The purpose of this study is to show the relationship between an ordinal scale toxicity index LT50-1 and a ratio scale toxicity index LDR50. One water sample per site was taken during June-December 2012, between 9AM-12PM with the assumption that household waste was released. Based on the results, minimum 2-3 grades of LT50-1 value is needed to obtain ideal condition to state the existence of relationship between LT50-1 and LDR50. To obtain value LT50-1 in the river with excessively high toxic or too low trial and error is needed by adding up hours of observation or by making a lower or higher concentrate. Finally, equation obtained for the relationship between LDR50 and LT50-1 is y = 0.1752x with R² = 0.9306. Furthermore, for better accuracy a more profound study is required. In future work, more data will be collected and identify the land use areas for each catchment still require to obtain accurate results. However, with an accurate equation result, it can be used for calculating toxicity of unknown concentrations of toxic compounds; which can subsequently be used to estimate toxic effects in organisms at any time of exposure for any level of concern.
Keywords: Lethal dilution rate (LDR50), median lethal time (LT50-1), toxicity index
Journal of Applied Sciences in Environmental Sanitation Vol. 9/ No. 3/ September 2014
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