ASSESSING THE VULNERABILITY OF GROUNDWATER TO FECAL CONTAMINATION ALONG THE RIVIERA MAYA, QUINTANA ROO, MEXICO

Little is known about the extent of pollution in groundwater that occurs along the Riviera Maya located along the eastern coast of the Yucatan Peninsula. With rampant growth in many areas throughout the peninsula there is a potential to release from wastewater a large number of contaminants including pathogens. Studies have shown that rural waters in this area can have high fecal coliform concentration but research has not been done on the sources of this fecal contamination (human or livestock). The objective of this research project was to sample a series of wells in the Tulum region, Quintana Roo that range from protected to impacted to determine the occurrence, source, and extent of fecal contamination and link this information to the hydrogeologic setting. The membrane filtration method and the IDEXX technique were used for the quantification of total coliforms. Qualitative isolation in reference to the source of the fecal contamination (human or non-human) is assessed by means of Bacteriodes 16S rRNA PCR analysis. Two assays were used to determine Bacteroides count: the AllBac assay and the HuBac assay. The AllBac assay determines the total number of Bacteroides (human and non-human) within a sample. The HuBac assay determines only the Bacteroides that are human specific. The results show that fecal contamination of the fresh groundwater supply of the Tulum region is occurring. It is also evident that a significant source of that contamination is human. The extent of contamination implies that there is a need for public awareness of the human impact on the region’s fresh water supply. The information provided here could assist scientists and members of the Riviera Maya community to be better equipped to construct community environmental and health education programs, amend waste disposal regulations and water management protocols, as well as seek ways to lessen tourism impact on the natural environment.