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Research topics in:
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Fischer, Eric, "An Introductory Assessment of the Water Quality of Quebrada Cañas, Alajuela." Adv. Juana María Coto. Grinnell. 1996. 28pp. During the dry-season months of March and April, the overall water quality of Quebrada Cañas, Alajuela was investigated in order to assess the health of the stream and the impact of the many sources of contamination encountered in its watershed. A number of chemical, physical, and biological parameters were analyzed and used to calculate the National Sanitation Foundation index of water quality. Samples of benthic fauna were collected in order to characterize the water quality using Beck's Biotic Index, in which biological species are used as an indication of the level of contamination. Both indices indicate the water to be highly impacted by contamination at all sites along the course of the stream; although it is impacted to a significantly greater degree upon receiving the effluents of two industries located in the lower portion. Residential waste waters, including sewage, appeared to contribute high concentrations of organic matter and non-biodegradable materials. One industry was found to be discharging alarmingly high concentrations of chromium, a toxic heavy metal. Overall, residential and industrial waste waters combined to produce a very dramatic deterioration in water quality. Additionally, informal interviews were conducted to reveal the perspectives held by community members toward the issues of water quality faced in the watershed. Mulcahy, Marybeth, "The Monitoring of the Levels of NO3-, Fl-, Cl-, SO4-2 and the pH of Acidic Rainfall Around a Natural Source of Contamination, Arenal Volcano, Costa Rica." Adv. Jorge Barquero. Colorado. 1996. 30pp. The threat of an active volcano does not only exist in the form of explosive eruptions, but also in the form of many small eruptions of gases. These gases contain some of the precursors to acid rain (CO2, H2, H2S, HF, SO2). Acid rain is dangerous because it is an irritant to eyes and skin, causes problems with breathing, deteriorates building materials, and burns vegetation (Barquero y Fernandez). Beginning February 26, 1996, rainwater and air samples were collected in the area around Arenal Volcano in Alajuela, Costa Rica (10º27´48"N, 84º42´12"W) every other day for 2 months. Trends of acid rain indicating ionic species (Cl-, NO3-, SO4-2, Fl-) and the pH of the rain fall were observed. This study differs from already established and ongoing studies of the scientists at OVSICORI-UNA whom collect samples every 15 days from containers that remain in the field during the time interval (Alfaro, et al). The winds in this area have a tendency to carry the gases to the west and because of this the investigation concentrated on the west side of the volcano. Collection sites were also placed on the north and east sides of the volcano for comparison. It is important that we monitor and understand the chemical composition of the rain and air so that public can be informed of the presence of this danger and because it may be an indicator to future, more explosive eruptions. All of the analysis were completed at the National University in Heredia, Costa Rica. While the study continues to confirm the presence of acid rain, it also raised questions of the the necessity of a more frequent collection schedule, significance of ash in samples, and the relationship between seismological activity and the strength of the acid rain. |
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