Influence of anthropogenic activities on microbial and nutrient levels along the Mara River tributaries, Kenya

Abstract

Background: A number of factors impact negatively on natural surface water resources across theworld. Although sources of surface water pollution are numerous, anthropogenic activities havebeen singled out as among the most important and of great concern. The aim of this study was toassess the influence of anthropogenic activities on nutrients and microbial levels along the Amalaand Nyangores tributaries of the Mara River in Kenya.Materials and Methods: Four sampling sites along each tributary were specifically selected fromwhich water samples were collected and analyzed for nutrients by use of spectrophotometrictechniques, and coliform bacterial presence by a multiple tube fermentation technique.Results: Higher levels of total phosphorus were recorded along the Nyangores than the Amalatributary (P= 0.02). Significant differences in phosphorus levels were recorded between differentsites along the Nyangores tributary (P=<0.001) and also along the Amala tributary (P= 0.0036).However, total nitrogen levels varied only within sites along the Nyangores tributary (P<0.0001) butnot along the Amala tributary. Similarly, Escherichia coli and total coliform levels varied significantlywithin Nyangores tributary sites. Sites with frequent and direct human and livestock contact hadhigher microbial and nutrient levels, indicative of a localized pollution effect.Conclusions: The findings imply that the health of local communities who depend on this water fordomestic use might be compromised. As such, regular monitoring, strict enforcement ofenvironmental protection laws, public education and proper sewage disposal is recommended.