Studies on the chemical composition of precipitation during 1991–92 rainy season in Zimbabwe

Abstract

The levels of various chemical constituents in composite samples of rainwater from six selected locations in Zimbabwe (Harare, Gweru, Kwekwe, Nyanga, Triangle and Hwange) for the 1991–92 rainy season were determined. For a typical composite precipitation sample (December 1991) from Gweru located in the midlands of Zimbabwe, the total monthly rainfall was 27 mm, and conductance and pH were respectively 6.20 μS cm‐1 and 6.78. The concentrations of the anions (μM 1‐1) were sulfate 4.37, chloride 6.77, nitrate 0.58 and bicarbonate 11.75. The cations levels (uM 1‐1) were ammonium 1.83, potassium 2.05, sodium 8.7, calcium 4.24 and magnesium 1.60 and H+ 0.17. The levels of selected heavy metals (uM 1‐1) were copper 0.03, nickel 0.01 and zinc 0.28. For internal consistency, quality of analytical data was also tested by calculating the charge balance and conductivity ratios. The quality status of the ambient environment in Zimbabwe is discussed.