Abstract
Mexico City has a population of 9 million inhabitants and was settled on a lakebed with high seismic potential. It is currently embedded in the Mexico City Metropolitan Area, which encompasses 22 million inhabitants and which was self-sufficient in water in the past, but currently extracts 70% from the regional aquifers and imports about 30% of the water required. Groundwater represents its main water source but its water quality is increasingly threatened. The purpose of this study was to determine the water quality in areas related to seismic fractures, which may increase the vulnerability of water provision, and to identify specific zones that could be affected. Official water quality data from the period 2002 to 2017 was analyzed and compared to recent data taken in wells in the city after the September 2017 earthquake. Statistical and temporal analyses were performed in order to understand the evolution and spatial distribution of water quality. The results show that free chlorine was below the limits according to the Mexican regulatory framework, while the presence of fecal coliforms, aluminum, ammonia, iron, and manganese exceeded the standards. The presence of arsenic, boron, and chrome was detected in some areas. Clusters show specific parameters that increase with time: turbidity, sulfates, nitrates, arsenic, manganese, lead, and iron. These tendencies could imply the deterioration of groundwater quality and a potential effect on the health of the exposed population. Spatially, vulnerability was observed in Iztapalapa, Tlahuac, Xochimilco, and Coyoacan. Wells coincide spatially with some of the geological damaged areas from the earthquakes in Iztapalapa and Xochimilco. In addition to water quantity, water quality represents a challenge for the urban future, since water disinfection systems are limited to treating the diversity of compounds detected. The water quality-monitoring program must be changed to improve its capacities within a framework of sustainable water management in different regions of the city, and based on the season, considering the potential exposure to the city’s population. This represents an opportunity to propose a strategic plan for the groundwater system in order to improve conditions toward a more equitable and sustainable pathway for Mexico City.
Highlights
The Mexico City Metropolitan Area (MCMA) is a megacity of 22 million inhabitants
Groundwater quality parameters were selected according to the following criteria: (1) Data reported after the September 2017 earthquakes, and (2) Data sequence reports as complete as possible during the period 2002–2017
The evidence found by analyzing data of 107 wells during 15 years indicated a temporal tendency for the concentration of certain compounds in specific areas of the city, mainly located in the Lake Zone iii in the Southern area of the city including Xochimilco, North of Tlalpan, Milpa Alta, and Tláhuac. These areas coincide with the most affected area since seismic waves entered the city in this particular earthquake in a southeast-northwest direction, showing this was already a problematic area and we don’t know if this was exacerbated after the earthquake
Summary
The Mexico City Metropolitan Area (MCMA) is a megacity of 22 million inhabitants. It is located within the Basin of Mexico, which covers an area of 9,600 km and is at an elevation of 2,240 meters above sea level. Seismic zones are related to the origin of the lacustrine plain in which Mexico City was built. Silting with volcanic products and river drift propitiated conditions for the formation of a lake system within the Basin of Mexico. Groundwater quality in Mexico City is closely related to these geological formations, which present different hydraulic conductivities, permeabilities, as well as to the type and depth of the extraction wells
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
