Concentration of I2, Na, K, Mg and Fe2+ in Soils, Plants, Ash and Salt Samples of Selected Areas of Western Kenya

Abstract

Table salt is one of the most used food additives with a unique place in food consumption. The chemical and physical composition of traditional salts is not well understood. Two types of reeds from Lugari and Busia regions of western Kenya were studied to establish the concentration of selected nutrients and determine some of the factors affecting the micronutrient content. Cyperus papyrus and Typha latifolia reeds of Lugari and Busia regions respectively, grow in weak acidic soils of pH range from 4.9-6.5. It was observed that an increase in the soil's percentage clay content increases CEC while an increase in soil bulk density decreases the soil's CEC. Soil iodine was found to depend largely on depth, SBD, percentage clay clay and moisture. An increase in depth led to a decrease in iodine level in soil with the top soils (0-15 cm,) recording higher iodine content than sub-soils (15-30 cm deep). As iodine increased with increase in SBD and % clay, Fe 2+ concentration increased with increase in depth in the dry season. There was higher concentration of iodine in Cyperus papyrus reeds from Bidimbidi than in Ululo during both the wet and dry seasons. The K content of T. latifolia was higher than that of C. papyrus with K levels increasing with increase in iodine concentration in both plants. Busia reeds had more Na and K than Lugari reeds for both the wet (2871.8 mg/kg > 2519 mg/kg) and the dry (367 mg/kg > 223 mg/kg) seasons. In the present study, Iodine, K, Na, concentrations increased with ashing process while a decrease in Mg was noted. The concentrations of K and Na were higher in soils than in plants with a Tf ranking order of Na > K > Mg > I for both Busia and Lugari regions. The order of decreasing concentration of the micronutrients in the salt was of the form Na> K >Mg for Busia while for Lugari it was K >Na >Mg. On average, Busia Cyperus papyrus salt had higher Na, pH and moisture content but lower K, 11,930 mg/kg, 10.3, 10.1 % and 3,736.2 mg/kg compared to Lugari Typha latifolia salt whose Na, K, pH and moisture are 3,943.8 mg/kg, 4,635.8 mg/kg, 9.7 and 0.8 % respectively.. Lugari salt samples had a Na:K ratio of 0.9 while Busia's C. papyrus salt had a Na:K ratio of 3.2. Comparing the Na: K ratio of the types of reed salts, T. latifolia has 0.85:1 while C. papyrus has 3.2:1 compared to 4:1 recommended by WHO 2006. From the results, Cyperus papyrus salt may be a better and ideal food salt than Typha latifolia.