Evaluation of sulfate rhizofiltration by Carpobrotus chilensis for treating mining waters.

Chile, the world's leading copper producer, generates significant volumes of mining waters, some of which cannot be recirculated into the production process. These mining waters are characterized by elevated sulfate (SO42-) concentrations, requiring sustainable management strategies for potential reuse. This study aims to evaluate the rhizofiltration technique using Carpobrotus chilensis for treating mining waters with a high SO42- concentration. Initially, the mining waters exhibited a pH of 7.97 ± 0.16 and a SO42- concentration of 2,743 ± 137 mg L-1, while the control water had a pH of 7.88 ± 0.08 and a SO42- concentration of 775 ± 19.0 mg L-1. The plants were hydroponically cultivated in 40 L containers with mining waters and drinking water as a control. Over an 8-week period, the pH of the mining water decreased to 3.12 ± 0.01, and the SO42- concentration declined to 2,200 ± 110 mg L-1. Notably, the fresh weight of roots was significantly higher in plants grown in mining water (22.2 ± 6.66 g) compared to those in the control treatment (14.3 ± 4.28 g). However, an undesirable increase in the acidity was observed in the mining waters after rhizofiltration, which was attributed to hydrogen sulfate (HSO4-) and/or root exudates. Despite the unexpected increase in acidity, C. chilensis effectively reduced the concentration of SO42- in mining waters by 20%. Additionally, the C. chilensis roots accumulated 4.84 ± 1.40% of sulfur (S), a level comparable to thiophore plants. This study provides evidence that this non-aquatic plant can be used in sulfate rhizofiltration.

Caprobrotus chilensis is a good candidate for sulfate rhizolfiltration in mining waters.The accumulation of sulfur by the roots of Carpobrotus chilensis reached 4.84%Mining waters with a high concentration of sulfates require control of the redox potential.

Availability of copper in mine tailings with humic substance addition and uptake by Atriplex halimus.

The chemical characteristics of mine tailings, organic amendments (doses), and plants are the critical factors that must be evaluated and monitored to ensure the sustainability of phytostabilization. The aim of this study was to evaluate the mobility of copper (Cu) in mine tailings (MT) of the Zone Central of Chile to which commercial humic substances were added, examining their effect on the uptake of Atriplex halimus. Two commercial humic substances (HS1 and HS2) extracted from leonardite (highly oxidized lignite), of different pH and total organic carbon, were evaluated by adsorption curve for Cu. In columns, soluble Cu, pH, and electrical conductivity in leachates were evaluated for MT, MT + HS1, and MT + HS2, and HS1 and HS2 in doses of 120 mg kg-1. In pot assay, seeds were germinated directly in MT and cultivated for 140 days with the addition of HS2 in 120 and 240 mg kg-1. Mine tailing presents high concentration of Cu (2016 ± 223 mg kg-1, pH 6.3 ± 0.1). The results of sequential extraction indicate that Cu is associated with the sulfide fraction of low risk of mobility. The amount of Cu sorbed by HS1 was higher than that sorbed by HS2, and both humic substances showing better fit to the Freundlich than Langmuir model. Lixiviation of Cu was significantly lower in MT + HS1 (0.166 ± 0.043 mg kg-1) and MT + HS2 (0.157 ± 0.018 mg kg-1) than in MT (0.251 ± 0.052 mg kg-1). Copper concentration in plants reached 185.8 ± 37.8 mg kg-1 in the roots and 32.6 ± 7.4 mg kg-1 in the aerial parts cultivated in MT without effect of the humic substance addition in Cu uptake nor growth. Copper concentrations in the aerial parts were adjusted to sufficient or normal levels in plant. A good management of mine tailings through phytostabilization could consider an adequate mixture of humic substances (to avoid leaching of metals) and an organic amendment that provides essential nutrients and increases biomass generation.

Atriplex atacamensis and Atriplex halimus resist As contamination in Pre-Andean soils (northern Chile).

