Heavy metal concentration in surface water after a one-year ban on ASM activities. The case of the Birim Basin in Ghana.

Heavy metals and physicochemical parameters of water from the Birim River and tributaries in the Birim River Basin were analysed to assess its suitability for human use and consumption after a one-year ban on ASM activities in the area. 64 water samples were collected from 32 sampling sites along the Birim River and tributaries within the basin during the dry season and the rainy season, in addition to two repeat samples and two blank samples. Six heavy metals and three physicochemical parameters were analysed and compared with World Health Organisation guidelines. Surface water from the Birim River basin was still unsafe for drinking or other domestic purposes even after a one-year ban on ASM activities. Heavy metal concentrations in surface water were: Iron (0.3 to 21.9 mg/L - wet and 0.3 to 19.3 mg/L - dry), arsenic (<0.0005 to 0.0092 mg/L -wet and <0.0005 to 0.0094 mg/L - dry), lead (<0.0005 to 0.0042 mg/L - wet and 0.007- 0.011 mg/L - dry), cadmium (<0.0001 to 0.0001 mg/L - wet and 0.0001- 0.0002 mg/L - dry), mercury (<0.0001 to 0.0004 mg/L - wet and <0.0001 - 0.003 mg/L - dry) and manganese (<0.038 to 0.76 mg/L - wet and 0.022- 0.56 mg/L - dry). The T-test and one-way analysis of variance (ANOVA) were conducted. Significant changes in pH and conductivity indicate that a discharge or some other source of pollution has entered the aquatic resource, in this case, pollution from ASM activities. This paper provides relevant information for policymakers, environmental experts, and other stakeholders in enhancing water quality. [ABSTRACT FROM AUTHOR]