Method development and validation for the simultaneous determination of organochlorine and organophosphorus pesticides in a complex sediment matrix.

The Xochimilco area in the southeastern part of Mexico City has a variety of socioeconomic activities, such as periurban agriculture, which is of great importance in the Mexico City metropolitan area. Pesticides are used extensively, some being legal, mostly chlorpyrifos and malathion, and some illegal, mostly DDT. Sediments are a common sink for pesticides in aquatic systems near agricultural areas, and Xochimilco sediments have a complex composition with high contents of organic matter and clay that are ideal adsorption sites for organochlorine (OC) and organophosphorus (OP) pesticides. Therefore, it is important to have a quick, affordable, and reliable method to determine these pesticides. Conventional methods for the determination of OC and OP pesticides are long, laborious, and costly owing to the high volume of solvents and adsorbents. The present study developed and validated a method for determining 18 OC and five OP pesticides in sediments with high organic and clay contents. In contrast with other methods described in the literature, this method allows isolation of the 23 pesticides with a 12 min microwave-assisted extraction (MAE) and one-step cleanup of pesticides. The method developed is a simpler, time-saving procedure that uses only 3.5 g of dry sediment. The use of MAE eliminates excessive handling and the possible loss of analytes. It was shown that the use of LC-Si cartridges with hexane-ethyl acetate (75+25, v/v) in the cleanup procedure recovered all pesticides with rates between 70 and 120%. The validation parameters demonstrated good performance of the method, with intermediate precision ranging from 7.3 to 17.0%, HorRat indexes all below 0.5, and tests of accuracy with the 23 pesticides at three concentration levels demonstrating recoveries ranging from 74 to 114% and RSDs from 3.3 to 12.7%.

Presence of polycyclic aromatic hydrocarbons (PAHs) in top soils from rural terrains in Mexico City.

A soil survey was carried out to determine the levels and sources and concentrations of 16 polycyclic aromatic hydrocarbons in 2 semi-rural terrains in Mexico City (Tlahuac and Milpa Alta) during 2008-2009. PAH determination was made by Soxhlet extraction and chromatographic clean-up with final analysis by gas chromatography with a flame ionization detector. The concentrations in Tlahuac were 9.13 mg/kg (dry season) and 11.22 mg/kg (wet season) and in Milpa Alta were 11.43 mg/kg (dry season) and 35.77 mg/kg (wet season). The variation of total PAH concentrations are due to environmental and anthropogenic conditions within Mexico City and also the addition of compost to the soils. According to Mexican regulations BaP, DaA, BbF and Ind were within the permissible limit (2 mg/kg) for agricultural and residential soils and BkF was close to the limit (8 mg/kg). The total PAH concentrations do however surpass the permissible European limit of 1,000 µg/kg and there is probably some risk to human health, in spite of measures aimed at decreasing contamination in Mexico City. Long term monitoring of soils will be necessary.

The removal of microorganisms and organic micropollutants from wastewater during infiltration to aquifers after irrigation of farmland in the Tula Valley, Mexico.

The Tula Valley receives untreated wastewater from Mexico City for agricultural irrigation, half of which infiltrates to aquifers from where drinking water is extracted. Samples of wastewater and infiltrated water from three areas of the valley were analyzed for microorganisms, organic micropollutants, and some basic parameters. Concentrations of microorganisms in the infiltrated water were generally very low but the incidence of fecal coliforms (present in 68% of samples), somatic bacteriophages (36%), Giardia spp. (14%), and helminth eggs (8%) suggested a health risk. Organic micropollutants, often present at high concentrations in the wastewater, were generally absent from the infiltrated water except carbamazepine which was in 55% of samples (up to 193 ng/L). There was no correlation between carbamazepine concentrations and the presence of microorganisms but highest concentrations of carbamazepine and boron coincided. A treatment such as nanofiltration would be necessary for the infiltrated water to be a safe potable supply.

Accumulation and leaching potential of some pharmaceuticals and potential endocrine disruptors in soils irrigated with wastewater in the Tula Valley, Mexico.

