Lead is a naturally occurring heavy metal, and usually presents in very small amount in the environment. Lead and its compounds may be found in products such as batteries, lead-based paints, lead-containing ceramics, lead solder and leaded petrol. In everyday life, lead is found everywhere and exposure seems inevitable. Notwithstanding this, it is always good for health to achieve the lowest possible lead level in the body.
Industries with particularly high potential exposures include: construction work involving welding, cutting, brazing or polishing on lead surfaces and application of lead solder; most smelter operations either as a trace contaminant or as a major product; secondary lead smelters where lead is recovered from batteries; and firing ranges.
Lead may be contaminated with hazardous concentrations in lead paint, cosmetics and herbal medicines. Common exposure sources of lead with very low level for general public include urban dust, contaminated food and contaminated water.
Health effects of lead
Lead can enter the human body by ingestion, inhalation and skin absorption. When lead is absorbed into the body in excessive amount, it is toxic to many organs and systems. For acute effect, accidentally exposure for high dose of lead may cause abdominal pain and vomiting. For chronic effects, depending on the lead level inside the body, significant exposure to lead is associated with a wide range of effects, including neurodevelopmental effects, anaemia, high blood pressure, gastrointestinal symptoms, impaired renal function, neurological impairment, impaired fertility and adverse pregnancy outcomes. Infants, young children, pregnant women and lactating women are more likely to be affected by its adverse effects.
How can one reduce the risks of exposure to lead?
- Avoid exposure to sources of lead.
- Do not allow children to chew or mouth painted surfaces of toys or furniture that may have been painted with lead-based paint.
- Clean the dust in your house regularly if it might be decorated with lead-based paint, especially when the paint is in deteriorating conditions. Wash children's hands and faces frequently to remove any lead dusts and soil.
- If lead should be present in the plumbing system, the longer water has been standing in the pipes, for instance, after several hours of non-use, overnight, over a weekend or after a holiday, the more lead it may contain. Flushing works by removing the water with the most lead from the drinking water system. Running water at a tap, usually for two to three minutes, prior to using it for drinking or food preparation will often reduce lead levels in the water.
- Keep all lead contaminated / contained products away from children. Some types of pigments that are used as make-up (e.g. surma or kohl) or hair colouring dye may contain lead.
Management of a raised blood lead level
The most important management is to identify and remove the source of exposure. When exposure stops, lead in the body will be gradually reduced through excretion in urine and bile. It is important to have a balanced diet with adequate amounts of vitamins and minerals, especially calcium and iron, as good nutrition lowers the amount of swallowed lead that is absorbed into the bloodstream. Patients who are symptomatic with high blood lead levels (i.e. more than 44 micrograms/dL in the more easily affected group and more than 50 micrograms/dL for adults) should be evaluated for further management, including chelation therapy.
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