Nutrient Cycling and Water Pollution in Lake Zapotlan, Mexico

• Main Author: Greenberg, Tracie
• Other Authors: Shear, Harvey
• Language: en_ca
• Published: 2009
• Subjects: Water Quality; Mexico; 0368; 0793; 0768
• Online Access: http://hdl.handle.net/1807/30132

Lake Zapotlán is a small (1100 ha) endorheic lake in western Mexico that is internationally recognized by RAMSAR. It receives point source pollution from partially treated sewage from two surrounding cities, as well as non-point sources, including urban runoff, agricultural runoff, erosion and consequent deposition of sediment as a result of deforestation surrounding the Lake. The purpose of this study was to determine the severity of pollution in the Lake through measurement of nutrient and bacteria levels and assess for potential human health and ecological risks in Lake Zapotlán. Results found that nutrient levels have increased since 1994 and that they are high enough to cause eutrophication problems. Partially treated wastewater contributes over 30 tonnes of phosphorus to the Lake each year. E. coli levels were extremely high and could pose a health risk to those participating in recreational activities on the Lake.