Analyzing the Physicochemical Characteristics of an Archaeological Glass Collection from Mexico City, Mexico

Physico-chemical and bacteriological characterization of wastewater from Mexico city

Physico-chemical and bacteriological characterization of wastewater from Mexico City

Fenton's reagent and coagulation-flocculation as pretreatments of combined wastewater for reuse

Identification and characterization of single use oxo/biodegradable plastics from Mexico City, Mexico: Is the advertised labeling useful?

The aim was to analyze the quality of commercial shampoo without prophylactic effect for dogs. The analysis was based on the evaluations and requirements established for human-line products since there is no guide for veterinary products in Mexico; such evaluations have not been carried out or published in Mexico. Physicochemical, sensory, performance, and consumer information tests of the shampoo were carried out. The sample consisted of twenty products marketed in Mexico City. During the evaluation of the label, a serious non-compliance with applicable regulations was found. The pH of the products ranged between 5.6 and 8.4; Significant differences (p⟨0.05) were found between the three groups with low (6.1), medium (7.2), and high (8.1) pH. Viscosity values were from 1131 to 3102. For the foam index, no statistically significant differences were found. 100% of the products analyzed complied with the rest of the quality tests carried out. The results of the quality analysis in this study will allow veterinarians specializing in small species to better select and recommend the products for their use and inform dog owners, about the safety, and value of the products.

To develop and evaluate nutritional supplements destined to a program of social assistance. In the design of the nutritional supplements a series of criteria were considered including nutrient composition, physicochemical properties and feasibility of production and utilization. Final products were initially evaluated to determine the level of acceptance in 40 children, 52 pregnant women and 62 lactating women in Mexico City. A community trial was also carried out to determine acceptance and consumption in 108 children and 128 women from a rural community in the state of Morelos. The specific formulation and technical processes of production of the nutritional supplements are presented. Products proved to be widely accepted, with average scores of 4.11-4.29 for the children's beverage, and 3.98-4.15 for a more viscous pap (range of scores was 1 to 5). Products for women received average scores from 4.75 to 5.70 in pregnant and from 4.8 to 5.4 in lactating women (range of scores from 1 to 7). In the community trial, supplements were very well accepted. Average consumption was > 75% among children and > 98% among women. Mean energy intake from supplements was 244 Kcal/day for women, and for children, 168 Kcal/day with the pap and 147 Kcal/day with the beverage. Consumption was consistent in all cases along the study. Nine nutritional supplements were developed and evaluated which comply with the necessary nutritional, physicochemical and hygienic characteristics for the target population, besides being relatively simple to prepare, and widely well accepted and consumed.

<p>Conservation and management of aquatic ecosystems that are significantly influenced by urban activities requires the classification and establishment of potential reference sites. However, in Latin American countries, policies are not available that outlines the identification and evaluation of such sites. Therefore, this study represents a proposal for evaluating the ecological quality of peri-urban rivers in the conservation soil (CS) areas/zones of Mexico City. The proposal accounts for the zone’s physicochemical, hydromorphological, and bacteriological characteristics along with its macroinvertebrate richness. Our evaluation was performed using a canonical correspondence analysis (CCA) and indicator values (IndVal) calculated for different species. River headwaters serve/work as a good physicochemical point for potential references sites. However, the hydromorphology of the CS has been gradually modified by numerous hydraulic alterations within the peri-urban zone. Using the CCA and IndVal, two types of sites were confirmed: sites in a good state of conservation and quality and sites modified by human activity, featuring lower discharge flow, poor quality hydromorphological values and Oligochaeta class organisms. At the sites featuring a good state of conservation and quality, higher hydromorphological values were positively correlated with discharge flow and certain macroinvertebrate taxa, including Nemouridae, Podonominae, Tanypodinae, Acarina,<em> </em><em>Baetis</em>,<em> Tipula</em>,<em> Antocha</em>, <em>Atopsyche</em>, <em>Glossosoma</em>, <em>Polycentropus</em>, <em>Hesperophylax</em> and <em>Limnephilus</em><em>. </em>In the sites modified by human activity, the genus <em>Simulium</em> was classified as a disturbance-tolerant organism. The river reach within the urban zone is basically an open-air drainage ditch. Evaluations of the ecological quality of the riparian zone were used to identify the most important hydromorphological qualities and discharge flow parameters and to select the most appropriate factors that should be monitored in peri-urban rivers of the Mexico Basin. </p>

