Bacteriological contamination in the karstic aquifer of Yucatán, Mexico

Abstract

The karstic aquifer of Yucatán serves as the only source of drinking water and the direct recipient of all sewage generated throughout the peninsula. Gastroenteritis, diarrhea, urinary tract infections and septicemia occur among the inhabitants of the rural areas as a result of usage and consumption of untreated ground water. In a rural region without sanitary facilities, multiple-tube fermentation technique was used for the quantification of total and faecal coliform. Qualitative isolation and identification by biochemical reactions was used to identify five tribes of the enterobacteriaceae family. We find that the bacteriological behavior of total and faecal coliform closely follow the precipitation pattern and that their concentrations exceeded the limit established by the Mexican Drinking Water Norm, as it ranged between 7,320 and 12,989 MPN/100 ml. Escherichia, Serratia and Enterobacter showed the higher percentage frequency occurrence values.