Mycoremediation of Heavy Metals from Electronic Waste Polluted Water Using Indigenous Fungi and Its Implications

Background: Heavy metals (HM) pollutants are crucial environmental and public health problems due to their toxicity, which has implications on public health. The site of study has been reported to be densely polluted with heavy metals as a result of dumping used electronic wastes into the water body.

Aim: This study was carried out to determine the biosorption potentials of indigenous fungi isolates in reducing heavy metal present in electronic wastes polluted water body.

Study Design: This was a laboratory based study.

Place and Duration of Study: The study was conducted at the Microbial Resources Research Laboratory, Department of Pure and Applied Biology, Ladoke Akintola University of Technology Ogbomoso, Nigeria from July 2021 to June 2022.

Methodology: Heavy metal polluted water sample was collected near the dumpsite of e-waste in Alaba International market, Lagos Nigeria. Fungi were isolated from the polluted water sample by carrying out serial dilution. Pure colonies were obtained and stored at 4°C. Media formulations (MF) trials for the biosorption process was achieved using brewery waste and honeycomb extracts. Exactly 200 ml of MF were dispensed into a 500 ml Elmeryer flask containing 100 ml of the e-waste polluted water and fugal discs. Atomic absorption spectrophotometer was used to determine the heavy metal concentration in the water samples. The biological interactions of the fungi with the polluted water sample was monitored using Fourier transform infrared (FTIR) spectroscopy. The pH, electrical conductivity and other physicochemical parameters were also determined.

Results: Trichoderma harzianum, T. viride, Fusarium oxysporum, Aspergillus flavus and A. niger were isolated from the heavy metal polluted water samples. Heavy metal such as Pb (13.30 mg/L), Cd (16.50 mg/L), Cr (6.41 mg/L), Ni (3.81 mg/L), Zn (8.85 mg/L), Cu (8.33 mg/L), Fe (5.60 mg/L) had values which were higher than the acceptable limits. Biosorption efficiency of each of the fungus in reducing the metals present in the sample was in the increasing order of A. niger<A. flavus<F. oxysporum<T. viride<T. harzianum. FTIR showed that some peaks were shifted to lower wavenumber as a result of the interactions of the fungus with the heavy metal in the water sample. This study revealed that T. harzianum had the highest biosorption efficiency for the removal of heavy metal in the polluted water sample.

Conclusion: It is essential that heavy metals be removed from polluted water body to avoid its deleterious effects on public health. This can be achieved biologically using any of the fungi isolated in this work.