Environmental Hazards Lead and Mercury

Lead is a metal with the symbol Pb. It is a soft, malleable metal that is bluish white, but which oxidizes to a dull gray when exposed to air. Yet lead resists further oxidation by creating an oxidation layer. When melted, it takes on a chrome like, shiny appearance. Lead melts at 46° centigrade or 621.43°Fahrenheit.  Because of its ease of extraction, malleability and melting point, lead is easy to smelt and to form or mold into blocks or into detailed and complex shapes.

Mercury, or quicksilver is a transition metal that lies between gold and thallium on the periodic table, with the symbol Hg. Mercury melts at -38.83°  C or 37.89° F. Mercury is liquid at a standard room temperature. Mercury is extracted from mercuric sulfide deposits and is in soluble form as mercuric chloride or methylmercury. When heated, mercury forms mercury oxide, which decomposes when heat is increased. Mercury is a fair electrical conductor and develops phosphorescence when electricity is applied, but is a poor conductor of heat.

Lead is found in older things. Lead based paint and plumbing was used in older homes, toys, furniture, lead crystal and in some pottery. The soil around homes and where cars that used leaded gas may contain enough levels of lead to be a problem. People who work around lead can carry it around on their clothes and in their hair. Lead particles can become airborne when smelted or in other industrial operations. Lead is involved with some crafts, such as stained glass, furniture refinishing, and some artists paints, such as the true “lead white” oil paint.

Lead is ingested by breathing the dust or orally, as when paint chips are eaten or liquids that have been stored for a time in lead crystal are ingested. Dust can be orally ingested by handling the dust and putting the hands in the mouth. Renovating older homes is a source of exposure to lead as demolition, scraping and other disturbance releases the particles so that they are breathed in or orally taken in.

The health effects of high levels of lead in the juvenile body include brain or neurological damage, behavior and learning problems, hyperactivity, retarded growth, hearing loss and headaches. There are also adult reproductive and mutagenic problems, hypertension, high blood pressure, nerve disorders, muscle and joint pain, and memory and concentration issues.

Mercury is naturally present in the human body. High levels of mercury in unborn or young children present problems for the developing nervous systems. Otherwise, it all depends on the levels of mercury, the duration of the exposure, the form of mercury and how it was ingested. In most adults, the doctor can examine urine, blood, breast milk, fingernails and hair.

Mercury is used in barometers,  older style thermometers and blood pressure testing devices, float valves and scientific instruments. Mercury vapor lights and, in a source of major dispute, dental almagam that is used for fillings. Methylmercury is ingested by eating fish and shellfish.

The body is capable of processing mercury, causing it to eliminate naturally and without help, but it can take a long time for it to processes out of the body. For a determination of or actual incidence of high enough levels of mercury to cause illness the different factors, such as amount, duration, type of mercury result in a case by case basis with consideration of the normal levels of mercury that are already in the human body. 

EPA, Mercury

EPA, Lead

Wikipedia, “Lead”

Wikipedia, “Mercury”