Syndemic Effects of Water Insecurity and Cyanobacteria Harmful Algal Blooms on Public Health and Livelihoods in Informal Settlements along Lake Victoria, Kisumu County, Kenya

Lake Victoria is a critical freshwater resource supporting fisheries, domestic water supply, and livelihoods for millions of Kenyans. However, increasing nutrient loading, climate variability, rapid urbanization, and expanding aquaculture activities have intensified the occurrence of cyanobacterial harmful algal blooms (cHABs), leading to declining water quality and elevated public health risks. In Kisumu County, informal settlements located along the lakeshore rely heavily on untreated lake water due to limited access to safe and affordable alternatives, increasing exposure to microcystin toxins and waterborne pathogens. Water insecurity in these communities intersects with poverty, inadequate sanitation, overcrowding, and limited health services, creating compounded biological and psychosocial vulnerabilities. Despite documented eutrophication in Lake Victoria, limited empirical research has examined the combined ecological, health, nutritional, and socio-economic impacts of cyanobacterial blooms on marginalized shoreline populations. This study aims to assess the syndemic effects of water insecurity and cyanobacterial harmful algal blooms on public health and livelihoods in informal settlements along Lake Victoria in Kisumu County, Kenya. A mixed-methods design will be employed, integrating household surveys (n=1,500), environmental exposure assessment, health facility record reviews, and qualitative interviews with community members and key stakeholders. Quantitative data will be analyzed using multivariate statistical models to determine associations between bloom exposure, water access patterns, and health outcomes, while qualitative data will provide contextual insights into coping strategies and institutional responses. The study will generate evidence to inform national water safety strategies, climate adaptation planning, fisheries sustainability policies, and targeted public health interventions aligned with Kenya’s Vision 2030 and the Bottom-Up Economic Transformation Agenda. Therefore; research seeks to strengthen resilience among vulnerable lake-dependent communities and contribute to sustainable aquatic resource management in Kenya