Table 3.

Heavy metal concentrations (mg/L) in each tap water

Element	min	max	average	SD	MCL EPA	MCL WHO
As	0.002	0.003	0.0025	4.33E-19	0.01	0.01
Cd	0.003	0.004	0.0035	4E-19	0.005	0.003
Cr	0.001	0.002	0.0015	4E-19	0.1	0.05
Ni	0.004	0.006	0.005	8.8E-04		0.07
Pb	0.0022	0.005	0.003	1E-03	0.015	0.01
B	0.142	1.441	0.46	4.2E-01		2.4
Al	0.014	0.072	0.05	1.9E-02	0.2	0.1
Hg	0.001	0.001	0.001	4E-19	0.002	0.006
Mn	0.001	0.036	0.004	9.43E-03		0.4
Zn	0.022	0.097	0.04	1.9E-02
Cu	0.003	0.011	0.01	2.6E-03	1.3	2
Fe	0.009	0.298	0.06	7.6E-02
Se	0.001	0.001	0.001	4E-19	0.05	0.04
Ba	0.001	0.026	0.02	7.5E-03	2	1.3
pH	6.6	7.8	7.15	3.4E-01	6.5–8.5	6.5–8.5