Table 2.

The maximum allowable limit of heavy metal ions in drinking water [28,29].

Heavy Metals	US EPA, 2018	WHO, 2011
Cr (total) (mg/L)	0.10 mg/L	0.05
Cd (II) (mg/L)	0.005 mg/L	0.003
Pb (II) (mg/L)	0.015 mg/L	0.01