longitudinal variability of size-fractionated N-2 fixation and DON release rates along 24.5 degrees N in the subtropical North Atlantic

Dinitrogen (N-2) fixation and dissolved organic nitrogen (DON) release rates were measured on fractionated samples (\u3e10 mu m and m) along 24.5 degrees N in the subtropical North Atlantic. Net N-2 fixation rates (N-2 assimilation into biomass) ranged from 0.01 to 0.4 nmol N L-1 h(-1), and DON release rates ranged from 0.001 to 0.09 nmol N L-1 h(-1). DON release represented approximate to 14% and approximate to 23% of \u3e10 mu m and (assimilation into biomass plus DON release), respectively. This implies that by overlooking DON release, N-2 fixation rates are underestimated. Net N-2 fixation rates were higher in the east and decreased significantly toward the west (r(s)=-0.487, p=0.002, and r(s)=-0.496, p=0.001, for the \u3e10 mu m and fractions, respectively). The sum of both fractions correlated with aerosol optical depth at 550 nm (AOD 550 nm) (r(s)=0.382, p=0.017) and phosphate (PO43-) concentrations (r(s)=0.453, p=0.018), suggesting an enhancement of diazotrophy as a response to aerosol inputs and phosphorus availability. In contrast, DON release was constant among size fractions and did not correlate with any of these variables. We also compared N-2 fixation rates obtained using the N-15(2) dissolved and bubble methods. The first gave average rates 50% (49% 39) higher than the latter, which supports the finding that previously published N-2 fixation rates are likely underestimated. We suggest that by combining N-2 fixation and DON release measurements using dissolved N-15(2), global N-2 fixation rates could increase enough to balance oceanic fixed nitrogen budget disequilibria

On the seasonal variability of the Canary Current and the Atlantic Meridional Overturning Circulation

Author Posting. © American Geophysical Union, 2017. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 122 (2017): 4518–4538, doi:10.1002/2017JC012774.The Atlantic Meridional Overturning Circulation (AMOC) is continually monitored along 26°N by the RAPID-MOCHA array. Measurements from this array show a 6.7 Sv seasonal cycle for the AMOC, with a 5.9 Sv contribution from the upper mid-ocean. Recent studies argue that the dynamics of the eastern Atlantic is the main driver for this seasonal cycle; specifically, Rossby waves excited south of the Canary Islands. Using inverse modeling, hydrographic, mooring, and altimetry data, we describe the seasonal cycle of the ocean mass transport around the Canary Islands and at the eastern boundary, under the influence of the African slope, where eastern component of the RAPID-MOCHA array is situated. We find a seasonal cycle of −4.1 ± 0.5 Sv for the oceanic region of the Canary Current, and +3.7 ± 0.4 Sv at the eastern boundary. This seasonal cycle along the eastern boundary is in agreement with the seasonal cycle of the AMOC that requires the lowest contribution to the transport in the upper mid-ocean to occur in fall. However, we demonstrate that the linear Rossby wave model used previously to explain the seasonal cycle of the AMOC is not robust, since it is extremely sensitive to the choice of the zonal range of the wind stress curl and produces the same results with a Rossby wave speed of zero. We demonstrate that the seasonal cycle of the eastern boundary is due to the recirculation of the Canary Current and to the seasonal cycle of the poleward flow that characterizes the eastern boundaries of the oceans.RAPROCAN Project ; Instituto Español de Oceanografía; and as part of the SeVaCan project Grant Number: CTM2013-48695; Ministerio de Economía y Competividad; Apoyo al Personal Investigador en Formación2017-12-0

Alterations of antitumor and metabolic responses in L5178Y-R lymphoma-bearing mice after only 30-minute daily chronic stress exposure

Aim: In stress research, reducing times of stress induction may contribute to improving the well-being of experimental animals, especially in cancer models, already under physiological distress. To support this idea, we evaluated the effects of a short-timed stress protocol on endocrine, metabolic and immune indicators in mice bearing the L5178Y-R lymphoma. Materials and Methods: A 30-minute daily stress protocol was applied for 28 days to healthy and lymphoma-bearing BALB/c mice; body weight, plasma levels of corticosterone, norepinephrine, Th1/Th2 cytokines, insulin, and leptin, were measured. Results: We found a 12% significant decrease in body weight in non-tumor bearing mice under stress (p < 0.007). The disruption of weight evolution was accompanied by a stress induced 85% decrease in plasmatic leptin (p < 0.01) and total reduction of insulin. Tumor burden alone was associated to an increase in more than two-fold of plasmatic levels of norepinephrine (p < 0.008). Neither stress nor tumor or their combination, resulted in an elevation of systemic IL-6. IFN-γ levels were 20 times higher in lymphoma-bearing animals when compared with non-tumor bearing mice (p < 0.01); however, under stress, this response was reduced by half, indicating a suppressing effect of chronic stress on the antitumor immune response. Conclusion: A short-timed stress induction is enough to cause significant alterations in the metabolism and immunity of healthy and tumor-bearing mice, supporting the use of short-timed protocols as an efficient way to induce chronic stress that also considers concerns regarding the well-being of experimental animals in biomedical research

