Heavy metal concentrations in surface water, sediments and fish and their potential toxicity in highly degraded multipurpose peri-urban Eleyele Lake, Ibadan City, Oyo State, south-western Nigeria

Figures & data

Figure 1. Map of sampled sites in Eleyele Lake, Ibadan City, Oyo State, south-western, Nigeria.

Table 1. The mean ± SD values of water quality parameters in Eleyele Lake, Nigeria 2017. The NSDQW and WHO values are added for comparison

Location	Month	DO (mg/L)	Temp (°C)	Turbidity (NTU)	EC (µS/cm)	pH	Secchi depth (m)
	April	3.01 ± 0.11	35.3 ± 3.22	3.58 ± 0.14	733.23 ± 100.23	8.11 ± 0.53	0.22 ± 0.02
E1	July	4.67 ± 0.23	29.2 ± 2.01	3.13 ± 0.23	656.12 ± 133.22	7.68 ± 0.46	0.17 ± 0.01
	Nove	5.22 ± 1.04	29.7 ± 2.11	2.88 ± 0.09	647.02 ± 122.24	7.78 ± 0.37	0.24 ± 0.02
	April	4.11 ± 0.66	29.9 ± 1.87	3.01 ± 1.21	520.10 ± 147.21	7.01 ± 0.33	0.89 ± 0.05
E2	July	4.88 ± 0.43	32.4 ± 2.34	3.10 ± 0.02	589.12 ± 144.22	7.04 ± 0.27	0.74 ± 0.02
	Nove	5.45 ± 0.67	28.6 ± 2.10	2.88 ± 0.11	523.33 ± 152.08	6.88 ± 0.45	0.82 ± 0.01
	April	5.23 ± 0.11	28.9 ± 2.99	2.67 ± 0.54	545.03 ± 177.11	7.01 ± 0.11	1.21 ± 0.37
E3	July	4.21 ± 0.12	31.1 ± 1.12	2.89 ± 0.67	570.66 ± 189.22	7.23 ± 0.36	1.01 ± 0.22
	Nove	4.11 ± 0.94	26.3 ± 1.34	3.33 ± 0.34	489.53 ± 115.37	7.65 ± 0.78	0.97 ± 0.21
	April	3.01 ± 0.34	27.2 ± 1.57	3.01 ± 0.27	501.73 ± 116.26	7.22 ± 0.47	1.34 ± 0.22
E4	July	3.23 ± 1.22	28.5 ± 1.49	2.96 ± 0.34	486.54 ± 154.02	7.89 ± 0.56	1.22 ± 0.18
	Nove	3.45 ± 0.89	30.4 ± 1.17	3.23 ± 0.26	430.18 ± 112.54	8.01 ± 0.56	1.27 ± 0.24
	April	3.32 ± 0.64	28.7 ± 2.44	2.87 ± 0.77	408.53 ± 155.94	7.99 ± 0.23	1.87 ± 0.11
E5	July	2.98 ± 0.76	27.5 ± 1.73	2.75 ± 0.45	504.23 ± 143.22	7.84 ± 0.77	1.77 ± 0.17
	Nove	3.22 ± 0.47	28.8 ± 1.86	2.80 ± 0.29	488.45 ± 133.37	7.73 ± 0.56	1.63 ± 0.45
	NSDQW	5	28–30	5	1000	6.5–8.5	N/A
	WHO	5.0–6.59	25.3	5	1000	6.59–8.5	N/A

Table 2. Spatial and temporal analysis of water quality parameters in Eleyele Lake, Nigeria 2017. Significant values (p < 0.05) are marked*

	DO (mg/L)	Temp (°C)	Turbidity (NTU)	EC (µS/cm)	pH	Secchi depth (m)
Location, H	13.5	9.27	11.10	5.81	4	7.861
p	0.009*	0.04*	0.026*	0.214	0.406	0.096
Month, H	0.999	0.38	0.020*	0.98	0.060	0.26
p	0.607	0.827	0.990	0.613	0.970	0.878