The reuse of wastewater for irrigation of agricultural land is a well established practice but introduces many contaminants into the terrestrial environment including pharmaceuticals and personal care products. This study reports the persistence and leaching potential of a group of acidic pharmaceuticals, carbamazepine, and three endocrine disruptors in soils from the Tula Valley in Mexico, one of the largest irrigation districts in the world that uses untreated wastewater. After irrigation of soil columns with fortified wastewater over the equivalent of one crop cycle, between 0% and 7% of the total added amounts of ibuprofen, naproxen, and diclofenac and between 0% and 25% of 4-nonylphenol, triclosan, and bisphenol-A were recovered from the soil profiles. Carbamazepine was more persistent, between 55% and 107% being recovered. Amounts in leachates suggested that movement through the soil was possible for all of the analytes, particularly in profiles of low organic matter and clay content. Analysis of soil samples from the Tula Valley confirmed the general lack of accumulation of the acidic pharmaceuticals (concentrations from below the limit of detection to 0.61 µgkg(-1)) and endocrine disruptors (concentrations from below the limit of detection to 109 µgkg(-1)) despite continual addition through regular irrigation with untreated wastewater; there was little evidence of movement through the soil profiles. In contrast, carbamazepine was present in horizon A of the soil at concentrations equivalent to several years of additions by irrigation (2.6-7.5 µgkg(-1)) and was also present in the deeper horizons. The persistence and mobility of carbamazepine suggested a potential to contaminate groundwater.

The analysis of a group of acidic pharmaceuticals, carbamazepine, and potential endocrine disrupting compounds in wastewater irrigated soils by gas chromatography-mass spectrometry.

The analysis of pharmaceuticals and potential endocrine disruptors in the environment has rightly concentrated on their presence in wastewaters and possible contamination of receiving bodies, such as groundwaters. However, wastewater is increasingly being reused for irrigation and in order to fully understand the environmental fate of these compounds, reliable methods for their analysis in soil are required, of which there are relatively few available. This article reports a method for a range of acidic pharmaceuticals, carbamazepine, and endocrine disrupting compounds in soils with final analysis by gas chromatography-mass spectrometry. Two soil types (Phaeozom and Leptosol) and three fortification levels were used to validate the method. Recoveries of acidic pharmaceuticals varied between 62 and 102%, carbamazepine from 75 to 118%, and potential endocrine disruptors between 54 and 109%; most recoveries were between 75 and 95% and relative standard deviations were generally less than 10%. Detection limits were between 0.25 and 2.5 ng/g except for phthalates and 4-nonylphenols (25 ng/g). The method was used to analyze soils where untreated wastewaters have been used to irrigate crops for approximately 90 years. Concentrations of acidic pharmaceuticals in the soil were <1 ng/g and potential endocrine disruptors varied from below the limit of detection (estrone, 17beta-estradiol, and 17alpha-ethinylestradiol) to 2079 ng/L (bis-diethylhexyl phthalate). This data indicated that despite the continuous application of the contaminants over many years, concentrations were generally lower than those expected to be contributed by a single irrigation event. Only carbamazepine, at concentrations of 6.48 ng/g (in Phaeozem) and 5.14 ng/g (in Leptosol), showed any evidence of persistence in the soils analyzed.

Determination of acidic pharmaceuticals and potential endocrine disrupting compounds in wastewaters and spring waters by selective elution and analysis by gas chromatography-mass spectrometry.

Although the trend in development of analytical methods for emerging contaminants is towards reduced sample preparation and increased detector selectivity, there are still benefits from removal of matrix material during sample preparation. This paper describes a simple method for acidic pharmaceuticals and a range of potential endocrine disrupting compounds in untreated wastewaters and spring waters. It is based on separation of the two classes during elution from the extraction cartridge with final analysis by gas chromatography-mass spectrometry. 3,4-D was used as the recovery standard for the acids while 4-n-nonylphenol and [2H4]estrone were used for the endocrine disrupters; mean recoveries varied between 89% and 111%. The method was also extensively validated by fortification with the target compounds. Recoveries of acids were from 68% to 97% with relative standard deviations generally less than 10% and recoveries of endocrine disrupters were 68-109% with relative standard deviations less than 20%. Detection limits varied from 0.005 to 1 ng/L in spring water, and from 0.5 to 100 ng/L in untreated wastewater. Concentrations of the analytes in the wastewater ranged from 0.018 to 22.4 microg/L. Values were comparable to reported data, although concentrations were generally relatively high, probably because of a lack of treatment. Triclosan, phthalates, estrone, 17beta-estradiol, ibuprofen, and naproxen were present in the spring water from aquifers recharged indirectly with this wastewater after its use for irrigation; concentrations ranged from 0.01 to 25.0 ng/L. The much lower concentrations compared to wastewater indicate effective removal processes on passage through the soil and subsoil.

Impact of drying and composting procedures on the concentrations of 4-nonylphenols, di-(2-ethylhexyl)phthalate and polychlorinated biphenyls in anaerobically digested sewage sludge.

