**3.3 Heavy metal concentrations in plant samples**

*E. hypnoides,* was investigated to establish the metal concentrations and the results are presented in **Tables 9** and **10**. The accumulation of heavy metals in plants show the site's heavy metal pollution status and also the potential of the plant species to uptake heavy metal from the soil [62].


### **Table 5.**

*The contamination factor and pollution load index of zinc at various sites and depths.*


### **Table 6.**

*The contamination factor and pollution load index of lead at various sites and depths.*


### **Table 7.**

*The contamination factor and pollution load index of arsenic at various sampled sites and depths.*

### *3.3.1 Zinc concentration*

The maximum concentration of Zn in the root of *E. hypnoides* was 77.3 mg/kg and the minimum was 21 mg/kg. In the root, the maximum concentration of Zn was 76 mg/ kg and 20 mg/kg were the lowest (**Table 9**). Higher concentration of Zn was recorded in the root of the plant than the leaf with the mean concentration of Zn in the root being 44.98 mg/kg while the average concentration of Zn in the leaf was 44.1 mg/kg. The concentration of Zn in the parts of plants were all more than the concentration of Zn in the soil where the plant sample was taken. This shows that plant bioaccumulate heavy metals in many folds than the soil under normal growing condition [78].

The recommended permissible limit of Zn in plant is 50 mg/kg according to the World Health Organization (WHO) [79]. This is higher than all the concentration of Zn in the roots and leaves of *E. hypnoides* except the eastern plant sample at 500 m (**Table 9**).

