Investigation on Possible Heavy Metals by Pawpaw (Carica Papaya) Cultivated Near a Dumpsite in Nekede Mechanic Village

Abstract

The research focused on possible adsorption of heavy metals by pawpaw (Carica Papaya) fruits cultivated near a dumpsite in Nekede. The projects were aimed at determining the extent of the absorption of heavy metals by the pawpaw and also determine if the pawpaw cultivated in a dumpsite is wholesome and fit for human consumption by comparing the results with the regulatory bodies (WHO/FAO and USEPA) permissible limits for food and soil respectively. Samples were collected in strict adherence to regulatory standard prior to transportation to the laboratory for analysis. Soil sample were collected using hand auger at 0-15cm for Top Soil and 15-30 cm for Sub Soil while the pawpaw fruits were wrapped in a sterile cellophane bag. The digested samples analyzed for heavy metal contents using the atomic absorption spectrophotometer (Model: FS 240 AA). The samples were analyzed to determine the presence of metallic ions of Copper, Cadmium, Zinc, Aluminium, Lead, Nickel and Arsenic. The research project found out that Arsenic had the highest concentration in pawpaw fruits in the three (3) sampled stations with a concentration of 4.55-6.31ppm. The least concentration of heavy metals in the pawpaw fruits was Cadmium in all the sampled locations with the range of 0.056-0. 142ppm.Aluminium had the highest concentration with the range of 26.74-40.67ppm and22.41-39.26ppm in all the sampled locations for top soil and sub soil respectively. Nickel had the least concentration in the analysis with the range of 0.096-0.275ppm for top soil while Cadmium had the least concentration in the analysis with the range of 0.168-0.209ppm for sub soil. The soil-plant transfer factor of different heavy metals shows that Nickel had the highest transfer potential. The transfer orders were: TFNi> TFAS >TFcd>TF2n>TFAI-TFCu>TFPb. Copper concentration in PFS2 and PFSC, Cadmium concentration in PFS1 and PFSC, Zinc concentration in PFS2, Lead concentration in PFSC

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