Assessment of trace metals in soil and vegetable samples irrigated from Borkena river, South Wollo Zone, Amhara Region, Ethiopia

Figures & data

Figure 1. Geographical map of the study area (Borkena upper, Leyole, Worka and Borkena lower irrigated farm land).

Figure 2. Soil and vegetable sample collection and pretreatment.

Table 1. Unspiked sample, spiked sample results (mg/kg) and percentage recoveries of trace metals (Fe, Mn, Zn, Cu, Cr, Ni, Pb and Cd)

samples	Unspiked samples								Spiked samples								% Recoveries
	Fe	Mn	Zn	Cu	Cr	Ni	Pb	Cd	Fe	Mn	Zn	Cu	Cr	Ni	Pb	Cd	Fe	Mn	Zn	Cu	Cr	Ni	Pb	Cd
Soils	0.14	0.44	0.45	0.06	0.42	0.42	1.22	0.27	2	2.3	2.7	2.1	2.4	2.2	2.82	1.99	92.7	91.2	112.55	102.48	96.6	87.8	79.9	85.9
vegetable	2.44	0.41	0.37	0.1	0.21	0.3	0.67	0.14	4.12	2.06	2.55	2.1	2.1	2.2	2.28	2	83.8	82.7	108.6	100.7	92.9	94.6	80.4	92.8

Table 2. The mean concentration of trace metals (mg/kg dry weight) in Soil samples

Study area	Soil from the farmland of	Values	Trace metals
			Fe	Mn	Zn	Cu	Cr	Ni	Pb	Cd
		Mean	618.87	48.9	3.18	1.03	1.42	1.83	4.68	1.74
Borkena lower	Lettuce & Swiss chard	range	648.8–553	47.82–49.61	3.15–3.23	1.023–1.044	1.382–1.452	1.827–1.833	4.619–4.740	1.717–1.767
				0.95	0.044	0.011	0.036	0.003	0.061	0.025
		St.d	56.6
		Mean	0.14	0.44	0.45	0.06	0.42	0.42	1.22	0.27
Leyole		Range	0.14–0.15	0.43–0.45	0.44–0.45	0.057–0.067	0.407–0.428	0.411–0.425	1.159–1.269	0.260–0.278
	Lettuce				0.008	0.003	0.011	0.007	0.056	0.01
		St.d	0.006	0.009
Worka		Mean	0.24	9.35	0.86	0.06	0.34	0.63	0.98	0.25
	Lettuce & Swiss chard	Range	0.22–0.26	9.32–9.39	0.85–0.88	0.057–0.072	0.340–0.350	0.619–0.642	0.919–1.061	0.230–0.261
					0.015	0.008	0.005	0.012	0.072	0.016
		St.d	0.019	0.037
Borkena upper	Lettuce & Swiss chard	Mean	0.18	2.54	0.64	0.06	0.38	0.86	1.18	0.3
		Range	0.17–0.19	-	0.63–0.69	0.060–0.069	0.369–0.392	0.546–0.576	1.120–1.229	0.268–0.320
			0.011		0.014	0.005	0.01	0.016	0.055	0.026
		St.d		0.003
Maximum limit:(Yirgalem
et al.,Yirgalem et al., 2012 and Ewers, 1991)			—	2000	300	100	100	50	100	3

St.d: standard deviation

Table 3. Average trace metals contents (mg/kg) in vegetables from Borkena River catchment

Study area	Vegetable	Values		Trace metal
	Lettuce		Fe	Mn	Zn	Cu	Cr	Ni	Pb	Cd
		Mean	2.25	0.3	0.35	0.1	0.23	0.31	0.7	0.16
Borkena lower		Range	2.19–2.32	0.29–0.31	0.35–0.36	0.095–0.10	0.219–0.23	0.299–0.31	0.678–0.724	0.146-.172
			1.304	0.007	0.008	0.002	0.006	0.008	0.023	0.014
		St.d
	Swiss chard	Mean	1.47	0.56	0.3	0.07	0.22	0.29	0.7	0.12
		Range	1.43–1.50	0.55–0.58	0.30–0.31	0.066–0.078	0.21–0.221	0.29–0.297	0.663–0.723	0.105–0.139
			0.037	0.011	0.008	0.006	0.006	0.006	0.7	0.12
		St.d
Leyole	Lettuce	Mean	2. 44	0.4	0.37	0.1	0.21	0.3	0.67	0.14
		Range	2.41–2.48	0.40–0.41	0.36–0.39	0.101–0.103	0.211–0.23	0.29–0.312	0.647–0.678	0.127–0.155
			0.037	0.006	0.011	0.001	0.003	0.008	0.018	0.016
		St.d
	Lettuce	Mean	1.28	0.26	0.25	0.09	0.3	0.26	0.62	0.11
		Range	1.26–1.31	0.25–0.26	0.24–0.26	0.086–0.089	0.29–0.311	0.2510.261	0.603–0.632	0.086–0.131
Worka			0.026	0.008	0.007	0.002	0.01	0.005	0.014	0.023
		St.d
	Swiss chard	Mean	0.49	0.15	0.1	0.04	0.23	0.26	0.59	0.1
		Range	0.48–0.52	-	0.10–0.11	0.043–0.045	0.229–0.239	0.25–0.266	0.583–0.596	0.099–0.108
			0.024		0.004	0.001	0.006	0.009	0.007	0.005
		St.d		0.004
	Lettuce	Mean	2.56	0.33	0.33	0.11	0.22	0.3	0.7	0.13
		Range	2.47–2.73	0.32–0.35	0.33–0.34	0.103–0.110	0.208–0.232	0.297–0.307	0.660–0.721	0.114–0.134
Borkena upper			0.147	0.017	0.006	0.004	0.012	0.005	0.033	0.011
		St.d
	Swiss chard	Mean	3.23	1.03	0.27	0.09	0.32	0.3	0.73	0.16
		Range	3.14–3.29	0.99–1.07	0.26–0.27	0.085–0.087	0.319–0.332	0.299–0.309	0.717–0.751	0.138–0.169
			0.078	0.039	0.006	0.002	0.007	0.005	0.017	0.017
		St.d
Safe limit^a			-	-	60	40	2.3	20	0.3	0.2

