INFLUENCE OF HEAVY METALS ON THE GROWTH OF TWO COMMON WEEDSHyptis suaveolens AND Sida acuta IN LAFIA, NASARAWA STATE

Abstract

An assessment of the influence of heavy metals on the growth of two common weeds Hyptis suaveolens and Sida acuta in soils of polluted areas and an unpolluted soil (control) in Lafia, Nasarawa State, Nigeria was carried out. Soil samples were collected in three replicates from an automobile workshop site (AWS), refuse dump site (RDS), and unpolluted soil (UPS) in Lafia. The growth of each plant was monitored in an interval of two weeks for a period of 8 weeks. The heavy metals investigated in the soil include Cu, Pb and Zn using digestion process and atomic Absorption Spectrophotometer (AAS). The heavy metal analysis revealed that AWS recorded highest concentration (0.71 mg/kg) while UPS recorded the least concentration of Pb (0.28 mg/kg) respectively. RDS had the highest concentration of Cu (0.61 mg/kg), while UPS had the highest concentration of Zn (0.19 mg/kg). It was observed that Hyptis suaveolens grew better on RDS and the growth parameters were seen to be significantly different from AWS and UPS. The AWS recorded least growth parameters which is likely due to the high level of metal concentration in the soil. Similarly, Sida acuta grew better on RDS and the least in AWS. The use of weeds which are not consumed by humans and animals should be encouraged in phytoremediation in order to prevent the effects of waste-related problems in the environment.