The spatial assessments of water supply quality from wells, springs, and surface bodies were performed during the dry and rainy seasons in six municipalities in the eastern regions of Michoacán (Central Mexico). Different physicochemical parameters were used to determine the supplies’ Water Quality Index (WQI); all of the communities presented good quality. The analysis indicates that many water quality parameters were within limits set by the international standards, showing levels of “excellent and good quality” according to WQI, mainly during the dry season (except at San Pedro Jácuaro and Irimbo communities in the rainy season). However, some sites showed “poor quality” and “unsuitable drinking water” related to low pH levels ( 1) in the rainy season for three target groups. At the same time, the carcinogenic risk (1 × 10⁻³) exceeded the acceptability criterion in the rainy season, which suggests that the As mainly represents a threat to the health of adults, children, and infants.

The growing global population and increasing water demand have intensified the urgency for efficient wastewater treatment strategies to address environmental pollution and water scarcity. Physicochemical treatment technologies remain among the most widely implemented solutions due to their high removal efficiency, operational simplicity, and relatively low cost. These processes effectively target a broad spectrum of contaminants—including suspended solids, heavy metals, recalcitrant organic compounds, and high salinity—through unit operations such as coagulation, flocculation, adsorption, and filtration. Nevertheless, they often generate concentrated waste streams that present significant disposal and environmental challenges. Applying these technologies within a circular economy framework enables wastewater reuse, resource recovery, and a reduced environmental impact. Circular strategies enable the recovery and reuse of water, energy, and materials, converting waste into valuable resources. Treated water can be safely reused, while by-products such as biogas and nutrients (e.g., phosphorus, nitrogen, and organic carbon) can be recovered and reintegrated into agricultural and industrial processes. Furthermore, advanced methods such as membrane separation and electrochemical treatments allow for the selective recovery of high-value metals. This review analyzes key physicochemical technologies for wastewater treatment and evaluates their integration into circular economy models, with a focus on waste valorization, resource recovery, and environmental impact reduction. By adopting circular approaches, wastewater treatment systems can enhance sustainability, improve economic performance, and contribute to achieving the global water and sanitation target.

Steroids are classified as endocrine disrupting chemicals; they are persistent with low biodegradability and are hardly degraded by conventional methods. Ozonation process has been effective for steroids degradation and the determination of the kinetics is a fundamental aspect for the design and operation of the reactor. This study assessed two methods: competitive kinetics and stopped flow, for determining the degradation kinetics of two steroids, estradiol (E2) and ethinylestradiol (EE2) in spiked water. Experiments were performed at pH 6, 21 °C, and using tertbutyl alcohol as scavenger of hydroxyl radicals; competitive kinetics method used sodium phenolate as reference compound. For the stopped flow, the experiments were performed in a BioLogic SFM-3000/S equipment. For both methods, the second order rate constants were in the order of 106 and 105 M−1 s−1 for E2 and EE2 respectively. The competitive kinetics can be applied with assurance and reliability but needing an additional analysis method to measure the residual concentrations. Stopped flow method allows the evaluation of the degradation kinetics in milliseconds and avoids the use of additional analytical methodologies; this method allows determining the reaction times on line. The methods are applicable for degradation of other emerging contaminants or other steroids and could be applied in water treatment at industrial level. Finally, it is important to consider the resources available to implement the most appropriate method, either competitive kinetics or the stopped-flow method.

The Guadalajara Metropolitan Area (GMA) has continuously presented atmospheric pollution problems due to particulate matter with an aerodynamic diameter less than or equal to 10 micrometers (PM₁₀). Therefore, this research aims to evaluate the risk of developing adverse health effects in children from 0 to 10 years old due to the inhalation of PM₁₀ during 2011–2018 in the GMA. As part of the methodology, the daily, monthly, seasonal, and annual average concentrations were calculated using ten monitoring stations that conform to the Jalisco Atmospheric Monitoring System. Subsequently, the daily and annual concentrations were compared with the current national and international regulatory concentrations. Besides, the hazard index was estimated to know the number of times that the concentrations recorded in the GMA exceed the regulatory concentrations. Finally, the risk was characterized by age groups, calendar year, and seasons by estimating the hazard quotient (HQ). The total HQ results ranged from 1.94 to 4.18, indicating that children from 0 to 10 years old who live in GMA have been at high risk of developing adverse health effects from inhaling high concentrations of PM₁₀ that each year exceeded the annual guideline levels established by the current national and international regulation levels.

Endocrine-disrupting compounds (EDC) are present in surface water bodies that supply water to the population. One of them is bisphenol A (BPA), which is listed as a carcinogen. This research addresses its degradation through the ozone reaction and presents a likely pathway established by analyzing products and degradation products using gas chromatography-mass spectrometry (GC-MS). BPA degradation was carried out under pseudo-first-order conditions, where liquid phase ozone was the limiting reactive, in doses of ≈2.29 × 10-4 M and BPA doses of 1.25 × 10-4, 17.5 × 10-4, and 35.0 × 10-4 M, looking to have molar ratios [BPA]> [O3]; the oxidation reaction was carried out in a stopped-flow system that allows obtaining results in the order of seconds. The degradation pathway obtained shows the rupture of one of the benzene rings, decreasing the phenolic toxicity of the BPA compound. The proposed pathway can contribute to the understanding of the degradation of BPA in the environment and tertiary treatment processes with the use of ozone. Likewise, it is intended to contribute with new data to the issues of drinking water treatment to offer safe water to the population.