Evaluation of water quality and heavy metal pollution in the shoots and roots of aquatic plants

Abstract

The safety of vegetables has been an issue of public concern in recent years. Thus, heavy metals (Cu, Cd, Mn, Pb, Zn and Fe) in the shoot and root of Sacciolepis africana, Ceratophyllun demersum and Pistia stratiotes in Owena reservoir, Nigeria were tested using Atomic Absorption Spectrophotometer while some Physico-chemical parameters of water were measured using multi parameter hand-held meter. The water quality result revealed that the average temperature, turbidity, conductivity, dissolved oxygen and pH were 27.77oC, 7.21NTU, 101.83Ω/S, 6.95mg/l and 6.55 respectively. The single factor pollution index showed that Temperature (0.93), DO (0.99) and pH (0.99) fell within the category of slight pollution while turbidity (1.20) and conductivity (1.02) fell within the medium pollution category. Sacciolepis africana bio-concentrated more heavy metals than Ceratophyllun demersum and Pistia stratiotes. The HRIs of Cu, Cd, Mn, Zn and Fe indicated no risk since all values were less than 1. However, there was a potential risk for Pb through the consumption of the plants despite that the HRI of the shoot of Ceratophyllun demersum (0.65) and root of Pistia stratiotes (0.46) were less than 1. The THQ and HI values for the root and shoot of all the vegetables were less than 1, indicating that they are unlikely to result in any chronic systemic risk-averse health effects.