Table 1.

Concentration of Pb, Cd and Hg in plants (wormwood, St. John’s wort, yarrow, cottonwood, nettle, horsetail) (mg/kg).

Herbal Plants	Metal	Mean	Median	Min	Max	SD	CV%
All plants	Pb	13.61	12.71	4.673	23.76	5.318	39.1
	Cd	0.412	0.300	0.010	1.511	0.396	96.3
	Hg	0.010	0.010	0.005	0.028	0.004	44.0
Wormwood	Pb	14.42	13.03	8.545	21.60	4.276	29.7
	Cd	0.434	0.270	0.012	1.040	0.429	99.0
	Hg	0.012	0.014	0.007	0.015	0.003	24.6
St. John’s wort	Pb	8.106	6.229	4.673	14.83	3.632	44.8
	Cd	0.102	0.059	0.010	0.325	0.113	110
	Hg	0.006	0.006	0.005	0.007	0.001	10.3
Yarrow	Pb	15.07	13.12	9.171	23.44	5.845	38.8
	Cd	0.864	0.896	0.013	1.511	0.455	52.6
	Hg	0.008	0.008	0.007	0.009	0.001	10.7
Cottonwood	Pb	12.38	9.970	5.860	23.67	6.673	53.9
	Cd	0.489	0.515	0.046	0.804	0.284	58.0
	Hg	0.009	0.010	0.006	0.011	0.002	23.2
Nettle	Pb	17.05	16.57	11.81	23.76	3.922	23.0
	Cd	0.336	0.244	0.065	0.745	0.285	84.9
	Hg	0.013	0.011	0.010	0.022	0.004	33.6
Horsetail	Pb	14.07	13.96	11.15	17.32	2.698	19.2
	Cd	0.139	0.117	0.010	0.394	0.148	107
	Hg	0.014	0.012	0.008	0.028	0.007	53.2