Table 3. The mean ± SD concentrations of heavy metals in water (mg/L) of Eleyele Lake, Nigeria 2017. The NSDWQ and WHO values are added for comparison

Location	Month	Fe	Co	Zn	Cu	Cd	Pb	Ni	Hg
	April	3.8 ± 1.70	0.08 ± 0.01	0.05 ± 0.01	0.47 ± 0.16	0.19 ± 0.11	0.45 ± 0.04	0.66 ± 0.07	0.01 ± 0.00
E1	July	2.39 ± 0.04	0.02 ± 0.01	0.19 ± 0.01	0.27 ± 0.09	0.05 ± 0.02	3.44 ± 0.61	0.09 ± 0.01	0.42 ± 0.05
	Nove	4.86 ± 1.25	0.089 ± 0.01	0.002 ± 0.00	0.076 ± 0.01	0.02 ± 0.00	0.48 ± 0.08	0.015 ± 0.01	0.01 ± 0.00
	April	4.31 ± 0.04	0.06 ± 0.01	0.07 ± 0.06	0.56 ± 0.32	0.23 ± 0.19	0.53 ± 0.03	0.54 ± 0.33	0.01 ± 0.00
E2	July	2.30 ± 0.36	0.06 ± 0.01	0.27 ± 0.06	0.30 ± 0.04	0.06 ± 0.01	3.66 ± 0.16	0.08 ± 0.01	0.42 ± 0.01
	Nove	5.76 ± 1.36	0.063 ± 0.01	0.005 ± 0.00	0.083 ± 0.01	0.014 ± 0.00	0.205 ± 0.02	0.052 ± 0.01	0.01 ± 0.00
	April	2.79 ± 0.62	0.07 ± 0.02	nd	0.42 ± 0.11	0.22 ± 0.13	0.49 ± 0.04	0.82 ± 0.14	0.01 ± 0.00
E3	July	2.23 ± 0.18	0.04 ± 0.02	0.22 ± 0.02	0.27 ± 0.09	0.07 ± 0.01	5.74 ± 1.46	0.07 ± 0.02	0.39 ± 0.02
	Nove	2.88 ± 0.11	0.042 ± 0.01	0.001 ± 0.00	0.073 ± 0.01	0.016 ± 0.01	0.28 ± 0.12	0.056 ± 0.02	0.02 ± 0.00
	April	3.65 ± 0.57	0.06 ± 0.01	0.02 ± 0.01	0.45 ± 0.03	0.23 ± 0.08	0.55 ± 0.13	0.83 ± 0.19	0.01 ± 0.00
E4	July	1.14 ± 0.07	0.07 ± 0.01	0.44 ± 0.04	0.42 ± 0.01	0.20 ± 0.02	4.55 ± 0.66	0.09 ± 0.01	0.75 ± 0.01
	Nove	3.69 ± 1.11	0.009 ± 0.00	0.007 ± 0.00	0.078 ± 0.01	0.018 ± 0.00	0.398 ± 0.12	0.032 ± 0.11	0.001 ± 0.00
	April	3.01 ± 0.42	0.07 ± 0.01	nd	0.51 ± 0.19	0.22 ± 0.13	0.46 ± 0.08	0.76 ± 0.07	0.02 ± 0.01
E5	July	1.14 ± 0.07	0.07 ± 0.01	0.44 ± 0.04	0.42 ± 0.01	0.20 ± 0.02	4.55 ± 0.66	0.09 ± 0.01	0.75 ± 0.01
	Nove	5.44 ± 2.89	0.028 ± 0.01	0.002 ± 0.00	0.084 ± 0.01	0.017 ± 0.00	0.354 ± 0.13	0.036 ± 0.02	0.001 ± 0.00
	NSDQW	0.05	0.003	1	0.3	0.01	0.02	0.001	3
	WHO	0.05	0.01	2	0.3	0.01	0.05	0.001	3

