RESUMEN
A molecularly imprinted polymer was developed and evaluated for selective determination of metronidazole (MNZ) in wastewater. This was achieved by using sodium methacrylate as monomer, toluene as porogen, ethylene glycol dimethacrylate as crosslinker, azobisisobutyronitrile as initiator and metronidazole as template molecule to generate the selectivity of the polymer for the compound, as well as non-imprinted polymers were synthesized. Two different polymerization approaches were used, bulk and emulsion and the polymers obtained by emulsion presented higher retention percentages the MIP 2-M presented the higher retention (83%). The performed method, was validated in fortified water, showing linearity from 10 up to 1000 ng/mL; limit of detection and quantification for compound were between 3 and 10 ng/mL, respectively. Finally, the method was applied in samples of a wastewater treatment plant in the city of San Luis Potosí, México, and the concentrations of MNZ in these samples were 84.1-114 ng/mL.
Asunto(s)
Metronidazol/análisis , Impresión Molecular/métodos , Ácidos Polimetacrílicos/síntesis química , Aguas Residuales/química , Contaminantes Químicos del Agua/análisis , Adsorción , Límite de Detección , Metacrilatos/química , México , Nitrilos/química , Ácidos Polimetacrílicos/química , Propiedades de Superficie , Tolueno/químicaRESUMEN
A simple and rapid focused ultrasound extraction method was developed for the determination of Persistent Organic Pollutants (POPs) in liver tissue obtained of giant toad (Rhinella marina) using a gas chromatography coupled to a mass detector with electron impact ionization. The performed method for POPs, was validated in fortified matrix, showing linearity from the LOQ up to 100 ng/mL; LODs and LOQs for each compound were between 1.7 and 4.8 and 3.5-7.5 ng/mL, respectively. Recovery rates were among 79%-116% for POPs determined. Finally, the method was applied in liver samples of giant toads found in a malarial area in Mexico. The sensitivity of the proposed method was good enough to ensure reliable determination of target analytes at concentration levels commonly found in this kind of samples.
Asunto(s)
Bufo marinus/metabolismo , Contaminantes Ambientales/metabolismo , Animales , Contaminación Ambiental , Cromatografía de Gases y Espectrometría de Masas , Límite de Detección , Hígado/metabolismo , MéxicoRESUMEN
The aim of this study was to conduct a POP biomonitoring programme for children in high-risk areas. We evaluated 247 serum samples from children between the ages of 6 and 12years old from two zones in Mexico: (1) indigenous zones, which included Cuatlamayan (CUA), Tocoy (TOC), and Santa Maria Picula (SAM); and (2) industrial zones, which included Tercera Chica (TC), Industrial San Luis (IND) and Rincon de San Jose (SJR); Mundo Nuevo (MN); and Alpuyeca (ALP). Our results showed that α-endosulfan was similar to CUA, TOC, SAM, TC and MN (178.6-306.9ng/g lipid). ß-Endosulfan levels were higher in ALP (901.5ng/g lipid), followed by CUA (139.9ng/g lipid) and TOC, SAM, TC and MN, which had similar levels (55.4-64.5ng/g lipid). For endosulfan sulfate, the ALP community had the highest concentration levels (1096.4ng/g lipid), whereas CUA and TOC (212.3 and 289ng/g lipid, respectively) had concentrations similar to those found in SAM and TC (99.5 and 119.1ng/g lipid, respectively). DDE levels were found in malaria-endemic areas of SAM, CUA and TOC (1782.2, 1358.3 and 57.0ng/g lipid), followed by MN (35.1ng/g lipid). HCB concentration levels were found to be higher in MN and SJR (691.8 and 575.4ng/g lipid, respectively), followed by CUA and TC (363.9 and 269.1ng/g lipid, respectively), with levels similar to those found in TOC and SAM (191.8 and 181.9ng/g lipid, respectively). Finally, PCB 101 concentration levels were found to be the highest in ALP (1032.7ng/g lipid), followed by similar levels of SJR and IND (567.5 and 327.3ng/g lipid, respectively) and TC and MN, with 109.1 and 144.5ng/g lipid, respectively. The evidence provided by this exploratory study indicates that the evaluation of the health risks posed to children living in contaminated areas is a high priority health issue.
Asunto(s)
Exposición a Riesgos Ambientales/estadística & datos numéricos , Contaminantes Ambientales/metabolismo , Compuestos Orgánicos/metabolismo , Niño , Preescolar , Diclorodifenil Dicloroetileno/metabolismo , Endosulfano/metabolismo , Exposición a Riesgos Ambientales/análisis , Monitoreo del Ambiente , Femenino , Sitios de Residuos Peligrosos , Humanos , Masculino , México , Bifenilos Policlorados/metabolismoRESUMEN
The aim of the present work was to complete an exposure assessment in three Mexican indigenous communities using the community-based health risk assessment, which is the first step in the CHILD framework. We used 1-hydroxypyrene (1-OHP) as an exposure biomarker to polycyclic aromatic hydrocarbons (PAHs) and trans, trans-muconic acid (t,t-MA) as an exposure biomarker to benzene, persistent organic pollutants (POPs), lead, manganese, arsenic, and fluoride. Anthropometric measurements were also taken. In these communities, high percentages of children with chronic malnutrition were found (28 to 49 %) based on their weight and age. All communities showed a high percentage of children with detectable levels of four or more compounds (70 to 82 %). Additionally, our results showed that in indigenous communities, children are exposed to elevated levels of certain environmental pollutants, including manganese with 17.6, 16.8, and 7.3 µg/L from SMP, TOC, and CUA, respectively. Lead and HCB levels were similar in the indigenous communities (2.5, 3.1, and 4.2 µg/dL and 2.5, 3.1, and 3.7 ng/mL, respectively). 1-OHP and t,t-MA levels were higher in TOC (0.8 µmol/mol of creatinine, 476 µg/g of creatinine, respectively) when compared with SMP (0.1 µmol/mol of creatinine, 215.5 µg/g of creatinine, respectively) and CUA (0.1 µmol/mol of creatinine, 185.2 µg/g of creatinine, respectively). DDE levels were 30.7, 26.9, and 9.6 ng/mL in CUA, SMP, and TOC, respectively. The strength of this study is that it assesses exposure to pollutants with indications for the resultant risk before an intervention is made by the CHILD program to manage this risk in the indigenous communities. Considering the large number of people, especially children, exposed to multiple pollutants, it is important to design effective intervention programs that reduce exposure and the resultant risk in the numerous indigenous communities in Mexico.
