In Brazil, Teixeira (32) has found that 11% of pipes used in the water distribution systems of 100 schools in São Paulo present lead levels above the limit considered safe by the WHO. In 2% of the water samples, the lead level was found to be five-fold higher than the highest acceptable value (< 10 µg/L, according to the WHO), thereby threatening the neuropsychiatric health of children.
Several studies have shown that high BLL in preschool children are strongly correlated with high lead levels in house dust (33-35). This association has been attributed to dust intake from the frequent hand-to-mouth behavior of young children. Flaking lead-based paint, road dust, garden soil and airborne lead-bearing particles are believed to be the sources of lead in household dust (36).
Leaded gas has caused more exposure to the metal than any other source worldwide (37). According to the São Paulo State Health Department (19), about 80% of the lead found in urban air samples before 1982 was derived from leaded gas. Car battery manufacture is the main source of secondary lead (38), but other sources cannot be discarded.
None of that is to say that lead is the only factor of course, just that I don't think your data disproves the theory that lead plays a significant part.
This article has some data about lead levels in children in Brazil: http://www.scielosp.org/scielo.php?script=sci_arttext&pid=S1...
In Brazil, Teixeira (32) has found that 11% of pipes used in the water distribution systems of 100 schools in São Paulo present lead levels above the limit considered safe by the WHO. In 2% of the water samples, the lead level was found to be five-fold higher than the highest acceptable value (< 10 µg/L, according to the WHO), thereby threatening the neuropsychiatric health of children.
Several studies have shown that high BLL in preschool children are strongly correlated with high lead levels in house dust (33-35). This association has been attributed to dust intake from the frequent hand-to-mouth behavior of young children. Flaking lead-based paint, road dust, garden soil and airborne lead-bearing particles are believed to be the sources of lead in household dust (36).
Leaded gas has caused more exposure to the metal than any other source worldwide (37). According to the São Paulo State Health Department (19), about 80% of the lead found in urban air samples before 1982 was derived from leaded gas. Car battery manufacture is the main source of secondary lead (38), but other sources cannot be discarded.
None of that is to say that lead is the only factor of course, just that I don't think your data disproves the theory that lead plays a significant part.