摘要
Two hundred and seven rain events from April to October 2012 were collected in Carmen Island, Campeche, Mexico, and the concentration of 8 major ions with the pH of the rainwater was analyzed. Chemical composition variations as a result of seasonal patterns, meteorological conditions, and mixed local and regional sources contribution were assessed. In spite of the fact that nitrate and sulfate levels were higher than background hemispheric values, the average pH values were almost neutral. Carmen Island was under the influence of both, local and long-range transported emissions. Chemical composition showed a dilution effect as a result of the monthly rainfall amount. Ca2+ and Na+ were the most abundant ions, and these ions acted as acid neutralizers and buffered the acidity of the rain, suggesting that marine and crustal aerosols played an important role in the acid-base interactions. Wet deposition fluxes obtained were compared with reference values proposed as critical loads, fluxes obtained in this study did not exceed the critical values reported for sensitive ecosystems in Europe, indicating that this site has yet enough capacity to support acidity, nitrogen and sulfur deposition. However, it is necessary to obtain reference values characteristics for tropical regions.
Two hundred and seven rain events from April to October 2012 were collected in Carmen Island, Campeche, Mexico, and the concentration of 8 major ions with the pH of the rainwater was analyzed. Chemical composition variations as a result of seasonal patterns, meteorological conditions, and mixed local and regional sources contribution were assessed. In spite of the fact that nitrate and sulfate levels were higher than background hemispheric values, the average pH values were almost neutral. Carmen Island was under the influence of both, local and long-range transported emissions. Chemical composition showed a dilution effect as a result of the monthly rainfall amount. Ca2+ and Na+ were the most abundant ions, and these ions acted as acid neutralizers and buffered the acidity of the rain, suggesting that marine and crustal aerosols played an important role in the acid-base interactions. Wet deposition fluxes obtained were compared with reference values proposed as critical loads, fluxes obtained in this study did not exceed the critical values reported for sensitive ecosystems in Europe, indicating that this site has yet enough capacity to support acidity, nitrogen and sulfur deposition. However, it is necessary to obtain reference values characteristics for tropical regions.