Table 4. The mean ± SD concentrations of heavy metals in sediments (mg/kg) of Eleyele Lake, Nigeria 2017. The USEPA values are added for normative comparison

Location	Month	Fe	Co	Zn	Cu	Cd	Pb	Ni	Hg
	April	15.17 ± 4.80	21.275 ± 4.43	42.12 ± 5.62	22.85 ± 10.61	3.06 ± 1.12	14.37 ± 2.46	30.25 ± 18.67	0.075 ± 0.04
E1	July	19.50 ± 17.33	36.26 ± 11.19	51.62 ± 22.62	31.88 ± 14.81	4.92 ± 1.12	15.08 ± 4.60	35.38 ± 14.42	0.045 ± 0.05
	Nove	24.45 ± 3.47	11.2 ± 2.37	21 ± 8.09	13.65±	0.4 ± 0.01	21.95±	6.95±	0.11±
	April	4.54 ± 1.57	5.8 ± 5.44	9.75 ± 0.00	22.85 ± 6.72	3.935 ± 0.39	10.125 ± 0.42	21.3 ± 1.84	0.095 ± 0.02
E2	July	8.38 ± 2.90	7.68 ± 5.32	9.75 ± 0.00	26.18 ± 7.01	4.12 ± 0.16	11.675 ± 0.91	25.07 ± 3.59	0.11 ± 0.01
	Nove	32.11 ± 10.43	14.2 ± 6.45	27.9 ± 9.24	11.7 ± 3.01	0.35 ± 0.01	11.35 ± 4.38	5.15±	0.09 ± 0.01
	April	2.70 ± 0.17	27.33 ± 13.89	95.3 ± 102.11	45.375 ± 2.16	5.245 ± 0.52	19.3 ± 2.74	79.75 ± 21.99	0.11 ± 0.01
E3	July	4.92 ± 0.64	22.33 ± 1.59	89.08 ± 33.30	53.92 ± 2.45	4.99 ± 1.44	20.95 ± 2.09	87.27 ± 28.36	0.14 ± 0.04
	Nove	20.21 ± 10.34	8.25 ± 4.32	35.8 ± 13.02	7.9 ± 2.11	0.6 ± 0.03	49.05 ± 22.31	2.2 ± 0.07	0.23 ± 0.08
	April	29.45 ± 13.21	28.23 ± 3.38	86.9 ± 14.57	38.85 ± 12.20	4.235 ± 1.33	17.86 ± 1.63	49.53 ± 13.77	0.15 ± 0.04
E4	July	27.50 ± 21.13	25.91 ± 15.97	98.85 ± 17.89	48.41 ± 25.18	4.78 ± 1.92	20.06 ± 3.26	52.68 ± 27.48	0.11 ± 0.01
	Nove	25.36 ± 11.34	9.85 ± 3.25	21.11 ± 5.33	9.9 ± 3.44	0.8 ± 0.02	316.5 ± 97.63	5.45 ± 1.11	0.01 ± 0.00
	April	5.29 ± 4.02	26.75 ± 1.56	134.00 ± 28.99	31.35 ± 3.32	7.41 ± 3.85	13.57 ± 5.22	34.1 ± 6.79	0.075 ± 0.04
E5	July	7.18 ± 4.31	22.46 ± 0.13	146.74 ± 21.91	31.86 ± 1.75	10.005 ± 4.56	15.48 ± 6.00	38.81 ± 5.80	0.05 ± 0.01
	Nove	22.14 ± 5.37	11.95 ± 2.86	12.25 ± 3.29	11.9 ± 4.41	0.2 ± 0.02	32.9 ± 13.24	8.62 ± 2.66	0.01 ± 0.00
	USEPA	50	0.99	31.6	20,000	35.8	22.7	0.02	121

