Influence of Soil and Rain on the Levels of Inorganic Anions in Amaranth Leaves from Selected Parts of Kenya

Abstract

The aim of this work was to determine the level of inorganic anions (NO₃^-, Cl^-, SO₄^2-, PO₄^3-, F^- and I^-) in the leaves of two species of amaranth (Amaranthus hypochondriacus and Amaranthus cruentus) planted in Kenya. The mean levels of inorganic anions, nitrate (NO₃^-), chloride (Cl^-), sulphate (SO₄^2-), phosphate (PO₄^3-), fluoride (F^-) and iodide (I^-), in the soil from four study regions (Kenyatta University (KU), Bureti, Kisii and Elgon) of Kenya were quantitatively determined. The levels were determined using spectrophotometric, potentiometric and titrimetric methods. The mean levels of  Cl^-, SO₄^2-, PO₄^3-, NO₃^-, F^- and I^- in soils ranged from 1146.54 to 2733.31 mg/100 g, 1821.60 to 2185.33 mg/100 g, 828.54 to 1111.36 mg/100 g, 1015.55 to 1910.66 mg/100 g, 66.95 to 79.77 mg/100 g and  8.00 to 12.57 mg/kg respectively. The levels of most anions in leaves of A. hypochondriacus and A. cruentus were not significantly different. The means levels of the anions in leaves of the two species indicated that Cl^- ion had range of 503.74 to 673.81 mg/100 g, SO₄^2- 701.61 to 955.17 mg/100 g, PO₄³ 532.36 to 629.46 mg/100 g, NO₃^- 495.79 to 880.99 mg/100 g, F^- 7.22 to 9.67 mg/100 g while I^- ranged from 2.54 mg/kg to 5.26 mg/kg dry weight. The levels of all inorganic anions determined were found to be within the allowed daily intake (ADI) values. Based on the results of this study, it is recommended that leaves and grains from both species of amaranthus grown in most regions in Kenya may be consumed for nutritional requirements. The consumption of between 250 g and 300 g of fresh amaranthus leaves is sufficient to provide the required daily intake of all the anions considered in this study for all healthy individuals.

Keywords: Amaranth, Anions, Amaranthus, Tonui