[Exposure of children to lead from contaminated soil]

To assess lead exposure in infants from contaminated soil a review of epidemiological studies was performed. Seventeen studies fulfilled criteria of individual exposure measures and a relevant confounder control. In 10 of these a clear association between blood lead and lead in soil was demonstrated after control of confounders. With some reservations three additional studies indicated an effect. No effect on blood lead from soil exposure was found in four studies. Quantitative estimates of the contributions to blood lead from soil varied within a wide range. In the best designed study-a controlled intervention against contaminated soil-blood lead values declined a little more than 1 microgram/100 ml per 1000 ppm. reduction of soil lead concentration. Oral exposure, probably by mouthing behaviour, was indicated by modification of the association between blood and soil lead from time spent outdoors, area with uncovered soil, age and mouthing behaviour in several studies. The conclusions from the review were that children's mouthing behaviour on lead contaminated soil may affect blood lead, but the contribution to overall lead exposure seems to be relatively small. Considering the limited margin of safety for lead exposure an intervention regimen for contaminated areas where infants have direct and continued contact with soil is suggested. Intervention in other places is unlikely to significantly reduce the lead burden of children. Simultaneously with intervention a programme for the evaluation of its effect is proposed.