Assessment of heavy metals from three renowed landfil leachates on Citrullus lanatus (Watermelon) Seedlings

Abstract

This study aimed to assess the levels of heavy metals (As, Cd, Co, Cu, Cr, Fe, Pb, Mo, Mn, Ni, and Zn) in the seedlings of Citrullus lanatus  and landfill leachate. Leachates were collected from three different landfill sites: Oko-Filling (Ok), Ojota (Oj), and Abule-Egba (AE), and  were used to grow contaminated seeds of C. lanatus. The seeds were planted in three replicates each. They were placed in 9 cm Petri  dishes lined with filter papers and moistened with 0.03 ml of the respective leachate at varying concentrations of 25%, 50%, 75%, and  100%. Untreated samples served as controls (0%). Seed germination parameters, including plumule length (PL), radicle length (RL), seed  vigor index (SVI), total seed length (TSL), fresh weight (FW), and dry weight (DW), were measured in the seedlings. Results showed that  seeds had 100% germination at 25% and 50% leachate concentrations from Abule-Egba, while other samples exhibited poor germination  rates. Control treatments had a lower germination percentage compared to other treatments. Olusosun landfill leachate contained the highest heavy metal concentrations, followed by Oko-Filling and Abule-Egba landfill leachate. The levels of heavy metals in both C. lanatus  seedlings and landfill leachate were below the WHO/FAO standard limits. Zinc (Zn) was found to be highest in seedlings treated  with AE50% leachate (0.06 ± 0.00) and lowest in those treated with AE25% leachate (0.02 ± 0.00). The results indicate that Citrullus lanatus  seedlings may be susceptible to heavy metal contamination when exposed to higher concentrations of these metals.