The Pre-Andean area of Chile exhibits saline soils of volcanic origin naturally contaminated with arsenic (As), and we hypothesise that revegetation with resistant species may be a valid alternative for soil management in this area. Thus, the xerophytic and halophytic shrubs Atriplex halimus and Atriplex atacamensis were cultivated in containers for 90 days in Pre-Andean soil, As-soil, (111±19 mg As kg(-1), pH8.4±0.1) or control soil (12.7±1.1 mg As kg(-1), pH7.8±0.1) to evaluate As accumulation and resistance using stress bioindicators (chlorophylls, malondialdehyde (MDA) and total thiols). Sequential extraction of As-soil indicated that 52.3% of As was found in the most available fraction. The As distribution was significantly different between the species: A. halimus translocated the As to leaves, whilst A. atacamensis retained the As in roots. At 30 and 90 days, A. halimus showed similar As concentrations in the leaves (approximately 5.5 mg As kg(-1)), and As increased in stems and roots (up to 4.73 and 16.3 mg As kg(-1), respectively). In A. atacamensis, As concentration was lower (2.6 in leaves; 3.2 in stems and 6.9 in roots in mg As kg(-1)). Both species exhibited a high concentration of B in leaves (362-389 mg kg(-1)). If the plants are used for animal feed, it should be considered that A. halimus accumulates higher concentration of As and B in the leaves than A. atacamensis. Neither plant growth nor stress bioindicators were negatively affected by the high levels of available As, with the exception of MDA in the leaves of A. halimus. The results indicate that these plants resist contamination by arsenic, accumulating mainly the metalloid in the roots and can be recommended to generate plant cover in As-contaminated soils in the Pre-Andean region, under saline conditions controlled, preventing the dispersion of this metalloid via wind and leaching.

Effect of citric acid on metals mobility in pruning wastes and biosolids compost and metals uptake in Atriplex halimus and Rosmarinus officinalis.

To assess metal mobility in pruning waste and biosolids compost (pH 6.9 and total concentration of metals in milligram per kilogram of Cd 1.9, Cu 132, Fe 8,513, Mn 192, Pb 81, and Zn 313), shrubs species Atriplex halimus and Rosmarinus officinalis were transplanted in this substrate and irrigated with citric acid (4 g L(-1), pH 2.9) and nutrient solution daily for 60 days. Citric acid significantly increased the concentrations of soluble Mn and Fe in the nutrient substrate solution measured by suction probes, while other metals did not vary in concentration (Cu and Zn) or were not observed at detectable levels (Cd and Pb). In plants, citric acid significantly increased the concentrations of Cu (2.7 ± 0.1-3.3 ± 0.1 mg kg(-1)), Fe (49.2 ± 5.2-76.8 ± 6.8 mg kg(-1)), and Mn (7.2 ± 1.1-11.4 ± 0.7 mg kg(-1)) in leaves of R. officinalis, whereas the concentration of only Mn (25.4 ± 0.3-42.2 ± 2.9 mg kg(-1)) was increased in A. halimus. Increasing Fe and Mn solubility by citric acid addition indicates the possibility of using it to improve plant nutrition. The mobility of metals in this substrate was influenced for the concentration of the metal, the degree of humification of organic matter and its high Fe content.

Phytoextraction of cadmium by four Mediterranean shrub species.

The possibility of remediating contaminated soils though the use of high biomass-generating, native plant species capable of removing heavy metals is receiving increased attention. The cadmium (Cd) accumulation capacities of the native Mediterranean, perennial shrubs Atriplex halimus, Phyllirea angustifolia, Rhamnus alaternus and Rosmarinus officinalis were tested by growing transplanted specimens in a pine bark compost substrate (pH 5.6) contaminated with 100 mg Cd kg(-1). After 70 days, only R. alaternus showed reduced growth. The increase in biomass seen in all the test species enhanced the phytoextraction of Cd. However, the species behaved as metal excluders, except for the halophyte A. halimus, which behaved as an indicator plant. In this species the leaf Cd concentration reached 35 mg Cd kg(-1), with the shoot responsible for some 86% of total Cd accumulation. Atriplex halimus showed the highest bioconcentration factor (BCF) (0.36) and leaf Cd transport index (1.68); consequently, this species showed the highest Cd phytoextraction capacity.

