The study hypothesizes that newborns (NB) in Santiago, Chile have a higher level of lead in their blood when they are born, than a comparison group of newborn in the smaller population of nearly San Felipe, and that this difference is partially related to higher levels of enviromental contamination. The study considered two groups a)804 mothers and newborns in the Maternity Section of the Hospital San Borja Arriaran (in Santiago) and b) 165 mothers and newborns in the Maternity Section of the Hospital San Felipe(10% of annual births) Stillbirths and newborns with less than 34 gestational weeks or birthweights less than 2500 g., were excluded from the study. After consent was obtained from the mothers, a questionaire was administered to measure risk factors, and tests were performed to determine levels of lead(Pb) in the mothers (PbM) and in the umbilical cord (PbCU), using the technique of electrothermal atomization with an atomic absortion spectrophotometer, which was verified periodically controls with the Center for Disease Control in Atlanta (corelation 0.93). Enviromental lead levels were measured weekly with PM 10 filters with high volume analizers.

In Santiago PbM and PbCU were higher (2.91 UG/dl) than in San Felipe (2.23 and 1.72). The difference was accentuated when the rural area of Maipu was excluded from consideration as part of Santiago. Atmospheric lead levels (PbA) in Santiago were greater, (2, 11 UG/m3 vs 0.21 p (0.05) PbCU (OR 17). The same relation exists when the exposition to Pba is higher than 1.5 UG/m3 (OR mother 3.2, OR NB 2.9). The exposition lower than 1.50 UG/m3 would have a protective effect (OR 0.4 mother and NB). To summarize: PbM and PbCU are greater in Santiago and are related to chronic exposure to enviromental lead Pb.