Table 1.

Heavy Metals and Their Source and Health Effect

Major Items	As	Pb	Hg	Cd
Main sources	Metal smelters, fungicides, pesticides	Burning of coal, paint, automobile emission, pesticides, mining, smoking	Batteries, pesticides, paper, and the dental industry	Electroplating, smoking, welding, fertilizer, pesticides
Health effect	Dermatitis, bronchitis, cardiovascular disorders	Liver and renal failure, development delay, mental retardation, fatal neonatal encephalopathy, acute and chronic damage to nervous system	Gingivitis, tremors, protoplasm poisoning, spontaneous abortion, nervous system disorder	Pneumonitis and lung cancer, renal dysfunction, bone defects, bone marrow, kidney damage