Environmental Toxicology and Chemistry in Africa: Exchanging Knowledge and Progress on Tackling Legacy and Emerging Pollutants

Tarryn Lee Botha, University of Johannesburg; Iseult Lynch, University of Birmingham; Jon McCosh, Institute of Natural Resources; Emily Forbes, Joint Nature Conservation Committee

The Environmental Toxicology and Chemistry in Africa session was the second of its kind at SETAC Europe, the first being in Dublin in 2023. This year, two proposed sessions were Africa-focused, and these were combined to include knowledge exchange and progress. The session aimed to bring researchers from various background together and thereby address common challenges in Africa. This would assist in facilitating knowledge-sharing, community-building and potentially stimulating new collaboration opportunities.

The session was kicked off with introductory remarks by Jon McCosh, who highlighted the World Mercator projection showing the world to its true size. He stated that Africa is larger than shown, that it is a developing nation with various challenges and that lessons can be learned through existing and emerging international research, but that solutions relevant to the African context are necessary. Four of the six presentations focused on work under the Environmental Pollution Programme in South Africa, which aims to build a legacy to manage the impacts of pollution, tackle diaper pollution, recover an estuarine environment after a catastrophic agrochemical spill, and use what is learned from the program to build a longer-term legacy. Other presentations included chemical mixtures in Kenyan Rivers, a scoping study on water quality challenges in South Africa, and a previous poster spotlight that was upgraded to a full presentation relating to polycyclic aromatic hydrocarbon emissions from pre-harvest sugar cane combustion.

Nick Rivers Moore presented on the Environmental Pollution Programme, which highlights waste and solid water impacts. He alluded to the Triple Planetary Crisis, which is climate change, pollution and biodiversity loss. Further to this, uneven water distribution often disrupts infrastructure and forward planning is required as wastewater treatment plants can be directly affected by flooding. The project includes a scoping and modeling phase that could be upscaled. He stated that the scoping phase would include service delivery hotspots to avoid further infrastructural damages that could lead to pollution events. A legacy could be achieved through the program impact by incorporating product, process and people. In a second presentation, he also covered river flow data and flushing events as part of the program.

Ayanda Lucky Shandu, presented on diaper (or nappy) pollution, which is a pressing global issue in both rural and urban environments. The talk outlined how nappy waste could be repurposed by investigating the use of used nappies in combination with fertilizer and biochar as soil amendments in a perennial fodder cropping system. It was found that tiller counts, chlorophyll concentrations and plant biomass were higher compared with treatments without amendments. The diapers immobilized fertilizer and retained water within the soil. Roots could penetrate the diaper, which holds moisture enabling plants access to water in the dry season. Further studies were needed to determine the abundance and movement of nutrients and microplastic pollution between the diaper, soil and plant.

Patricia Forbes gave an intriguing talk on sugarcane burning as part of its production, and how its air quality effects are beyond nuisance. The study assessed PAH distribution by using a portable air quality monitor (the size of a punch hole) in burn events, which took approximately ten minutes to complete, and found that standard techniques underestimate PAH levels. Small smoldering fires coupled with high winds increased PAH levels and the type of sugar cane harvested shifted these levels further. The talk outlined the need for best practices at every stage of harvest.

Mzamo Mpendulo Mnikathi, presented on an environmental catastrophe that occurred in South Africa during the 2022 protests, where a chemical warehouse containing vast amounts of agrochemicals was burnt down leading to environmental contamination. Three areas are being monitored to compare the recovery of the impacted estuary against reference sites. Periodic sampling was undertaken to understand the recovery of the river and estuarine system using the Fish Response Assessment Index (FRAI) and The South African Scoring System (SASS) for macroinvertebrates along with water quality monitoring. While Mnikathi was able to note some signs of recovery, it was highlighted that ongoing chronic pollution was likely a factor limiting recovery. The recovery of the system is under continual biomonitoring.

Isaac Cheruiyot Tanui presented a poster spotlight showing a comprehensive chemical analysis in Kenyan River systems specifically related to water scarcity. Water samples were collected and screened for chemical contaminants and toxicity testing was undertaken using algae, daphnia and fish. Tanui found that in the dry season, 96% of chemicals exceeded risk limits. He suggested more conversation continue at his poster.

An additional aspect is a call for European and other researchers with an interest in or focus on Africa to participate in the SETAC Africa-hosted meetings every other year as this opens clear lines of collaboration and strengthens the CARE (Collective Benefit, Authority to Control, Responsibility, and Ethics) research data management principles for research in Africa. African scientists provide a unique perspective on the socio-economic challenges and geological backgrounds. Please also join us next year in Vienna for the third Environmental Toxicology and Chemistry in Africa session.

Author’s contact: [email protected]