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Nowadays, one of the most critical challenges is reduced access to water. Climate change, industrialization, and population growth have caused many countries to suffer from water crises, especially in arid and semi-arid areas. The Culiacan River basin in Sinaloa is a region of great importance in Mexico due to its intensive agricultural activity. Hence, water quality assessment has become a necessity to ensure sustainable water use. This study describes the spatiotemporal water quality features of the Humaya, Tamazula, and Culiacan Rivers within the Culiacan River basin and their sources of contamination. Twenty-two water quality parameters were analyzed from samples taken every 6 months from 2012 to 2020 at 19 sampling sites in the basin. A multivariate statistical analysis revealed significant correlations (r > 0.85) between the water quality parameters. The modified Integrated Water Quality Index (IWQI) identified severe pollution in samples from the urban river section of the basin, while good water quality conditions were found upstream. Severe contamination was observed in 26.32% of the samples, whereas only 13.45% evidenced good water quality. The Water Quality Index (WQI) indicated that 94.74% of the samples presented fair water quality, suggesting that the surface waters of the Culiacan River Basin are suitable for agricultural irrigation. This study provides insights into the current water quality status of the surface waters in the Culiacan River Basin, identifying significant pollution sources and areas of concern. The spatiotemporal dynamics of water quality in the Culiacan River basin revealed the importance of continuous monitoring and effective water management practices to improve water quality and achieve sustainable agricultural practices.

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The use of biomarkers in fish for biomonitoring is a valuable approach to reveal effects of human impacts on biota health. Top predator fish are effective models for monitoring human activities' impacts on aquatic ecosystems. The Guaraguaçu River is the largest river-system on coastal region of South Brazil and a World Heritage site. The river receives contaminants from disorderly urban growth, including discharges of domestic sewage and small fishery boats, particularly during the tourist season. Our study aimed to assess impact of anthropogenic activities on water quality in the Guaraguaçu River by analyzing environmental contamination biomarkers in the top fish predator Hoplias malabaricus. Fish were collected using a fyke net trap across sectors representing a gradient of anthropic impact: sector 1 - pristine; sector 2 - impacted; and sector 3 - less impacted. Water samples were collected to analyze the presence of trace elements and pesticide. Biomarkers of the antioxidant system, histopathology, genotoxicity, neurotoxicity, and concentration of trace elements were analyzed in fish tissues. In water samples Al, Fe and Mn were detected, but no pesticides were found. In fish muscle, zinc and iron were detected. Brain acetylcholinesterase activity decreased in impacted sectors, indicating neurotoxic effects. The antioxidant system increased activity in gills and liver, and damage from lipoperoxidation was observed, particularly in sector 2 when compared to sector 1, suggesting oxidative stress. Histopathological biomarkers revealed lesions in the liver and gills of fish in impacted sectors. Micronuclei, a genotoxicity biomarker, were observed in organisms from all sectors. Our results demonstrate detrimental effects of poor water quality on biota health, even when contaminants are not detected in water.

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Tap water quality concerns and advertisements often drive increased bottled water consumption, especially in communities with historical tap water quality problems (e.g., Nogales, Arizona). The study objective was to assess contamination of municipal tap and bottled water in Nogales, Arizona. Bottled (sealed, open/partially consumed bottles, and reusable containers for vended water) and tap water samples were collected from 30 homes and analyzed for chemical and microbial contaminants. Fisher exact tests and Wilcoxon rank sum tests were used to compare proportions of positive samples and contaminant concentrations between tap and bottled water samples. While none of the chemical contaminants were above MCLs, there were statistically significantly greater concentrations and proportions of positive samples for some contaminants, including arsenic, in tap vs. bottled water. E. coli concentrations were >0 CFU/100mL in some unsealed bottled water samples but not for sealed bottles. This study demonstrates that 1) the measured concentrations in tap and bottled water likely pose low risks, as they are below the MCLs, 2) more education in this community on hygiene maintenance of refillable or opened bottled water containers is needed, and 3) using tap water over bottled water is advantageous due to likely lower E. coli risk and lower cost.

