Table 1: Permissible limits and health effects of various toxic heavy metals.

Metal contaminant Permissible limits for industrial effluent discharge (in mg/L) (DOE Malaysia, 1979) [7]Permissible limits for drinking water (in mg/L) (WHO, 2011) [6]Health hazards

Arsenic0.050.010.01Carcinogenic, producing liver tumors and skin and gastrointestinal effects

Mercury0.0050.050.006Corrosive to skin, eyes, and muscle membrane, dermatitis, anorexia, kidney damage, and severe muscle pain

Cadmium0.010.020.003Carcinogenic, cause lung fibrosis, dyspnea, and weight loss

Lead0.10.50.01Suspected carcinogen, loss of appetite, anemia, muscle and joint pains, diminishing IQ, cause sterility, kidney problem, and high blood pressure

Chromium0.210.05Suspected human carcinogen, producing lung tumors, and allergic dermatitis

Nickel0.210.07Causes chronic bronchitis, reduced lung function, cancer of lungs, and nasal sinus

Zinc113Causes short-term illness called “metal fume fever” and restlessness

Copper0.212Long term exposure causes irritation of nose, mouth, and eyes, headache, stomachache, dizziness, and diarrhea