To meet the challenge of feeding a global population estimated to reach 9.7 billion by 2050, alongside addressing the impact of climate change on food production and utilization, there's been a suggestion to expand the use of seaweed. This approach holds promise for long-term development in West Africa. However, the presence of hazardous heavy metals such as arsenic (As), mercury (Hg), lead (Pb), and cadmium (Cd) in seaweed raises concerns, as they can accumulate and become toxic above specific thresholds. Between April and July 2022, researchers gathered 41 samples of 25 different seaweed species along the Senegalese coast, spanning from the Cap-Vert peninsula to the Petite Côte. Microwave Plasma Atomic Emission Spectroscopy and XRF-fluorescence spectrophotometry were employed to determine metal concentrations. The findings reveal that 36% of the studied specimens exceeded the threshold of 10 mg kg-1 of dry seaweed for arsenic concentration, as set by the Norwegian National Institute of Nutrition and Seafood Research (NIFES, 2016). Additionally, all specimens surpassed the toxicity threshold of 0.5 mg kg-1 of dry seaweed for cadmium, as established by French health agencies. While 97% of the samples had cadmium values below 10 mg kg-1, which is the minimum concentration determinable with acceptable uncertainty. Hypnea musciformis, a seaweed species found in significant quantities along Senegal's coastline, exhibited lead concentrations exceeding four times the maximum suggested limit by French health agencies. The study originally aimed to extend its scope to cover the entire coastline over two years, intending to identify seasonal variations in heavy metal concentrations.