WHAT IS LEAD?
Lead is a heavy metal that is found in mineral deposits in the earths crust and has been in industrial use for thousands of years. It is pale silvery grey when freshly cut it darkens on exposure to air. It is heavy Malleable and a poor conductor of electricity. Lead may be used in its pure elemental form or combined chemically with other elements to form lead compounds. It is resistant to corrosion; it has a low melting point and is soft so it is easy to work with.
WHERE IS LEAD FOUND?
Today lead has many industrial uses. Inorganic lead compounds are used in pigments, paints, glasses, plastics and rubber compounds. It can be in materials such as paints, coatings, mortar, concrete, solder, batteries, ammunition, sheet metal and devices to shield x-ray.
Houses built in before 1960 are likely to have been painted with lead based paint, although it may have been removed. There is little need for concern about lead levels for homes built after 1980 and as of 1992; all paints for indoor use in Canada are virtually lead free.
WHY IS LEAD A CONCERN?
Shortly after lead is inhaled or ingested, it can enter the bloodstream and travel to soft tissues such as the liver, kidneys, lungs, brain, spleen, muscles, and heart. After several weeks, most of the lead moves into your bones and teeth and can be stored there for a long time. Therefore, exposure to small amounts of lead can build up over time and the more lead you have in your body, the more likely it is that you will experience health problems. Small amounts are very harmful to infants, young children and pregnant women.
WHAT HEALTH EFFECTS CAN LEAD CAUSE?
Harmful effects can follow a high exposure over a short period of time (acute poisoning), or long-term exposure to lower doses (Chronic Poisoning). Symptoms of acute lead poisoning include a metallic taste in the mouth, convulsions, coma, even death and gastrointestinal symptoms such as vomiting, abdominal cramps, constipation, and diarrhea. Symptoms of chronic lead posing are more difficult to recognize because they are similar to many common complaints and may be less noticeable. However, severe chronic poisoning can lead to more characteristic symptoms, such as a blue line on the gums, wrist drop(the inability to hold the hand extended) and anemia when the number of red blood cells in your body is below normal and may damage the nervous system. Other symptoms are appetite loss, abdominal pain, constipation, fatigue, sleeplessness, irritability, headache and pallor.
Lead exposure is very serious for young children because they absorb lead more easily than adults and are more susceptible to its harmful effects. Even low level exposure may harm the intellectual development, behavior, size and hearing of infants and children. Any woman in her childbearing years should avoid exposure to lead whenever possible. During pregnancy, lead can cross the placenta and affect the health and growth and development of the unborn child.
Lead can also cause serious damage to a number of systems in the body.
Overexposure to lead can affect:
BLOOD: Lead can interfere with the body’s ability to manufacture hemoglobin, the molecule in red blood cells responsible for carrying oxygen to the tissues. This may lead to anemia.
KIDNEYS: Kidneys purify blood before it is distributed for use by the rest of the body. However, kidneys are not effective in filtering lead from the bloodstream. In addition, lead can damage the kidneys and reduce its ability to filter waste from the bloodstream.
GASTROINTESTINAL SYSTEM: Lead poisoning may result in abdominal pain, loss of appetite, vomiting, nausea, constipation and/or diarrhea.
NERVOUS SYSTEM: Lead poisoning can cause peripheral nerve damage that result in muscle weakness. It may also lead to behavioral changes and to impairment of vision and hearing. At very high levels, lead can affect the brain, causing convulsions, coma and even death.
REPRODUCTIVE SYSTEM: Lead may harm the developing fetus because of the shared blood supply between a mother and her fetus. Exposure of pregnant women to excessive lead may result in miscarriages and stillbirths. Overexposure to lead in men can impair sperm production.
BONES AND TEETH: Absorbed lead can be deposited and stored in mineralizing tissues (bones and teeth) for a long period of time. Under certain circumstances, the release of stored lead increases and can re-enter the blood and target other systems in the body. The release of stored lead increases during periods of pregnancy, lactation, menopause, physiologic stress, chronic disease, hyperthyroidism, kidney disease, broken bones and advanced age and is exacerbated by calcium deficiency.