Lead
LEAD is found in all plant and animal tissues, the environment, foods, and drinks, with higher levels in processed foods. Toxicities have been significantly reduced since the removal of lead from paints and by replacing tin in cans with aluminum. However, one toxicity problem was traded with another in that effort. Plastics, pottery glazes, and printing ink still contain lead, which can leach into foodstuffs from containers used improperly. Water supplies and cigarette smoke are the biggest contributers to ingested lead.
When lead enters the cells of the body, it binds to active enzyme sites, blocking their function. Lead can also interfere with ion transport, plasma membrane function, cellular respiration, and large molecule synthesis. It is noted that humans accumulate lead slowly and gradually with age (the half life of lead is about twenty years), implying that excretion is not able to maintain a balance. About 10% of the lead in the body is found in the blood, and the other 90% is found in the skeleton. Body stores can be mobilized as a result of stress, injury, or pregnancy, thus causing poisoning even when current intakes are low.
Signs and symptoms of lead poisoning can be vague at first with lassitude, loss of appetite, and pallor. Later, colic and stomach pain develop. Increasing ingestion leads to anemia, peripheral neuropathy (nerves affected in the extremeties), encephalopathy (brain degeneration), and kidney damage. Experimentally induced lead deficiency proved to be associated with retarded physical and mental growth, anemia, decreased stores in the blood/liver/and spleen, elevated serum cholesterol/phospholipids/and bile acids, decreased liver concentrations of glucose/triglycerides/and phospholipids, increased liver cholesterol, and altered blood and liver enzymes. However, very minute amounts are required for normal growth and health, but the balance between toxic and deficient is precarious.
Modern culprits vary, but one to watch is the water dispenser. Water coolers may have high lead levels because they usually have holding tanks that contain the substance, and no one ever thinks to flush out a water dispenser. Even tap water that sits unused in the pipe overnight can contain high levels of lead with the first flushing. The hot water tap contains the most lead and should never be used in food preparation. When a crisis occurs, it is often suggested that water is to be boiled to kill any bacteria present, but, in doing so, lead becomes concentrated significantly, raising its levels.
There is a way to tell if water pipes are lead. Bang the pipes with a metal object. If the pipes are lead, a "thunk" instead of a "clang" will be heard. Color and texture are also clues. Lead is a soft dull gray color that can be scratched with a fingernail. The possibilities do not stop there, however. The joints of copper piping are often lead. New solder can leach into the water for as long as five years. One consolation, howbeit minute, is that if the water that flows through these pipes has a high mineral content, a buildup will occur, blocking the leaching of lead into the water. However, as with aluminum, one problem is solved with the creation of another.
Summary:
Names include: Pb and element 82.
Toxicity symptoms include: decreased appetite, constipation, metallic taste in mouth, nausea, slight albumin in urine, protein in urine, heart burn, decreased weight, hearing changes, balance deterioration, mental sluggishness, decreased IQ, destruction of nerve tissues, tingling/numbness/paralysis of extremeties, convulsions, coma, swallowing difficulties, vision deterioration, breathing deterioration, voice changes, very fine facial twitching, slight trembling of hands and fingers, headaches, dizziness, fatigue, joint pain, vague aching, neck/shoulder pain, occasional cramps or stiffness, anemia, small spontaneous bruising, anxiety, depresssion, emotional agitation, insomnia.
Inhibitors are Vitamins C, E, N, calcium, iron, selenium, zinc. There are no known helpers.
Sources include: air/vehicle/water pollution, insecticides, food contamination, and piping.
