The development of the organisms extracellular and intracellular mechanisms for the uptake of heavy metals were conducted by using the natural detoxification strategies of the organism to toxicity. Aspergillus foetidus was used as a test case organism to examine these processes. Aspergillus foetidus was adapted to multi-metals (Al, Co, Cr, Cu, Fe, Mg, Mn, Ni and Zn) by a sequential method for tolerance development. The detoxification strategies of A. foetidus occurred by two mechanisms. The first mechanism is the production of extracellular metabolites that is capable of adsorbing and precipitating the metal ions on the cell surface. The second mechanism for the detoxification of metals is the intracellular binding of heavy metals to thiol containing compounds such as GSH and sequestering these metalthiol complexes into sub-cellular compartments or vacuoles. These detoxification strategies resulted in adapted organisms with tolerance to multi-heavy metals concentrations and significantly higher metal uptake with adaptation.

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The performance of various commercially available epoxy mortar coatings was compared by measuring their sulphuric acid diffusivity. Apparent diffusivities, which were measured gravimetrically, were found to be dependent on coating tortuosity. In composite materials like epoxy mortars, the tortuosity was determined by filler properties and polymer alignment. Tortuosity was found to depend on the filler size, their dispersion, filler aspect ratio and concentration. The order and greater alignment of polymer aggregates, which characterises thinner coatings effects higher tortuosity and thus lower permeabilities. The result is that sulphuric acid diffusivities were observed to increase with coating thickness, which challenges the notion that greater coating thicknesses provide greater protection or environmental barrier. The effect of film thickness and filler properties observed in this study has significant implications to the current selection of coatings and sewer protection.