Code of practice for "Lead"

Solution Preview

Please see response attached.

Health Sciences, Health Promotion and Disease & Injury Prevention
Year 3
Code of practice for "Lead"
Hi,
Let's do an extensive on-line search then, using the Google search engine (my favorite) using the search words "toxicological effects of lead" to see how many hits we get. Often the first hits are the most helpful, but not always. Wow, we received over a millions hits (1,890,000). I provided some of the excerpts in full below and additional links as well.
Let's take a closer look at what we located:
I. I have been asked to compile as much information regarding lead as possible. Among a million other areas where I am looking at lead, specifically toxicological effects,
Article 1:
Hazard Summary-Created in April 1992; Revised in January 2000
Lead is used in the manufacture of batteries, metal products, paints, and ceramic glazes. Exposure to lead can occur from breathing contaminated workplace air or house dust or eating lead-based paint chips or contaminated dirt. Lead is a very toxic element, causing a variety of effects at low dose levels. Brain damage, kidney damage, and gastrointestinal distress are seen from acute (short-term) exposure to high levels of lead in humans. Chronic (long-term) exposure to lead in humans results in effects on the blood, central nervous system (CNS), blood pressure, kidneys, and Vitamin D metabolism. Children are particularly sensitive to the chronic effects of lead, with slowed cognitive development, reduced growth and other effects reported. Reproductive effects, such as decreased sperm count in men and spontaneous abortions in women, have been associated with high lead exposure. The developing fetus is at particular risk from maternal lead exposure, with low birth weight and slowed postnatal neurobehavioral development noted. Human studies are inconclusive regarding lead exposure and cancer.
________________________________________
Please Note: The main sources of information for this fact sheet are EPA's Integrated Risk Information System (IRIS), which contains information on the carcinogenic effects of lead, and the Agency for Toxic Substances and Disease Registry's (ATSDR's) Toxicological Profile for Lead.
Uses
• The primary use of lead is in the manufacture of batteries. (1)
• Lead is also used in the production of metal products, such as sheet lead, solder (but no longer in food cans), and pipes, and in ceramic glazes, paint, ammunition, cable covering, and other products. (1)
• Tetraethyl lead was used in gasoline to increase the octane rating until lead additives were phased out and eventually banned from use in gasoline in the U.S. by the EPA by 1996. (1)
Sources and Potential Exposure
• The largest source of lead in the atmosphere has been from leaded gasoline combustion, but with the phasedown of lead in gasoline, air lead levels have decreased considerably. Other airborne sources include combustion of solid waste, coal, and oils, emissions from iron and steel production and lead smelters, and tobacco smoke. (1,2)
• Exposure to lead can also occur from food and soil. Children are at particular risk to lead exposure since they commonly put hands, toys, and other items in their mouths, which may come in contact with lead-containing dust and dirt. (1,2)
• Lead-based paints were commonly used until 1978 and flaking paint, paint chips, and weathered paint powder may be a major source of lead exposure, particularly for children. (1,2)
• Lead in drinking water is due primarily to the presence of lead in certain pipes, solder, and fixtures. (1,2)
• Exposure to lead may also occur in the workplace, such as lead smelting and refining industries, steel and iron factories, gasoline stations, and battery manufacturing plants. (1,2)
• Lead has been listed as a pollutant of concern to EPA's Great Waters Program due to its persistence in the environment, potential to bioaccumulate, and toxicity to humans and the environment. (3)
Assessing Personal Exposure
• The amount of lead in the blood can be measured to determine if exposure to lead has occurred. (1,2)
• The level of lead in the blood is measured in micrograms per deciliter (µg/dL).
• Exposure to lead can also be evaluated by measuring erythrocyte protoporphyrin (EP), a component of red blood cells known to increase when the amount of lead in the blood is high. This method was commonly used to screen children for potential lead poisoning. (1,2)
• Methods to measure lead in teeth or bones by X-ray fluorescence techniques are not widely available. (1)
Health Hazard Information
Acute Effects:
• Death from lead poisoning may occur in children who have blood lead levels greater than 125 µg/dL and brain and kidney damage have been reported at blood lead levels of approximately 100 µg/dL in adults and 80 µg/dL in children. (1,2)
• Gastrointestinal symptoms, such as colic, have also been noted in acute exposures at blood lead levels of approximately 60 µg/dL in adults and children. (1,2)
• Short-term (acute) animal tests in rats have shown lead to have moderate to high acute toxicity. (4)
Chronic Effects (Noncancer):
• Chronic exposure to lead in humans can affect the blood. Anemia has been reported in adults at blood lead levels of 50 to 80 µg/dL, and in children at blood lead levels of 40 to 70 µg/dL. (1,2)
• Lead also affects the nervous system. Neurological symptoms have been reported in workers with blood lead levels of 40 to 60 µg/dL, and slowed nerve conduction in peripheral nerves in adults occurs at blood lead levels of 30 to 40 µg/dL. (1,2)
• Children are particularly sensitive to the neurotoxic effects of lead. There is evidence that blood lead levels of 10 to 30 µg/dL, or lower, may affect the hearing threshold and growth in children. (1,2)
• Other effects from chronic lead exposure in humans include effects on blood pressure and kidney function, and interference with vitamin D metabolism. (1,2,5)
• Animal studies have reported effects similar to those found in humans, with effects on the blood, kidneys, and nervous, immune, and cardiovascular systems noted. (1,2,5)
• EPA has not established a Reference Concentration (RfC) or a Reference Dose (RfD) for elemental lead or inorganic lead compounds. (6)
• EPA has established a Reference Dose (RfD) for tetraethyl lead (an organometallic form of lead) of 1 x 10-7 milligrams per kilogram body weight per day (mg/kg/d) based on effects in the liver and thymus of rats. The RfD is an estimate (with uncertainty spanning perhaps an order of magnitude) of a daily oral exposure to the human population (including sensitive subgroups) that is likely to be without appreciable risk of deleterious noncancer effects during a lifetime. It is not a direct estimator of risk, but rather a reference point to gauge the potential effects. At exposures increasingly greater than the RfD, the potential for adverse health effects increases. Lifetime exposure above the RfD does not imply that an adverse health effect would necessarily occur. (7)
• EPA has ...