Research work titled: ‘Enrichment and Geo-Accumulation of Heavy Metals in Superficial Sediments, Macrophytes and Edible Leafy Vegetables’, secured Dr Elizabeth Kola a PhD in Biological Sciences from the University of KwaZulu-Natal (UKZN).
Heavy metals pose a high risk to human health, aquatic life and ecosystems, explained Kola: “Most activities around aquatic areas discharge some material which contains heavy metals. Heavy metals tend to accumulate in water, sediments, aquatic organisms and even macrophytes.
“To minimise heavy metal contamination in wetlands, it is very important to implement immediate measures to control industrial emissions entering the wetlands,” she said.
Kola acknowledged that conventional methods such as membrane filtration, reverse osmosis and activated carbon are effective in removing heavy metals; however, they are often costly, energy-intensive and environmentally unsustainable.
“This has highlighted the need to develop more affordable, energy-efficient and sustainable treatment approaches,” said Kola, who researched plant-based solutions by assessing the bioaccumulation of heavy metals using aquatic macrophytes (Phragmites australis, Cyperus papyrus, Cyperus dives and Typha capensis) and sediments.
Her study was conducted across five riverside wetlands situated along the Crocodile River in Mpumalanga Province. Kola undertook a subsequent study to determine whether the same heavy metals could also accumulate in the Tonga area, where local communities use water from the wetlands and the river for the irrigation of edible leafy vegetables.
“My findings demonstrated that macrophytes and edible leafy vegetables are the best candidates for phytoremediation,” she said. “These plants and sediments can accumulate different concentrations of heavy metals, which are influenced by seasons.” Kola found that during the hot-dry season, heavy metals were concentrated in different plant tissues, sediments and locations compared to the rainy season.
Born in Moletjie (Ga-Hlahla) and growing up in Ga Matlala (Ga-Sebotse) in Limpopo Province, Kola chose UKZN for her doctoral studies because of its reputation for excellence in teaching, facilities and diversity. Learning from successful and knowledgeable colleagues who obtained their degrees from UKZN also influenced her choice.
She commended UKZN’s various postgraduate training interventions, which she said helped make the research process easier. She was also grateful for financial assistance from the National Research Foundation (NRF), the Aquatic Systems Research Group (ASRG) and the University of Mpumalanga.
During her studies, Kola published all of her chapters and presented one in 2025 at an international conference hosted in Italy by the Society of Medicinal Plants and Natural Products (GA).
She received fieldwork assistance from ASRG students based at the University of Mpumalanga, which made her data collection process more interesting. “Even though it was not easy at times, I drew strength from God,” she said.
Kola thanked her supervisors, Professor Caswell Munyai and Professor Tatenda Dalu, for guiding her professionally throughout her PhD. “I enjoyed this journey and am eager to continue long-term collaboration with my supervisors,” she added.
She also thanked her mother, sisters and brothers for their unconditional love and support; acknowledged her friends and research group colleagues for their moral support and assistance; and thanked UKZN for the supportive, safe and professional environment the University provided.
Kola is currently a lecturer in Plant Studies at the University of Mpumalanga.
Words: Sally Frost
Photograph: Sethu Dlamini