The load and diversity of plant growth-promoting rhizobacteria (PGPR) are used as biomarkers to evaluate the health and quality of the soil. In the present study, the diversity of PGPRs and the physicochemical properties of the soil were used as comparative biomarkers in two adjacent soils (a pine forest soil and an agricultural soil) of the same region in Mexico City in order to investigate the effects of land use change. Bacterial diversity and physicochemical properties differed between the two soils. In the pine forest soil, PGPR were distributed at similar proportions in the Proteobacteria (29.41%), Actinobacteria (29.41%) and Firmicutes (35.29%) phyla, whereas the remaining PGPR were in Bacteroidetes (5.88%). In the agricultural soil, most PGPR belonged to the Phylum Firmicutes (50%), with the remaining belonging to Proteobacteria (22.73%), Actinobacteria (18.18%) and Bacteroidetes (9.09%). Percentages of bacteria producing indole acetic acid (90.91%) and siderophores (40.91%) were higher in agricultural soil. A canonical correspondence analysis (CCA) was used to correlate PGPR with the physicochemical characteristics of the soils. The CCA revealed that differences between both soils and the physicochemical properties of the soils affected isolated bacterial species and their distribution. These results demonstrate that the PGPR are correlated with the physicochemical properties of the soil, exhibiting differences between an agricultural soil and a pine forest soil.

Background: Cerro de la Estrella (CE) is a natural reserve in Mexico City that suffers from afforestation, and its restoration with Acacia farnesiana is being considered . 
 Question: Will the nodule-forming rhizobia and arbuscular mycorrhizal fungi (AMF) associated with the CE soil support A. farnesiana growth?
 Study species: Acacia farnesiana (L.) Willd . (Fabaceae).
 Methods: Mycorrhizal fungi, nodule-forming rhizobia and physicochemical characteristics of the CE soil were studied to determine if they are suitable for improving the growth of Acacia farnesiana .
 Results: Four different families of AMF were found which generated 13 % mycorrhization with A. farnesiana . However, A. farnesiana from CE did not nodulate, suggesting the lack of native rhizobia. The CE soil has low fertility. Nodules of A. farnesiana were obtained from the soil in Ticuman, Morelos, and 66 rhizobia were isolated from them. Rhizobium isolates were individually added to A. farnesiana grown in the CE soil. Five of the 66 isolates yielded significant differences in shoot dry weight, shoot height, number of nodules, nodulation time and nitrogenase activity compared with the Sinorhizobium americanum CFNEI 156 control strain ( p < 0.05). Three isolates were named as S. americanum ENCBTM1, ENCBTM31 and ENCBTM43, and last two as Sinorhizobium sp. ENCBTM34 and ENCBTM45.
 Conclusions: CE soil had low fertility and lacked specific rhizobia for A. farnesiana . The individual addition of S. americanum (ENCBTM1, ENCBTM31 or ENCBTM43) or Sinorhizobium sp. (ENCBTM34 or ENCBTM45) improved the growth of A. farnesiana.

