RESUMO
The surface water systems of Ghana serve as a major source of drinking water, besides other multi-purpose benefit of hydro-electrical power generation and transportation. Thus, the dependence and benefits from such resources are of national interest. For instance, the Pra river of the South-Western surface water system of Ghana was a major consideration for a projected 5 billion m3 water demand in the year 2020 and "African Water Vision 2025". In recent times, the colour state of the Pra river and similar surface water bodies of the Offin and Oda rivers has attracted intense public discussion. The prime issue relates to incessant illegal artisanal gold/diamond mining on or along these rivers. In order to assess the state of these rivers, water samples were taken, and analysed at the Council of Scientific and Industrial Research Laboratory (CSIR, Accra-Ghana) to investigate their physico-chemical quality. The research objective was to assess the extent of their water pollution by measuring physico-chemical parameters of turbidity, colour, pH and content of selected metals. A total of 18 preserved bottled samples [(5 from Offin river and 2 boreholes), 5 from Oda river and 5 from Pra river and 1 borehole)] were analysed, and results compared with portable water standards as defined by the WHO and CSIR (GS-175-1) of Ghana. Results on turbidity, colour, mercury and iron from the river and water samples generally exceed WHO or GS-175-1 limit. The Pra river recorded the most alarming result; range for turbidity (2,010 to 2,745 NTU), colour (3,000 to 4,500 Hz), total suspended solutes (2,240 to 2,570 mg/L) and total dissolved solutes (97.80-99.60 mg/L, excluding 319.00 to 25,440 mg/L). The Oda river shows lowest parameter values among the three rivers, as the areas have been dormant from illegal gold mining for 5 years. Current data suggests polluted river bodies and boreholes, and that none of these water resources meets the portable water consumption criteria unless treated prior to usage. As the current state of the water bodies may incur higher cost of water treatment or purification, an integrated water governance under Ghana's Ministry of Water Resource, Work and Housing, and the Minerals Commission and Environmental Protection Agency are recommended for the management of these valuable water resources.
RESUMO
This study was primarily aimed at investigating the physicochemical and microbial quality of water in 14 such dugouts from five districts in the northern region of Ghana. Results obtained suggest that except for colour, turbidity, total iron and manganese, many physicochemical parameters were either within or close to the World Health Organisation's acceptable limits for drinking water. Generally, colour ranged from 5 to 750 Hz (mean 175 Hz), turbidity from 0.65 to 568 nephelometric turbidity units (NTU; mean 87.9 NTU), total iron from 0.07 to 7.85 mg/L (mean 1.0 mg/L) and manganese from 0.03 to 1.59 mg/L (mean 0.50 mg/L). Coliform counts in water from all the dugouts in both wet and dry seasons were, however, above the recommended limits for drinking water. Total and faecal coliforms ranged from 125 to 68,000 colony forming units (cfu)/100 mL (mean 10,623 cfu/100 mL) and <1 to 19,000 cfu/100 mL (mean 1,310 cfu /100 mL), respectively. The poor microbial quality, as indicated by the analytically significant presence of coliform bacteria in all samples of dugout water, strongly suggests susceptibility and exposure to waterborne diseases of, and consequent health implications on, the many people who continuously patronise these vital water resources throughout the year. In particular, more proactive sustainable water management options, such as introduction to communities of simple but cost-effective purification techniques for water drawn from dugouts for drinking purposes, education and information dissemination to the water users to ensure environmentally hygienic practices around dugouts, may be needed.