Table 5. Spatiotemporal analysis of metals in water and sediments in Eleyele Lake, Nigeria 2017. *p < 0.05 indicate significant values

Metal	Fe	Co	Zn	Cu	Cd	Pb	Ni	Hg
Water
Site, H	2.512	1.479	2.078	1.404	0.829	0.342	0.235	0.233
p	0.642	0.830	0.722	0.843	0.935	0.987	0.994	0.991
Month, H	10.238	1.908	9.551	12.128	11.642	11.601	12.589	10.420
p	0.006*	0.3853	0.0084*	0.0023*	0.003*	0.003*	0.001*	0.006*
Sediment
Site, H	6.267	4.233	5.844	1.444	2.1	8.433	4.286	6.964
p	0.1801	0.3753	0.2111	0.837	0.717	0.077	0.681	0.138
Month, H	4.580	3.38	3.461	9.998	9.62	4.34	9.62	0.342
p	0.101	0.185	0.177	0.007*	0.008*	0.114	0.008*	0.842

Table 6. Bioconcentration factors of metals in Eleyele Lake, Nigeria 2017. Bioconcentration of metals classified as low<250, moderately high 250–1000 and high >1000

Location	April	Fe	Co	Zn	Cu	Cd	Pb	Ni	Hg
E1		3.992	265.938	842.400	48.617	16.105	31.933	45.833	7.500
E2		1.0534	96.667	139.286	40.804	17.109	19.104	39.444	9.500
E3		0.968	390.429	0.000	108.036	23.841	39.388	97.256	11.000
E4		8.068	470.500	4345.000	86.333	18.413	32.473	59.675	15.000
E5		1.757	382.1429	0.000	61.471	33.682	29.500	44.868	3.750
	July
E1		8.159	1813.000	271.684	118.074	98.400	4.384	393.111	0.107
E2		3.643	128.000	36.111	87.267	68.667	3.189	313.375	0.262
E3		2.206	558.250	404.909	199.704	71.286	3.649	1246.714	0.359
E4		24.123	370.143	224.659	115.262	23.900	4.409	585.333	0.147
E5		6.298	320.857	333.500	75.857	50.025	3.402	431.222	0.067
	November
E1		5.031	125.843	10,500.000	179.605	20.000	45.729	463.333	11.000
E2		5.575	225.397	5580.000	140.964	25.000	55.366	99.038	9.000
E3		7.017	196.429	35,800.00	108.219	37.500	175.179	39.286	11.500
E4		6.873	1094.444	3015.714	126.923	44.444	795.226	170.313	10.000
E5		4.069	426.786	6125.000	141.667	11.765	92.938	239.444	10.000

Table 7. Pollution Load Index (PLI) for metals in surface sediments of Eleyele Lake, Nigeria 2017. Polluted sites (PLI>1) are marked*

Site	April	July	November
E1	0.455	0.642	2.860*
E2	0.030	2.527*	2.989*
E3	0.457	0.454	0.282
E4	0.012	0.173	1.054*
E5	0.389	0.252	0.814
Mean	0.268	0.809	1.599

Table 8. Geoaccumulation Index (Igeo) for metals in surface sediments of Eleyele Lake, Nigeria 2017. Copper showing extreme contamination (I_geo) >5 is marked*

