Assessment of pond effluent effect on water quality of the Asuofia Stream, Ghana

Abstract

The study was done to assess the effects of potential pond effluent on the physico-chemical parameters of the receiving streams. Forty two (42) samples were collected from five ponds, upstream and downstream stations of the receiving stream for a period of six months. In situ measurement was conducted for physical parameters using a portable multi-parameter water quality meter (HANNA, HI9828). Samples were collected and transported to the Water Research Institute laboratory, Tamale for the analysis. pH values recorded ranged between 7.6 and 7.9 pH-unit with a mean of 7.69±0.13 pH-unit for pond samples, 7.48 to 7.73 pH-unit with a mean of 7.59±0.1 pH-unit for downstream samples and 7.25 to 7.5 pH-unit with a mean of 7.36±0.11 pH-unit for upstream samples. The nitrate concentrations at the upstream stations (7.57±0.93 mg/l) was found to be higher than that of downstream (5.02±0.25 mg/l) and in ponds (5.0±0.25 mg/l). Comparatively, aquaculture ponds recorded physico-chemical parameters that are significantly higher than those recorded in stream locations. Nitrate and dissolve oxygen were significantly higher at the upstream than downstream and ponds. The study reveals that activities such as vegetables and cereal cultivation, livestock farming and refuse dumping within the watershed serves as source of pollution and nutrient enrichment in the receiving stream.