Input of Pollutants by the Tributaries of Lake Yojoa, Honduras

抄録

Lake Yojoa is the only freshwater lake in Honduras. Its principal water sources are Yure and Varsovia Rivers and Cianuro Creek. There are three principal contaminants of the Lake Yojoa: agrochemical contaminants, microbiological pathogens and heavy metals. So, the main objective of this study is to evaluate and quantify the amounts of pollutants that each water source deposits in the Lake Yojoa. Based on the historical data of precipitation over the watersheds, water samples taken from each water source were analyzed for calculating specific load in each watershed. The specific load was calculated by multiplying the water flow with the concentration and then divided by the area of each watershed. In addition, statistical analysis was conducted employing "SPSS 15". As a result, there was no statistical difference in the amounts of monthly rainfalls among watersheds. The water flow, concentration as well as load and specific load differed among water sources. The results indicated that there was a tendency for Cianuro Creek to be the highest in specific load of organic matter and the only one in nitrogen as nitrite among water sources. The highest in specific load of potassium and chlorine was observed in Yure River. In addition, the quantity of pollutants discharged into the Lake Yojoa from water sources presents a threat of water degradation, especially eutrophication. A need of mitigating and reducing the amounts of pollutants is a reality. The high load of sulfate released by Cianuro Creek and Yure River present a threat not only for wild life, but also for humans that live near the lake. It was proposed that a filtering system should be prepared specifically to extract the pollutants carried by water sources that can be easily applied.