Relationship of macroinvertebrate communities and fecal Coliform organisms: as an alternative means to predict fecal Contamination

Abstract

quality assessments in pollution profiles of rivers and streams have been undertaken in different parts of Ethiopia, using fecal coliform, physicochemical and macroinvertebrate as indicator organisms However, there are no studies on assessment of relationship between macroinvertebrate diversity and fecal Coliform counts. Therefore, this study was aiming to show the relationship of fecal coliform with macro invertebrates, so that they could be a potential indicator for fecal contamination of streams and rivers. For this purpose Field assessment and laboratory based cross-sectional study was conducted from June to September 2012. Macroinvertebrate assemblage score together with the data of fecal Coliform and physicochemical parameters all together analyzed using SPSS statistical software. One-way ANOVA was computed to identify mean difference among sites .Also Bivariate Pearson correlation, regression and correspondence analysis were used to describe relationship of fecal coliform with macroinvertebrate indices, families and physicochemical parameters. Results of BMWP, FLBI and ASPT showed that all the study sites were in the range of poor water quality. But Gibe Seka had relatively better water quality while Mite Seka had more poor water quality. There was significant mean difference among sample sites in Coliform colonies (p=0.00) at significance level of 0.05. The count of fecal Coliform was positively correlated with % CHIR (r= 0.77, p=0.003) and FLBI (r=0.6,p=0.016) while negatively correlated with BMWP(r=-0.591,P=0.021) Chironomidae,Gomphidae,sphaeridae,Coenagridae and Ashinidae were observed in sites where high fecal coliform colonies were counted while Cordullidae, Tripulidae Leptoceridae were in streams that had releatively low Fecal coliform colonies . Fecal Coliform count was significantly correlated negatively with Turbidity(r=-0.899, p=0.000) and water TO(r=-0.619, p=0.032). In contrast, positively correlated with EC(r=0.591, p=0.043) and Nitrate(r=0.794, p=0.002).Generally based on this finding and with further model development ,relationships will be used in areas where peoples who have been used surface water for drinking and not have well equipped laboratory for bacteriological analysis.