Available online at www.pelagiaresearchlibrary.com Pelagia Research Library Advances in Applied Science Research, 2013, 4(4):55-62 ISSN: 0976-8610 CODEN (USA): AASRFC 55 Pelagia Research Library Effectiveness of water Hyacinth (Eichhornia crassipes) in remediating polluted water: The case of Shagashe river in Masvingo, Zimbabwe Phanankosi Moyo, Lazarus Chapungu and Boycen Mudzengi Department of Physics, Geography and Environmental Science, Faculty of Science, Great Zimbabwe University, Masvingo, Zimbabwe _____________________________________________________________________________________________ ABSTRACT The aim of this study was to investigate the effectiveness of water hyacinth (Eichhornia crassipes) in remediating a polluted river. Triplicate samples were collected on three different points designated SR1, SR2 and SR3 along the Shagashe River. The course of the river stretching from SR1 to SR3 was covered by over 95% water hyacinth during the period of study. SR1 was located on the upper stream, SR2 centrally and SR3 furthest downstream. Analysis for electrical conductivity, total dissolved solids (TDS), sulphates, phosphates, total hardness, pH, nitrates, nitrites and total nitrogen on all samples was done. Statistical analysis was done to check if there was a significant reduction of the parameters moving downstream. The results indicate that water hyacinth was remediating the river as noted by the significant reduction of electrical conductivity (25% decrease), total dissolved solids (TDS) (26%), sulphates (45%), phosphates (33%) and total hardness (37%) between the sample points SR1 and SR3. Statistical analysis showed no significant changes for the other parameters. Keywords: Water hyacinth, bioremediation, physico-chemical parameters, pollution, phytoremediation _____________________________________________________________________________________________ INTRODUCTION Water pollution is a major environmental nuisance confronting modern day society which could lead to the uptake and accumulation of pollutants by edible plants and fish posing a risk to human and animal health [1]. Every day, 2 million tons of sewage, industrial and agricultural waste is discharged into the world’s water [2]. Rapid urban growth characterised by an increase in human population and industrialisation has seen most municipalities failing to cope with the corresponding rise in waste material they have to handle. In most developing countries this is more often exacerbated by limited municipal budgets [3]. In Zimbabwe, inconsistent electricity supply has worsened the situation. This in some cases has forced some municipalities to adopt unconventional means in handling waste such as dumping raw sewer into water bodies [4]. In developing countries, water pollution accounts for close to 14 000 deaths per day due to consumption of water contaminated by raw sewage [5]. Some studies have shown a link between sewer pollution and an increase in bloody diarrhoea amongst five year old children in Zimbabwe [6]. The effects of water pollution are far outreaching not only having implications on health, but also disruption of aquatic ecosystems [7-9]. There are a numerous types of pollutants found in water. Of major concern in developing countries is the presence of raw sewage waste material, a source of nitrates and phosphates. Nutrients from sewage such as nitrates and phosphates in excess may lead to the process of eutrophication [10]. This is the exponential growth of aquatic plants such as phytoplankton stimulated by an excess concentration of phosphates and nitrates in water leading to what is commonly referred to as an “algal bloom”. As the plants die and decompose, there is oxygen depletion to lower levels resulting in the death of aquatic organisms such as fish. Some algae are also toxic to both plants and humans in some cases leading to mortality of animals [11]. Heavy metal pollution has become a problem which according to Kara [12] can be toxic to both humans and animals even at very low concentrations. This has become more