Water pollution in Ghana and beyond
Water quality is of growing concern in Ghana, with about 60% of the water bodies being polluted with most in critical condition (1). The main cause of this pollution is unregulated industrial activities, such as illegal mining, which leeches toxic heavy metals into the water, while poor plastic waste management leads to severe microplastic pollution.
Figure 1. Map of the Birim River in Ghana. Town locations along the Birim River are illustrated alongside levels of toxic heavy metals above the permissible limits of the World Health Organization (WHO). Toxic heavy metals in question are arsenic, cadmium, mercury, and lead. Adapted from Afuwu and Owusu, 2016 (2).
PE TA LUTION
Our solution was to create a system which enables access to clean and potable water for Ghana by providing a way to remove their two major pollutants: heavy metals and PET plastic.
To this extent, we created PETALUTION which is a holistic solution to water health, where heavy metal biosensors, a heavy metal sequestering bioremediation device through metallothionein-mediated binding, and an enzyme cocktail for PET biodegradation can provide ways to detect and remove pollutants from contaminated water.
Heavy Metal Biosensor
We wanted to create a cell-free biosensor to combine with our bioremediation device to provide a way to quickly detect the target metals cadmium, lead, arsenic or mercury (commonly detected heavy metals in Ghana’s River waters). These biosensors are transcription-only which minimises the device’s necessary components effectively increasing usability and also reducing cost.
Through a literature search, we found the target protein metallothioneins which are metal-chelating proteins. We synthesised and then extracted the metallothioneins, these proteins were then immobilised into a cellulose hydrogel to create our cell-free bioremediation device. The hydrogel is able to take in water which allows the metallothioneins to chelate the toxic heavy metals out of the water and keep them in the hydrogel.
PET Biodegradation Device
We used mutated varieties of the PETase enzyme which can break down and covert polyethylene terephthalate (PET) plastic into more usable monohydroxyethyl terephthalate (MHET). These were synthesised these enzymes and then immobilised onto silica beads. These beads could then be placed in water to break down PET.
Project Promotion Video
- Ampomah B. 60% of Ghana’s water bodies polluted. Water Resources Commission. 2017.
- Oppong Afum B. Heavy Metal Pollution in the Birim River of Ghana. International Journal of Environmental Monitoring and Analysis. 2016;4(3):65.
- Adika S, Mahu E, Crane R, Marchant R, Montford J, Folorunsho R et al. Microplastic ingestion by pelagic and demersal fish species from the Eastern Central Atlantic Ocean, off the Coast of Ghana. Marine Pollution Bulletin. 2020;153:110998.