Risk Assessment of Heavy Metals Level in soil and Jute Leaves (Corchorus olitorius) Treated with Azadirachtin Neem seed Solution and Organochlorine Pesticides

Abstract

Synthetic agrochemicals are increasingly being relied upon as the easiest of way eliminating pests on our farm. However, synthetic chemical increases heavy metals in the soil, which is then likely transferred to plants that grow on such soils, with the associated risks of long term toxicity to humans that consume them and other biota in the ecosystem. Nonetheless, some plants like the neem plant have been reported to contain components that are natural pesticides. This study was therefore to determine the comparative presence and concentration of some heavy metals in Jute leaves (Corchorus olitorius) treated with Azadirachtin Neem Seed Solution (ANSS) and Organochlorine Dichloro-diphenyl-trichloroethane (DDT) pesticides and the human health risk associated with their consumption.Jute plant treated with ANSS and DDT and their corresponding soils were collected in triplicate from 6 pots and a control without treatment using same soil and seed. Physicochemical properties of the soil samples were determined using a standard methods. The concentrations of Pb, As, Cd, Cr and Cuin the soil before and after planting and in the leaves were determined using Atomic Absorption Spectrophotometry. The potential health risk from the consumption of these vegetables was assessed using standard methods. Results obtained showed the presence of heavy metals (Pb, As, Cd, Cr and Cu) in Corchorus olitorius leaves and soils treated with each pesticide. Treatment with DDT pesticide elicited higher (P<0.05) heavy metals concentrations in the soil and vegetable compare to ANSS biopesticide treatment.The concentrations of Pb, As, Cd, Cr and Cu were 1.41, 2.06, 1.04, 1.85 and 3.78mg/kg respectively in Corchorus olitorius treated with DDT exceeded the WHO/FAO permissible limit of (0.3, 0.5, 0.2, 0.3, and 3.0mg/kg respectively) for edible vegetable. The Hazard Index (HI) of heavy metal contamination in the vegetables treated with ANSS and DDT was less than 1 suggestingit is safe for consumption, however the result shows that children are at greater risk from continuous consumption of Corchorus olitorius treated with DDT pesticide. The study concludes that the concentration of heavy metals in Corchorus olitorius treated with DDT pesticide exceeded the WHO/FAO permissible limits in vegetable. This showed that consumption of these vegetables treated with synthetic pesticide could pose health risk from heavy metal contamination.