Exposure to lead

Exposure to lead

Lead, one of the earliest metals utilized by humanity, has been documented for its toxic effects since the time of Hippocrates. While occupational lead poisoning has declined in most advanced nations, it remains a concern, particularly in small-scale workplaces, highlighting lead toxicity as a significant issue in industrial and environmental health. Recently, the emergence of various health problems due to low-level environmental lead exposure has underscored its considerable public health implications.

 

■ Characteristics of Lead

Lead, with an atomic number of 82, is a soft bluish or grayish metal. It has an atomic weight of 207.20 and a density of 11.34g/cm3 at 20°C. Lead is the most widely used metal among all non-ferrous metals.

 

■ Lead Exposure in the Workplace

Exposure to lead in the workplace is particularly hazardous in tasks involving high temperatures. Welding or cutting structures coated with lead-containing paints always carries risks. The operating temperatures typically range from 1,000 to 3,000°C, leading to significant lead fumes. Primary and secondary refining operations also generate substantial lead fumes due to high temperatures. Secondary refining, which involves reprocessing lead from waste such as used batteries, produces lead oxide dust. Lead exposure occurs in various processes including battery manufacturing. Firefighters tackling fires in lead-rich environments are at risk of occupational lead exposure. In the United States, emphasis is placed on highlighting the potential risks of lead exposure among firefighters.

 

■  Exposure to Lead in the Environment

Lead exposure in the living environment has emerged as a major societal issue in developed countries, including the United States. A significant concern is childhood lead poisoning resulting from lead-containing paints previously used indoors. In older homes, paint chips containing lead pose a risk if ingested by young children, leading to lead poisoning.

 

< Lead in the Environment (1)>

 

Globally, the use of leaded gasoline has had the most significant impact on blood lead levels in the general population. Since the 1920s, tetraethyl lead was widely used as an additive to raise the octane rating of gasoline, but its use was discontinued after epidemiological studies confirmed the association between lead exposure and childhood neurodevelopmental disorders in the 1970s. Following this, the use of leaded gasoline was phased out, with US completely discontinuing leaded gasoline usage by 1986. Consequently, the atmospheric lead levels in the United States have been consistently decreasing over time.

 

< The atmospheric lead levels in the United States (annual maximum 3-month average concentration) (2)>

 

Moreover, improper use of lead-containing ceramics and crystalware has been a major source of lead exposure, as well as exposure to lead-contaminated illicit drugs leading to lead poisoning. Additionally, there is a risk of lead exposure through food consumption and drinking water conveyed through old lead pipes.

 

■    References

The content is primarily based on Casarett and Doull’s Toxicology 9th edition and the NTP Monograph Health Effects of Low-Level Lead (https://ntp.niehs.nih.gov/sites/default/files/ntp/ohat/lead/final/monographhealtheffectslowlevellead_newissn_508.pdf).

(1)   Lead in the Environment Infographic.

https://www.cdc.gov/nceh/lead/prevention/infographic-lead-in-environment.htm. Access date: 2024-03-01

(2)   ATSDR. Toxicological Profile for Lead