Site/April E1		Fe	Co	Zn	Cu*	Cd	Pb	Ni	Hg
		2.70	1.15	2.95	5.48	1.86	2.34	0.39	0.78
E2		2.18	0.58	2.31	5.48	1.97	2.19	0.55	0.88
E3		1.95	1.26	3.30	5.78	2.09	2.47	0.02	0.95
E4		2.99	1.27	3.26	5.71	2.00	2.43	0.18	1.08
E5		2.24	1.25	3.45	5.62	2.25	2.31	0.34	0.78
	July
E1		2.81	1.24	2.95	5.63	2.07	2.36	0.33	0.56
E2		2.45	0.71	2.31	5.54	1.99	2.25	0.48	0.95
E3		2.21	1.17	3.27	5.89	2.08	2.50	0.06	1.04
E4		2.96	1.24	3.32	5.81	2.06	2.48	0.15	0.95
E5		2.38	1.17	3.49	5.63	2.38	2.37	0.28	0.56
	Nove
E1		2.91	0.87	2.65	5.26	0.98	2.52	1.05	0.95
E2		3.03	0.97	2.78	5.19	0.92	2.23	1.15	0.86
E3		2.83	0.74	2.88	5.02	1.16	2.87	1.52	1.27
E4		2.93	0.81	2.64	5.12	1.28	3.680	1.15	0.09
E5		2.87	0.89	2.41	5.20	0.68	2.69	0.95	0.09

Table 9. Potential Ecological Risk Index (PERI) for metals in surface sediments of Eleyele Lake, Nigeria 2017. Nickel showing significantly high serious ecological risk RI≥600 is marked*

Metal	Fe	Co	Zn	Cu	Cd	Pb	Ni*	Hg
Site				April
E1	0.30	107.45	1.33	0.01	2.56	3.17	1512.5	0.003
E2	0.09	29.23	0.31	0.01	3.29	2.23	1065	0.003
E3	0.05	138.01	3.02	0.01	4.40	4.25	3987.5	0.004
E4	0.59	142.55	2.75	0.01	3.55	3.93	2476.5	0.01
E5	0.11	135.10	4.24	0.01 July	6.21	2.98	1705.0	0.003
E1	0.39	132.60	1.33	0.05	4.12	3.32	1770	0.05
E2	0.17	38.79	0.31	0.05	3.45	2.57	1250	0.05
E3	0.09	112.75	2.82	0.05	4.19	4.61	4360	0.05
E4	0.55	130.86	3.13	0.05	4.00	4.42	2640	0.05
E5	0.14	113.43	4.64	0.05	8.38	3.41	1940.5	0.05
					November
E1	0.49	56.57	0.66	0.05	0.34	4.83	347.5	0.05
E2	0.64	71.72	0.88	0.05	0.29	2.5	257.5	0.05
E3	0.40	41.67	1.13	0.05	0.50	10.80	110	0.05
E4	0.51	49.75	0.67	0.05	0.67	69.71	272.5	0.05
E5	0.44	60.35	0.39	0.05	0.17	7.25	431	0.05

Table 10. Metal concentrations in tissues of the African Sharptooth mud catfish (N = 34; Mean weight = 0.845 ± 0.28 kg) and Nile Tilapia (N = 36; Mean weight = 0.437 ± 0.45 kg) sampled in Eleyele Lake 2017. Food and Agriculture Organization (1983) limits are also shown for comparison