^aSource: FAO/WHO (2001)

Table 4. The transfer factors of trace metals in Lettuce and Swiss chard vegetables grown by Borkena River and its tributaries farm land

No.	Sampling area	Types of Vegetables	Transfer of trace metals
			Fe	Mn	Zn	Cu		Cr	Ni	Pb	Cd
1.	Borkena lower	Lettuce	0.002	0.006	0.11	0.10		0.16	0.17	0.15	0.09
		Swiss chard	0.002	0.011	0.09	0.07		0.155	0.16	0.15	0.06
2.	Leyole	Lettuce	17.4	0.91	0.80	1.67		0.50	0.71	0.55	0.52
3.	Worka	Lettuce	5.33	0.03	0.29	1.5		0.88	0.41	0.63	0.44
		Swiss chard	2.04	0.02	0.12	0.67		0.68	0.41	0.60	0.40
4.	Borkena upper	Lettuce	14.22	0.13	0.52	1.83		0.58	0.35	0.59	0.43
		Swiss chard	17.94	0.40	0.42	1.5		0.84	0.35	0.62	0.53

Table 5. The mean hazard quotient values of trace metals by eating of lettuce and Swiss chard vegetables in the study area

	Vegetable	Consumers	Heavy metals
Site			Fe	Mn	Zn	Cu	Cr	Ni	Pd	Cd
1.	Lettuce	Children	0.015	0.015	0.008	0.018	0.001	1.1	1.4	1.1
		Adults	0.013	0.013	0.007	0.016	0.001	0.955	1.234	0.98
	Swiss chard	Children	0.015	0.028	0.007	0.012	0.001	1.03	0.123	0.85
		Adults	0.013	0.025	0.006	0.107	0.001	0.895	1.234	0.74
2.	Lettuce	Children	0.025	0.020	0.009	0.018	0.001	1.05	1.36	0.99
		Adults	0.011	0.018	0.008	0.016	0.001	0.925	1.18	0.86
3.	Lettuce	Children	0.013	0.013	0.006	0.016	0.001	0.92	1.25	0.78
		Adults	0.011	0.011	0.005	0.014	0.001	0.8	1.09	0.68
	Swiss chard	Children	0.005	0.008	0.002	0.007	0.001	0.92	1.19	0.71
		Adults	0.004	0.007	0.002	0.006	0.001	0.8	1.04	0.62
4	Lettuce	Children	0.026	0.017	0.017	0.019	0.001	1.05	1.4	0.92
		Adults	0.022	0.007	0.007	0.017	0.001	0.925	1.23	0.8
	Swiss chard	Children	0.033	0.052	0.006	0.016	0.002	1.05	1.48	1.1
		Adults	0.028	0.045	0.006	0.014	0.001	.925	1.29	0.98

Table 6. The higher, the lower and the percentage hazard index within the tested vegetables in each sampling site

Sampling site	Type of vegetables	Observed Higher HI	Values	% of HI	Observed Lower HI	Values	% of HI
Borkena Lower	Lettuce	Children	3.657	65%	Adults	3.219	48.4%
	Swiss chard	Adults	3.021	51.6%	Children	1.96	35%
Leyole	Lettuce	Children	3.473	-	Adults	3.019	-
Worka	Lettuce	Children	2.999	51.3%	Adults	2.612	51.3%
	Swiss chard	Children	2.843	48.7%	Adults	2.48	48.7%
Borkena Upper	Lettuce	Children	3.45	48%	Adults	3.009	48%
	Swiss chard	Children	3.739	52%	Adults	3.289	52%

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