Today the standards of lead exposure set by the US Centre for Disease Control and Prevention (CDC) allow up to 10 micrograms per decilitre. However, recent studies show that this may still be too high, as many teenagers responded badly to hearing tests while lead was traceable in their blood.
Even though the amount of lead in the environment has dropped over the years, it is still traceable in old houses, soil and sometimes even in tap water. According to the researchers behind the study, lead exposure should still be considered as a cause of hearing loss in youth.
Hearing loss in children and teens can be problematic, as they are dependent on their hearing while socialising with peers. It can also be a source of stress and lead to learning disabilities at a young age.
Less exposure - better hearing
A study, led by Dr. Josef Shargorodsky from the Massachusetts Eye and Ear Infirmary, USA, measured the levels of lead in 2,500 teenagers' blood and urine. The results were published in Archives of Otolaryngology-Head and Neck Surgery, and showed that the lead levels did not exceed the limits set by the CDC, which is progress in itself.
However, when a hearing test was administered, 31% of the 12 to 19-year-olds with a lead level of two or more micrograms per decilitre in their blood failed the test. Only 17% of the teens with less than one microgram failed.
Earlier studies show that when exposed to lead, it can cross into the brain and interfere with the transmission and processing of sound.
Dr. Shargorodsky therefore advises parents to protect their children from exposure to lead and other heavy metals in general, even though the amount of the substances in the environment is defined as ”?safe'.