Biosorption of copper ions with olive pomace and walnut shell.

The removal of copper ions, from synthetic solutions, using walnut shell and olive pomace waste as biosorbents was studied. Synthetic copper solutions were used, and the contact time, initial pH, biosorbent dose, and initial concentration of copper ions were evaluated. The used particle size of both biosorbents was inferior to 600 µm. In the elimination of copper ions, the walnut shell reached 88% (30 min), and the olive pomace 86.5% (40 min). The maximum removal of copper ions was at pH 5 with both biosorbents. The elimination of copper ions was constant with increasing doses of bio-sorbent; however, a decrease close to 90% in the biosorption capacity was determined, when the dose of biosorbent increased from 1 to 10 g/L. The effect of the biosorption capacity increased proportionally with the initial concentration of copper ions; achieving biosorption of 8.3 and 12.9 mg of Cu+2/g of biosorbent, with walnut shell and olive pomace, respectively. Both biosorbent allowed copper ions removal close to 90%; however, to the olive pomace was not necessary a size reduction and had a higher copper ions biosorption capacity than the walnut shell.

RESUMEN: Se estudió la remoción de iones cobre desde solución sintética, usando cáscara de nuez y orujo de oliva como biosorbentes; se evaluó el tiempo de contacto, pH inicial, dosis de biosorbente y concentración inicial de iones cobre. El tamaño de partícula usado de ambos biosorbentes fue inferior a 600 µm. En la eliminación de iones cobre, la cáscara de nuez alcanzó 88 % (30 min) y el orujo de oliva 86,5 % (40 min). La máxima remoción de iones cobre fue a pH 5 con ambos biosorbentes. La eliminación de iones cobre fue constante con dosis crecientes de biosorbente; pero, se determinó una disminución cercana al 90 % en la capacidad de biosorción, cuando la dosis de biosorbente incrementó de 1 a 10 g/L. El efecto de la capacidad de biosorción aumentó proporcionalmente con la concentración inicial de iones cobre; obteniéndose biosorción de 8,3 y 12,9 mg de Cu+2/g de biosorbente, con cáscara de nuez y orujo de oliva, respectivamente. Ambos biosorbentes permitieron una remoción de iones cobre cercana al 90%; sin embargo, el orujo de oliva no necesitó reducción de tamaño y tuvo mejor capacidad de biosorción de iones cobre que la cáscara de nuez.

Uptake of Cu, Hg, and As in wild vegetation, associated to surface water in the Copiapó valley, before the 2015 alluvium.

In an annual monitoring in the Copiapó valley, the concentration of Cu, Hg, and As in sediments was related to environmental transfer processes, these elements also being present in surface water. The goal was to evaluate the uptake of the mentioned elements in wild plants of the Copiapó Valley, to determine if these species could be indicator plants to prevent environmental risks in local agriculture. From the same monitoring, the uptake of the elements was determined in wild plants growing near the irrigation channels; canopy of Tessaria absinthioides, Equisetum giganteum, Arundo donax, Melilotus indicus, Cortaderia rudiscula, and Sarcocornia neei was analyzed for the same elements. These plants were able to uptake Cu, Hg and As in concentration between 19 and 4674.5 times the environmental limits allowed for edible plants. This result shows that crop plants can also capture contaminants elements due to the frequency of irrigation. These plants can be used as indicators for the diagnosis of capture of the pollutants elements by plants and to prevent environmental hazards to human health in agricultural products from the Copiapó valley.

Contamination of As, Cd, Cr, Hg and Pb in soils in Arica commune (Chile).

The objectives of this study are (a) to determine the background concentration of As, Cd, Cr, Hg and Pb in Arica commune; (b) to determine the degree of soil contamination in Arica city using environmental indices and (c) to evaluate the human health risk of these potentially toxic elements. In the rural area of Arica commune, 169 samples were taken and 283 samples were taken in the urban area of Arica city. Total concentrations of Cd, Pb and Cr were determined by EPA 3052 and EPA 6010 C. Mercury was determined by EPA 7473. Arsenic was determined by EPA 7061A. The available concentrations of As and Cr were determined by dilute hydrochloric acid and EPA 6010C. Environmental indices were applied for pollution and US EPA model was used to evaluate human health risk. Background concentrations were As 18.2, Cd 1.12, Cr 73.2, Hg 0.02 and Pb 11.8 mg kg-1, respectively. Environmental indices show that soil samples are located between slightly contaminated to extremely contaminated. Human health risk analysis shows that children have higher levels of risk than adults. The analysis with available concentrations of As and Cr shows no carcinogenic risk for adults and children, but 81% and 98% of the samples were between 10-6 and 10-4, that means intermediate risk.

