Water Quality Assessment of Irrigation Water Used by Informal Peri Urban Vegetable Irrigation Farmers: The Case of Tamale Metropolis, Ghana

Abstract

The study assesses water quality of irrigated water used by urban vegetable farmers in Tamale metropolis. It was not only limited to water quality assessment but also dug-out the perceptions of farmers, vendors, consumers and institutions involved as stakeholders in the practice. Also, stakeholder institutions challenges in monitoring the use of wastewater/low-quality water was also unearthed in this study. Mixed method of research design was employed in this study to collect data for analysis. Data collection instruments such as field surveys, policy sustainability test tool was used. Both physical and chemical methods were used to obtained water quality data. The study observed from laboratory analysis of irrigation sites presents of E. coli and heavy metals in all the water samples from the sites. The mean heavy metals concentrations measured in all the sample sites were in the trend Ar˃ Cd ˃ Zn ˃ Pb ˃ Cu ˃ Mn ˃ Fe. The mean concentrations of nutrients such as ammonia, nitrate, nitrite and phosphate were recorded as 0.022mg/l to 5.98mg/l for ammonia, 1.06mg/l to 7.52mg/l for nitrate, 0.031mg/l to 0.056mg/l for nitrite and 0.037mg/l to 0.069mg/l for phosphate respectively. E. coli and Total coliforms levels for Sangani, Kamina and waterworks from the laboratory analysis were recorded as 3.2 × 103 CFU 100m/l and 5.5 × 102 CFU 100m/l, 4.0 × 103 CFU 100m/l and 1 × 102 CFU 100m/l, and 2.1 × 103 CFU 100m/l and 4.6 × 102 CFU 100m/l respectively. Physical parameters were recorded as mean turbidity values were 19NTU and 122NTU whiles mean TDS range between 290.5mg/l and 426.5mg/l. pH was between 6.84 and 7.79. From the documentary review of regulations, guidelines and policy actions, it was revealed that none of the institutions had activities put in place to monitor wastewater reuse. Thus, all guidelines reviewed in this research were all silent on the use of wastewater for vegetable irrigation. Administratively, institutions lacked financial support and were understaffed to carry out its activities. Sustainability policy test revealed that wastewater/low-quality water reuse policy supported the socio-economic and cultural objectives of Ghana.