Thermal and phase transformations analysis in a PREMOMET® steel

Thermal analysis in a PREMOMET® steel has been performed by differential scanning calorimetry (DSC) and highresolution dilatometry. The phase transformation temperatures (Ac1, Ac3, Ms and Mf) of this steel were obtained by the two methods at different heating rates showing good agreement between both techniques. The enthalpy of α-γ transformation for this steel was measured using the thermograms acquired by DSC and microstructure was analyzed by scanning electron microscope (SEM). The results showed that this steel retained a martensitic structure for all conditions

Thermal and phase transformations analysis in a PREMOMET® steel

Thermal analysis in a PREMOMET® steel has been performed by differential scanning calorimetry (DSC) and highresolution dilatometry. The phase transformation temperatures (Ac1, Ac3, Ms and Mf) of this steel were obtained by the two methods at different heating rates showing good agreement between both techniques. The enthalpy of α-γ transformation for this steel was measured using the thermograms acquired by DSC and microstructure was analyzed by scanning electron microscope (SEM). The results showed that this steel retained a martensitic structure for all conditions

Plasma Non-Enzymatic Antioxidant Capacity (NEAC) in Relation to Dietary NEAC, Nutrient Antioxidants and Inflammation-Related Biomarkers

The results presented in this article constitute part of the C.J. Carrión-García’s Doctoral Thesis performed in the Nutrition and Food Science Doctorate Program of the University of Granada.(1) Background: Little is known about the interlinkages between dietary and plasma non-enzymatic antioxidant capacity (D-NEAC and P-NEAC, respectively) and the body’s antioxidant and inflammation response. Our aim was to explore these associations in 210 participants from two Spanish European Prospective Investigation into Cancer and Nutrition (EPIC) centers. (2) Methods: D-NEAC was estimated using published NEAC values in food. P-NEAC and total polyphenols (TP) were quantified by FRAP (ferric-reducing antioxidant power), TRAP (total radical-trapping antioxidant parameter), TEAC-ABTS (trolox equivalent antioxidant capacity-Azino Bis Thiazoline Sulfonic), ORAC (oxygen radical absorbance capacity) and Folin–Ciocalteu assays. Nutrient antioxidants (carotenes, α-tocopherol, ascorbic acid, retinol, uric acid, Q9 and Q10 coenzymes) and inflammation markers (IL-6, IL-8, CRP, TNF-α, PAI-I, resistin and adiponectin) were also analyzed. Spearman correlation and linear regression analyses were performed in association analyses. Analyses were stratified by covariates and groups were defined using cluster analysis. (3) Results: P-FRAP was correlated with D-NEAC, and significantly associated with P-NEAC in multivariate adjusted models. P-FRAP levels were also significantly associated with plasma antioxidants (log2 scale: TP β = 0.26; ascorbic acid β = 0.03; retinol β = 0.08; α-tocopherol β = 0.05; carotenes β = 0.02; Q10 β = 0.06; uric acid β = 0.25), though not with inflammation-related biomarkers. Different profiles of individuals with varying levels of P-NEAC and biomarkers were found. (4) Conclusions: P-NEAC levels were to some extent associated with D-NEAC and plasma antioxidants, yet not associated with inflammation response.This research was co-funded by the Health Research Found (FIS), Acción Estratégica en Salud (AES), of the Spanish Ministry of Economy and Competitiveness, grant number PI12/00002, and the European Regional Development Fund (ERDF)

Determination of cutoff values on computed tomography and magnetic resonance images for the diagnosis of atlantoaxial instability in small-breed dogs.

OBJECTIVE To determine cutoff values for the diagnosis of atlantoaxial instability (AAI) based on cross-sectional imaging in small-breed dogs. STUDY DESIGN Retrospective multicenter study. SAMPLE POPULATION Client-owned dogs (n = 123) and 28 cadavers. METHODS Dogs were assigned to three groups: a control group, a "potentially unstable" group, and an AAI-affected group, according to imaging findings and clinical signs. The ventral compression index (VCI), cranial translation ratio (CTR), C1-C2 overlap, C1-C2 angle, atlantoaxial distance, basion-dens interval, dens-to-axis length ratio (DALR), power ratio, and clivus canal angles were measured on CT or T2-weighted magnetic resonance (MR) images. Receiver operating characteristic (ROC) analysis was performed to define cutoff values in flexed (≥25°) and extended (<25°) head positions. RESULTS Cutoff values for the VCI of ≥0.16 in extended and ≥0.2 in flexed head positions were diagnostic for AAI (sensitivity of 100% and 100%, specificity of 94.54% and 96.67%, respectively). Cutoff values for the other measurements were defined with a lower sensitivity (75%-96%) and specificity (70%-97%). A combination of the measurements did not increase the sensitivity and specificity compared with the VCI as single measurement. CONCLUSION Cutoff values for several imaging measurements were established with good sensitivity and specificity. The VCI, defined as the ratio between the ventral and dorsal atlantodental interval, had the highest sensitivity and specificity in both head positions. CLINICAL SIGNIFICANCE The use of defined cutoff values allows an objective diagnosis of AAI in small-breed dogs. The decision for surgical intervention, however, should remain based on a combination of clinical and imaging findings