Phase V – Microplastic: Assesment of the Ecological Aspects of Microplastic Pollution in Dar es Salaam, Zanzibar and Mombasa Coastal Marine Environments (MICROMARE)

The MICROMARINE project, approved by the Western Indian Ocean Marine Science Association (WIOMSA) in 2018, brought together a consortium of six researchers from Tanzania, Kenya, and Denmark to assess microplastic pollution in the coastal waters of East Africa. The project aimed to evaluate microplastic levels in sediment, water, and biota samples, identify the primary polymer types present, and study their uptake and effects on the representative marine fish species, Oreochromis urolepis. Additionally, the project investigated the interactions of microplastics with Persistent Organic Pollutants (POPs), reconstructed the historical pollution narrative, and assessed stakeholder perceptions regarding plastic waste management.

Field studies were conducted through sampling campaigns in key locations such as Dar es Salaam, Zanzibar, and Mombasa. These studies revealed varying abundances and distributions of microplastics, with significant drivers identified as rainfall, river discharge, climate variability, ocean currents, and anthropogenic activities. The results demonstrated that polypropylene and high-density polyethylene were the predominant polymer types found, particularly in waters near industrial areas where human activities contributed to higher pollution levels. The findings stressed the need for awareness programs on microplastic pollution and advocated for sustainable management strategies to mitigate future risks.

Laboratory investigations using fluorescent microbeads enabled detailed studies of microplastic uptake and potential trophic transfer in O. urolepis, revealing critical insights about the impacts of microplastics on fish health and growth, along with potential implications for food security and marine ecosystems. Notably, the project elucidated the potential toxicity of chemical additives found in plastics and the associated pollutants, comparing these toxicological risks to those posed by the polymers themselves. These findings contribute valuable scientific knowledge for developing regulations concerning chemicals used in plastic production, providing public and private stakeholders with the necessary evidence for compliance with environmental standards.

The project also focused on building a diverse, scientifically trained workforce through coastal and ocean education programs. Innovative academic curricula were developed based on current research methodologies, aimed at training both undergraduate and postgraduate students in practical applications related to microplastic research. Furthermore, the MICROMARINE project successfully raised public awareness about the risks posed by microplastics to marine ecosystems and human health, fostering a sense of urgency around environmental stewardship.

Finally, the project determined the uptake, tissue distribution, and final fate of microplastics in organisms representative of pelagic and benthic ecosystems. It also investigated the potential role of microplastics as vectors for marine pollutants and their capacity for trophic transfer within marine food webs. The collective results of the MICROMARINE project have laid the foundation for informed management interventions designed to reduce human impacts on marine life and foster healthier coastal environments. As a result, the initiative set the stage for developing effective policy frameworks centered on sustainable plastic management in the Western Indian Ocean.