Originally from Zimbabwe, Migeri found herself at UKZN for her undergraduate Bachelor of Science in Agriculture studies thanks to a scholarship that matched her with the University, her choice of study being influenced by her school results and her parents’ encouragement.

Adjusting to a new environment and acclimatising to the campus was a challenge, but Migeri became comfortable in her surroundings, and exposure to different research perspectives during the final year of her undergraduate studies ignited an interest in postgraduate studies.

Her master’s research, under the supervision of Professor Alfred Odindo, focused on urine and urine-derived products as potential new fertiliser sources for crop production.

The topic was initiated during her final-year research project. Despite the stigma that surrounded working on human waste-based research, Migeri was encouraged in her work during her master’s when she attended conferences and workshops. Seeing the impact that the research could have, she engaged with inspiring people working on research-based solutions. She did not think twice about pursuing a PhD.

During her PhD studies, Migeri became involved with the Rural-Urban Nexus: Establishing a Nutrient Loop to Improve City Region Food System Resilience (RUNRES) project, funded by the Swiss Agency for Development and Cooperation’s Global Programme Food Security and led by Professor Johan Six of ETH Zürich together with UKZN, the International Institute of Tropical Agriculture in Bukavu in the Democratic Republic of the Congo (DRC) and Kigali in Rwanda, and Ethiopia’s Arba Minch University.

The international project aims to establish a circular economy for resilient city region food systems in South Africa, Ethiopia, the DRC and Rwanda through solutions-oriented and transdisciplinary innovation platforms with collaborators from academia, the private sector, government and local communities.

Migeri’s PhD research expanded on whether crop plants can absorb antiretroviral drugs from human urine-derived fertilisers and how this affects soil microbial activity and human health. With urine being a richer source of nutrients than faeces, there has been an explosion of multidisciplinary research into the quantity and quality of these nutrients and how to safely and effectively reuse them while dealing with the pathogenic, olfactory and transportation challenges associated with working with urine.

Knowing plants would take up nutrients no matter the source, Migeri realised the importance of dealing with pharmaceuticals to improve perceptions of using urine-based fertilisers. Given the extensive use of ARVs in South Africa and their excretion in urine, Migeri focused on the effects of these, growing radishes, peppers and ryegrass in clay-like and sandy soils at UKZN’s Controlled Environment Facility. She applied different urine-based fertilisers, including untreated urine stored for three months, to allow pathogens to dissipate; dried urine powder as a nitrogen source; struvite as a phosphorous source; and liquid nitrified urine.

The arrival of the COVID-19 pandemic and associated lockdowns just two weeks after she planted her trials was a practical and emotional setback. Procurement challenges would also delay her research, however, she eventually succeeded in finding that in clay-like soils, plants did not take up much of the ARVs, which remained in the soil. In more sandy soil, plants took up the ARVs. In terms of toxicological thresholds, Migeri found there were no human health risks to consuming these crops because of the minimal amounts absorbed; a person would need to consume 20-40 kg of pepper daily for there to be any harmful effects.

Involvement with the RUNRES project appealed to Migeri owing to its community engagement aspect, which puts research into action and implements innovations. It also provided the opportunity to enhance her interpersonal skills.

Migeri took up the role of project scientist at the Sustainable Agroecosystems Group at ETH Zürich in late 2023. In the long-term, she sees herself working on developmental projects with research institutes as she has appreciated seeing the impact of her work.

She expressed gratitude for her support systems that got her through her PhD. She thanked her supervisors, Odindo and Professor Jeff Hughes for their holistic support, encouragement and belief in her. She thanked her husband, Mr Jethro Marukutira, for his support and for being a sounding board for her work, adding that the support of her office mates at UKZN was indispensable. She also thanked the RUNRES South African team, led by Odindo, for their patience and unwavering encouragement; her parents and three siblings for their support; as well as her church family for providing a diversion from her research.

Words: Christine Cuénod

Photographs: Sethu Dlamini and supplied