New Information on Lead in Dirt and Dust as Related to the Childhood Lead Problem

Abstract

It has been known for many years that the eating of leaded paint is the prime cause of lead poisoning and elevated blood leads of children living in deteriorated housing. Recently, there has been speculation that children may eat dirt and dust contaminated with lead exhausted from cars and that this amount of ingested lead is sufficient to contribute significantly to the childhood lead problem. This paper reports on a twopart study conducted to evaluate the validity of the dirt-and-dust hypotheses. The first part of the study was made to determine the source of lead in dirt to which children are normally exposed. Dirt samples were taken in old urban areas around 18 painted frame houses and 18 houses of brick construction. Samples also were taken around seven old frame farmhouses remote from traffic. Based on the fact that lead concentrations in the dirt were similar in city and rural yards at corresponding distances from the houses, it is clear that nearly all of the lead in dirt around these houses is due to paint from the houses. Lead antiknock additives are therefore not a significant contributor to the lead content of dirt around houses where children usually play. The second part of the study used a naturally occurring radioactive tracer 210Pb to determine the relative amounts of dust and other lead-containing materials (e.g., paint) eaten by young children. This tracer is present in very low concentrations in paint and in significantly higher concentrations in fallout dust. Stable lead and 210Pb were analyzed in fecal material from eight children suspected of having elevated body burdens of lead and ten children living in good housing where lead poisoning is not a problem. The normal children averaged 4 μg Pb/g dry feces, with a range of 2 to 7. Of the eight children suspected of having elevated lead body burdens, two had fecal lead values within the normal range. However, the remaining six were 4 to 400 times as high. Despite these differences in fecal lead between the two groups, the groups were essentially identified in the 210Pb content of their feces. The “elevated” children averaged 0.040 pCi of 210Pb dry feces, while the normal group averaged 0.044 pCi/g. The results provide sound evidence that these children suspected of elevated lead body burden were not ingesting dust or air-suspended particulate.

Alluvial and riparian soils as major sources of lead exposure in young children in the Philippines: the role of floods

“…For many years, the ingestion of lead from lead-containing paint had been the primary cause of elevated blood leads and lead poisoning in children (AAP 2005;CDC 2011;Haar and Aronow 1974). However, lead in house dust and soil have now become a major source of lead exposure in children compared to lead ingested from lead paint, and in some areas, lead from soil and house dust have become more important sources of lead exposure in children who are engaged in handto-mouth and pica behavior (Mielke et al 2010;Lanphear et al 1998).…”

Seasonality and Children’s Blood Lead Levels: Developing a Predictive Model Using Climatic Variables and Blood Lead Data from Indianapolis, Indiana, Syracuse, New York, and New Orleans, Louisiana (USA)

“…In the 1970s, the assumed source of soil Pb contamination was Pb-based house paint (Ter Haar and Aronow 1974). An early study of garden soils conducted in metropolitan Baltimore, Maryland, raised questions about that assumption.…”

Potential human health effects of acid rain: report of a workshop

“…This weathering process is not restricted to deteriorated housing in inner urban areas of the U.S. but can also occur in rural areas as well. It is known that significant external weathering of painted surfaces over time is an active process (81,82), and there is potential for acid precipitation in hastening this process with concomitant transfer to soils and dusts in contact with children, since a common ingredient in high lead paint is basic lead carbonate.…”