In the Mexican Caribbean, a deficient drainage network and wastewater treatment, together with the lack of policies that regulate the management of recreational tourist sites, such as ´cenotes´, have resulted in a degradation of water quality. The subject of this study was to evaluate the effect of anthropogenic activities in a continental water body, using dissolved inorganic nutrients, and stable isotopes, fecal bacteria, using a spectrophotometer, isotope ratio mass spectrometer and the IDEXX method. In the Cenote Manatí, Tulum, Quintana Roo between July and November 2019 and January 2020, the NO3- concentrations ranged from eutrophic to mesotrophic. The highest concentration of NH4+ was recorded after the maximum peak of tourist activity (i.e. 5.3 ± 3.3 November 2019). A fraction of this dissolved inorganic nitrogen was related to anthropogenic origin, since the δ15N in the filamentous algae presented values ​​of 5.5 ‰, attributed to the contribution of wastewater. In addition, the E. coli/enterococci ratio <4 suggests recent fecal contamination of human origin. In the Cenote Manatí, the effect of anthropogenic activities has been traced, showing poor water quality. That can cause: 1) health problems and 2) eutrophication water. Regulation for a sustainable use of these sities is essential since their deterioration due to the close connection with coastal systems through underwater discharges of groundwater puts at risk one of the most valuable environmental resources of the Mexican Caribbean. Currently the load capacity of the site is unknown, it is proposed to carry out the analysis to regulate its use.

https://zoom.us/j/96955089713?pwd=RGk1NmZUOWloMHRxbU9TTHJYTUdSZz09