No abstract

This study was conducted with the objective of determining whether there is a depuration of organochlorine pesticides in breast milk according to breastfeeding time. In total, 171 samples from mothers that lived in the State of Guerrero, Mexico were analyzed. There was a weak negative relationship between pp'DDE (r = -0.216) and Σ-DDT (r = -0.222) concentrations with the days of lactation. In a comparison analysis, a statistically significant decrease of pp'DDT and pp'DDE levels was observed, as well as the Σ-DDT from the first to the fifth week of lactation. A reduction of 0.188 mg/kg lipid of pp'DDE and 0.181 mg/kg lipid of Σ-DDT per week was obtained. HCB, β-HCH and op'DDT concentrations were low and had no major fluctuations between subgroups. The low levels found and the observed reduction in time involve less exposure to the infant to these pollutants. Through this methodology changes in levels of certain organochlorine pesticides in various stages of human milk production may be shown.

El manejo de los residuos sólidos urbanos (MRSU) en Xaltianguis es realizado por la misma comunidad, generando contaminación y deterioro ambiental. Este artículo estudia el MRSU enfocándose en la participación comunitaria. Para estimar la generación, composición y emisión se aplicó la calculadora del clima. El MRSU se obtuvo mediante una encuesta y entrevistas. Los tiraderos a cielo abierto (TCA) se georreferenciaron utilizando los sistemas de información geográfica, cuyos resultados mostraron una generación de 1017 toneladas anuales (t/a) de residuos; 62.1% fueron orgánicos y emitían 1036 t/a de CO2-eq. Existían dos sistemas de recolección, el municipal operaba semanalmente, mientras el informal a diario depositaba en un TCA y se registraron otros 22 TCA. El 48% de la población considera participar. Prácticas como el reúso (44%) y reciclaje (2.3%) aportarían a un eficiente MRSU, pero este solo puede lograrse con corresponsabilidad y compromiso de la comunidad y el municipio.

This work proposes a methodology whereby the selection of hydrologic and land-use cover change (LUCC) models allows an assessment of the proportional variation in potential groundwater recharge (PGR) due to both land-use cover change (LUCC) and some climate change scenarios for 2050. The simulation of PGR was made through a distributed model, based on empirical methods and the forecasting of LUCC stemming from a supervised classification with remote sensing techniques, both inside a Geographic Information System. Once the supervised classification was made, a Markov-based model was developed to predict LUCC to 2050. The method was applied in Acapulco, an important tourism center for Mexico. From 1986 to 2017, the urban area increased 5%, and by 2050 was predicted to cover 16%. In this period, a loss of 7 million m3 of PGR was assumed to be caused by the estimated LUCC. From 2017 to 2050, this loss is expected to increase between 73 and 273 million m3 depending on the considered climate change scenario, which is the equivalent amount necessary for satisfying the water needs of 6 million inhabitants. Therefore, modeling the variation in groundwater recharge can be an important tool for identifying water vulnerability, through both climate and land-use change.

Different groups of emerging pollutants (EPs) were identified (drugs, pesticides, hormones, illicit drugs, and fire retardant), and the removal of four antibiotics was determined (sulfamethoxazole 62.2–94.4%, ciprofloxacin 71–83.1%, norfloxacin 82–89%, and ofloxacin 78–97.9%) in a municipal wastewater treatment plant (WWTP) in Acapulco, Gro. Mexico. The compounds were extracted from influent and effluent samples by solid phase extraction (SPE). The identification of non-target EPs was performed by liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS). The antibiotic quantification was performed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Most of the non-target compounds were detected only in the influent samples. Antibiotics levofloxacin and nalidixic acid, the anticonvulsants carbamazepine and oxycarbamazepine, the local anesthetic lidocaine, and the pesticide tridemorph were the main EPs not removed by the WWTP. In this study, it was shown that the Aguas Blancas WWTP does not manage to remove 100% of the various EPs identified in the effluent, although the elimination degree is high in most cases, despite being one of the model plants in Mexico.