Determination of Heavy Metal levels in Soil and Vegetable Samples around Automobile Workshops in Iworoko-Ekiti, Nigeria

Abstract

This study identified and determined levels of eighteen heavy metals in six soil and twelve vegetable samples (Talinum triangulare and Amaranthus hybridus) from selected automobile workshops at Iworoko Ekiti using Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF). Identical samples were also collected outside this neighborhood as control and analyzed using the same analytical technique. The results indicated that the observed heavy metals in the samples from the sites and control were within the range (1.044-3180.224) mg/kg and (1.002-1845.744) mg/kg. The soil samples were slightly enriched in vanadium, manganese, nickel, copper ,zinc, arsenic, selenium  and rubidium (Enrichment Factor (EF) = 1.033 – 2.179). Significant differences also exist between the levels of calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, arsenic, and yttrium (at p < 0.05, t = 0.00002 – 0.03950). The accumulation factors of the vegetable samples in Amaranthus hybridus were in the range 0.0006 – 824.1057 and those of Talinum triangulare were in the range 0.00019 – 338.76885. The relatively higher levels of chromium, manganese, iron, nickel, copper, zinc and arsenic in the vegetable samples from the sites compared with WHO/FEPA permissible limits was an indication of contamination: The consumption of vegetables in such an environment could be detrimental to health.