Lead is a naturally occurring toxic metal found in the earth’s crust. Its widespread use has resulted in extensive environmental contamination, human exposure and significant public health problems in many parts of the world. Important sources of environmental contamination include mining, smelting, manufacturing and recycling activities, and, in some countries, the continued use of leaded paint, leaded gasoline, and leaded aviation fuel. More than three-quarters of global lead consumption is for the production of lead-acid batteries for motor vehicles. Lead is, however, also used in many other products, for example, pigments, paints, solder, stained glass, lead crystal glassware, ammunition, ceramic glazes, jewellery, toys and in some cosmetics and traditional medicines (World Health Organization [WHO], 2019).
Sources and routes of exposure
People can become exposed to lead through occupational and environmental sources. This mainly results from inhalation of lead particles generated by burning materials containing lead, for example, during smelting, recycling, stripping leaded paint, and using leaded gasoline or leaded aviation fuel; and ingestion of lead-contaminated dust, water (from leaded pipes), and food (from lead-glazed or lead-soldered containers).
The prevention of lead exposure
The prevention of lead exposure continues to be a major public health challenge in developed countries. In well-resourced countries, major lead exposure reduction interventions have resulted in significant improvements in childhood blood lead distributions. On the other hand, while lead exposure and poisoning remain serious public health concerns in developing countries, a range of prevailing factors and circumstances, such as poverty, a large informal sector, competing public health challenges, low levels of awareness of lead hazards and weak capacity to enforce legislation, contribute to an increase in the scale and intensity of the challenge, and limit the prospects of comparable success in the foreseeable future.
The role of lead as a neurological toxin is well established. Lead exposure has been associated with reductions in intelligence scores, hearing loss, hyperactivity, shortened concentration spans and poor school performance in children, as well as lowered lifetime earnings (Tong et al., 2000). In recent years a growing number of studies have also pointed to links between lead exposure and aggression or violent behaviour (Needlemanet al., 2002, 1996; Nevin, 2007; Wright et al., 2008). A factor which complicates this matter is that there is no blood lead level that does not have deleterious effects. The Centers for Disease Control and Prevention (CDC) recommend that children with blood lead levels > 5 mcg/dL (0.24 micromol/L) must have remediation, retesting, and serial monitoring as well as assessment for vitamin deficiency and general nutritional status (O’Malley & O’Malley, 2020).
Gerald F. O’Malley
Patients at risk should be screened by measuring PbB. Measures that reduce risk of household poisoning include regular hand washing, regular washing of children’s toys and pacifiers, and regular cleaning of household surfaces; drinking water, household paint (except in houses built after 1978), and ceramic ware made outside the US should be tested for lead. Adults exposed to lead dust at work should use appropriate personal protective equipment, change their clothing and shoes before going home, and shower before going to bed.