Trends analysis relating to pollution in Sakumo Lagoon, Ghana
Sakumo Lagoon, situated near Accra, is a Ramsar-listed coastal wetland threatened by urban and agricultural waste, being located in an urban area where access to domestic and waste disposal facilities is a major problem. The aim of this study was to assess the pollution status as well as trends, in terms of pollution loading, in the lagoon. Nutrients, dissolved oxygen, biochemical oxygen demand, suspended solids, temperature, pH and faecal coliforms were monitored on a quaterly basis from 1997–1998 and 2001–2002, covering both wet and dry seasons. Significant increases in the mean concentrations of suspended solids, ammonia-nitrogen, phosphate-phosphorus and biochemical oxygen demand indicated an increase in the level of pollution in the lagoon. Faecal coliform counts were fairly high, exceeding 130 counts 100 ml–1, which is the maximum acceptable count in Ghana for water used for recreation. Results from the study suggested rapid deterioration of the lagoon water quality between 1997 and 2002. Domestic and agricultural discharges into feeder streams were the main sources of pollution, as well as decaying plant material in the lagoon.