Irrigation water quality analysis of Mitheu Stream in Machakos Municipality, Kenya

Abstract

Water samples for physico-chemical, heavy metals and bacteriological analyses were collected from 4 selected points along Mitheu Stream flowing through Machakos Municipality once every month from June 2019 to September 2019. The samples were analyzed in Kenya Plant and Health Inspectorate Service and Water Resources Authority laboratories then data subjected to one-way analysis of variance to test significant differences (P≤0.05). The results were compared with World Health Organization guidelines to assess the suitability of the water for irrigation use. Results showed that the levels of the Biological Oxygen Demand and the Chemical Oxygen Demand in Mitheu Stream were higher than critical values permitted by the World Health Organization for irrigation water. Nitrates and Sulphates were within critical limits; however, Phosphates were higher than permissible limits at all the sampling points. Heavy metals concentrations for Cu, Pb, Zn and Cr were within allowable limits for irrigation water, but Cd was above the limit. Both total coliforms and Escherichia coli counts exceeded allowable limits for irrigation water. As such, Mitheu Stream can be considered polluted and the water unfit for irrigation farming. The Municipal authorities, working with other relevant stakeholders should take appropriate measures to mitigate stream pollution from untreated effluent discharged into the stream.

Assessment of Water Quality in Kalundu Stream and Kalundu dam in Kitui County, Kenya

“…Microbial contamination in the study area is coming from domestic wastes, untreated municipal wastes and urban runoff in the riverine system. The findings were comparably lower than those recorded by Kitulu et al, (2020) in Mitheu stream in Machakos town.…”

“…COD values recorded ranged from 104.04 to 9537.0mg/L with a mean value of 3752.38±3485.52 mg/L measured at sampling site S2 which exhibited significant difference from the other two sampling sites (p=0.015). The mean COD values recorded were higher than those recorded at Mitheu stream in Machakos town (Kitulu et al, 2020) but the mean BOD levels were lower in the same urban stream.…”

Heavy Metals and Macronutrients Concentrations in Sewage Sludge Obtained from Decentralized Treatment Facility, Machakos Town, Kenya

“…Currently, Machakos town uses a Decentralized Treatment Facility (DFT) to treat wastewater from the town and this does not cover all the municipal wastewater produced in the town. Large quantities of wastewater are disposed to an old sewerage system that has encountered challenges due to vandalization by urban farmers carrying out agricultural activities adjacent to the plant [18]. The sewage sludge from the DFT is usually removed on weekly basis and left to dry in sludge drying beds.…”

“…Currently, there is urban farming taking place adjacent the Machakos DTF. This includes cultivation of crops and vegetables, and farmers use wastewater from broken sewer lines to irrigate their farms [18]. This study determined the level of selected heavy metals (Zn, Cu, Mn and Fe) and five macronutrients (N, P, K, Mg and Ca) in sewage sludge obtained from Machakos DFT with the aim of knowing its suitability for use as an agricultural fertilizer.…”