Asunto(s)
Exposición a Riesgos Ambientales/estadística & datos numéricos , Contaminantes Ambientales/metabolismo , Pirenos/metabolismo , Arsénico/metabolismo , Benceno/metabolismo , Biomarcadores/metabolismo , Niño , Preescolar , Creatinina , Exposición a Riesgos Ambientales/análisis , Contaminantes Ambientales/análisis , Femenino , Humanos , Masculino , México , Hidrocarburos Policíclicos Aromáticos/metabolismo , Medición de Riesgo , Ácido Sórbico/análogos & derivados , Ácido Sórbico/metabolismoRESUMEN
A simple and rapid focused ultrasound extraction (FU) based method is presented for the determination of persistent organic pollutants (POPs) in soil using a gas chromatography coupled to a mass detector with electron impact ionization. The main experimental parameters affecting the FU step have been optimized by applying a PERMANOVA and PCO analysis allowing us to obtain a maximum amount of information with a minimum number of assays. The limits of detection for POPs fell within the 0.9-6.8 ng/g d.w. interval; a linear method was used with correlation coefficients (r) higher than 0.99. Recovery percentages at low concentrations (25 ng/g d.w.) were 75.8%-110%, and at high concentrations (75 ng/g d.w.) 82.3%-109%; the evaluated precision as RSD% of repeatability and reproducibility were within a range of 0.5%-11% and 0.3%-18%, respectively.
Asunto(s)
Contaminantes del Suelo/análisis , Cromatografía de Gases/métodos , Reproducibilidad de los Resultados , UltrasonidoRESUMEN
A simple and rapid headspace solid-phase microextraction (HS SPME) based method is presented for the determination of Persistent Organic Pollutants (POPs) in human serum by gas chromatography (GC) coupled to mass detector (MS) with electron impact ionization (EI). As an outcome of the assessment of several polymer phases; the one with the best result was the PDMS fiber (100 µm). A multivariate analysis of variance by permutations (PERMANOVA) was performed to establish the optimal extraction conditions as a function of temperature and time variables. The results were 1 mL serum+200 µL H2SO4 9M+1 mL of deionized water at 600 rpm with a temperature of 80°C for 50 min to expose the fiber. The limits of detection (LOD) for POPs pesticides fell within the 0.22-5.41 ng/mL interval, and within 0.07-1.79 ng/mL for PCBs; a linear method was used with correlation coefficients (r) higher than 0.99. Recovery percentages at low concentrations (15 ng/mL) were 67.8-120.2%, and at high concentrations (75 ng/mL) 80.2-119.2%. Evaluated precision as percentage Relative Standard Deviation (RSD%) of repeatability and reproducibility was within a range of 0.5-9% and 0.3-21%, respectively. This analytical method prevents some of the main problems for quantifying POPs in human serum, such as the elimination of the solvents, sample handling, integration of extraction steps, pre-concentration and introduction of samples; consequently, the time and cost of analyzing the sample can be significantly reduced. The method developed was applied to determine exposure to POPs in samples of children living in different polluted sites in Mexico. In children living in indigenous communities results show exposure to DDE (median 29.2 ng/mL range 17.4-52.2 ng/mL) and HCB (median 2.53 ng/mL range 2.50-2.64 ng/mL); whereas in the industrial scenario, exposure to HCB (median 2.81 ng/mL range 2.61-3.4 ng/mL) and PCBs (median Σ-PCBs 22.2 ng/ml range 8.2-74.6 ng/mL) and finally in petrochemical scenario was demonstrated exposure to HCB (median 2.81 ng/mL range 2.61-3.4 ng/mL) and PCBs (Σ-PCBs median 7.9 ng/mL range 5.4-114.5 ng/mL).
Asunto(s)
Contaminantes Ambientales/análisis , Cromatografía de Gases y Espectrometría de Masas/métodos , Plaguicidas/análisis , Microextracción en Fase Sólida/métodos , Niño , Monitoreo del Ambiente/métodos , Contaminantes Ambientales/sangre , Humanos , Análisis Multivariante , Compuestos Orgánicos/análisis , Compuestos Orgánicos/sangre , Plaguicidas/sangre , Bifenilos Policlorados/análisis , Reproducibilidad de los Resultados , Factores de TiempoRESUMEN
The aim of this study was to develop a methodology for identifying and quantifying Fipronil and its degradation products in soil by gas chromatography-electron capture detector previously extracted using a focused ultrasound probe. This methodology was obtaining a range of recovery between 85% and 120%, decreasing approximately solvent used time and cost, respect to other methodologies such as bath ultrasonic, solid-phase extraction, liquid-liquid extraction and soxhlet. The method was validated in fortified matrix, presented linearity in the range of 25-400 µg kg(-1), and limit of detection for Fipronil and their products desulfinyl, sulfide and sulfone was 14.7, 9.8, 8.9 and 10.7 µg kg(-1), respectively. This process was applied to samples of agricultural soils, where two degradation products desulfinyl and sulfone were found.