Table 3: Drinking water contaminants and maximum admissible limit by different international organizations.

Heavy metals ( g/L)
CrMnCoNiCuZnAsCdPb

US-EPA (2008)100501001001300500010515
WHO (2008)50400 aNM702000NGLb10310

aNM: not mentioned.
bNGL: no guideline, because it occurs in drinking water at concentrations well below those at which toxic effects may occur.