Environmental quality assessment of Upper Birim River (Ghana)

Abstract

The communities along the Upper Birim River use the water resource for domestic and agricultural purposes, and the environmental quality of the river was assessed to determine the level of pollution and associated health risks from consumption and direct contact with the water. The water quality was assessed by the physico-chemical and bacteriological quality parameters. In addition, the impacts of land use activities along the river were also evaluated. Water samples were collected from 6 locations from November 2010 to January 2011 (dry season), and March to May 2011 (wet season). While the mean values of the physico-chemical parameters were within the Ghana Standards Authority (GSA) safety limits for drinking water, the levels of Fe (33.56 ± 31.94 mg/L), As (0.052 ± 0.088 mg/L) and Mn (4.01 ± 4.42 mg/L) were higher than the recommended GSA limits. The faecal contaminations were high, as the mean total coliforms, mean faecal coliforms and the level of faecal streptococci were respectively 1925 ± 708 cfu/100 mL, 1073 ± 900 cfu/100 mL and 16 ± 9 cfu/100 mL. The water quality index (WQI) of 71.79 for the Birim River indicated that most uses of the water were protected, but a few might be threatened or impaired. Hazard quotients determined for Hg, As and Ag were less than 1 at all sampling stations, implying low health risk. Provision of adequate sanitary facilities, enforcement of environm-ental regulations and introduction of livelihood diversification programmes would safeguard the integrity of the River from adverse anthropogenic activities.