Removal and transformation of recalcitrant organic matter from stabilized saline landfill leachates by coagulation–ozonation coupling processes

Urban dust is composed mostly of particles emitted by anthropogenic processes such as industry, vehicular, and maritime transport, so it may contain heavy metals and PM10 and PM2.5 particles, which affect human health, so its characterization should be taken into account in an environmental monitoring plan. Regarding UD, there are studies about heavy metal contamination conducted in Mexico City (CdMx) and the suburbs of the State of Mexico, but to date, there are none for the Tampico, Ciudad Madero, and Altamira. The manuscript describe the elemental distribution found in urban dust and the possible relationship of the detected elements with emission sources according to the meteorological parameters of the area. The study presents the elemental composition of dust particles from 17 samples collected in the January-April 2023 period, at determined points in the Tampico-Madero-Altamira metropolitan area (TMA). The samples were collected in polyethylene bags and analyzed by X-ray fluorescence in air at an energy of 50 kV. There were 21 elements identified in the TMA. Through the Mexican regulation Pollutant Release and Transfer Register (RETC), it was possible to identify and relate some of the detected elements to some elements reported by local companies such as nickel, lead, and chromium. The most frequently detected metals were Ca, Mn, Zr, Sr, Pb, and V. These results indicate that more extensive work is needed to quantify elements such as Ni, Cr, Pb, and V due to the health problems they may cause. Funded by CONAHCYT 2022-321595.

Air pollution has long posed a significant environmental challenge in the North American region, including both the USA and Mexico. Among its impacts, acid rain, which is characterized by a pH lower than 5.6, negatively affects ecosystems and biodiversity. This study evaluates and compares the physicochemical characteristics of precipitation in the urban areas of Denver, New York City, Los Angeles, and the Mexico City Metropolitan Area (MCMA) during the period 2003–2019. Long-term analysis revealed a substantial decline in sulfate concentrations in New York City after 2009, accompanied by a gradual rise in precipitation pH. In contrast, sulfate levels in the MCMA remained elevated and variable, while Los Angeles exhibited persistently acidic precipitation despite relatively low sulfate concentrations. Nitrate trends were weak or irregular across cities, and ammonium increased only in New York City. Results indicated the presence of acid rain in New York City, Los Angeles, and the MCMA, but not in Denver, where precipitation in 2017 did not exhibit acidic pH values. The highest concentrations of SO42− and NO3− in precipitation were observed in the MCMA, likely due to SO2 emissions from the Tula–Vito–Apasco industrial corridor and high NOx emissions from mobile sources. The SO42−/NO3− ratio was used to determine the predominant ion influencing precipitation acidity. SO42− was dominant in New York City and the MCMA, whereas NO3− was more prevalent in Los Angeles and Denver. Strategies implemented in the USA, such as the transition to cleaner fuels, policies for monitoring emission sources, and the expansion of atmospheric deposition networks, could inform efforts to reduce emissions of acid rain precursors in the MCMA.

Performance of basaltic dust issued from an asphaltic plant as a flocculant additive for wastewater treatment

In this work a new approach to the physicochemical characterization of polychrome archaeological glasses through elemental maps is presented. It is the first time that elemental mapping both by Laser Ablation-ICP-MS and EPMAWDS was performed on ancient glass. The glass elemental mappings are here proposed as useful tools for a preliminary study of the overall pattern of a glass surface concerning each analyzed element. The visual inspection of the maps gives the distribution of the elements and their degree of homogeneity; this allows the identification of the correlations between elements, in order to get information about chromophores, opacifiers and their associated ores, as well as about the glass deterioration. The LA-ICP-MS quantitative elemental maps of 54 elements were performed on a glass sample area. The concentrations of the element oxides were visualized in pseudo-colors, both in 2D and 3D. EPMA-WDS elemental maps were performed on areas of surface and break-section of the samples, at the interface between bulk and decorations. LAICP- MS elemental mapping can be functional to the determination of the glass chemical composition patterns and of associations between elements, while WDS elemental mapping is mainly aimed to identify the distribution of crystalline phases or to visualize concentration gradients of elements at the interfaces of different areas, such as bulk and decorations. Both the techniques can be functional to the study of glass superficial weathering.