Regionalization based on water chemistry and physicochemical traits in the ring of cenotes, Yucatan, Mexico

Abstract

Assessing water quality in aquifers has become increasingly important as water demand and pollution concerns rise. In the Yucatan Peninsula, sinkholes, locally known as cenotes, are karst formations that intercept the water table. Cenotes are distributed across the peninsula, but are particularly dense and aligned along a semicircular formation called the Ring of Cenotes. This area exhibits particular hydrogeological properties because it concentrates, channels, and discharges fresh water toward the coasts. In this study, we identify spatial and temporal variations in chemical and physical variables at twenty-two cenotes to identify groups that share similar characteristics. Water samples from each cenotes were taken at three depths (0.5, 5.5, and 10.5 m) and during three seasons (dry, rainy, and cold-fronts season). Field measurements of pH, temperature, electrical conductivity, and dissolved oxygen were taken, and the concentrations of major ions (K + , Na + , Mg 2+ , Ca 2+ , HCO 3 ) were quantified. Identifying regions of the cenotes were done by applying multivariate statistical techniques (PCA, PERMANOVA, CAP). The chemical variables revealed spatial trends among the cenotes. We identified three main regions. Region 1 is associated with sea-water encroachment and high levels of sulfate that travel through preferential groundwater flowpaths from evaporites in the southern Yucatan Peninsula; Region 2 is a recharge zone, and Region 3 is characterized by sea water encroachment and by the high chemical and physical variability associated with groundwater flow from the east.

Contamination by organochlorine pesticides in the aquifer of the Ring of Cenotes in Yucatán, México

“…), covering 11 municipalities of Yucatan, Mexico, and was taken from a study by Pérez‐Ceballos et al . (Table ). The climate is warm and humid, with an average temperature of 25–27°C.…”

Groundwater Quality: Analysis of Its Temporal and Spatial Variability in a Karst Aquifer

“…Location of the study area in the State of Yucatan along with average annual precipitation isohyets. The dots represent the locations of some sinkholes within the ring of sinkholes delimited by the two semicircles (Pérez‐Ceballos et al ). Contours of precipitation are adapted from PROCOMAR ().…”

Connectivity in a Karst System Using Electrical Resistivity Tomography and Network Theory

“…The aquifer is highly vulnerable to contamination, as shown by previous studies that reported that groundwater within the top 15 to 20 m of the aquifer does not meet the standards for human consumption (Marín et al ; Pacheco‐Castro et al ). Six kilometers to the east of our study site, Pérez‐Ceballos characterized a group of seven cenotes with low pH values, high , and high and and concluded that these cenotes in the center of the RC are in an aquifer recharge zone (Pérez‐Ceballos et al ).…”

“…The ERTs were performed to obtain information on possible underground water cavities which connect cenotes. The water in the region studied has a resistivity between 6 and 12 ohm‐m (Pérez‐Ceballos et al ) but since the inversion process introduces a degree of uncertainty, we consider a larger range for the resistivity: 1 to 47 ohm‐m. Later in the paper, we will see evidence for 23 water cavities.…”

“…The cross‐sectional area for each cavity was calculated as: where A i is the area of the cavity with color ai (Figure ) and W i is the weight that represents the percentage of water contained in a material with resistivity ai. We use previous studies as a reference (Telford et al ; Bauer‐Gottwein et al ) to assign the following values for W : W 1 = 0.8, since this is typical for saline water; W 2 = 0.9, because in this resistivity range (3 to 6 ohm‐m), most of water is saturated with salt; W 3 = 1.0, this is the resistivity for free water in the cenotes (Pérez‐Ceballos et al ); W 4 = 0.5 and W 5 = 0.3, correspond to water trapped in rocks with different densities.…”