MACROINVERTEBRATES AS BIOINDICATORS OF POINT SOURCE POLLUTION OF SAMBUL RIVER, KENYA ...............

Water pollution is a serious global challenge that necessitates regular monitoring of contamination levels in water bodies. Water-borne illnesses are thought to kill approximately 14,000 people per day around the world. Contaminants from a single recognised source are referred to as point source contamination. Residents living near the Sambul River are concerned about pollution of the river's waters by effluent from Moi University's sewage treatment plant (STP). Residents of the Sambul area rely on the Sambul River for both household and agricultural purposes. This research looked at the efficacy of the (sewage treatment plant) employing macro-invertebrates as bio-indicators of contamination in the Sambul River's waters. Three sampling points were chosen using a purposeful sampling design: downstream of the Sambul River, where bio-treated sewage had combined with river waters, at the effluent discharge point to the river, and upstream (control) of the Sambul River, where river water does not mix with STP effluent. Water samples in triplicate were collected biweekly at each sampling station and delivered to the laboratory for examination. From May to August 2015, samples were taken. The Shannon- Wiener diversity index was used to assess the influence of bio-treated effluent on the abundance of aquatic macro invertebrates in the Sambul River. The Shannon-Wiener diversity index (H) and ANOVA results revealed that treated effluent had no significant effect on aquatic macro invertebrate abundance in the receiving river. Upstream (H=2.504), wetland (H=2.4096), and downstream (H=2.371) were the H-values. A high H-value suggests a low number of species diversity, whereas a low H-value indicates a higher macro-invertebrates variety. Higher biodiversity indicates that the wastewater from the STP has been treated to the National Environmental Management Authority's recommended quality (NEMA). The phosphorus concentrations in the various sampled places ranged from 0.05 0.01 to 5.50 0.15 mg/L. Upstream (control) phosphate levels were considerably lower than outlet (F4, 115 = 1125.73; p 0.0001) and inlet (F4, 115 = 1125.73; p 0.0001), but there were no significant differences between downstream (F4, 115 = 1125.73; p = 0.9931) or wetland (F4, 115 = 1125.73; p = 1.0000). The outcomes of this study are critical in demonstrating to interested parties, such as the public and the government; NEMA, that the effluent from Moi University STP is treated in accordance with industry standards. This will restore public confidence in the use of water from the Sambul River.

Please see the link :- https://www.ikprress.org/index.php/JOGEE/article/view/4371