Physicochemical quality of water and health risks associated with consumption of African lung fish (Protopterus annectens) from Nyabarongo and Nyabugogo rivers, Rwanda

OBJECTIVE: To determine the quality of water, heavy metal content of edible muscles of a piscivorous fish (Protopterus annectens) and assess the health risks associated with using water and consumption of P. annectens from Nyabarongo and Nyabugogo rivers of Rwanda. RESULTS: All the water quality parameters were within World Health Organization’s acceptable limits except total nitrogen, iron, manganese and lead levels. Edible muscles of Protopterus annectens contained 272.8 ± 0.36, 292.2 ± 0.25, 8.8 ± 0.36, 135.2 ± 0.15, 148.0 ± 0.21 and 432. 0 ± 0.50 mg/kg of iron, manganese, copper, zinc, chromium and lead at Ruliba station and 336.0 ± 0.70, 302.6 ± 1.22, 6.4 ± 0.26, 44.7 ± 0.20, 138.2 ± 0.17 and 302.4 ± 1.50 mg/kg of iron, manganese, copper, zinc, chromium and lead at Kirinda bridge of Nyabarongo river. Health risk assessments indicated that though ingestion and dermal contact with heavy metals in water from the rivers may not cause obvious health effects, consumption of Protopterus annectens from Nyabarongo river may lead to deleterious health effects.