Assessing heavy metal pollution in mangrove ecosystems of the Kribi-Campo sub-basin, Cameroon

Mangrove ecosystems provide crucial ecological services, yet they are increasingly threatened by anthropogenic pollution, particularly from heavy metals. This study investigated heavy metal contamination (Pb, Fe, Ni, Cu) in four mangrove sites within the Kribi-Campo sub-basin, Cameroon, during the dry and rainy seasons of 2023. Physicochemical parameters (temperature, pH, conductivity, dissolved oxygen, salinity) were measured in situ, and heavy metal concentrations in water samples were determined using X-ray fluorescence spectrometry. Results revealed spatial variations in physicochemical parameters, with the Mpolongwé site showing excessive mineralization (conductivity > 1000 µS/cm) likely attributed to industrial and domestic effluents. Lead contamination was restricted to Londji (0.05 - 0.21 mg/L), potentially linked to fishing activities. Iron concentrations were highest at Londji (0.67 mg/L) and Nziou (0.61- 0.68 mg/L), while nickel was absent only at Eboundja. Notably, copper was ubiquitous across all sites (2.68 - 3.31 mg/L), highlighting its widespread distribution. Londji emerged as the most contaminated site, harboring detectable levels of all analyzed metals. These findings underscore the vulnerability of Kribi’s mangroves to heavy metal pollution, emphasizing the need for continuous monitoring and implementation of mitigation measures to ensure the sustainable management of this valuable ecosystem.