210 likes | 333 Views
Thuli and Mzingwane catchments’ hydrochemistry Implications for risks. WHY HYDROCHEMISTRY. Aim is to improve water availability But quality of water affect the quality Human healthy crops health Livestock health
E N D
Thuli and Mzingwane catchments’ hydrochemistryImplications for risks
WHY HYDROCHEMISTRY • Aim is to improve water availability • But quality of water affect the quality • Human healthy • crops health • Livestock health • Thus starting point for any improvement in human health & agricultural productivity increasing/retaining the right quality of water.
Scope of this work • Determination of hydrochemistry to provide • Baseline data • Water quality risk assessment
Methods 36 Surface water (SW) and Groundwater (GW) SW= rivers and dams, GW= borehole samples from alluvial aquifers. Analysed at National Water Quality Laboratory, Harare. Analysed for cadmium, copper, iron, manganese, nickel, arsenic, zinc, calcium, , potassium, sodium, magnesium, nitrate,nitrite, chloride, phosphate, sulphate, alkalinity, total dissolved solids and pH.
Methods pH and electrical conductivity – electrodes As, Cd, Ca, Cu, Mg, Mn, Ni, K, Na Zn - AAS Fe, nitrate, nitrite and phosphate -Ultra-violet spectrophotometry. Chloride, alkalinity and total hardness – titration total dissolved solids - gravimetry. Sulphate - turbidimetric method.
Risks to human health Cd in GW and SW Throughout the two sub catchment Nitrates – GW- Localised Manganese –SW - Localised
Risks to livestock and Crops Chloride ( livestock) –GW- Localised Iron ( crops)- GW- Localised
Aesthetic and Taste Manganese – GW & SW- throughout Iron -SW- localised TDS- GW- Localised TH- GW- Localised
Comparison to other catchments Similar results Zhulube catchment (Tunhuma) Hg noted in Zhulube not analysed in this study Lesser sites contaminated than Moza (Chilundo) Zn, Cu, Fe, Na+, Ca2+, Mg2+ noted in Moza not a problem in study area As & Se noted in S.A not analysed in the two sub catchments
Recommendations Follow up Cd problem (different lab) Establish source of Cd (natural vs pollution) Establish threshold limits for the communities associated Hg not analysed due to costs need to be followed up as it was picked in Zhulube Encourage responsible farming so that the quality of water does not deteriorate further