Level of Heavy Metals and Potential Ecological Risks in Irrigated Horticultural Farms in the Vicinity of Lake Ziway, Central Ethiopian Rift Valley Region

Table 4

Comparison of heavy metal concentrations (mg·kg⁻¹) in soil reported from the nearby Ethiopian rift valley areas with the present study.

Study area	Mean concentrations in mg·kg^−1 at sampling site(s)									Reference
	As	Pb	Zn	Cd	Hg	Cu	Ni	Co	Cr
Hawassa vegetable farms	6.7	10.9	133.0	0.2	—	28.7	14.0	—	19.7	Samuel et al. [47]
	8.4	12.9	140.0	0.3	—	73.3	22.0	—	26.1
Modjo vegetable farms	24.1	37.93	98.9	5.3	6.3	26.0	35.6	15.1	36.2	Gebeyehu and Bayissa [48]
	24.1	35.80	93.7	4.8	7.3	25.5	30.5	14.9	35.9
Koka vegetable farms	20.9	37.30	97.8	4.4	6.1	19.8	35.0	13.5	48.1	Bayissa and Gebeyehu [49]
	27.7	43.60	108.3	6.0	6.7	24.0	40.3	15.9	49.2
	29.8	47.20	126.8	6.0	7.7	26.3	42.5	18.9	49.9
	31.4	48.60	138.9	6.4	8.2	28.7	50.7	21.7	60.7
Ziway vegetable farms	3.0	12.75	35.9	0.3	1.4	3.7	1.8	0.9	3.4	This study
	5.6	42.34	60.7	1.1	2.0	8.6	7.0	2.4	9.5
	5.8	43.70	62.4	1.2	2.3	10.1	8.4	3.5	10.1