Total and bioavailable arsenic concentration in arid soils and its uptake by native plants from the pre-Andean zones in Chile.

Arsenic is the most important contaminant of the environment in northern Chile. Soil samples and plant organs from three native plant species, Pluchea absinthioides, Atriplex atacamensis and Lupinus microcarpus, were collected from arid zones in order to determine the total and bioavailable arsenic concentrations in soils and to assess the bioconcentration factor (BCF) and transport index (Ti) of arsenic in the plants. Total arsenic concentrations in soils (pH 8.3-8.5) where A. atacamensis and P. absinthioides were collected, reached levels considered to be contaminated (54.3 ± 15.4 and 52.9 ± 9.9 mg kg⁻¹, respectively), and these values were approximately ten times higher than in soils (pH 7.6) where L. microcarpus was collected. Bioavailable arsenic ranged from 0.18 to 0.42% of total arsenic concentration. In the three plant species, arsenic concentration in leaves were significantly (p ≤ 0.05) higher than in roots. L. microcarpus showed the highest arsenic concentration in its leaves (9.7 ± 1.6 mg kg⁻¹) and higher values of BCF (1.8) and Ti (6.1), indicating that this species has a greater capacity to accumulate and translocate the metalloid to the leaf than do the other species.

Chemical characterization and evaluation of composts as organic amendments for immobilizing cadmium.

The ability of three composted materials to immobilize cadmium (Cd) was examined in order to assess their potential for recovering soils contaminated with this metal. Composted pine bark (PB) pH 5.6, spent mushroom compost (SM) pH 8.0, and composted pruning waste+biosolids (BS) pH 6.9 (containing 81%, 75% and 47% total organic matter, respectively) were characterized. FT-IR and CP-MAS (13)C NMR spectroscopy indicated the BS and SM to have a higher percentage of aliphatic and carboxyl groups than PB. The composts were artificially contaminated with Cd (80 and 200 mg kg(-1)) and, after 4 weeks incubation, subjected to sequential extraction. In column leaching experiments, the total Cd leached from the composts exposed to both Cd treatments was similar, but much less leached from the BS (0.2%) than the PB (4.0%) or SM (0.7%). The greater capacity of BS to immobilize Cd was attributed to the greater humification of its organic matter and higher content of inorganic components, particularly Fe.

Micropropagación y determinación cromosómica del género Croton Productores de látex / Micropropagation and chromosomal determination of the latex producing gender Croton

El presente trabajo de investigación tuvo como objetivos: determinar las diferencias en el desarrollo in vitro de yemas provenientes de plantas juveniles de Croton productores de látex; evaluar la respuesta a la aclimatación de plántulas Croton de mejor comportamiento in vitro y determinar el número cromosómico de individuos seleccionados del género Croton productores de látex. El medio de cultivo para la introducción in vitro fue determinado evaluando el comportamiento de Croton draconoides en cinco tratamientos cuyo medio básico fue el de Murashige y Skoog (MS) tomando en consideración que las especies en estudio pertenecen al mismo género. Las yemas provenientes de plantas juveniles de Croton productor de látex color vino fueron las que mejor comportamiento tuvieron en el medio de cultivo seleccionado (MS + 0,01mg/l de ANA + 0,1 mg/l de BAP y AG3 + 20 ml de agua de coco), presentando mayor altura, número de hojas y porcentaje de sobrevivencia en relación a Croton productor de látex color rojo y ocre. Las plántulas de Croton productor de látex color vino, previamente enraizadas in vitro, fueron llevadas a aclimatación, probando cuatro substratos, determinándose que las respuestas de las plántulas varían de acuerdo a la composición del sustrato, las condiciones de riego (nebulización), el control de hongos (benlate al 0.1%) y la aplicación del bioestimulante biogen 1 al 0,1%. El número cromosómico determinado en las plantas del género Croton productoras de látex rojo, vino y ocre fue de 40.