Catfish/Tissue	Month	Fe	Co	Zn	Cu	Cd	Pb	Ni	Hg
	April	1041.5 ± 103.37	11.1 ± 3.32	56.8 ± 13.11	32.7 ± 9.67	2.9 ± 0.42	3.9 ± 0.77	36.2 ± 8.87	0.1 ± 0.01
Gill	July	136.2 ± 27.12	26.6 ± 17.11	48.9 ± 7.51	40.1 ± 2.03	2.2 ± 0.60	12.1 ± 1.25	28.4 ± 3.85	0.03 ± 0.01
	Nove	404.2 ± 10.15	6.2 ± 0.63	67.5 ± 14.47	12.9 ± 3.90	0.8 ± 1.09	2.03 ± 1.52	1.3 ± 0.26	0.1 ± 0.06
	April	144.8 ± 23.83	4.6 ± 0.51	3.5 ± 1.09	1.7 ± 0.56	0.9 ± 0.11	1.3 ± 0.36	2.5 ± 0.56	0.1 ± 0.04
Muscle	July	82.1 ± 5.39	10.6 ± 0.73	35.1 ± 3.04	30.8 ± 2.17	1.1 ± 0.07	11.1 ± 0.26	23.6 ± 1.54	0.03 ± 0.01
	Nove	363.0 ± 80.32	6.6 ± 1.04	35.9 ± 8.87	15.6 ± 10.23	0.8 ± 0.82	1.3 ± 0.74	0.7 ± 0.52	0.1 ± 0.04
Tilapia/Tissue
	April	2303.8 ± 1578.68	19.2 ± 12.94	55.3 ± 9.29	25.4 ± 11.07	3.7 ± 2.58	5.4 ± 2.26	39.3 ± 10.19	0.02 ± 0.01
Gill	July	209.0 ± 9.54	41.6 ± 3.14	41.6 ± 0.96	33.0 ± 1.58	2.1 ± 0.04	11.3 ± 1.08	29.5 ± 1.38	0.01 ± 0.00
	Nove	326.7 ± 74.20	5.9 ± 0.15	56.7 ± 23.01	1.9 ± 0.86	0.3 ± 0.01	1.8 ± 0.60	1.8 ± 1.39	0.2 ± 0.02
	April	530.6 ± 198.79	10.5 ± 6.06	71.2 ± 37.49	25.9 ± 14.07	4.2 ± 2.26	4.3 ± 1.83	34.2 ± 15.24	0.03 ± 0.01
Stomach Muscle	July	104.5 ± 1.57	19.2 ± 1.80	30.5 ± 2.05	28.5 ± 0.55	1.9 ± 0.09	9.6 ± 0.52	26.1 ± 1.02	0.01 ± 0.001
	Nove	228.7 ± 15.28	4.9 ± 0.14	25.2 ± 2.08	1.3 ± 0.06	0.3 ± 0.04	2.16 ± 0.031	2.7 ± 0.12	0.2 ± 0.04
FAO limits			0.5	30	100	0.5			30

Table 11. Spatio-temporal analysis of metals in gills and stomach tissues of fish in Eleyele Lake, Nigeria 2017. *p < 0.05 indicate significant values

Tissue	Fe	Co	Zn	Cu	Cd	Pb	Ni	Hg
Gill, H	3.37	5.74	2.91	10.34	20.54	79.26	23.38	1.54
p	0.834	0.783	0.634	0.175	0.238	0.802	0.356	0.552
Month, H	4.98	8.45	5.07	12.23	25.43	103.93	386.39	3.17
p	0.111	0.048*	0.109	0.037*	0.013*	0.001*	0.001*	0.182
Muscle, H	1.22	2.53	0.03	1.83	1.019	22.094	1.69	3.42
p	0.654	0.496	0.479	0.99	0.812	0.939	0.732	0.532
Month	1.22	2.53	0.03	1.83	1.02	22.09	1.69	3.42
p	0.40	0.22	0.97	0.30	0.46	0.02*	0.32	0.17

Table

IGEO	Class	Pollution status
0	0	Practically uncontaminated
1	0–1	Uncontaminated to moderately contaminated
1–2	2	Moderately contaminated
2–3	3	Moderately to heavily contaminated
3–4	4	Heavily contaminated
4–5	5	Heavy to extremely contaminated
> 5	6	Extremely contaminated

Table

Risk range (Er and RI)			Classification
Er <40; RI <150			Low ecological risk
40 < Er ≤80; 150 < RI <300			Moderate ecological risk
80 < Er ≤160; 150 < RI <300			Appreciable ecological risk
160 < Er ≤320; 300 < RI <600			High ecological risk
Er >320; 300 < RI <600			Serious ecological risk
Er >320; RI ≥ 600			Significantly high serious ecological risk

Food and Agriculture Organization. (1983). Compilation of legal limits for hazardous substances in fish and fishery products. FAO Fishery Circular, (464), 5–100.

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