Concentration of Fo in Paint TABLE II TOTAL LEAD INGESTION FROM PAINT, ug (Daily Average) Based upon absorbing 10% of all ingested lead from the GI tract, Table III can be constructed. TABLE III TOTAL LEAD ABSORPTION FROM PAINT, ug (Daily Average) Table 4. Effect in Adults of Various Ambient Air Concentrations Lead Exposure Lead Absorption 'Assumes inhalation of 23 m3/day and 30% lung retention. 2Assumes 10% absorption from gastrointestinal tract. 3Computed from regression formula: Blood lead = -69.2052 + 54.7605 x log ug Pb absorped daily as given in Chapter 3 of Airborne Lead in Perspective by the National Research Council, National Academy of Sciences.. 4Excess body burden associated with ambient air exposure above 2.0 μg Pb/m3. -6 Clearly, according to Table III, the only lead paint concentration that offers reasonably complete protection is 0.01%. Even at 0.05% lead in paint, ingestion of only one twentieth of a teaspoon of paint per day (containing 12.5 ug lead) will nearly double baseline absorption from food and water (13 ug) in a 1-3 year old child (10 18 Kg). Although data on children are limited, the best available evidence in adults indicates that doubling daily intake (absorption) of lead from a baseline of 40 ug per day in a 70 Kg adult raises blood lead concentration from about 20 to 35 ug/ 100 g, a level closely associated with significant impairment of hemoglobin synthesis (10) [See Table 4]. Quadrupling baseline absorption in adults raises blood leads to greater than 50 ug/ 100 g, a level close to that occasionally associated with clinical lead poisoning in some children (11). Ingestion of only 1/10 of a teaspoon of 0.1% lead paint per day more than quadruples baseline absorption of 13 ug per day in a 1-3 year old child. paint containing even 0.1% lead used in residential areas poses a significant potential danger to future generations of children. Thus, Although the data in Table III have not been substantiated by direct experimental evidence, they certainly are a most conservative estimate of lead ingestion from paint. Most chips of peeling lead paint are significantly denser than water. Table III is based upon -7 However, ingestion of lead chips that are only as dense as water. pertinent other factors such as dietary deficiency states (low iron and low calcium) which potentially might predispose to increased lead absorption from the gut in excess of 10% have not been considered Furthermore, no additional safety factor has been in this analysis. included in these calculations. Although There may be room for debate regarding whether 0.05% or 0.01% lead in paint should be the upper acceptable limit, clearly a level higher than this is unacceptable. In a recent press release (12), based upon an independent method of analysis, the American Academy of Pediatrics strongly recommended that lead paint in excess Their estimate is in close of 0.06% lead should not be permitted. agreement with ours. SUMMARY A control strategy to prevent childhood lead ingestion from paint in future generations is presented. This is based upon no significant increase of lead intake beyond baseline levels from food and water. According to our analysis, lead in paint even at 0.05% is a potential hazard to children prone to pica. A lead concentration of 0.01% would reasonably protect all children except those with extreme tendencies for paint ingestion. Independent analyses support our view that at no time should future use of paint containing lead in excess of 0.05%, and preferrably not in excess of 0.01%, be permitted in residential areas. -9 |