The present investigation had the purpose of: determining the differences in the in vitro development of buds from Croton young plants of latex producers; to evaluate the response to the acclimatization of Croton’s plantulas with better behavior in vitro, and to determine the chromosomal number of selected individuals of Croton latex producers. The culture medium for the in vitro introduction was determined evaluating the behavior of Croton draconoides in five treatments with the basic medium murashige and skoog (ms) taking into consideration that the species in the study belong to the same gender. The buds coming from Croton young plants producers of wine latex had the best behavior in the selected culture medium (ms + 0,01mg/I ANA + 0,1mg/I of BAP and AG3 + 20 ml of coconut water) presenting an increase in height, number of leaves and percentage of survival in relationship to Croton producers of red and ocher latex. The plantulas of Croton producers of wine latex, previously rooted in vitro, were taken for acclimatization. Four substrates were tested, determining that the response of the plantulas changes according to the substrate composition, watering conditions (nebulization), fungus control (benlate to 0,1%) and the application of the bioestimulant biogen 1 to 0,1%. The chromosomal number determined in plants of the gender Croton producers of red, wine and ocher latex was of 40.

Comparación de la eficacia en el alivio de dolor neuropático crónico agudizado con oxicodona más lidocaína intravenosas frente a tramadol más lidocaína intravenosas / Comparison of the effi cacy of oxycodone plus lidocaine versus tramadol plus lidocaine in continuous infusion in relieving acute neuropathic pain

Objetivo: Se evaluó la eficacia de oxicodona más lidocaína en comparación con tramadol más lidocaína por vía intravenosa en el alivio del dolor neuropático crónico agudizado. Material y métodos: Previa aprobación por el comité de ética del Hospital General de México (núm. DIC/08/203/03/070) se realizó, en la Clínica del Dolor y Cuidados Paliativos, un ensayo clínico controlado de tipo experimental, prospectivo, comparativo, longitudinal y aleatorizado, que incluyó a 27 pacientes con diagnóstico de dolor espontáneo de tipo neuropático crónico agudizado, moderado a severo, de cualquier etiología, al menos 1 mes de evolución con escala visual analógica (EVA) >= 4, sin criterios de exclusión, los cuales se distribuyeron en 2 grupos: grupo de estudio u oxicodona (10 mg) más lidocaína (3 mg/kg) en perfusión continua (n = 14), y grupo control o tramadol (100 mg) más lidocaína (3 mg/kg) en perfusión continua (n = 13). Se evaluaron las variables demográficas, características del dolor, categoría diagnostica, EVA para dolor espontáneo, alodinia táctil, alodinia al frío e hiperalgesia, así como grado de sedación, efectos secundarios, satisfacción a tratamiento y parámetros cardiovasculares. El análisis estadístico se llevó a cabo por medio de la prueba de X2 y U de Mann-Whitney a través del programa SPSS versión 11. Resultados: Se observaron cambios significativos (p < 0,05) en los pacientes manejados con oxicodona más lidocaína en perfusión continua con relación a dolor espontáneo en los momentos 7 y 8 del estudio, así como cambios en las cifras de presión arterial diastólica únicamente en el momento 8 (p < 0,001). No se reportaron cambios notables en el nivel de sedación de los pacientes, incidencia de efectos secundarios y satisfacción con el tratamiento. No se observaron cambios considerables en las variables de frecuencia cardíaca y presión arterial sistólica en ambos grupos durante las fases del estudio realizado (p > 0,05)...(AU)

