Phyto remediation of soils in municipal garden used for production of vegetables was investigated in growing urban community of Makurdi Nigeria. Morphological effects of the metals on vegetable (pig weed) and concentration in garden soil were studied during the growth of the plant. 50kg was sampled between 0-60cm depth (crop root zone) using auger and preserved in polyethene bags to the laboratory and tested for presence of heavy metals. The soil was digested and placed in argon plasma to produce ions that were matched in ration of mass to charge for the heavy metals. Healthy seeds of pig weed obtained from field not associated with dumpsites were planted on the soil sample with agronomic advice and natured to maturity. Plants were harvested and the portals dried r 48 hrs at temperature at 60°C using an oven. Milling of the dried plant parts into powder was performed with a laboratory blender and preserved in glass bottles. All the heavy metals identified to be present in different portals of the plant were quantified and compared with RDA standards. The concentration of As was highest (67.7pmm) while Hg was lowest (19.7pmm) in soil. The extraction of heavy metal which is characterized by bioconcentation factor (BCF) is in the order Hg > As > Cu > Pb > Ni > Cr. These translate to their respective higher values in the TF. The best relationship was established in Hg with 99% regression coefficient although all the metals uptake correlates positively with the period of growth of the pigweed.
Keywords: Urban farming, garden soil, heavy metals, bioremediation and pigweeds