Research Article
Alemayehu Wudneh, Abdulnasi
Abstract
Both surface and ground water sources have being likely subjected to various pollutants from intensive farming practices in the study area. But, no attempt has been made so far to understand the impact of intensive farming practices on local water resources. This research was conducted in Sinana district of Bale zone particularly nearby Oromia Seed Enterprise (OSE) farms. Ground and surface water samples were collected from upper, middle and lower parts using depth integrated and composite sampling techniques. Selected physico-chemical water quality were analyzed and compared with human and livestock drinking standards. In-situ measurements were done for sensitive water quality parameters while other parameters were analyzed at Hawassa University’s technology laboratory. Kruskal-Walis H-test revealed that the intensive farming practices of OSE have not significantly increased the expected pollutant level to the water bodies (mean rank between upper, middle and lower part of the study area were 24.47, 24.57 and 24.47 order). This indicates that eco-friendly farming practices by the Enterprise and due to the subsoil characteristics of the study area, the mobility of nitrate and other anions decrease with increasing positive net charge in the local soils. The mean temperature, major nutrients (NO2-, NO3-, NH3 and PO4-), Si2O, DO, COD, TOC, Cl, and Fl, were far below WHO acceptable limit whereas TDS, EC, metallic ions (K, Ca, Mg, Fe, Mn, Cu and Al) and turbidity have exceeded the WHO limits for some water samples of surface and ground water. Most of the water samples’ dissolved oxygen was within 5.5-9.5 mg/l of WHO minimum permissible limits which were between 5.64-8.37 mg/l. Only at one sample site during wet season, Iron concentration scored above acceptable limit (0.3 mg/l) by 0.29 mg/l for human drinking and only copper level in the water is above permissible limit (2 mg/l) twice during dry and wet seasons (5.2 and 2.05 mg/l, respectively). However, all water samples' potassium level were above WHO upper limit i.e. 1.5 mg/l. Manganese level was above acceptable limit (0.5 mg/l) for a ground water sample during wet season by 0.15 mg/l. 16.67%, 50% and above 75% of samples indicated turbidity, magnesium, and calcium level were above WHO standard, respectively. About 66% of water samples TDS were less than 440 mg/l during both seasons which can potentially increase water and feed intake of livestock. The occasional water quality levels exceeded the WHO guideline values may not be a difficulty for immediate anxiety, but rather activate for further monitoring and study in the nearby future.