Bioaccumulation of Trace Elements in Fish From Lake Kivu and Its Potential Risk to Consumers in Rwanda

Area of Science:

• Environmental Science
• Ecotoxicology
• Analytical Chemistry

Background:

• Lake Kivu faces trace element contamination from geological and anthropogenic sources.
• Understanding trace element accumulation in fish is crucial for ecosystem and human health assessment.

Purpose of the Study:

• To investigate the bioaccumulation of trace elements in 13 fish species from Lake Kivu.
• To assess the potential health risks associated with consuming contaminated fish.

Main Methods:

• Fish samples were collected from fishermen in Rubavu, Karongi, and Rusizi.
• Trace element concentrations were analyzed using atomic absorption spectrophotometry (AAS).
• Bio-concentration factors (BCF) and target hazard quotients (THQ) were calculated.

Main Results:

• Mercury (Hg) showed the highest bio-concentration factor (BCF), particularly in *Oreochromis niloticus* (16,867 L/kg).
• Mercury posed a potential risk to adults in 77% of fish species (THQ > 1).
• Cadmium (Cd), Chromium (Cr), and Mercury (Hg) posed risks to children in over 75% of species.

Conclusions:

• Fish from Lake Kivu accumulate significant levels of trace elements, especially mercury.
• Consumption of certain fish species presents potential health risks to both adults and children.
• Urgent, continuous monitoring of trace element levels in Lake Kivu's water and fish is recommended.