ASSESSMENT of WATER QUALITY USING PHYSICO CHEMICAL AND MACROINVERTABRETE INDICES, IN CASE OF AWETU RIVER, JIMMA ETHIOPIA.

Abstract

The quality of water resource of Ethiopia is declining as a resulting of severe environmental degradation and some human made problems. It is necessary that the quality of drinking water should be checked at regular time interval, due to use of contaminated drinking water, human population suffers from varied of water borne diseases. The aim of the study was to assess the Pollution status of Awetu River by physico chemical parameter and the extent of microbial with environmental matrices. In this study water samples were collected from six sample sites of Awetu River using sterilized bottles and have been analyzed for some physico chemical parameters like pH, electrical conductivity (EC), total suspended solids (TSS), alkalinity (A), biological oxygen demand (BOD), chemical oxygen demand (COD), dissolved oxygen (DO), Nitrates and phosphates. Analysis was done using complete randomized design (CRD) with three composite replicates in each sample stored in 4 oC and subjected to analysis with interval of 24 hours. Bottles and materials were sterilized and covered to protect contacts. Canonical correspondence analysis (CCA) was used for the identification of physicochemical parameters which was more affect the assemblage of macroinvertabretes. Shannon and Simpson diversity indices were performed for calculation of taxa, data analysis was performed by variance (ANOVA) using statistical analysis software (PAST-3) software. The result of physicochemical parameters such as pH, temp, Conductivity and Turbidity were determined (7.78, 23.86 OC, 94.46µs/cm,7.6 NTU) respectively at site, where as TSS, COD, BOD, Nitrate, Alkali and orthophosphate were (152.5mg/l, 957mg/l, 765.5mg/l, 2.02mg/l, 375.8mg/l, and 0.051mg/l) respectively identified in laboratory. From the result data PH and DO were in a permissible standard of WHO (6.5-8.5), (5-7) mg/l respectively. Turbidity, TSS, COD, BOD, and Alkali were not the standard of WHO. Macroinvertabrates result of the river was a total of 1142 individual, 8(eight) and (30) families were collected from upstream to downstream of the river. Results reveal that there is a highly significant difference between the 6 (six) selected sample site of the river. Ec, BOD, alkali and orthophosphates were more affect the benthos assemblage communities of the River. macroinverabretes indices value of the all sample site shows (Shannon and Simpson) diversity indices result (2.269-2.952)bit and (0.897-0.932)bit respectively, shows the river was lightly and very lightly polluted by solid and liquid waste disposed to the river. So that direct using of the river for drinking and washing of food causes healthy risk.to control the pollution risk, avoiding waste discharge to the river