Objective: We evaluated the efficiency of oxycodone plus lidocaine in comparison with tramadol plus lidocaine in continuous infusion in relieving acute neuropathic pain. Material and methods: Approval was granted by the local ethics committee of the General Hospital of Mexico (Num DIC/08/203/03/070) to perform a prospective, longitudinal, randomized, experimental clinical trial at the pain clinic and palliative care center. Twenty-seven patients with a diagnosis of moderate-to-severe spontaneous acuteneuropathic pain of any cause with onset at least 1 month previously, visual analogue scale of four or more, and no exclusion criteria were distributed in two groups: a study group (n = 14) which received oxycodone (10 mg) plus lidocaine (3 mg per kg) in continuous infusion and a control group (n = 13) which received tramadol (100 mg) plus lidocaine (3mg per kg) in continuous infusion. Demographic variables, pain characteristics, diagnostic category, visual analogue scale for spontaneous pain, tactile allodynia, cold allodynia and hyperalgesia, level of sedation, adverse effects, treatment satisfaction and cardiovascular parameters were evaluated. The statistical analysis was performed with the Chi-squared test and the Mann-Whitney U-test using the SPSS version 11 statistical package. Results: The group treated with continuous infusion of oxycodone plus lidocaine showed significant changes in spontaneous pain at phases 7 and 8 of the study (p < 0.05). Significant changes were also found in diastolic blood pressure at phase 8 (p < 0.001). No significant changes were found in the level of sedation, the incidence of adverse effects or treatment satisfaction. No significant changes were found in heart rate or blood pressure in either of the two groups during the distinct study phases (p > 0.05)...(AU)

Urban infestation by Triatoma dimidiata in the city of Mérida, Yucatán, México.

The observation of widespread seasonal infestation by Triatoma dimidiata in rural villages around the city of Mérida, Yucatán, México, led us to reconsider the presence of Chagas disease vectors and the risk factors for house infestation in the city itself. Bugs were collected in 150 houses from 30 neighborhoods distributed throughout the city. We observed a widespread infestation by T. dimidiata in the city, with 38% of infested houses and 48% of the collected triatomines testing positive for Trypanosoma cruzi. House infestation by triatomines was greatest during the months of April-June. Infestation risk factors were related with backyard characteristics rather than housing type and quality of housing: houses located in the periphery of the city, with abandoned lots on the sides and large backyards, had a higher risk of being infested, while those with mosquito screens and occasional insecticide spraying in their yards had a lower risk. Several human blood meals were also identified and seropositive patients were distributed through most of the city, confirming the potential for urban transmission of Chagas disease to humans. This study shows that urban Chagas disease should not be neglected and surveillance programs should be implemented to further evaluate the magnitude of the problem.

Predominance of the multiresistant 23F international clone of Streptococcus pneumoniae among isolates from Mexico.

During a surveillance study to determine the relative prevalence of capsular types of Streptococcus pneumoniae and antimicrobial susceptibility of invasive isolates in children <5 years old in Mexico City, 220 isolates were collected. The serotype 23F was the most common found, followed by types 6A + B, 14, 19F, and 19A. Diminished susceptibility to penicillin was detected in 106 isolates (48.2%), and high penicillin resistance was found in 49 strains (22.2%), 31 belonging to type 23F. Resistance was also observed to erythromycin (13.1%), to chloramphenicol (43.1%), and to cefotaxime (10.9%). No strains were resistant to ofloxacin or vancomycin. Forty-four of the highly penicillin resistant isolates (penicillin MIC > or =2.0 microg/ml) were examined with molecular fingerprinting techniques; 29 (65.9%) of these isolates (all except two strains) were serotype 23F and shared subtype variants of PFGE type A characteristic of the internationally spread Spanish/USA clone of S. pneumoniae. These strains were also resistant to trimethoprim/sulfametoxasole (TMP/SMX), chloramphenicol, and tetracycline, and most of them were susceptible to erythromycin. Another 6 of the highly penicillin-resistant strains (serogroups 9 and 14) showed PFGE fingerprints and antimicrobial susceptibility pattern characteristic of a second internationally spread clone (French/Spanish clone) and carried resistance to penicillin and TMP/SMX. The rest of the 9 penicillin-resistant isolates were represented by 7 distinct additional PFGE types. The findings suggest that almost 80% of all highly penicillin resistant strains may have been "imported" into Mexico.