Introduction

1. Lead is second only to iron among the most widely used metals, having applications in the manufacture of batteries, pigments, alloys, plastics and ammunition. It has also been used widely in organic compounds as a petrol additive, although this application is now declining. It is no longer mined in the United Kingdom, but industrial workers may be exposed to it in smelting and refining operations, battery manufacture, scrap metal work, painting, soldering, ship repair and demolition, plumbing, manufacture of pottery and many other less common situations.
2. Lead can be absorbed into the body both through the lungs and through the stomach and intestines. Thus people may be at risk of absorbing it when exposed either in the air, dust, soil or as a contaminant in food and drink. In industrial situations there is a risk from inhaling lead-bearing dust or fumes from heated lead and much of our knowledge of its harmful effects comes from study of such workers. Among the general public two sources of exposure are of particular importance; contamination of drinking water from lead pipes and contamination of the air from industrial sources and from combustion of leaded petrol. Lead in the air may not only be absorbed directly by the lungs but may also settle out and contribute to contamination of crops and of dust ingested inadvertently by children.
3. Lead has been known for centuries to be harmful to people working with it, and in particular has severe adverse effects on the blood, the nervous system and the kidneys. However, these clinical effects only occur as a consequence of high exposures and are relatively easily prevented. Of greater concern are the more subtle effects caused by lower exposures, such as may occur from the presence of lead in drinking water, paint and dust, and in the ambient air. The effects of lead on the intellectual development of children have been of especial concern. Children appear to be more susceptible to lead than adults, and may also absorb it to a greater extent when exposed.
4. In this report, the Panel discuss the main sources of lead exposure, including the relative contributions of lead in the air and lead in the diet, and the methods by which it is measured in the air. The Panel also consider the airborne concentrations recorded to date in the United Kingdom, ways in which lead is handled by the body, and its toxic effects on people. We then recommend an Air Quality Standard for the United Kingdom for lead.