Seasonal Variation in Heavy Metal Content of Lake and Underground Water in Some Selected Towns around the Bosomtwe Crater Lake

The levels of Arsenic, Iron, Lead, Zinc, Chromium, Cadmium and Nickel in water samples from Lake Bosomtwe and Bore Holes in some towns around the Lake have been determined using Atomic Absorption Spectrophotometer (Varian AAS 220). The levels of Arsenic, Cadmium and Nickel were generally small and were below the detection limit of the instrument. The results showed seasonal variations in the mean levels of Pb, Fe, Zn and Cr in water from the Bosomtwe Crater Lake. There were significant correlations between the mean levels of Fe and Pb in the underground water in the two seasons whilst Zn and Cr showed weak correlation in underground water for the wet and dry seasons. The levels of the metals in the bore holes were generally below the WHO standard values compared to the levels of the metals in the water samples from the lake. The mean pH values for water samples from the bore holes in the towns around the Bosomtwe Crater Lake were within the WHO standard of 6.50-8.50. Keywords: Lake Bosomtwe, Borehole, Crater, Heavy metals, Atomic Absorption Spectrophotometer

Chemical Analysis of Freshwater Bodies in the Kumasi Metropolis and Its Environs, Ghana

One of the main environmental problems facing the city of Kumasi the second largest city in Ghana over the years has been the pollution of water bodies arising from anthropogenic activities. This has become a potential health threat to the inhabitants of the city which was formerly referred to as the garden city of Ghana and its environs. The most affected are the surrounding rural areas that rely solely on the rivers for drinking, domestic and agricultural purposes. This study focused on the extent of chemical pollution of these water bodies through the determination physicochemical parameters such as pH, temperature, conductivity, total dissolved solids (TDS), Total suspended solids (TSS), alkalinity, Total hardness, nitrates, sulphates as well as heavy metals and biological contamination through the determination of total coliform and Escherichia coli. Eight samples were taken from three main rivers in the Kumasi metropolis namely Wiwi, Sisa and Subin. This data showed variations in the parameters in the samples as follows: pH, 6.67-7.50; temperature, 28-29°C; electrical conductivity (EC), 220-2120 mS/cm; TDS,10-1800 mg/l; alkalinity, 24-124 mg/l; total hardness, 25-365 mg/l; nitrates, b/d-0.47 mg/l; sulphate,0.352-40.30 ; phosphates, 5.2-30 mg/l; Pb, 6.620-6.797 mg/l; Fe. 14.81-45.65 mg/l; Mn, 0.726-4.7427 mg/l; Cd, 0.156-0.219 mg/l; Cr, 0.03-0.10 mg/l; Ni, 0.002-0.018 mg/l; Cu 0.113-2.258 mg/l and Zn 0.368-5.255 mg/l.  However, all the results obtained for the levels of the metals exceeded the EPA Maximum contaminant level (MCL) with the exception of the zinc where only one of the samples exceeded the MCL level. Keyword: environmental, chemical pollution, Maximum contaminant level, physicochemical parameters, Kumasi-Ghan

Bioaccumulation of Heavy Metals in Some Tissues of Fish in Lake Geriyo, Adamawa State, Nigeria

Bioaccumulation of heavy metals (Zn, Pb, Cd, and Cu) was determined in the liver, gills, and flesh from benthic and pelagic fish species collected from Lake Geriyo covering two seasons. The levels of the heavy metals varied significantly among fish species and organs. Flesh possessed the lowest concentration of all the metals. Liver was the target organ for Zn, Cu, and Pb accumulations. Cd however exhibited higher concentration in the gills. Fish species showed interspecific variation of metals. These differences were discussed for the contribution of potential factors that affected metals uptake like age, geographical distribution, and species-specific factors. The concentration of metals in fish flesh was accepted by the international legislation limits for Cu, Zn, and Cd; however, Pb transcend in Clarias and Tilapia during wet season and Heterotis in both seasons, hence unsafe for human consumption and a threat to public health. These levels might be due to anthropogenic inputs as there is no industrial activity around the lake

Mercury and arsenic in the gold mining regions of the Ankobra River basin in Ghana

The river Ankobra flows through the principal gold mining centres in Western Ghana, draining a total area of 8272 km$^2$ to join the Atlantic ocean. Mercury is used by thousands of small-scale miners in the region to amalgamate gold. Ores mined in some deep shafts and surface mines are arsenopyrites and the region is marked by the presence of heaps of arsenic - rich mine tailings from both past and recent activities. This study was conducted to assess the impact of mining activities on the distribution and speciation of arsenic and mercury in the aquatic environment of the Ankobra River. In all, water (filtered and non-filtered) and bed sediments were collected from various locations within the watershed. Principal parameters investigated include total mercury, arsenic (III), arsenic (V), monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA). Seasonal and spatial variations of these parameters were investigated. Quality control systems were adopted at both the environmental and analytical stages of the study. ln general, areas close to the mining centres are the most pollilited. As (V)/As (III) ratios in water are reversed after the first 100-km of the river length with the onset of industrial influence downstream