Heavy Metal Concentrations in Sewage Effluent from Durumi, Federal Capital Territory (FCT), Abuja, Nigeria

Abstract

The research was carried out to assess physicochemical and metal qualities of sewage effluent from Durumi in Gudu District of FCT, Abuja. Sewage effluent samples were collected during the dry and rainy seasons in 2014, and analyzed for some physicochemical parameters and heavy metal concentrations, using APHA methods and atomic absorption spectrometry (AAS) respectively. pH ranged from 7.9±1.0 – 7.55±0.1 in dry season and 7.55±1.0 – 7.90±0.00 during rainy season. HCO3- (44.5±2.0 mg/L ), NO3- (0.17±0.01 mg/L ), NO2- (0.06±0.00 mg/L) and BOD (4.2±0.01 mg/L) levels increased at Durumi I, and Cl- (31.00 ± 2.0 mg/L) at Durumi II in rainy season. Physicochemical parameters decreased at Durumi III in dry season. Pb levels at Durumi I (0.01±0.00 mg/L), Durumi II (0.02±0.00 mg/L) and Cu at Durumi III (0.85±0.01 mg/L) decreased during rainy season.  Concentrations of Zn (2.50±0.1 – 2.95 mg/L), Mn (1.62±0.1 – 2.0±0.1 mg/L), and Ni (1.57±0.1 – 1.95±0.1 mg/L) were relatively high, while Cd (0.01±0.00 – 0.03±0.00 mg/L) and Pb (0.01±0.00 – 0.03±0. 00 mg/L) were low. Zn correlated strongly with Cu (0.8077) at Durumi I and Ni (0.9667) at Durumi II in dry season. Correlation for Zn/Cd (0.9359) at Durumi II was strong during the rainy season. Heavy metal concentrations for the two seasons were not significantly different (P= .05). Physicochemical parameters and metal concentrations determined were within FAO safe limits criteria for irrigation.