Plants like other living organisms respond differently under different environmental conditions.
An elevated level of heavy metals is one of the stresses which results into three classes of plants
depending on their heavy metal content. The classes of plant species according to their
accumulated heavy metals around North Mara Gold Mine were not known. To study such classes,
a line transect of 700m long was established opposite the gold mine wastes. A total of eight
sampling points were systematically established each after every 100m in that transect. Fifteen
plant species were sampled; at least one species per sampling point. Approximately 5g of the root
and shoot portions of the plants were separately collected from each plant. Three soil samples
were also collected at each sampling point where vegetations were previously sampled. The soils
and vegetations were analyzed for heavy metals (copper, lead, chromium, zinc, cadmium and
nickel) by AAS. Of 15 plant species; 10, 6, 6 were hyperaccumulators, excluders and indicators
for heavy metals respectively. Detailed studies on the agronomical requirements, optimizations,
growth rates and the incidence of pests and diseases are required on the identified heavy metal
hyperaccumulator plants for possible future remediation of the study area.
Mkwawa University College of Education