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Detection of an environmental contaminant requires the use of expensive measurement equipment, which limits the realization of in situ tests because of their high cost, their limited portability, or the extended time duration of the tests. This paper presents in detail the development of a portable low-cost spectrophotometer which, by using a specialized chemosensor, allows detection of mercuric ions (Hg2+), providing effective and accurate results. Design specifications for all the stages assembling the spectrophotometer and the elements selected to build them are presented along with the process to synthesize the chemosensor and the tests developed to validate its performance in comparison with a high-precision commercial laboratory spectrophotometer.

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El agua es una necesidad universal que ha sido reportada por las Naciones Unidas (ONU) y la Organización Mundial de la Salud (OMS) como una prioridad. Existe una necesidad apremiante de acceso gratuito al agua potable para las poblaciones de los países en desarrollo. Además, las fuentes de agua de los países desarrollados también requieren atención debido a la presencia de un alto nivel de contaminantes emergentes. Por lo tanto, la nanotecnología parece ser una herramienta poderosa que podría usarse como sensores, filtros, superficies antibacterianas y nanoantimicrobianos. En esta revisión, hemos discutido la aplicación de las nanopartículas y los nanocompuestos para el tratamiento de aguas y aguas residuales. Además, el impacto de las nanopartículas libres como contaminantes emergentes en las plantas de tratamiento de agua, así como en las aguas subterráneas, merece más estudios.

The water is a universal need that has been reported by the United Nations (UN) and World Health Organization (WHO) as a priority. There is a pressing need for free access to drinking water for populations from developing countries. Furthermore, the water sources of developed countries also require attention due to the presence of a high level of emergent contaminants. Therefore, nanotechnology appears to be a powerful tool that could be used as sensors, filters, antibacterial surfaces, and nanoantimicrobials. In this review, we have discussed the application of nanoparticles and nanocomposites for water and wastewater treatment. Moreover, the impact of free-nanoparticles as emergent contaminants in water treatment plants as well as groundwater warrants further studies.

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Considerando a importância da qualidade da água tratada nos serviços de diálise para prevenção de riscos aos pacientes renais crônicos, foi estabelecido o programa de monitoramento com a finalidade de avaliar a qualidade da água tratada nos serviços de diálise do Estado de São Paulo, com base nos parâmetros estabelecidos pela Resolução RDC nº 154/2004. Foi atestada a efetividade das ações de vigilância sanitária que tem resultado em aumento dos níveis de qualidade da água tratada em vários dos parâmetros analisados, o que indica a importância da continuidade dos programas de monitoramento com intuito de garantir a segurança dos pacientes.

Considering the relevance of the quality of treated water in dialysis units to prevent the risks for patientswith chronic kidney diseases, a Monitoring Program has been established in order to evaluate the quality of treated water used in the dialysis units of the state of São Paulo, based on the parameters establishedby Resolution RDC # 154/2004. The effectiveness of the sanitary surveillance activities was evidencedbecause the consistent water quality has been improved on several analyzed parameters, which indicatesthe importance of keeping up the treated water-monitoring program at hemodialysis units in order toguarantee the patients safety.

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Considering the relevance of the quality of treated water in dialysis units to prevent the risks for patients with chronic kidney diseases, a Monitoring Program has been established in order to evaluate the quality of treated water used in the dialysis units of the state of São Paulo, based on the parameters established by Resolution RDC / 154/2004. The effectiveness of the sanitary surveillance activities was evidenced because the consistent water quality has been improved on several analyzed parameters, which indicates the importance of keeping up the treated water-monitoring program at hemodialysis units in order to guarantee the patients safety.

Considerando a importância da qualidade da água tratada nos serviços de diálise para prevenção de riscos de infecção aos pacientes com insuficiência renal crônica, foi estabelecido o programa de monitoramento nos serviços de diálise do Estado de São Paulo, com base nos parâmetros estabelecidos pela Resolução RDC nº 154/2004. Foi atestada a efetividade das ações de vigilância sanitária que tem resultado em aumento dos níveis de qualidade da água tratada em vários dos parâmetros analisados, o que indica a importância da continuidade dos programas de monitoramento com intuito de garantir a segurança dos pacientes.