Table 1: Limit concentrations of common heavy metals in drinkable water, suggested by the World Health Organization (WHO) and the Environmental Protection Agency (EPA).

Contaminant WHO
(mg/L)
EPA
(mg/L)
Potential Health Effects from Long-Term Exposure Sources of Contaminant in Drinking Water
As 0.010 0.010 Skin damage or problems with circulatory systems, and may have increased risk of getting cancer Erosion of natural deposits; runoff from orchards, runoff from glass and electronics production wastes
Ba 7 2 Increase in blood pressure Discharge of drilling wastes; discharge from metal refineries; erosion of natural deposits
Cd 0.003 0.005 Kidney damage Corrosion of galvanized pipes; erosion of natural deposits; discharge from metal refineries; runoff from waste batteries and paints
Cr
(total)
0.050 0.100 Allergic dermatitis Discharge from steel and pulp mills; erosion of natural deposits
Cu 2 1.300 Liver or kidney damage Corrosion of household plumbing systems; erosion of natural deposits
Hg
(inorganic)
0.006 0.002 Kidney damage Erosion of natural deposits; discharge from refineries and factories; runoff from landfills and croplands
Pb 0.010 0.015 Kidney problems; high blood pressure Corrosion of household plumbing systems
Sb 0.020 0.006 Increase in blood cholesterol; decrease in blood sugar Discharge from petroleum refineries; fire retardants; ceramics; electronics; solder