Analysis of heavy metal accumulation in aquatic plants from River Oli, Kainji Lake National Park, Nigeria

Abstract

This study assessed the heavy metal concentrations in sediment and four selected macrophytes from River Oli, Kainji Lake National Park, Nigeria. Sediments and freshly harvested Pistia stratioties (water lettuce), Eichorrnia crassipes (water hyacinth), Nymphaea lotus (water lily), and Ipomoea aquatica (water spinach) samples were collected and labeled, processed, and analyzed for Lead (Pb), Chromium (Cr), Zinc (Zn), Copper (Cu), Iron (Fe), and Cadmium (Cd) using Atomic Absorption Spectrophotometer (AAnalyst 200). The heavy metals detected in plants collected showed the presence of all metals tested at varying concentrations. Pistia stratiotes (water lettuce) had significant high (p < 0.05) concentration of Fe (6655.18 ± 215.33 mg.kg-1), Zn (42.62 ± 3.26 mg.kg-1), Cu (3.95 ± 0.03 mg.kg-1) and Pb (1.74 ± 0.50 mg.kg-1). The level of Cr (0.006 ± 0.002 mg.kg-1) was relatively (p < 0.05) high in Ipomoea aqautica (water spinach). Furthermore, all metal elements had similar pattern of bioaccumulation (Fe > Zn > Cu > Pb > Cd > Cr) in all aquatic plant sampled. The study revealed considerable variations in the bioaccumulation potential of metals in aquatic macrophytes. It is evident from the study that all investigated plants could be an important bioindicators in the environmental monitoring assessment.