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

Table 3

Heavy metal concentrations (mg·kg⁻¹) in the soil from the study sites (mean ± SD, n = 15).

Site	As	Pb	Zn	Cd	Hg	Cu	Ni	Co	Cr
S1	5.58 ± 1.26^a	42.34 ± 35.55^b	62.37 ± 9.51^a	1.10 ± 0.36^a	2.04 ± 0.37^b	10.03 ± 3.23^a	6.98 + 2.33a	2.37 + 1.28^a	10.05 + 1.37^a
S2	5.82 ± 2.06^a	43.7 ± 35.36^a	60.67 ± 13.61^b	1.23 ± 0.6^a	2.34 ± 0.65^a	8.57 ± 3.01^b	8.43 + 5.24b	3.52 + 2.08^b	9.52 + 4.1^b
S3	3.04 ± 0.14^b	12.75 ± 0.62^c	35.89 ± 1.14^c	0.32 ± 0.03^b	1.38 ± 0.05^c	3.71 ± 0.19^c	1.81 + 0.18^c	0.89 + 0.05^c	3.39 + 0.29^c
All S	5.17 ± 1.76	30.9 ± 24.31	56.39 ± 14.06	1.0 ± 1.76	1.96 ± 0.54	8.21 ± 3.47	6.53 ± 4.12	2.60 ± 1.99	8.50 ± 3.58
MPL	14	10	50	0.3	0.3	20	50	8	100

Mean values with the same superscript letters in a column are not significantly different () from each other at α = 0.05. MPL = maximum permissible limit for agricultural soils according to [27, 28]. Bold values show that the four elements are much higher than MPL.