RESUMEN
This study was developed to evaluate the removal potential of ibuprofen, naproxen and 17-ß-estradiol in artificial wetlands constructed on a laboratory scale, using eight experimental devices planted with L. octovalvis species, tested with gravel substrate and without gravel substrate, which were fortified with synthetic mixtures at concentrations of 1, 2 and 5 mg/L of the three compounds, during a batch exposure time of nine days. The removal efficiency for 17-ß-estradiol was 94.5 ± 2.47%, followed by ibuprofen 94.03 ± 1.96% and naproxen 81.57 ± 8.74%, respectively. The treatment with the highest removal was the one performed without the presence of gravel substrate. The highest removal efficiency occurred from the third day of exposure for the three compounds, so it was established as the optimum residence time. The model that best explained the adsorption process of the three compounds studied, was the Langmuir isotherm. The observed results demonstrate that L. octovalvis can be used as a native species in artificial wetlands for the efficient removal of pharmaceutical compounds.
Through the use of a macrophyte plant native to the state of Morelos, an artificial wetland was built, which was capable of removing several drugs with tolerance to changes in concentration, which constitutes an economic and sustainable alternative that can be coupled to the treatment of wastewater contaminated with this type of compounds.
RESUMEN
Ambient PM2.5 samples were taken at 24 h intervals at two sites (Centro and Miravalle) in the city of Guadalajara from January to June 2008. The Centro site is located in the downtown, while the Miravalle site is located in an industrial zone south of the downtown. For both sites the higher concentrations of PM2.5 were between January and May. High correlation coefficients between sulfate, nitrate and ammonium of 0.95, 0.92 and 0.91, respectively, showed low variations in the concentrations of these species in the city. It was estimated that sulfate, nitrate and ammonium represented almost 47% of the PM2.5 mass in June at the Centro site, but in general the contributions in the other months were less than 21%, while at Miravalle this percentage was between 7.7% and 27.6%.
Asunto(s)
Contaminantes Atmosféricos/análisis , Material Particulado/análisis , Estaciones del Año , Aniones/análisis , Cationes/análisis , Monitoreo del Ambiente , México , Tamaño de la PartículaRESUMEN
With the aim to determine the presence of individual nitro-PAH contained in particles in the atmosphere of Mexico City, a monitoring campaign for particulate matter (PM(10) and PM(2.5)) was carried out in Northern Mexico City, from April 2006 to February 2007. The PM(10) annual median concentration was 65.2µgm(-3) associated to 7.6µgm(-3) of solvent-extractable organic matter (SEOM) corresponding to 11.4% of the PM(10) concentration and 38.6µgm(-3) with 5.9µgm(-3) SEOM corresponding to 15.2% for PM(2.5). PM concentration and SEOM varied with the season and the particle size. The quantification of nitro-polycyclic aromatic hydrocarbons (nitro-PAH) was developed through the standards addition method under two schemes: reference standard with and without matrix, the former giving the best results. The recovery percentages varied with the extraction method within the 52 to 97% range depending on each nitro-PAH. The determination of the latter was effected with and without sample purification, also termed fractioning, giving similar results. 8 nitro-PAH were quantified, and their sum ranged from 111 to 819pgm(-3) for PM(10) and from 58 to 383pgm(-3) for PM(2.5), depending on the season. The greatest concentration was for 9-Nitroanthracene in PM(10) and PM(2.5), detected during the cold-dry season, with a median (10th-90th percentiles) concentration in 235pgm(-3) (66-449pgm(-3)) for PM(10) and 73pgm(-3) (18-117pgm(-3)) for PM(2.5). The correlation among mass concentrations of the nitro-PAH and criteria pollutants was statistically significant for some nitro-PAH with PM(10), SEOM in PM(10), SEOM in PM(2.5), NO(X), NO(2) and CO, suggesting either sources, primary or secondary origin. The measured concentrations of nitro-PAH were higher than those reported in other countries, but lower than those from Chinese cities. Knowledge of nitro-PAH atmospheric concentrations can aid during the surveillance of diseases (cardiovascular and cancer risk) associated with these exposures.