| Title | Chemical and Isotopic Monitoring of Rainfall Around the Los Azufres and Los Humeros Geothermal Systems: Preliminary Results |
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| Authors | M. P. Verma, Ma. E. Fernandez, J. L. Quijano, C. Johnson and J. Y. Gerardo-Abaya |
| Year | 2000 |
| Conference | World Geothermal Congress |
| Keywords | rainwater |
| Abstract | A comparative chemical and isotopic study of rainwater at Los Azufres in 1995 and Los Humeros in 1996 is presented. Los Humeros is situated about 200 km east of Mexico City, whereas Los Azufres is 200 km west. The concentration of NO3 - in samples from all sites in Los Humeros is very low. Alkalinity is positive for all sites at Los Humeros, whereas a few samples have negative values at Vivero, Los Azufres. Thus rain is not acidic at Los Humeros. A mixing model for Cl-/SO4 2- versus ‰34S suggests that there is 10-25% sulfate from sea spray in rainwater at Los Humeros, whereas there is less then 10% seaspray sulfate at Los Azufres. These data suggest that the clouds formed in the Gulf of Mexico bring rain to the Central part of Mexico. Los Humeros is located east of any big industrial sites, therefore the rainwater has less anthropogenic SO4 2- and NO3 -. Rainwater at Los Azufres has contaminants from industrial sites to the east. It can be concluded that there is no discernable influence of geothermal emissions on rainwater acidity. |