English

Abstract

The status of waste and its impact on macroinvertebrate assemblages along Msimbazi River was assessed between May 2014 and August 2014. The aim was to identify the type of waste, their potential sources, and the assemblage of macroinvertebrate taxa that have been affected by waste disposal in the river. The study involved field study and laboratory analysis. Results indicated that organic and inorganic waste are the main types of waste dumped into the river; industries and communities living adjacent and along the river are the main waste producers. Macroinvertebrates belonging to eight orders and 27 families were recorded. Macroinvertebrates of the Gastropoda and Diptera orders were the most dominant in occurrence of all macroinvertebrate taxa, contributing 27 and 21%, respectively of the total macroinvertebrates. Based on macroinvertebrates sensitivity, 21 taxa (77.77%) were identified as being highly tolerant to pollution, six taxa (22.23%) as moderately tolerant and none of the most sensitive taxa. Macroinvertebrate diversity indices yielded a slightly lower Shannon-Weiner diversity index (H’=0.42) and the Shannon Evenness Index (0.2050) amongst sites. These findings are indicative of disturbed systems whose severity seems to be driven by the on-going waste disposal within and along the river continuum. Key words: Benthic macrofauna, diversity indices, organic waste, inorganic waste, pollution, waste management.