Enhanced treatments of sewage sludge produce a more manageable product for agricultural use by stabilizing the material, removing water, and reducing the possibility of pathogen transfer. We investigated the impact of pilot-scale composting and drying of sludge on physicochemical characteristics and on the concentrations of some organic contaminants. During the 143 day composting procedure, organic matter fell 22% and moisture by half. Concentrations of 4-nonylphenols (4-NPs) fell by 88% and di-(2-ethylhexyl) phthalate (DEHP) by 60%; losses continued throughout the procedure. Losses of total polychlorinated biphenyls (PCBs) were 11%, mostly from the lower molecular weight congeners, suggesting volatilization as the most likely loss mechanism. The drying process was much shorter, 40 days, yet organic matter content decreased by 27% and moisture by 85%. Losses of 4-NPs (39%) and DEHP (22%) were less than in composting and stopped when moisture content became constant. There were no losses of PCBs. Both treatments are simple, practical procedures that reduce the volume of waste and are applicable in situ on farms. Composting would be the method of choice for reducing organic contaminants but requires much longer times than drying.

Fístula arterio-arterial sistémico-pulmonar: presentación de un caso clínico / Systemic pulmonary arterio-arterial fistula: presentation of a clinical case

Reportamos el caso de una escolar femenina, 9 años, con hallazgo de fístula arterio-arterial sistémico-pulmonar. Como trayecto anómalo comunica la aorta descendente con la rama izquierda de la arteria pulmonar. Se trata de una malformación congénita aislada con una expresión clínica dada por la auscultación de un soplo continuo de acentuación sistólica en el área infraclavicular izquierda. Signos electrocardiográficos de sobrecarga diastólica del ventrículo izquierdo. El Doppler continuo demuestra un flujo turbulento sisto-diastólico en la rama pulmonar; dilatación de cavidades izquierdas con el ecocardiograma-bidimensional. Las radiografias torácicas muestran una sombra de aspecto hídrico paracardíaca izquierda con crecimiento hemicardio izquierdo. La cineangio reveló la emergencia del ramo anómalo, tortuoso y dilatado en sus extremos desde la aorta torácica, sin aspecto aneurismático. Paciente prácticamente asintomática salvo los hallazgos ya mencionados. Como opción terapéutica se plantea la ligadura y sección de la porción medial del trayecto vascular aberrante. Se analizan las diferencias con las fístulas arterio-venosas pulmonares

Fenómeno de Raynaud como manifestación primaria de Mixona auricular izquierdo / Raynaud syndrome as primary manifestation of left atril mixoma

Se describe el caso de un escolar de 8 años de edad, varón, en quien se diagnóstica tumor cardiaco (Mixoma), el cual se manifiesta simulando enfermedad del tejido conectivo fenómeno de Raynaud. Además el paciente presenta trastornos del metabolismo de los lípidos, lo que nos permitió ubicarlo en el grupo II A de Fredickson y Levy. El propósito de la presente comunicación es describir una forma excepcional de presentación

Fiebre reumática / Rheumatic fever

Los autores hacen una actualización de la fiebrereumática en cuanto a definición, epidemiología, clínica y tratamiento, orientada hacia el pediátra general que enfrenta estos casos. En nuestro medio la fiebre reumática es la primera causa de cardiopatía adquirida en niños. Se hace énfasis en la necesidad de demostrar la presencia de infección streptococcica (streptococo Beta Hemolítico grupo A), para asegurar la existencia de la enfermedad. Se exponen en forma resumida las bases del tratamiento antiinflamatorio y de prevención de lafiebre reumática

Un nuevo enfoque del proceso de enfermería: aplicado en el Síndrome de Kawasaki / The new approach of the nursing process: applicated on Kawasaki Syndrome

El Síndrome de Kawasaki o Síndrome Linfomucocutáneo, es una enfermedad multisistémica de etiología desconocida. Se presenta de forma aguda, con un cuadro de hipertensión resistente a los antipiréticos, asociada a una conjuntivitis no purulenta, inflamación de las mucosas, descamación de las manos y los pies, linfadenitis cervical, eritema generalizado y una posible afección de las arterias coronarias. Afecta generalmente a niños, en su mayoría menores de 5 años, representando una de las principales causas de mortalidad de las cardiopatias infantiles adquiridas. Este trabajo tiene por objeto presentar la aplicación del Proceso de Efermería an la atención de estos pacientes mediante un nuevo modelo que incluye, no sólo la valoración y documentación, sino también el monitoreo de los signos y síntomas a través de la previsión o anticipación de éstos madiante el conocimiento de la evolución de la enfermedad y las posibles complicaciones que se puedan presentar. Actualmente se esta realizando una revisión de la casuística presentada entre los años de 1982 a 1989 en el Centro Médico Docente La Trinidad y el Hospital J.M. de Los Ríos. El cuadro de casos presentado en el trabajo sólo representa una muestra didáctica sin conclusiones con fines estadísticos