[Use and non-use of pedestrian bridges in Mexico City. The pedestrian perspective]. / Motivos de uso y no uso de puentes peatonales en la Ciudad de México. La perspectiva de los peatones.

OBJECTIVE: To analyze the motives for using and not using pedestrian bridges (PB). MATERIAL AND METHODS: A cross-sectional survey was conducted of a sample of pedestrian users and non-users of PB; a logistic regression model was used to analyze the motives for use and non-use. RESULTS: The prevalence of non-use was 50.5 % of 813 surveyed pedestrians; the principal reason to use a PB was safety, and not to use it was "laziness". There were significant differences when analyzing the reason of non-use in the age groups 19 to 36 years, adjusted for education and physical characteristics of the PB ([aOR=1.7; 95 % CI=1.06-2.86] and [ORa.1.9; 95 % CI=1.14-3.33], respectively). CONCLUSIONS: The results of this study allow us to identify important aspects to consider--from the perspective of the pedestrians--when constructing new PB and improving existing PB to increase use in areas with a high risk of pedestrian injuries.

Entomopathogenicity of native bacteria from Anastrepha fraterculus and Ceratitis capitata against the pest Phyllocnistis citrella.

In Piura (Peru), the pest Phyllocnistis citrella Stainton damages the photosynthetic rate and new bud production of Citrus aurantiifolia Swingle (sweet lemon), decreasing the yield, productivity and commercial price of its fruit. Biological control was evaluated through the crossed effect of bacteria obtained from pests (Anastrepha fraterculus Wied., Ceratitis capitata Wied. and Rhynchophorus palmarum L.) that are pathogenic against their original host species. Enterobacter cloacae (Jordan) Hormaeche & Edwards and Serratia marcescens Bizio (from A. fraterculus and C. capitata) and Pseudomonas mendocina Palleroni (from R. palmarum) were used against P. citrella. The bacterial strains were inoculated into its food and the accumulated mortality was evaluated. Larvae of P. citrella treated with P. mendocina had the highest mortality (66.7%). These bacterial species were entomopathogenic against the original source pest in laboratory and greenhouse bioassays, and this result widens the pathological activity range of these bacterial species.

Phylogenetic relationships of plant species from the flowering desert of the Atacama Region / Relaciones filogenéticas de especies de plantas que crecen en el desierto florido de la Región de Atacama

Every 3 to 7 year angiosperms species of the flowering desert appear in the Atacama Region of Chile, as a result of the climatic phenomenon "El Niño". Our objective was to evaluate the universality of matK and rbcL barcode markers of these species, and validate their taxon through phylogenetic relationships. Argemone hunnemannii, Oenothera coquimbensis, Malesherbia humilis, Leucocoryne appendiculata, Loasa elongata, Nicotiana solanifolia, Stachys grandidentata, Aristolochia chilensis, Alstroemeria kingii and Adesmia eremophila, almost all classified as endemic to Chile, were collected in Pan de Azúcar and Llanos de Challe National Park (Atacama Region, Chile) at the end of October 2017. The phylogeny of these ten angiosperm species from the flowering desert was analyzed using rbcL and matK markers with the maximum likelihood and Bayesian inference methods. The results showed that 70% of the species can be distinguished with the matK or rbcL locus, however, 100% were distinguished using both loci. The phylogenetic results showed that the species formed clades with high reliability and high support with both the matK and rbcL genes, when comparing our results with sequences obtained from GenBank. The matK and rbcL genes are efficient markers for analyzing phylogenetic relationships and validating the taxonomy of flowering species.

