Table 4.

Concentration of heavy metals in stem samples of medicinal plants

		Mean heavy metal concentration in stem samples (ppm)
S/N	Plant species	Mn	Cr	Pb	Fe	Cd	Ni	Co	Zn	Hg
1	Acacia nilotica	5.22 ± 0.1040	1.87 ± 0.0202	0.25 ± 0.0088	25.30 ± 0.1464	BDL	0.45 ± 0.0240	0.04 ± 0.0088	2.42 ± 0.2173	BDL
2	Bacopa monnieri	4.23 ± 0.0744	2.62 ± 0.0240*	2.34 ± 0.0173	17.16 ± 0.1763	0.02 ± 0.0033	0.26 ± 0.0284	0.05 ± 0.0033	6.75 ± 0.1223	BDL
3	Commiphora wightii	2.51 ± 0.0176	2.87 ± 0.0202*	0.63 ± 0.0088	19.45 ± 0.2334	BDL	0.55 ± 0.0173	0.02 ± 0.0088	7.74 ± 0.0802	BDL
4	Ficus religiosa	4.52 ± 0.0176	2.67 ± 0.0371*	0.36 ± 0.0317	24.35 ± 0.1808	0.02 ± 0.0010	0.64 ± 0.0145	0.12 ± 0.01201	4.17 ± 0.0736	BDL
5	Glycyrrhiza glabra	4.78 ± 0.0240	3.56 ± 0.0305*	0.41 ± 0.0185	21.21 ± 0.0173	0.03 ± 0.0120	0.06 ± 0.0120	0.20 ± 0.0185	5.52 ± 0.0202	BDL
6	Hemidesmus indicus	5.43 ± 0.0173	4.89 ± 0.0202*	0.66 ± 0.0352	15.42 ± 0.0176	0.03 ± 0.0145	1.07 ± 0.0057	0.23 ± 0.0881	7.13 ± 0.0115	BDL
7	Salvadora oleoides	2.85 ± 0.0218	3.68 ± 0.0202*	0.83 ± 0.0088	11.89 ± 0.0317	BDL	0.47 ± 0.0115	0.13 ± 0.0173	5.59 ± 0.0317	BDL
8	Terminalia bellirica	6.13 ± 0.0176	3.80 ± 0.0450*	0.63 ± 0.0115	16.34 ± 0.0392	0.03 ± 0.0088	0.43 ± 0.0173	0.21 ± 0.0290	5.46 ± 0.0545	BDL
9	Terminalia chebula	5.67 ± 0.0384	2.92 ± 0.0202*	0.62 ± 0.0384	16.19 ± 0.0633	0.03 ± 0.0152	0.64 ± 0.0750	0.20 ± 0.0589	6.32 ± 0.0202	BDL
10	Withania somnifera	2.39 ± 0.0218	4.93 ± 0.0185*	2.64 ± 0.0260	19.13 ± 0.0176	0.04 ± 0.0088	0.53 ± 0.0296	0.14 ± 0.0152	8.93 ± 0.0264	BDL

*Beyond permissible limit defined by WHO.