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

Table 2 Heavy metal concentrations in P. annectens from Nyabarongo river in comparison with other global studies

Study area	Mean heavy metal concentration (mg/kg)							Year	Authors
Study area	Fe	Mn	Cu	Zn	Cr	Cd	Pb	Year	Authors
Nyabarongo river, Rwanda^a	272.8 ± 0.36 (336.0 ± 0.70)	292.2 ± 0.25 (302.6 ± 1.22)	8.8 ± 0.36 (6.4 ± 0.26)	135.2 ± 0.15 (44.7 ± 0.20)	148.0 ± 0.21 (138.2 ± 0.17)	BDL (BDL)	432. 0 ± 0.50 (302.4 ± 1.50)	2020	This study
Lower River Benue, Nigeria	0.36 ± 0.02	ND	ND	ND	ND	ND	0.09 ± 0.01	2018	[15]
Oguta Lake, Nigeria	ND	ND	30.10	ND	3.75	0.41	18.10	2016	[16]
Nkisa river, Nigeria	174.66	11.81	4.92	211.33	1.03	0.79	0.98	2014	[17]
Benin city, Nigeria.	ND	ND	ND	ND	ND	0.32^F, 0.52^D	ND	2011	[18]
Anambra river, Nigeria	60.23 ± 0.37^b	0.94 ± 0.06	3.01 ± 0.40	10.60 ± 0.08	0.16 ± 0.03	ND	0.01 ± 0.02	2009	[19]
Anambra river, Nigeria	54.60 ± 0.20^c	1.00 ± 0.01	2.86 ± 0.31	11.40 ± 0.30	0.17 ± 0.02	ND	0.01 ± 0.02	2009	[19]
FAO/WHO limit	30.0	1.0	30.0	40.0	10.0	0.5	0.5		[20]

Detection limits calculated with reagent blanks were 1.50, 0.20, 0.60, 2.50, 0.50, 1.14, 1.20 and 0.37 mg/kg for Fe, Mn, Cu, Zn, Cr, Cd and Pb, respectively. Values in italics are higher than their corresponding heavy metal permissible limits in fish
ND not determined, F fresh sample, D dry sample, BDL below method detection limit
^aResults in parentheses are for P. annectens from Kirinda bridge; ^{b, c} results in these rows were obtained in wet and dry seasons respectively

ISSN: 1756-0500