The Fluoride and Trace Metals Contents in the Rift Valley Lake Eyasi Salt a Possible Threat to Human Health

Abstract

The objective of the present investigation was to determine the actual concentrations  of both fluoride and trace metals in Lake Eyasi salts and later to decide whether the salt is safe for human consumption. The importance of knowing optimum concentration of both fluoride and trace metals in human meals cannot be overemphasized, however, if it is left to exceed a minimum set by WHO may be detrimental to human health in both short and long term. This paper has revealed that lake brines and salt crusts contain fluoride concentration with mean values of 273 mg.dm^-3F^- and 2.30 g.Kg^-1F^-, respectively of which are above the acceptable values. In addition, lead content in lake brines is up to 1.83 mg.dm^-3 Pb; Cd = 1.40 mg.dm^-3; Mn = 0.46 mg.dm^-3, and iron is up to 6.60 mg.dm^-3 Fe, thus exceeding WHO and Tanzanian limits which are 0.10 mg.dm^-3 Pb and 0.10 to 1.00 mg.dm^-3  Fe,  respectively. In fact silicon is another contaminant noted in the salt crust which is up to 72.40 g.Kg^-1. It is imperative for Lake Eyasi salts to undergo a thorough purification to remove all contaminants found and stop population from using impure salts which might have long term health problems (ageing, fluorosis, thyroid gland, hypothyroidism, neurological complications, urinary stone deposition of iron oxide and inflammations).