Lead is a metal that occurs naturally in minerals such as cerussite and hydrocerussite. It is toxic and can be hazardous if inhaled or ingested. Occupational exposure to lead can cause lead poisoning, which is often fatal.
Several environmental pollutants such as sulphur, phosphorus, and heavy metals may react with lead to form lead compounds that are soluble in water. These compounds may be present in the atmosphere, soil, and food.
The solubility of lead is strongly influenced by pH and dissolved inorganic carbon (DIC) concentrations. The minimum solubility of lead occurs at a pH of about 9.8 and DIC of about 40 mg/L. This is a good target for minimizing release to the environment, but it should be remembered that lead may also be released in particulate form.
In addition, dissolved lead in the water can be higher when it is present in pipes that contain lead. This is because a layer of hardly soluble alkalic lead carbonate forms on the underlying lead inside the pipe, which prevents it from dissolving completely in hard water.
Ingestion and inhalation of lead can cause severe toxicity, including hearing loss, lowered IQ and behavioral problems in children. It is especially dangerous to pregnant women and infants, because it can interfere with their development and cause birth defects. It is also a possible carcinogen to humans. It is therefore important to protect the workers from exposure to it by using personal protective equipment and proper ventilation.