Bacteria; mycorrhizal fungi; freshwater algae; saltmarsh metallophytes; lichens; bryophytes and pteridophytes; angiosperms (asteraceae, poaceae, caryophyllaceae); angiosperms (brassicaceae); aquatic macrophytes; plant response to aluminium toxicity in acid soil; tree crops; tree bark; tree rings and dendroanalysis; heavy metal interactions in soils and implications to soil microbial biodiversity; behaviour of heavy metals in soils.