Las especies de angiospermas del Desierto Florido de la Región de Atacama de Chile aparecen cada 3 a 7 años, influenciado por el fenómeno climático "El Niño". Nuestro objetivo fue evaluar la universalidad de los marcadores de código de barra matK y rbcL de estas especies, y validar su taxón por medio de relaciones filogenéticas. Las especies Argemone hunnemannii, Oenothera coquimbensis, Malesherbia humilis, Leucocoryne appendiculata, Loasa elongata, Nicotiana solanifolia, Stachys grandidentata, Aristolochia chilensis, Alstroemeria kingii y Adesmia eremophila son clasificadas la mayoría endémicas de Chile. Estas especies fueron colectadas en el Parque Nacional Pan de Azúcar y Llanos de Challe, Región de Atacama, Chile. La colecta se realizó a fines de octubre de 2017. Con los marcadores rbcL y matK se analizó la filogenia con los métodos máxima verosimilitud e inferencia bayesiana en diez especies de angiosperma del Desierto Florido. Los resultados mostraron que el 70% de las especies pueden ser distinguidas con un locus matK o rbcL, sin embargo, el 100% se distinguió usando ambos locus. Los resultados filogenéticos mostraron que las especies formaron clados con alta fiabilidad y alto soporte tanto con los genes matK y rbcL, al comparar con accesos de secuencias obtenidas de GenBank. Lo genes matK y rbcL son marcadores eficientes para analizar relaciones filogenéticas y validar el taxón de las especies de flor.

Concentrations of heavy metals in urban soils of Talcahuano (Chile): a preliminary study.

Concentrations of Cd, Cr, Ni, Pb, and Zn in the top-(0-10 cm) and sub-surface (10-20 cm) soils of the Talcahuano urban area were measured. The main soil properties (organic matter, CaCO3, pH, particle sizes) were determined for a network of representative sampling sites. The mean Cr, Ni, Pb, and Zn contents in the urban topsoil samples from Talcahuano (37.8, 22.6, 35.2, 333 mg kg(-1), respectively) were compared with mean concentrations for other cities around the world. The results revealed higher concentrations of heavy metals in topsoil samples than in sub-surface samples. The samples from IS1, IS2, and IS3, located in the Talcahuano industrial park, had higher Cr, Ni, Pb, and Zn contents than did samples from the other sites. This was probably due to local pollution by industrial (metallurgical) dust, although other diffuse pollution throughout the entire port region (shipyards, metallurgy, the dismantling of old ships), and contributions from the wind from adjacent industrial, storage, and vessel areas clearly played a role. Heavy metals were lowest in the sample taken on school grounds (SG).

Motivos de uso y no uso de puentes peatonales en la Ciudad de México: la perspectiva de los peatones / Use and non-use of pedestrian bridges in Mexico City: the pedestrian perspective

OBJETIVO. Analizar los motivos de uso y no uso de puentes peatonales (PP). MATERIAL Y MÉTODOS. Se empleó un diseño transversal, a partir de una muestra de peatones usuarios y no usuarios de PP; se utilizó regresión logística para identificar los factores que influyen en el uso y no uso de PP. RESULTADOS. La prevalencia de no uso fue 50.5 por ciento en 813 peatones entrevistados; la principal razón para usar PP fue "seguridad", del no uso fue "flojera". Hubo diferencias significativas al analizar motivos de no uso de PP en las edades de 19 a 36 años, ajustando por escolaridad y características físicas del PP, con RMa. 1.7 (IC95 por ciento 1.06-2.86) y RMa. 1.9 (IC95 por ciento 1.14-3.33), respectivamente. CONCLUSIONES. Los resultados de este estudio permiten identificar aspectos importantes a considerar desde la perspectiva de los peatones, antes de construir nuevos PP, así como aquéllos que deben mejorarse para incrementar su uso en zonas de alto riesgo de lesiones por atropellamiento.

OBJECTIVE. To analyze the motives for using and not using pedestrian bridges (PB). MATERIAL AND METHODS. A cross-sectional survey was conducted of a sample of pedestrian users and non-users of PB; a logistic regression model was used to analyze the motives for use and non-use. RESULTS. The prevalence of non-use was 50.5 percent of 813 surveyed pedestrians; the principal reason to use a PB was safety, and not to use it was "laziness". There were significant differences when analyzing the reason of non-use in the age groups 19 to 36 years, adjusted for education and physical characteristics of the PB ([aOR=1.7; 95 percent CI=1.06-2.86] and [ORa.1.9; 95 percent CI=1.14-3.33], respectively). CONCLUSIONS. The results of this study allow us to identify important aspects to consider "from the perspective of the pedestrians" when constructing new PB and improving existing PB to increase use in areas with a high risk of pedestrian injuries.