Lake Victoria is eutrophicated with Myxophyceae (blue green algae blooms), Vassia cuspidate griff (hippo grass) and Eichhornia crassipers (water hyacinth) being evident. Several problems have been identified that have arisen out of this eutrophication problem in the Lake, among them being but not limited to water quality. This book therefore, endeavored to substantiate the source of the reported phosphates in Rivers Nzoia, Yala, Kisat and Nyalenda waste water treatment plants in Kenya. This was achieved by assessing phosphate levels in water, sediments and air above the rivers both upstream and downstream. Sediment and water samples were collected using a grab sampler while air samples were collected using the atmospheric deposition sampling method. Sampling was done during the long wet and dry seasons. Water and atmospheric air samples were analyzed using UV-Visible spectrophotometer for total phosphates as sediments being analyzed for bio-available and exchangeable phosphates. Completely randomized design three factors was used, replicate of air, water and sediment from Rivers Nzoia, Yala, Kisat and Nyalenda waste water treatment plants in Kenya.