Water quality in wells from Cozumel Island, Mexico [Calidad del agua en pozos de la isla Cozumel, México].

Abstract

Physical and chemical variables related with groundwater quality, were surveyed in several wells from Cozumel Island, Quintana Roo, Mexico. During the annual cycle (November 2007 to October 2008), the observations were compared with local and international norms for drinking water. The goal is to determine the areas with the best water quality on the Island, through the evaluation of both geographic information, and physical and chemical features through all seasons. Significant differences were found between wells in the annual cycle with a Kruskal-Wallis test (p<0.05). On the other hand, the result of a cluster analysis (UPGMA, Euclidian distances) suggests spatial discontinuities between the systems related with ionic content in the surveyed area. Ionic concentration wassmaller (with better water quality) in the central-northern wells of the island, intermediate in the east, and higher in the west (low water quality). Therefore, the central-northern region of the Island is proposed as an important zone of fresh water supply because of the low electrical conductance, and low chloride concentration. The evidence supports the hypothesis that the temporal behavior of some groundwater variables is related to meteorological, or seasonal changes. This information could be usefulfor resource management and conservation of drinking water on the Island