Water quality at the habitat of the Podostemaceae in Ghana

The water quality and river catchment characteristics of Ankasa, Asuboni and Pawnpawn rivers in Ghana where Podostemaceae grow were determined using standard methods. The altitude of the sites ranged from 100 to 290 mabove sea level. The catchment areas for the sites vary from 35 to 171 km2. Between 10–81% of the catchment areas of the sites are within forest reserves. The study showed that the Podostemaceae in Ghana inhabit rivers with the following range of physico-chemical characteristics: pH 6.7–7.3, calcium 2.2–16.0 mg l-1, ammonia-nitrogen 0.07–0. 90 mg l-1, chloride 6.8–38.0 mg l-1, electrical conductivity 26.4–138.0 mS cm-1, magnesium 0.4–9.7 mg l-1, nitrate-nitrogen 0.1–0.6 mg l-1, phosphate 0.01–0.30 mgl-1, silicate 0-21.4 mg l-1 and sulphate 1.5–20.8 mg l-1. The results indicate the quality of water at the habitat of Podostemaceae in Ghana

Water chemistry and the distribution of Podostemaceae in Ghana

The physico-chemical parameters of several rivers in southern Ghana were determined during the dry season.  Other environmental features, e.g. canopy cover, rock substrate type, etc. of each site sampled were also recorded.  Four Podostemaceae species were recorded in 10 of the rivers sampled.  The distribution of the Podostemaceae appeared to relate to availability of rock substrate, open canopy and some level of plant nutrients, e.g. phosphates and nitrates in the water.  Further data must be collected at the sites where Podostemaceae grow in the tropics, particularly in Africa, to enable a better understanding of the contribution of river chemistry and other environmental parameters to the distribution of the Podostemaceae.

Cyanobacteria species identified in the Weija and Kpong reservoirs, Ghana, and their implications for drinking water quality with respect to microcystin

The Kpong and Weija reservoirs supply drinking water to Accra, Ghana. This study was conducted to identify the cyanobacteria present in these reservoirs and to ascertain whether current treatment processes removewhole cyanobacteria cells from the drinking water produced. Cyanotoxins are mostly cell bound and could easily be removed during water treatment. However, certain water treatment practices, such as pre-chlorinationand the use of algicides, lead to lyses of cyanobacteria cells and the release of toxins into the water. The study shows that the water treatment process in the two reservoirs is not effective in the removal of all cyanobacterial cells. Out of the six cyanobacteria species identified in the reservoirs, four produce toxins: Anabaena flos-aquae, Cylindrospermopsis raciborskii, Microcystis aeruginosa and Planktothrix agardhii. These four species constituted about 70–90% of the total algal biomass at all the water treatment stages, including the final product supplied to consumers.Preliminary toxicological analysis of intracellular toxin of samples from the raw water intakes of the two reservoirs indicated the presence of microcystin, with the highest concentration (3.21ìg l–1) found in the WeijaReservoir. This study provides the first report of microcystins in drinking water supplies in Ghana